Bagshui/Components/Inventory.Layout.lua

-- Bagshui Inventory Prototype: Window Layout
-- Categorizing, Sorting, Putting Things On The Screen, etc.
-- Most of the functions here shouldn't be called directly as Inventory:Update() handles the coordination.

Bagshui:AddComponent(function()
  local Inventory = Bagshui.prototypes.Inventory

  -- When deciding whether there are differences between a dry run and current state,
  -- some tables need to be compared deeper than the default of 1 level. Set those here.
  local LAYOUT_LOOKUP_TABLE_COMPARE_DEPTH = {
    categoryIdsGroupedBySequence = 2,
    groupItems = 2,
  }

  -- Reusable variable for use in `Inventory:Update()`.
  local update_cascadeInventory

  --- This is the main workhorse for orchestrating UI changes; it's called when almost anything happens.
  ---@param cascade boolean? After completing the update process for this inventory, trigger it for any docked inventory.
  function Inventory:Update(cascade)
    -- self:PrintDebug(string.format("Update() windowUpdateBlocked=%s", tostring(self.windowUpdateBlocked)))

    -- Only update if we haven't been blocked from doing so.
    -- One of the main reasons this can happen is when the window is being dragged --
    -- see `Inventory:SaveWindowPosition()` for details.
    if self.windowUpdateBlocked then
      return
    end

    -- Don't redraw while the window is being dragged. A full redraw (for example from a BAG_UPDATE
    -- while looting in combat) resizes and re-lays out every button of a frame that is moving,
    -- which shows up as a hitch. The update runs as soon as the window is dropped.
    if self:IsDragInProgress() then
      self.updateDeferredByDrag = true
      self.updateDeferredByDragCascade = self.updateDeferredByDragCascade or cascade
      return
    end

    -- Update is only needed if the window is visible.
    if not self:Visible() and not self.forceCacheUpdate then
      self.windowUpdateBlocked = false
      return
    end

    -- Decide whether we'll need to cascade, and pass everything along.
    update_cascadeInventory = cascade and (self.dockedInventory or self.dockedToInventory)
    if update_cascadeInventory then
      update_cascadeInventory.forceCacheUpdate = update_cascadeInventory.forceCacheUpdate or self.forceCacheUpdate
      update_cascadeInventory.forceResort = update_cascadeInventory.forceResort or self.forceResort
      update_cascadeInventory.windowUpdateNeeded = update_cascadeInventory.windowUpdateNeeded or self.windowUpdateNeeded
    end

    -- Reset per-update transient flags before running the pipeline.
    self.cacheChanged = false
    self.cacheNeedsCategorize = false
    self.lookupTablesWereRebuilt = false
    -- We're updating!
    self.windowUpdateBlocked = true

    -- Before doing anything else, we need to know if we're online.
    self:UpdateOnlineStatus()

    -- Was a full redraw already requested before the cache update?
    local windowUpdateWasNeeded = self.windowUpdateNeeded

    -- Always update the cache if we get this far.
    self:UpdateCache()

    -- self.forceCacheUpdate was true, but the window might not be visible.
    if not self:Visible() then
      -- No need to redraw everything when we're not visible.
      self.windowUpdateBlocked = false
      return
    end

    -- Only items locking/unlocking (picked up, or moving between bags and bank): refresh those
    -- buttons so they turn gray and back, instead of redrawing the whole window.
    if
      self.cacheOnlyLockChanges
      and not windowUpdateWasNeeded
      and not self.forceResort
      and not self.resortNeeded
      and not self.lookupTablesStale
      and not self.editMode
    then
      self:RefreshLockChangedItemButtons()
      self.windowUpdateNeeded = false
      self.windowUpdateBlocked = false
      if update_cascadeInventory then
        update_cascadeInventory:Update()
      end
      return
    end

    -- Nothing changed and nothing is waiting for a redraw -- skip the entire pipeline.
    -- This is the primary optimization for spurious BAG_UPDATE events.
    if not self.cacheChanged and not self.windowUpdateNeeded and not self.forceResort and not self.lookupTablesStale then
      self.windowUpdateBlocked = false
      if update_cascadeInventory then
        update_cascadeInventory:Update()
      end
      return
    end

    -- Perform all updates in the necessary order.
    self:ValidateLayout()
    -- Capture resort signals before ManageDryRun(true) clears forceResort.
    -- A forced resort (Resort button, settings, Edit Mode) re-categorizes every item.
    if self.forceResort then
      self.fullCategorizeNeeded = true
    end
    local needsCategorizeAndSort = self.forceResort or self.resortNeeded
    self:ManageDryRun(true) -- First call decides whether we're in dry run mode (`self.dryRun`).
    self:UpdateLayoutLookupTables()
    -- New category/group lookup tables mean every item's group may be different.
    if self.lookupTablesWereRebuilt then
      self.fullCategorizeNeeded = true
    end
    if self.cacheNeedsCategorize or self.lookupTablesWereRebuilt or needsCategorizeAndSort then
      self:CategorizeAndSort()
    end
    self:ManageDryRun(false) -- Second call re-points lookup tables if needed and sets `self.enableResortIcon`.
    -- If the dry run shows the layout is identical to last render, the window
    -- update request came only from CategorizeAndSort, and no cache items actually
    -- changed, skip the full redraw. The cache-changed guard is essential: both
    -- proposedLayoutState and currentLayoutState hold the same live pointers into
    -- self.inventory, so ObjectsEqual() always reports them as identical after
    -- UpdateCache() writes new data in place -- even when item A replaced item B
    -- in the same slot. Without the guard the texture would not update.
    -- UpdateWindow() still runs its lightweight path (colors, border, strata).
    if self.dryRun and not self.enableResortIcon and self.windowUpdateNeededByCategorize and not self.cacheChanged then
      self.windowUpdateNeeded = false
    end
    self.windowUpdateNeededByCategorize = false
    -- Always refresh item button visual state when the window is visible and
    -- the full layout rebuild is being skipped (keeps search and highlights current).
    if not self.windowUpdateNeeded and self:Visible() then
      self:UpdateItemSlotColors()
    end
    self:FindSpecialItems()
    self:UpdateWindow()
    self:UpdateBagBar()
    self:UpdateToolbar()

    -- Reset status.
    self.windowUpdateBlocked = false

    -- Automatically cascade updates to docked inventory.
    if update_cascadeInventory then
      update_cascadeInventory:Update()
    end
  end

  --- Force a window redraw with optional cache update.
  ---@param cascade boolean? Parameter for `Inventory:Update()`.
  ---@param updateCache boolean? `true` to trigger a cache update.
  function Inventory:ForceUpdateWindow(cascade, updateCache)
    self.cacheUpdateNeeded = updateCache or false
    self.windowUpdateNeeded = true
    self.forceResort = false
    self:Update(cascade)
  end

  --- Re-apply the look of item buttons whose item only locked or unlocked in the last cache update
  --- (gray while locked, badges dimmed). Same as what a full redraw does for those buttons.
  function Inventory:RefreshLockChangedItemButtons()
    local changed = self.lockOnlyChangedItems
    if not changed then
      return
    end
    for _, button in ipairs(self.ui.buttons.itemSlots) do
      local buttonInfo = button.bagshuiData
      if buttonInfo and buttonInfo.item and changed[buttonInfo.item] and button:IsVisible() then
        self.ui:AssignItemToItemButton(button, buttonInfo.item, buttonInfo.groupId)
      end
    end
  end

  --- Refresh only item slot colors without all the overhead of calculating the window layout.
  --- High-performance -- much better than `UpdateWindow()`/`ForceUpdateWindow()`, so it should be used for
  --- changing highlights or opacity (searching, bag bar mouseover, Edit Mode highlighting, etc.).
  function Inventory:UpdateItemSlotColors()
    for _, button in ipairs(self.ui.buttons.itemSlots) do
      if button:IsVisible() then
        self.ui:UpdateItemButtonColorsAndBadges(button)
      end
    end
  end

  --- Refresh cooldown animations on all visible item slot buttons without rebuilding the window layout.
  --- Called in response to BAG_UPDATE_COOLDOWN so cooldown timers appear immediately after item use.
  function Inventory:UpdateItemSlotCooldowns()
    local cooldownStart, cooldownDuration, isOnCooldown
    for _, button in ipairs(self.ui.buttons.itemSlots) do
      if button:IsVisible() and button.bagshuiData.item then
        cooldownStart = 0
        cooldownDuration = 0
        isOnCooldown = nil
        if button.bagshuiData.item.itemString ~= nil then
          cooldownStart, cooldownDuration, isOnCooldown =
            _G.GetContainerItemCooldown(button.bagshuiData.bagNum, button.bagshuiData.slotNum)
        end
        _G.CooldownFrame_SetTimer(
          button.bagshuiData.buttonComponents.cooldown,
          cooldownStart,
          cooldownDuration,
          isOnCooldown
        )
      end
    end
  end

  --- Ensure there will be no errors when using the active layout.
  function Inventory:ValidateLayout()
    -- Completely empty layouts need at least a row and a group.
    if table.getn(self.layout) == 0 then
      table.insert(self.layout, {})
      BsUtil.TableCopy(BS_NEW_PROFILE_TEMPLATE.structure.primary.layout, self.layout)
    end

    -- Validate categories assigned to the layout.
    for row = 1, table.getn(self.layout) do
      for group = 1, table.getn(self.layout[row]) do
        local groupCategories = self.layout[row][group].categories
        if groupCategories then
          -- Remove invalid categories.
          -- Need to step backwards so we can use table.remove().
          for catNum = table.getn(groupCategories), 1, -1 do
            local categoryId = groupCategories[catNum]
            if not BsCategories.list[categoryId] then
              table.remove(groupCategories, catNum)
            end
          end
        else
          -- This group needs a categories property.
          self.layout[row][group].categories = {}
        end
      end
    end
  end

  --- Control whether the current layout update is a dry run or not.
  --- **Should not be called directly!** Use `Inventory:Update()` to coordinate the process.
  ---
  --- Doing a dry run means storing information in the `proposedLayoutState` tables
  --- instead of `currentLayoutState`. The proposed state can then be compared
  --- to current to decide whether resorting is needed.
  ---
  --- This must be called twice during the `Update()` process - once prior to categorizing/sorting
  --- with a parameter of `true` and again just after with `false` (or nil) before calling `UpdateWindow()`.
  ---@param phase1 boolean? Pass `true` the first time the function is called.
  function Inventory:ManageDryRun(phase1)
    if phase1 then
      -- Determine whether this is real or if we're just simulating to decide whether there are changes.
      self.dryRun = false
      -- Ensure items don't shift around when the window is open under normal usage.
      -- self.forceResort can be used to override (usually when the user clicks the Resort button).
      if (not self.resortNeeded or self:Visible()) and not self.forceResort then
        self.dryRun = true
        -- 	self:PrintDebug("++++DRY RUN ON++++")
        -- else
        -- 	self:PrintDebug("----dry run off----")
      end

      -- Reset force resort flag.
      self.forceResort = false

      -- Point layout state tracking keys to the correct tables.
      for key, _ in pairs(self.currentLayoutState) do
        self[key] = self[self.dryRun and "proposedLayoutState" or "currentLayoutState"][key]
      end
    else
      -- Resetting tables to current if needed.
      -- Decide whether the resort icon needs to be enabled.
      self.enableResortIcon = false
      -- Special stuff for dry run mode:
      -- - Manage the resort icon.
      -- - Re-point layout state tables.
      if
        self.dryRun
        -- Safety check to ensure pointers are always reset.
        or self.groups ~= self.currentLayoutState.groups
      then
        -- We can immediately know to enable resorting if any empty slot is peeled off its stack.
        self.enableResortIcon = (self.emptySlotStackingAllowed and self.hasSlotsWithStackingPrevented)

        for key, _ in pairs(self.currentLayoutState) do
          if
            self.dryRun
            and not self.enableResortIcon -- No need to keep checking once we've hit true.
            and not BsUtil.ObjectsEqual(
              self.proposedLayoutState[key],
              self.currentLayoutState[key],
              nil,
              nil,
              LAYOUT_LOOKUP_TABLE_COMPARE_DEPTH[key] or 1
            )
          then
            self.enableResortIcon = true
          end

          -- Always swap back to the "current" layout state for UpdateWindow() instead
          -- of the dry run one so that nothing moves around undesirably.
          self[key] = self.currentLayoutState[key]
        end
      end
    end
  end

  --- Assign inventory items to Bagshui categories and sort into the correct order for display.
  --- **Should not be called directly!** Use `Inventory:Update()` to coordinate the process.
  ---
  --- Inventory cache to lookup table relationships:
  --- - Cache is stored as `self.inventory[bagNum][slotNum]`
  --- - Group items store references to the inventory cache items:
  ---     `self.groupItems[groupNum][position] = <reference to self.inventory[bagNum][slotNum]>`
  function Inventory:CategorizeAndSort()
    --self:PrintDebug("CategorizeAndSort()")

    -- Categorize items and assign to groups.
    self:CategorizeItems()

    -- Sort items within groups.
    self:SortGroups()

    -- Reset flags.
    self.resortNeeded = false
    self.windowUpdateNeeded = true
    self.windowUpdateNeededByCategorize = true
  end

  --- Fill the lookup tables that are used when building the interface.
  --- ***Generally* should not be called directly!** Use `Inventory:Update()` to coordinate the process.
  ---
  --- Lookup tables managed by this function:
  --- - `activeGroups`: `{ <Group ID> = <Reference to group> }`
  --- - `categoryIdsGroupedBySequence` is used to determine the order of execution for category matching:
  --- ```
  --- 	{
  --- 		[<Sequence Num 1>] = {
  --- 			[<Category ID 1>],
  --- 			[<Category ID 2>],
  --- 		},
  --- 		[<Sequence Num 2>] = {
  --- 			[<Category ID 3>],
  --- 		},
  --- 	}
  --- ```
  --- - `sortedCategorySequenceNumbers` is just an array of the sequence numbers from `categoryIdsGroupedBySequence`
  --- so that it can easily be sorted. This avoids having to resort the sequence numbers in `categoryIdsGroupedBySequence`
  --- on every call to `Categories:Categorize()`.
  --- - `categoriesToGroups` is exactly what it sounds like - the mapping of category IDs to group IDs (which are simply row:position)
  --- and is used by `CategorizeAndSort()` when filling the groupItems table.
  function Inventory:UpdateLayoutLookupTables()
    --self:PrintDebug("UpdateLayoutLookupTables()")
    -- self:PrintDebug(BsCategories.list)

    -- Only rebuild when the layout structure has actually changed.
    -- Also rebuild if the current tables are unpopulated: ManageDryRun() can switch self.groups
    -- (and the other layout-state tables) to the proposedLayoutState copies, which start empty
    -- and won't have been filled yet if this is the first dry-run pass since the last rebuild.
    if not self.lookupTablesStale and next(self.groups) ~= nil then
      return
    end
    self.lookupTablesWereRebuilt = true

    -- This will be used at the end if defaultCategoryFound is still false.
    local lastGroupId = ""
    local defaultCategoryFound = false

    -- Wipe all the lookup tables managed by this function.
    BsUtil.TableClear(self.activeCategoryIds)
    BsUtil.TableClear(self.activeGroups)
    BsUtil.TableClear(self.categoriesToGroups)
    BsUtil.TableClear(self.categorySequenceNumbers)
    BsUtil.TableClear(self.groups)
    BsUtil.TableClear(self.sortedCategorySequenceNumbers)
    -- Don't remove unused sequence number tables - no need to upset the garbage collector.
    -- (This could be slightly more efficient with something like Compost, but it's not a huge deal.)
    for _, categoryIds in pairs(self.categoryIdsGroupedBySequence) do
      BsUtil.TableClear(categoryIds)
    end

    -- Process the layout and update lookup tables.
    for rowNum, rowGroups in ipairs(self.layout) do
      for groupNum, groupDetails in ipairs(rowGroups) do
        local groupId = rowNum .. ":" .. groupNum
        lastGroupId = groupId

        -- Store reference to the group for easy access later.
        self.groups[groupId] = groupDetails

        -- Store the group ID on the group so it's easily accessible for use by Update()
        groupDetails.groupId = groupId

        -- Groups aren't technically active unless they have categories assigned and at least one category is valid.
        if groupDetails.categories and table.getn(groupDetails.categories) > 0 then
          for _, categoryId in ipairs(groupDetails.categories) do
            self:AddCategoryToLookupTables(categoryId, groupId)

            if categoryId == BsCategories.defaultCategory then
              defaultCategoryFound = true
            end
          end
        end
      end
    end

    -- Ensure the default category is always assigned to a group. This is a failsafe and really shouldn't ever be reached.
    if not defaultCategoryFound then
      self:PrintDebug("WARNING: no default category found!")
      self:AddCategoryToLookupTables(BsCategories.defaultCategory, lastGroupId)
    end

    -- Order sortedCategorySequenceNumbers by category sequence.
    table.sort(self.sortedCategorySequenceNumbers)

    self.lookupTablesStale = false
  end

  --- Helper function to add a category to the lookup tables.
  ---@param categoryId string ID of the category.
  ---@param groupId string ID of the group to associate with the category.
  function Inventory:AddCategoryToLookupTables(categoryId, groupId)
    -- Ensure this is a valid category.
    -- Shouldn't ever really be an issue because ValidateLayout() is called first, but let's be safe.
    if BsCategories.list[categoryId] then
      -- Get info about the category.
      local categoryDetails = BsCategories.list[categoryId]

      -- This is an active category (used when checking for errors).
      self.activeCategoryIds[categoryId] = true

      -- We haven't seen this sequence number yet.
      if self.categoryIdsGroupedBySequence[categoryDetails.sequence] == nil then
        self.categoryIdsGroupedBySequence[categoryDetails.sequence] = {}
      end

      -- Add sequence number to sortedCategorySequenceNumbers so it can be used during categorization.
      if not self.categorySequenceNumbers[categoryDetails.sequence] then
        self.categorySequenceNumbers[categoryDetails.sequence] = true
        table.insert(self.sortedCategorySequenceNumbers, categoryDetails.sequence)
      end

      -- Create the category-to-group relationship in categoryIdsGroupedBySequence[<sequence>][<categoryId].
      self.categoryIdsGroupedBySequence[categoryDetails.sequence][categoryId] = groupId

      -- Add to the flat category-to-group relationship table.
      self.categoriesToGroups[categoryId] = groupId

      -- This is a an active group.
      self.activeGroups[groupId] = self.groups[groupId]
    end
  end

  -- Sorted-order cache helpers, defined below SortGroups()'s cache tables.
  local MarkGroupForResort, InvalidateAllSortedGroups

  --- Assign categories and groups to all items in the inventory cache.
  --- **Should not be called directly!** Use `Inventory:Update()` to coordinate the process.
  ---
  --- Lookup tables managed by this function:
  --- - `groupItems` stores the sorted list of items that belong to each group.
  ---
  --- Also updates each item's `bagshuiGroupId` and `bagshuiCategoryId` properties.
  function Inventory:CategorizeItems()
    -- groupItems stores the list of items that belongs to each group.
    -- Start clean each time we categorize and sort.

    -- groupItems is a table of tables, so only wipe the 2nd level tables to keep the garbage collector happy.
    for groupId, _ in pairs(self.groupItems) do
      BsUtil.TableClear(self.groupItems[groupId])
    end
    -- Using groups instead of activeGroups here just to ensure every possibility is initialized.
    for groupId, _ in pairs(self.groups) do
      if not self.groupItems[groupId] then
        self.groupItems[groupId] = {}
      end
    end

    local defaultGroupId = self.categoriesToGroups[BsCategories.defaultCategory]
    local groupId

    -- Full pass (every item) or only items whose category may have changed?
    -- See `Inventory:CategoryCacheStale()` and where `fullCategorizeNeeded` is set.
    local fullPass = self.fullCategorizeNeeded
    if fullPass then
      self.categorizeEpoch = (self.categorizeEpoch or 0) + 1
      self.fullCategorizeNeeded = false
      self.lastFullCategorizeTime = _G.GetTime()
      -- Every group gets re-sorted after a full pass (see SortGroups()).
      InvalidateAllSortedGroups()
    end

    -- Perform the actual categorization.
    for _, bagNum in ipairs(self.containerIds) do
      -- Only process bags that have contents.
      if self.containers[bagNum].numSlots > 0 and table.getn(self.inventory[bagNum]) > 0 then
        -- Process all bag slots.
        local bagNumSlots = self.containers[bagNum].numSlots
        if bagNumSlots > 0 then
          for slotNum = 1, bagNumSlots do
            -- Categorize each item whose category may have changed since last time. New and changed
            -- items are always categorized so they never show up with an unknown category in the
            -- Bagshui tooltip; unchanged items keep the category from the last pass.
            if fullPass or self:CategoryCacheStale(self.inventory[bagNum][slotNum]) then
              local previousGroupId = self.inventory[bagNum][slotNum].bagshuiGroupId
              BsCategories:Categorize(
                self.inventory[bagNum][slotNum],
                nil, -- Categorization as any alternate character is not currently enabled.
                self.sortedCategorySequenceNumbers,
                self.categoryIdsGroupedBySequence
              )
              self:StoreCategorySignature(self.inventory[bagNum][slotNum])
              -- The group this item left and the group it's in now both need re-sorting.
              MarkGroupForResort(previousGroupId)
              MarkGroupForResort(self.inventory[bagNum][slotNum].bagshuiGroupId)
            end

            -- Fall back to the default group if one wasn't assigned.
            groupId = self.inventory[bagNum][slotNum].bagshuiGroupId
            if string.len(tostring(groupId or "")) == 0 then
              groupId = defaultGroupId
            end

            -- Empty slots are now allowed to stack since they've been through the categorizing process.
            -- (When an empty slot is first seen during a cache update, it gets the _bagshuiPreventEmptySlotStack
            -- property set so that empty slots don't just "disappear" into a stack when the window is open
            -- and the user moves an item out of a slot.)
            if not self.dryRun and self.inventory[bagNum][slotNum].emptySlot == 1 then
              self.inventory[bagNum][slotNum]._bagshuiPreventEmptySlotStack = nil
            end

            -- Final safety check to ensure we don't somehow try to assign to a group that doesn't exist.
            if not self.groupItems[groupId] then
              groupId = defaultGroupId
            end

            -- Add to group positions lookup table.
            table.insert(self.groupItems[groupId], self.inventory[bagNum][slotNum])
          end -- bagNumSlots loop
        end -- bagNumSlots > 0
      end -- Known bag check
    end -- self.containerIds loop

    -- Show the error button if there were problems.
    self.errorText = BsCategories:GetErrors(self.activeCategoryIds)
  end

  -- Sorted-order cache for groups (see SortGroups()). A group's cached order is reused when none of
  -- its items were re-categorized since it was sorted (an item that changed in any way the sort can
  -- see is re-categorized, see CategoryCacheStale()) and it still holds exactly the same items.
  -- `groupSortVersions[groupId]` goes up whenever an item enters or leaves a group or changes;
  -- `sortEpoch` goes up after every full categorization pass (rules, settings, sort orders...).
  local groupSortVersions = {}
  local sortEpoch = 0
  -- { [groupItems table] = { list = {...}, set = { [item] = true }, count, version, epoch } }
  local sortedGroupCache = setmetatable({}, { __mode = "k" })

  MarkGroupForResort = function(groupId)
    if groupId and groupId ~= "" then
      groupSortVersions[groupId] = (groupSortVersions[groupId] or 0) + 1
    end
  end

  InvalidateAllSortedGroups = function()
    sortEpoch = sortEpoch + 1
  end

  --- Put a group's items back in their last sorted order if nothing relevant changed.
  ---@return boolean restored
  local function RestoreSortedGroup(items, groupId)
    local cached = sortedGroupCache[items]
    local count = table.getn(items)
    if
      not cached
      or cached.epoch ~= sortEpoch
      or cached.version ~= (groupSortVersions[groupId] or 0)
      or cached.count ~= count
    then
      return false
    end
    for i = 1, count do
      if not cached.set[items[i]] then
        return false
      end
    end
    for i = 1, count do
      items[i] = cached.list[i]
    end
    return true
  end

  --- Remember a group's sorted order.
  local function StoreSortedGroup(items, groupId)
    local cached = sortedGroupCache[items]
    if not cached then
      cached = { list = {}, set = {} }
      sortedGroupCache[items] = cached
    end
    BsUtil.TableClear(cached.list)
    BsUtil.TableClear(cached.set)
    local count = table.getn(items)
    for i = 1, count do
      table.insert(cached.list, items[i])
      cached.set[items[i]] = true
    end
    cached.count = count
    cached.epoch = sortEpoch
    cached.version = groupSortVersions[groupId] or 0
  end

  -- What each item's last categorization was based on: { [item] = signature }.
  -- Weak keys so replaced item tables don't linger; kept out of the item tables so nothing extra
  -- ends up in SavedVariables.
  local categorySignatures = setmetatable({}, { __mode = "k" })

  --- Could this item's category be different from its last categorization?
  --- True when anything the category rules read from the item or its bag has changed, or when a
  --- full pass has happened since (rules, profiles, settings, quests, gear, zone, window opened...).
  ---@param item table Inventory cache entry.
  ---@return boolean
  function Inventory:CategoryCacheStale(item)
    local sig = categorySignatures[item]
    return not sig
      or sig.inventory ~= self
      or sig.epoch ~= self.categorizeEpoch
      or sig.itemString ~= item.itemString
      or sig.bagNum ~= item.bagNum
      or sig.slotNum ~= item.slotNum
      or sig.bagType ~= item.bagType
      or sig.count ~= item.count
      or sig.charges ~= item.charges
      or sig.stockState ~= item.bagshuiStockState
      or sig.tooltip ~= item.tooltip
      or not item.bagshuiGroupId
      or item.bagshuiGroupId == ""
  end

  --- Remember what the item's categorization was based on (see `Inventory:CategoryCacheStale()`).
  ---@param item table Inventory cache entry.
  function Inventory:StoreCategorySignature(item)
    local sig = categorySignatures[item]
    if not sig then
      sig = {}
      categorySignatures[item] = sig
    end
    sig.inventory = self
    sig.epoch = self.categorizeEpoch
    sig.itemString = item.itemString
    sig.bagNum = item.bagNum
    sig.slotNum = item.slotNum
    sig.bagType = item.bagType
    sig.count = item.count
    sig.charges = item.charges
    sig.stockState = item.bagshuiStockState
    sig.tooltip = item.tooltip
  end

  -- Sort each group's items in the configured order.
  -- **Should not be called directly!** Use `Inventory:Update()` to coordinate the process.
  function Inventory:SortGroups()
    for groupId, groupConfig in pairs(self.activeGroups) do
      -- Groups whose items didn't change keep their previous sorted order (see RestoreSortedGroup()).
      if not RestoreSortedGroup(self.groupItems[groupId], groupId) then
        BsSortOrders:SortGroup(self.groupItems[groupId], groupConfig, self.settings.defaultSortOrder)
        StoreSortedGroup(self.groupItems[groupId], groupId)
      end
    end
  end

  --- Return approximate dimensions for a row of groups using the same slot/group math as UpdateWindow().
  ---@param rowGroups table[] Layout groups to measure.
  ---@param maxColumns number Maximum item columns allowed in the row.
  ---@param adjustedItemSlotSize number Scaled item slot size.
  ---@param itemSlotMargin number Space around item slots.
  ---@param groupPadding number Group padding.
  ---@return number actualWidth
  ---@return number actualHeight
  ---@return number visibleGroupCount
  ---@return number rowWidthInItems
  function Inventory:GetLayoutRowDimensions(rowGroups, maxColumns, adjustedItemSlotSize, itemSlotMargin, groupPadding)
    local numGroupsInRow = table.getn(rowGroups)
    local totalItemsInRow = 0
    local rowWidthInItems = 0
    local rowHeightInItems = 1
    local unshrinkableGroupCount = 0
    local groupWidthsInItems = {}
    local groupId

    for columnNum = 1, numGroupsInRow do
      groupId = rowGroups[columnNum].groupId
      groupWidthsInItems[groupId] = self.groupItemCounts[groupId] or 0
      totalItemsInRow = totalItemsInRow + groupWidthsInItems[groupId]
    end

    rowWidthInItems = totalItemsInRow

    while rowWidthInItems > maxColumns do
      rowHeightInItems = rowHeightInItems + 1
      repeat
        rowWidthInItems = 0
        unshrinkableGroupCount = 0
        for columnNum = 1, numGroupsInRow do
          groupId = rowGroups[columnNum].groupId

          if groupWidthsInItems[groupId] > 1 then
            local newWidth = groupWidthsInItems[groupId] - 1
            if self.groupItemCounts[groupId] / newWidth <= rowHeightInItems then
              groupWidthsInItems[groupId] = newWidth
            else
              unshrinkableGroupCount = unshrinkableGroupCount + 1
            end
          else
            unshrinkableGroupCount = unshrinkableGroupCount + 1
          end
          rowWidthInItems = rowWidthInItems + groupWidthsInItems[groupId]
        end
      until rowWidthInItems <= maxColumns or unshrinkableGroupCount >= numGroupsInRow

      -- If every group is already at its minimum width, this row can't fit within
      -- maxColumns. Stop measuring instead of looping forever.
      if rowWidthInItems > maxColumns then
        local canShrink = false
        for columnNum = 1, numGroupsInRow do
          if groupWidthsInItems[rowGroups[columnNum].groupId] > 1 then
            canShrink = true
            break
          end
        end
        if not canShrink then
          break
        end
      end
    end

    local actualWidth = 0
    local visibleGroupCount = 0
    for columnNum = 1, numGroupsInRow do
      groupId = rowGroups[columnNum].groupId
      if groupWidthsInItems[groupId] > 0 then
        actualWidth = actualWidth
          + (groupWidthsInItems[groupId] * (adjustedItemSlotSize + itemSlotMargin))
          + itemSlotMargin
          + (groupPadding * 2)
        visibleGroupCount = visibleGroupCount + 1
      end
    end

    if totalItemsInRow == 0 then
      return 0, 0, visibleGroupCount, rowWidthInItems
    end

    return
      actualWidth,
      (rowHeightInItems * (adjustedItemSlotSize + itemSlotMargin)) + itemSlotMargin + (groupPadding * 2),
      visibleGroupCount,
      rowWidthInItems
  end

  --- Build a temporary layout for rendering visible groups in a smaller footprint.
  --- Does not mutate the saved Structure profile layout.
  ---@param maxColumns number Maximum item columns allowed by the window setting.
  ---@param adjustedItemSlotSize number Scaled item slot size.
  ---@param itemSlotMargin number Space around item slots.
  ---@param groupPadding number Group padding.
  ---@param groupXSpacing number Horizontal space between groups.
  ---@param groupYSpacing number Vertical space between groups.
  ---@return table renderLayout Temporary layout table.
  function Inventory:BuildAutoCompactRenderLayout(
    maxColumns,
    adjustedItemSlotSize,
    itemSlotMargin,
    groupPadding,
    groupXSpacing,
    groupYSpacing
  )
    local visibleGroups = {}
    local hideGroup
    local groupId

    for rowNum = 1, table.getn(self.layout) do
      for columnNum = 1, table.getn(self.layout[rowNum]) do
        groupId = self.layout[rowNum][columnNum].groupId
        if groupId then
          hideGroup = false
          if self.groups[groupId] and self.groups[groupId].hide then
            hideGroup = true
            self.hasHiddenGroups = true
          end

          if not self.showHidden and hideGroup then
            self.groupItemCounts[groupId] = self.highlightItemsInContainerLocked
                and self:GetGroupItemCountForLayout(groupId, self.highlightItemsInContainerLocked)
              or 0
          else
            self.groupItemCounts[groupId] = self:GetGroupItemCountForLayout(groupId)
          end

          if self.groupItemCounts[groupId] > 0 then
            table.insert(visibleGroups, {
              groupId = groupId,
              name = self.layout[rowNum][columnNum].name,
              sourceRowNum = rowNum,
              sourceColumnNum = columnNum,
            })
          end
        else
          Bagshui:PrintWarning("Inventory update call should have forced resort!")
        end
      end
    end

    if table.getn(visibleGroups) == 0 then
      return {}
    end

    local bestLayout
    local bestArea
    local bestWidth

    for targetWidth = 1, maxColumns do
      local candidateLayout = {}
      local currentRow = {}

      for groupNum = 1, table.getn(visibleGroups) do
        local trialRow = {}
        for currentRowGroupNum = 1, table.getn(currentRow) do
          table.insert(trialRow, currentRow[currentRowGroupNum])
        end
        table.insert(trialRow, visibleGroups[groupNum])

        local _, _, _, trialRowWidthInItems = self:GetLayoutRowDimensions(
          trialRow,
          targetWidth,
          adjustedItemSlotSize,
          itemSlotMargin,
          groupPadding
        )

        if table.getn(currentRow) > 0 and trialRowWidthInItems > targetWidth then
          table.insert(candidateLayout, currentRow)
          currentRow = {}
        end
        table.insert(currentRow, visibleGroups[groupNum])
      end

      if table.getn(currentRow) > 0 then
        table.insert(candidateLayout, currentRow)
      end

      local candidateWidth = 0
      local candidateHeight = 0
      local visibleRows = 0
      for rowNum = 1, table.getn(candidateLayout) do
        local rowWidth, rowHeight, visibleGroupCount = self:GetLayoutRowDimensions(
          candidateLayout[rowNum],
          maxColumns,
          adjustedItemSlotSize,
          itemSlotMargin,
          groupPadding
        )
        if visibleGroupCount > 0 then
          rowWidth = rowWidth + ((visibleGroupCount - 1) * groupXSpacing)
          if rowWidth > candidateWidth then
            candidateWidth = rowWidth
          end
          candidateHeight = candidateHeight + rowHeight
          visibleRows = visibleRows + 1
        end
      end
      if visibleRows > 1 then
        candidateHeight = candidateHeight + ((visibleRows - 1) * groupYSpacing)
      end

      local candidateArea = candidateWidth * candidateHeight
      if
        not bestArea
        or candidateArea < bestArea
        or (candidateArea == bestArea and candidateWidth < bestWidth)
      then
        bestLayout = candidateLayout
        bestArea = candidateArea
        bestWidth = candidateWidth
      end
    end

    return bestLayout
  end

  --- Actually do the work of updating the UI.
  --- **Should not be called directly!** Use `Inventory:Update()` or `Inventory:ForceWindowUpdate()` to coordinate the process.
  ---
  --- This function handles:
  --- - Sizing and placing groups so everything fits within the allowed number of columns
  --- - Calling `AssignItemsToSlots()` to fill item slot buttons
  --- - Stacking/unstacking empty slots
  --- - Hiding/showing components and setting window colors based on preferences
  --- - Sizing the window
  function Inventory:UpdateWindow()
    -- self:PrintDebug("UpdateWindow()")

    -- Clear the "never online" message once we're online.
    if self.online then
      Bagshui.currentCharacterData[self.inventoryTypeSavedVars].neverOnline = nil
    end

    -- Can only highlight changes if there's something to highlight.
    self.highlightChangesEnabled = (
      self.hasChanges
      or (self.dockedInventory and self.dockedInventory.hasChanges)
      or (self.dockedToInventory and self.dockedToInventory.hasChanges)
    ) or false

    -- Safeguard: Turn off Highlight Changes if there's nothing to highlight.
    if not self.highlightChangesEnabled then
      self.highlightChanges = false
    end

    -- There are a few things that always need to happen even if we're not
    -- doing a full layout update.

    self.windowColor = self.settings.windowBackground
    self.borderColor = self.settings.windowBorder

    if self.settings.windowUseSkinColors and BsSkin.skinBackgroundColor then
      self.windowColor = BsSkin.skinBackgroundColor
    end
    if self.settings.windowUseSkinColors and BsSkin.windowBackdrop then
      self.windowColor = BsSkin.windowColor or { 1, 1, 1, 1 }
    end

    if not self.online then
      self.borderColor = BS_COLOR.RED
    elseif self.settings.windowUseSkinColors and BsSkin.skinBorderColor then
      self.borderColor = BsSkin.skinBorderColor
    elseif self.settings.windowUseSkinColors and BsSkin.windowBackdrop then
      self.borderColor = BsSkin.windowBorderColor or { 1, 1, 1, 1 }
    end

    self.uiFrame:SetBackdropColor(self.windowColor[1], self.windowColor[2], self.windowColor[3], self.windowColor[4])
    self.uiFrame:SetBackdropBorderColor(
      self.borderColor[1],
      self.borderColor[2],
      self.borderColor[3],
      self.borderColor[4]
    )

    self.uiFrame:SetFrameStrata(self.settings.windowStrata)

    -- Update the utilization display setting.
    -- Done here because it's consumed in `UpdateBagBar()` and `UpdateToolbar()`.
    self.alwaysShowUsageSummary = (
      self.settings.bagUsageDisplay == BS_INVENTORY_BAG_USAGE_DISPLAY.ALWAYS
      or (self.settings.bagUsageDisplay == BS_INVENTORY_BAG_USAGE_DISPLAY.SMART and not self.settings.stackEmptySlots)
      or false
    )

    -- Only do the intensive work of redrawing the UI if we have to.
    if self.windowUpdateNeeded then
      BsUtil.TableClear(self.groupsIdsToFrames)

      local uiFrames = self.ui.frames
      local groupFrames = uiFrames.groups
      local uiButtons = self.ui.buttons

      local itemSlotSize = self.settings.itemSize
      local itemSlotScale = self.ui:GetItemButtonScale(self.ui.buttons.itemSlots[1], itemSlotSize)
      local adjustedItemSlotSize = self.ui:GetItemButtonScaledSize(self.ui.buttons.itemSlots[1], itemSlotSize)
      local itemSlotMargin = self.settings.itemMargin + (BsSkin.itemSlotMarginFudge or 0)

      local groupMarginFudged = self.settings.groupMargin + BsSkin.groupMarginFudge
      local groupLabelHeight = groupFrames[1].bagshuiData.text:GetHeight() + math.abs(BsSkin.groupLabelMinPadding)
      local groupPadding = self.settings.groupPadding
        + (BsSkin.groupPaddingFudge or 0)
        + ((BsSkin.itemSlotMarginFudge / 2) * itemSlotScale)

      local maxColumns = self.settings.windowMaxColumns
      -- Edit Mode shows every group, including empty ones, so rows have many more groups than usual.
      -- Squeezing them into the normal limit makes the window absurdly tall, so allow it to be wider.
      if self.editMode and maxColumns < BS_EDIT_MODE_MIN_MAX_COLUMNS then
        maxColumns = BS_EDIT_MODE_MIN_MAX_COLUMNS
      end
      local anchorLeft = self.settings.windowContentAlignment == "LEFT"
      local showGroupLabels = (self.settings.showGroupLabels and not self.settings.hideGroupLabelsOverride)
        or self.editMode

      local firstFrame, widestRowLastFrame, topmostFrame

      -- Window component visibility.
      local showHeader = ((self.settings.showHeader and not self.dockTo) or self.temporarilyShowWindowHeader)
      local showFooter = (
        (self.settings.showFooter and not self.dockTo)
        or self.temporarilyShowWindowFooter
        or self.temporarilyShowBagBar
      )

      -- Reset hidden group and item tracking.
      self.hasHiddenGroups = false -- Updated in this function.
      self.hasHiddenItems = false -- Updated in GetGroupItemCountForLayout().
      self.hasOpenables = false -- Updated in AssignItemsToSlots().
      self.nextOpenableItemBagNum = nil -- Updated in AssignItemsToSlots().
      self.nextOpenableItemSlotNum = nil -- Updated in AssignItemsToSlots().
      self.nextOpenableItemSlotButton = nil -- Updated in AssignItemsToSlots().

      -- Full reset of empty slot stack counts is needed so that the tracking of which
      -- bag they represent is rebuilt.
      self:ResetEmptySlotStackCounts(true)

      -- Is empty slot stacking currently allowed?
      self.emptySlotStackingAllowed = (
        self.settings.stackEmptySlots -- User setting.
        and not self.expandEmptySlotStacks -- Temporary expansion.
        and not self.editMode -- Always expand in Edit Mode.
      )

      -- Used to track row changes so they include group move targets (the normal
      -- rowNum variable is just an iteration over self.layout).
      local uiRowNum = 0

      -- These three rowGroup* variables control which direction we step though
      -- the groups (left-to-right or right-to-left).
      local rowGroupStart, rowGroupEnd, rowGroupStep

      -- Exactly what it says on the tin.
      local numGroupsInRow
      local totalItemsInRow = 0
      local rowWidthInItems = 0
      local rowHeightInItems = 0
      local finalWindowWidth = 0
      local finalWindowHeight = 0
      local hideGroup = false

      -- Used to track which row is actually the widest after the frames are positioned.
      local widestRowLastFrameOutsideX = 0
      local currentRowLastFrameOutsideX

      -- Used during row width calculations to determine the point when we need
      -- to increase the row height again.
      local unshrinkableGroupCount = 0

      -- The uiGroupNum* variables are used to keep track of which group frame(s)
      -- we should be using for each row and the overall progress as we step through the layout.
      local uiGroupNum = 1 -- Need to have a default value here since we use uiGroupNum later to hide unused groups.
      local uiGroupNumStart = 1
      local uiGroupNumEnd

      -- currentItemSlotButtonNum tracks the progress of assigning items to buttons.
      local currentItemSlotButtonNum = 1

      -- Groups can have some weird padding going on because of their edge textures,
      -- so we need to adjust the group spacing so the visual outcome is correct.
      local groupXSpacing = groupMarginFudged

      -- Similarly, the initial position of everything isn't straightforward and
      -- gets affected by Edit Mode.
      local groupEdgeOffset = groupMarginFudged
      -- Increase the space between the bottom edge and the first group when the footer is visible.
      local groupEdgeYOffset = groupMarginFudged - (showFooter and BsSkin.groupMarginFudge or 0)

      -- When group labels are shown, we may need more Y space.
      local groupYSpacing = groupXSpacing
      if showGroupLabels then
        if groupYSpacing < groupLabelHeight then
          groupYSpacing = groupLabelHeight
        end
        groupYSpacing = groupYSpacing + BsSkin.groupLabelYPadding
      end

      -- Don't need to calculate the row (horizontal) group move target width outside Edit Mode.
      local rowGroupMoveTargetWidth = 0

      -- Edit Mode spacing adjustments -- keep things as tight as possible since the window will
      -- almost always grow due to more groups being visible.
      if self.editMode then
        groupXSpacing = -1
        groupYSpacing = groupXSpacing
        groupEdgeOffset = BsSkin.inventoryEditModeMargin
        groupEdgeYOffset = groupEdgeOffset

        -- The horizontal group move target is basically the width of a single group.
        rowGroupMoveTargetWidth = adjustedItemSlotSize
          + (itemSlotMargin * 2)
          + (groupPadding * 2)
          + ((BsSkin.groupMoveTargetThinDimension + BsSkin.groupMoveTargetAnchorOffset) * 2)
      end

      -- Reset group move target count tracking for ShowNextGroupMoveTarget().
      self.groupMoveTargetCount = 0

      -- Column number adjustment for insertion via group move targets.
      -- This is needed so that we get the correct insertion point regardless of
      -- whether we're going from left to right or vice versa.
      local groupMoveTargetLeadingColumnNumAdjustment = 0
      local groupMoveTargetTrailingColumnNumAdjustment = 0

      -- Prepare to use ShowFrameInNextPosition() for groups.
      self:InitFramePositioningTable(
        "UpdateWindow", -- Position tracking table.
        groupXSpacing, -- Frame X spacing.
        groupYSpacing, -- Frame Y spacing.
        uiFrames.main, -- Initial frame to anchor to.
        -groupEdgeOffset,
        groupEdgeYOffset
      )

      -- Reset tracking tables.
      BsUtil.TableClear(self.groupItemCounts) -- How many items are in each group.
      BsUtil.TableClear(self.groupWidthsInItems) -- Group width in items (actual count EXCEPT in Edit Mode, where 0 becomes 1 to force the group to be visible when empty).
      BsUtil.TableClear(self.actualGroupWidths) -- Group width in screen units.

      local renderLayout = self.layout
      if self.settings.autoCompactLayout and not self.editMode then
        renderLayout = self:BuildAutoCompactRenderLayout(
          maxColumns,
          adjustedItemSlotSize,
          itemSlotMargin,
          groupPadding,
          groupXSpacing,
          groupYSpacing
        )
      end

      -- Groups are placed starting at the bottom of the main frame and working upwards.
      -- Since we're starting at the bottom of the window, we need to start at the last row of the layout table.
      for rowNum = table.getn(renderLayout), 1, -1 do
        -- self:PrintDebug("ROW "..rowNum)

        -- Get the number of groups in this row.
        numGroupsInRow = table.getn(renderLayout[rowNum])
        -- Use that information to figure out the number of the end group.
        uiGroupNumEnd = uiGroupNumStart + numGroupsInRow - 1

        -- Determine anchoring.
        if anchorLeft then
          rowGroupStart = 1
          rowGroupEnd = numGroupsInRow
          rowGroupStep = 1
          groupMoveTargetLeadingColumnNumAdjustment = 0
          groupMoveTargetTrailingColumnNumAdjustment = 1
        else
          rowGroupStart = numGroupsInRow
          rowGroupEnd = 1
          rowGroupStep = -1
          groupMoveTargetLeadingColumnNumAdjustment = 1
          groupMoveTargetTrailingColumnNumAdjustment = 0
        end

        -- Populate lists that are used to determine how tall each group needs to
        -- be in order to fit all items within the maximum column count.
        totalItemsInRow = 0
        for columnNum = rowGroupStart, rowGroupEnd, rowGroupStep do
          local groupId = renderLayout[rowNum][columnNum].groupId

          if groupId then
            hideGroup = false

            -- Determine whether this group is visible and update hasHiddenGroups
            -- to control whether the Show/Hide toolbar button is enabled.
            if self.groups[groupId] and self.groups[groupId].hide then
              hideGroup = true
              self.hasHiddenGroups = true
            end

            -- Determine how many items are in each group in this row based on group visibility.
            if not self.editMode and not self.showHidden and hideGroup then
              -- Set the groupItemCounts for this group to 0 if it's not visible unless it contains
              -- items from the bag that has highlight lock set.
              self.groupItemCounts[groupId] = self.highlightItemsInContainerLocked
                  and self:GetGroupItemCountForLayout(groupId, self.highlightItemsInContainerLocked)
                or 0
            else
              self.groupItemCounts[groupId] = self:GetGroupItemCountForLayout(groupId)
            end

            -- Increment total for this row.
            totalItemsInRow = totalItemsInRow + self.groupItemCounts[groupId]

            -- Starting width for all groups is the number of items in the group.
            self.groupWidthsInItems[groupId] = self.groupItemCounts[groupId]

            -- groupWidthsInItems gets fudged for Edit Mode to make all groups visible, even if they're empty.
            if self.groupWidthsInItems[groupId] == 0 and self.editMode then
              self.groupWidthsInItems[groupId] = 1
            end
          else
            Bagshui:PrintWarning("Inventory update call should have forced resort!")
          end
        end

        -- Starting values for row height/width.
        rowWidthInItems = totalItemsInRow
        rowHeightInItems = 1

        -- Shrink group widths until everything fits within the configured column limit. Basically:
        -- 1. Increment the row height by 1.
        -- 2. Loop through all columns and decrease width of each by 1 (so long as that's possible and won't make it too tall).
        -- 3. See if everything fits now. If not, go back to step 2 unless all groups are now too tall, in which case, go back to step 1.
        -- (No need to do any of this unless there are too many items in the row to fit in the configured number of columns.)
        while rowWidthInItems > maxColumns do
          rowHeightInItems = rowHeightInItems + 1
          repeat
            rowWidthInItems = 0
            unshrinkableGroupCount = 0
            for columnNum = rowGroupStart, rowGroupEnd, rowGroupStep do
              local groupId = renderLayout[rowNum][columnNum].groupId

              -- Shrink the group by 1, if possible.
              if self.groupWidthsInItems[groupId] > 1 then
                local newWidth = self.groupWidthsInItems[groupId] - 1
                -- Make sure this width would't make the group too tall for this row height.
                if self.groupItemCounts[groupId] / newWidth <= rowHeightInItems then
                  self.groupWidthsInItems[groupId] = newWidth
                else
                  unshrinkableGroupCount = unshrinkableGroupCount + 1
                end
              else
                unshrinkableGroupCount = unshrinkableGroupCount + 1
              end
              rowWidthInItems = rowWidthInItems + self.groupWidthsInItems[groupId]
            end
          until rowWidthInItems <= maxColumns or unshrinkableGroupCount >= numGroupsInRow

          -- Failsafe for impossible rows: if there are more visible groups than
          -- allowed columns, every group bottoms out at width 1 and can't shrink
          -- any further.
          if rowWidthInItems > maxColumns then
            local canShrink = false
            for columnNum = rowGroupStart, rowGroupEnd, rowGroupStep do
              if self.groupWidthsInItems[renderLayout[rowNum][columnNum].groupId] > 1 then
                canShrink = true
                break
              end
            end
            if not canShrink then
              break
            end
          end
        end

        -- Is there anything to display on this row?
        if totalItemsInRow == 0 and not self.editMode then
          -- All groups are not visible.
          for groupNum = uiGroupNumStart, uiGroupNumEnd do
            -- This check doesn't seem like it should be necessary, but https://github.com/veechs/Bagshui/issues/172
            -- says otherwise.
            if groupFrames[groupNum] then
              groupFrames[groupNum]:Hide()
            end
          end
        else
          -- There are groups to display, so let's continue.
          -- Calculate the actual group widths, which we need to know when we make the group frame visible.
          local totalActualGroupWidths = 0 -- Will be used to determine how wide the window needs to be.
          for columnNum = rowGroupStart, rowGroupEnd, rowGroupStep do
            local group = renderLayout[rowNum][columnNum]

            -- Make sure this group will be displayed before adding it to the totals.
            if self.groupWidthsInItems[group.groupId] > 0 or self.editMode then
              self.actualGroupWidths[group.groupId] = (
                                -- Item slot widths, margin included.
(self.groupWidthsInItems[group.groupId] * (adjustedItemSlotSize + itemSlotMargin))
                -- This accounts for the space on the opposite side of the last item.
                + itemSlotMargin
                -- Left and right group padding.
                + (groupPadding * 2)
              )
              totalActualGroupWidths = totalActualGroupWidths + self.actualGroupWidths[group.groupId]
            else
              self.actualGroupWidths[group.groupId] = 0
            end
          end

          -- Every group on the row gets the same height even if it's not full of items.
          local actualGroupHeight =
            -- Item slot heights, margin included.
            (rowHeightInItems * (adjustedItemSlotSize + itemSlotMargin))
            -- This accounts for the space above the last item.
            + itemSlotMargin
            -- Top and bottom group padding
            + (groupPadding * 2)

          -- Edit Mode accommodations
          if self.editMode then
            -- Group labels move inside in Edit Mode and need to be added to the height.
            actualGroupHeight = actualGroupHeight + groupLabelHeight

            -- Show the between-row group move target below this row.
            uiRowNum = uiRowNum + 1
            self:ShowNextGroupMoveTarget(
              rowGroupMoveTargetWidth,
              BsSkin.groupMoveTargetThinDimension,
              uiRowNum,
              rowNum + 1,
              1,
              BS_INVENTORY_LAYOUT_DIRECTION.ROW
            )
          end

          -- Put the groups in their places.
          uiGroupNum = uiGroupNumStart
          uiRowNum = uiRowNum + 1

          for columnNum = rowGroupStart, rowGroupEnd, rowGroupStep do
            local groupId = renderLayout[rowNum][columnNum].groupId

            -- Ensure the group exists.
            self.ui:CreateGroup(uiGroupNum)
            local group = groupFrames[uiGroupNum]

            -- Store a reference to the group widget so it's easily accessible via group ID.
            -- Primarily used when an item needs to be assigned to a new group in ManagePendingGroupAssignments().
            self.groupsIdsToFrames[groupId] = group

            -- Show leading group move target for this group in Edit Mode.
            if self.editMode then
              self:ShowNextGroupMoveTarget(
                BsSkin.groupMoveTargetThinDimension,
                actualGroupHeight,
                uiRowNum,
                rowNum,
                columnNum + groupMoveTargetLeadingColumnNumAdjustment,
                BS_INVENTORY_LAYOUT_DIRECTION.COLUMN
              )
              -- In Edit Mode, the group move target should be used for height/width calculations.
              if not firstFrame then
                firstFrame = self.positioningTables.UpdateWindow.anchorToFrame
              end
            end

            -- Display the group.
            if self.groupWidthsInItems[groupId] > 0 then
              -- Update info on the UI object.
              group.bagshuiData.groupId = groupId
              group.bagshuiData.rowNum = renderLayout[rowNum][columnNum].sourceRowNum or rowNum
              group.bagshuiData.columnNum = renderLayout[rowNum][columnNum].sourceColumnNum or columnNum

              -- Add the group to the window.
              self:ShowFrameInNextPosition(
                "UpdateWindow",
                uiRowNum,
                group,
                self.actualGroupWidths[groupId],
                actualGroupHeight
              )

              -- This is the group that should be used for height/width calculations.
              if not firstFrame then
                firstFrame = self.positioningTables.UpdateWindow.anchorToFrame
              end

              -- Set background and border colors.
              self.ui:SetGroupColors(group)

              -- Labels.
              if showGroupLabels then
                -- Move to the correct location depending on whether we're in Edit Mode.
                group.bagshuiData.labelFrame:SetHeight(groupLabelHeight)
                group.bagshuiData.labelFrame:ClearAllPoints()
                if self.editMode then
                  group.bagshuiData.labelFrame:SetWidth(
                    self.actualGroupWidths[groupId] - (groupPadding * 2) - itemSlotMargin
                  )
                  group.bagshuiData.labelFrame:SetPoint(
                    "TOPLEFT",
                    group,
                    "TOPLEFT",
                    BsSkin.groupLabelEditModeXOffset,
                    BsSkin.groupLabelEditModeYOffset
                  )
                  group.bagshuiData.labelFrame:EnableMouse(false)
                else
                  group.bagshuiData.labelFrame:SetWidth(
                    self.actualGroupWidths[groupId] + BsSkin.groupLabelRelativeWidth
                  )
                  group.bagshuiData.labelFrame:SetPoint(
                    "BOTTOMLEFT",
                    group,
                    "TOPLEFT",
                    BsSkin.groupLabelXOffset,
                    BsSkin.groupLabelYOffset
                  )
                  group.bagshuiData.labelFrame:EnableMouse(true)
                end

                -- Set text to group name, or a single space if the group name is empty.
                -- The single space is necessary so that the height can be measured properly.
                group.bagshuiData.text:SetText(
                  string.len(renderLayout[rowNum][columnNum].name or "") > 0 and renderLayout[rowNum][columnNum].name
                    or " "
                )

                group.bagshuiData.labelFrame:Show()
              else
                -- Labels are turned off.
                group.bagshuiData.labelFrame:Hide()
              end

              -- Assign items to the group (only if there are items in the group).
              if self.groupItemCounts[groupId] > 0 then
                currentItemSlotButtonNum = self:AssignItemsToSlots(
                  groupId,
                  uiGroupNum,
                  currentItemSlotButtonNum,
                  self.groupWidthsInItems[groupId],
                  groupPadding,
                  itemSlotSize,
                  itemSlotMargin
                )
              end

              -- Give groups mouse input and display group manager buttons in Edit Mode.
              self.ui:SetGroupInteractivityEnabled(group, self.editMode)
            else
              -- Group should not be visible.
              group:Hide()
            end

            uiGroupNum = uiGroupNum + 1
          end

          -- Display the trailing group move target for this row.
          if self.editMode then
            self:ShowNextGroupMoveTarget(
              BsSkin.groupMoveTargetThinDimension,
              actualGroupHeight,
              uiRowNum,
              rowNum,
              rowGroupEnd + groupMoveTargetTrailingColumnNumAdjustment,
              BS_INVENTORY_LAYOUT_DIRECTION.COLUMN
            )
          end

          -- Update the widest row record so we can make the window the correct width.
          currentRowLastFrameOutsideX = (
            anchorLeft and self.positioningTables.UpdateWindow.anchorToFrame:GetRight()
            or self.positioningTables.UpdateWindow.anchorToFrame:GetLeft()
          )
          if
            widestRowLastFrameOutsideX == 0
            or (
              anchorLeft and widestRowLastFrameOutsideX < currentRowLastFrameOutsideX
              or widestRowLastFrameOutsideX > currentRowLastFrameOutsideX
            )
          then
            widestRowLastFrameOutsideX = currentRowLastFrameOutsideX
            widestRowLastFrame = self.positioningTables.UpdateWindow.anchorToFrame
          end
        end

        uiGroupNumStart = uiGroupNumStart + numGroupsInRow
      end

      -- Add the final group move target above the last row.
      if self.editMode then
        uiRowNum = uiRowNum + 1
        self:ShowNextGroupMoveTarget(
          rowGroupMoveTargetWidth,
          BsSkin.groupMoveTargetThinDimension,
          uiRowNum,
          1,
          1,
          BS_INVENTORY_LAYOUT_DIRECTION.ROW
        )
      end

      -- Hide unused item slot buttons, groups, and group move targets.
      local itemSlotButtonCount = table.getn(uiButtons.itemSlots)
      if currentItemSlotButtonNum <= itemSlotButtonCount then
        for buttonNum = currentItemSlotButtonNum, itemSlotButtonCount do
          uiButtons.itemSlots[buttonNum]:Hide()
        end
      end
      for i = uiGroupNum, table.getn(uiFrames.groups) do
        uiFrames.groups[i]:Hide()
      end
      for i = self.groupMoveTargetCount + 1, table.getn(uiFrames.groupMoveTargets) do
        uiFrames.groupMoveTargets[i]:Hide()
      end

      -- The last frame to be placed is always going to be the highest one vertically,
      -- unlike the frame used for horizontal sizing, which is dependent on which row is the widest.
      topmostFrame = self.positioningTables.UpdateWindow.anchorToFrame

      -- Show the "No inventory data" message for when the cache has never been populated.
      if not self.editMode and BsUtil.TrueTableSize(self.inventory) == 0 then
        self.ui.text.noData:Show()
      else
        self.ui.text.noData:Hide()
      end

      -- Calculate what we always know for width and height (header/footer are added next).
      finalWindowWidth =
        -- Inventory content.
        ((firstFrame and widestRowLastFrame) and math.abs(firstFrame:GetRight() - widestRowLastFrame:GetLeft()) or 0)
        -- Outer group margins.
        + groupEdgeOffset * 2
        -- Window padding.
        + BsSkin.inventoryWindowPadding * 2

      finalWindowHeight =
        -- Inventory content.
        ((topmostFrame and firstFrame) and (topmostFrame:GetTop() - firstFrame:GetBottom()) or 0)
        -- Bottom group margin.
        + groupEdgeYOffset
        -- Edit Mode messes with the sizing.
        + (
          self.editMode
            and BsSkin.groupMoveTargetThinDimension
          or (
                        -- Top group margin is the standard one.
groupEdgeOffset
            -- Need some breathing room above the topmost labels.
            + (showGroupLabels and (groupLabelHeight - BsSkin.groupMarginFudge) or 0)
          )
        )
        -- "No data" message
        + (self.ui.text.noData:IsShown() and self.ui.text.noData:GetHeight() or 0)
        -- Window padding.
        + BsSkin.inventoryWindowPadding * 2

      -- Show/hide header/footer (toolbars) and add to window dimensions.
      if showHeader then
        -- Ensure main frame anchor is correct.
        uiFrames.main:SetPoint("TOP", uiFrames.header, "BOTTOM", 0, 0)
        uiFrames.header:Show()
        -- Update window height.
        finalWindowHeight = finalWindowHeight
          + (uiFrames.header:GetHeight())
          + math.abs(BsSkin.inventoryHeaderFooterYAdjustment)
      else
        -- When the header is hidden, the main frame needs to anchor to the UI frame instead.
        uiFrames.main:SetPoint("TOP", self.uiFrame, "TOP", 0, BsSkin.inventoryWindowPadding)
        uiFrames.header:Hide()
      end

      if showFooter then
        -- Ensure main frame anchor is correct.
        uiFrames.main:SetPoint("BOTTOM", uiFrames.footer, "TOP", 0, 0)

        -- Show/hide Bag Bar and mini utilization summary.
        if self.settings.showBagBar or self.temporarilyShowBagBar then
          uiFrames.bagBar:Show()
          self.ui.frames.miniSpaceSummaryBottom:Hide()
        else
          uiFrames.bagBar:Hide()
          if self.alwaysShowUsageSummary then
            self.ui.frames.miniSpaceSummaryBottom:Show()
          end
        end

        -- Remove space summary from top toolbar.
        self.ui.frames.miniSpaceSummaryTop:Hide()

        -- Apply bag bar scaling and opacity.
        local bagBarScale = (itemSlotSize / uiButtons.itemSlots[1].bagshuiData.originalSizeAdjusted)
          * BsSkin.bagBarScale
        uiFrames.bagBar:SetScale(bagBarScale)
        -- Invert scaling for available space display so text is the normal size.
        uiFrames.spaceSummary:SetScale(1 / bagBarScale)
        -- Invert scaling for borders if needed.
        -- If bag bar scaling was reworked to scale the individual buttons, Ui:SetItemButtonSize()
        -- could be used to handle this automatically, but that refactor is not happening now.
        if BsSkin.itemSlotBorderInverseScale then
          for _, bagSlotButton in ipairs(self.ui.buttons.bagSlots) do
            bagSlotButton.bagshuiData.buttonComponents.border:SetScale(1 / bagBarScale)
          end
        end

        -- Determine footer height based on whether the bag bar is visible.
        local footerHeight = math.max(
          (
                        -- Bag bar visible.
self.settings.showBagBar and (uiButtons.itemSlots[1].bagshuiData.originalSizeAdjusted * bagBarScale)
            or 0
          ),
          BsSkin.inventoryHeaderFooterHeight
        )

        uiFrames.footer:SetHeight(footerHeight)
        uiFrames.footer:Show()

        -- Update window height.
        finalWindowHeight = finalWindowHeight + footerHeight + BsSkin.inventoryHeaderFooterYAdjustment
      else
        -- When the footer is hidden, the main frame needs to anchor to the UI frame instead.
        uiFrames.main:SetPoint("BOTTOM", self.uiFrame, "BOTTOM", 0, BsSkin.inventoryWindowPadding)
        uiFrames.footer:Hide()
      end

      -- We can finally size the window frame.
      self.uiFrame:SetWidth(math.max(finalWindowWidth, BsSkin.inventoryWindowMinWidth))
      self.uiFrame:SetHeight(finalWindowHeight)

      -- Set scale and anchor for docked frame.
      if self.dockTo then
        -- Scaling of docked frames is accomplished by scaling the Main frame, then changing the
        -- dimensions of the window frame. This is done instead of just scaling self.uiFrame to keep
        -- the window border looking the same as the frame it's docked to; it looks a little weird if
        -- the border of the docked frame is shrunk.
        local dockedFrameScale = BsSkin.inventoryDockedScale * Bagshui.components[self.dockTo].uiFrame:GetScale()
        self.ui.frames.main:SetScale(dockedFrameScale)
        self.uiFrame:SetWidth(finalWindowWidth * dockedFrameScale)
        self.uiFrame:SetHeight(finalWindowHeight * dockedFrameScale)

        -- Determine how to anchor the docked window based on how the parent window is docked.
        self.uiFrame:ClearAllPoints()
        local anchorY = "BOTTOM"
        local anchorX = "RIGHT"
        local anchorToY = "TOP"
        local anchorToX = "RIGHT"
        local xOffset = 0
        local yOffset = -4

        if Bagshui.components[self.dockTo].settings.windowAnchorXPoint == "LEFT" then
          anchorX = "LEFT"
          anchorToX = "LEFT"
        end

        if Bagshui.components[self.dockTo].settings.windowAnchorYPoint == "TOP" then
          anchorY = "TOP"
          anchorToY = "BOTTOM"
          yOffset = -yOffset
        end

        self.uiFrame:SetPoint(
          anchorY .. anchorX,
          Bagshui.components[self.dockTo].uiFrame,
          anchorToY .. anchorToX,
          xOffset,
          yOffset
        )
      else
        -- Set scale and anchor for non-docked frame.
        self.uiFrame:SetScale(self.settings.windowScale)
        -- Ensure the window stays in the right place as it resizes.
        -- WoW will change the anchor point to TOPLEFT when the frame is dragged, so we need to reset it.
        self:FixWindowPosition()
      end
    end

    -- Check for mouse over state for interact-able elements to ensure tooltips stay current.
    Bagshui:QueueClassCallback(self, self.ItemSlotAndGroupMouseOverCheck)

    -- Reset statuses.
    self.lastExpandEmptySlotStacks = self.expandEmptySlotStacks
    self.windowUpdateNeeded = false
  end

  --- Fill the given UI group frame with the items assigned to the given group.
  ---@param groupId number ID of the group to which items should be assigned.
  ---@param uiGroupNum number Frame in the `self.ui.frames.groups` table to use for display.
  ---@param currentItemSlotButtonNum number Frame in the `self.ui.frames.buttons.itemSlots` table to use next.
  ---@param groupWidthInItems number Count of items to place on each row of the group.
  ---@param groupPadding number Padding between group edge and item slots.
  ---@param itemSlotSize number Height/width of the item slot button.
  ---@param itemSlotMargin number Margin around the outer edge of each item slot button.
  ---@return any currentItemSlotButtonNum Index of the last frame from `self.ui.frames.buttons.itemSlots` that was used.
  function Inventory:AssignItemsToSlots(
    groupId,
    uiGroupNum,
    currentItemSlotButtonNum,
    groupWidthInItems,
    groupPadding,
    itemSlotSize,
    itemSlotMargin
  )
    -- self:PrintDebug(string.format("AssignItemsToSlots() groupId=%s uiGroupNum=%s groupWidthInItems=%s", groupId, uiGroupNum, groupWidthInItems))

    local itemsPlacedInCurrentRow = 0
    local rowNum = 0
    local genericBagType
    local button
    local isEmptySlotStack

    -- We need the real item count here to be able to step through all items.
    -- (Using the count for layout from upstream won't work if empty slot
    -- stacking is on because we can end up missing items).
    local groupItemCount = table.getn(self.groupItems[groupId])

    -- Make sure there are items to assign in this group.
    if groupItemCount > 0 then
      local buttons = self.ui.buttons
      local frames = self.ui.frames

      local groupFrame = frames.groups[uiGroupNum]

      -- Prepare for layout
      local initialOffset = groupPadding + itemSlotMargin
      self:InitFramePositioningTable(
        "AssignItemsToSlots", -- Position tracking table
        itemSlotMargin, -- Frame X spacing
        itemSlotMargin, -- Frame Y spacing
        groupFrame, -- Initial frame to anchor to
        -initialOffset, -- Initial X offset
        initialOffset -- Initial Y offset
      )

      -- Update empty slot stack count for this group.
      if self.emptySlotStackingAllowed then
        self:CountEmptySlots(groupId)
      end

      -- Need to go in reverse because we're building right to left.
      local firstItem = groupItemCount
      local lastItem = 1
      local step = -1
      local item = nil
      local hideItem = false
      local bagIsHidden = false
      for position = firstItem, lastItem, step do
        -- Grab the item info.
        item = self.groupItems[groupId][position]
        genericBagType = self.containers[item.bagNum].genericType

        -- Item hiding and empty slot handling
        hideItem = false
        isEmptySlotStack = false

        -- Items (and empty slots) in bags the user has hidden.
        bagIsHidden = self:IsBagHiddenInLayout(item.bagNum)

        if bagIsHidden then
          hideItem = true
        -- Empty slot stacking.
        elseif
          self.emptySlotStackingAllowed -- Empty slot stacking must be on.
          and item.emptySlot == 1 -- This item must be an empty slot.
          and not item._bagshuiPreventEmptySlotStack -- This slot must not be temporarily blocked from stacking (usually if it just became empty and re-sorting hasn't occurred yet).
        then
          -- We've already shown one empty slot of this type in this group, so hide all the others.
          if self.emptySlotStacks[genericBagType].displayed then
            hideItem = true
          else
            -- Prevent any more empty slots of this generic container type from appearing in this group.
            self.emptySlotStacks[genericBagType].displayed = true
            -- Override the normal empty slot item with the stack so the count displays.
            item = self.emptySlotStacks[genericBagType]
            isEmptySlotStack = true
          end
        end

        -- Determine whether this item is hidden.
        if
          not self.editMode
          and not self.showHidden
          and self.highlightItemsInContainerLocked ~= item.bagNum -- Unhide items when bag highlighting is locked on.
          and self.hideItems[item.id]
        then
          hideItem = true
        end

        if not hideItem then
          -- Ensure slot button exists.
          self.ui:CreateInventoryItemSlotButton(currentItemSlotButtonNum)

          button = buttons.itemSlots[currentItemSlotButtonNum]

          -- Ensure parentage of item slot button is set to current group frame.
          -- This is required to get the layering right -- without it, stuff can end up behind groups.
          button:SetParent(groupFrame)

          -- Record details of this button's assignments so we can access
          -- them during UI events.
          button.bagshuiData.groupId = groupId
          button.bagshuiData.position = position
          -- These always need to refer to the original item's location so
          -- empty slot stacks magically work with click events
          button.bagshuiData.bagNum = self.groupItems[groupId][position].bagNum
          button.bagshuiData.slotNum = self.groupItems[groupId][position].slotNum
          button.bagshuiData.isEmptySlotStack = isEmptySlotStack

          -- Display the item slot button.
          self:ShowFrameInNextPosition("AssignItemsToSlots", rowNum, button, itemSlotSize)

          -- Add the item to the button (texture, tooltip, etc.).
          self.ui:AssignItemToItemButton(button, item, groupId)

          -- Should the Clam button be enabled?
          if item.openable == 1 then
            self.hasOpenables = true
            -- The first openable item we come across will be the one the Clam button targets.
            if not self.nextOpenableItemBagNum then
              self.nextOpenableItemBagNum = item.bagNum
              self.nextOpenableItemSlotNum = item.slotNum
              self.nextOpenableItemSlotButton = button
            end
          end

          -- Increment counters.
          itemsPlacedInCurrentRow = itemsPlacedInCurrentRow + 1
          currentItemSlotButtonNum = currentItemSlotButtonNum + 1

          -- When we reach the end of a row, move to the next one.
          if itemsPlacedInCurrentRow == groupWidthInItems then
            itemsPlacedInCurrentRow = 0
            rowNum = rowNum + 1
          end
        end
      end
    end

    return currentItemSlotButtonNum
  end

  --- Call this before using `UpdateEmptySlotStackCount()` to zero the counts on the self.emptySlotStacks items
  ---@param resetBagsRepresented boolean? Clear the `_bagsRepresented` property of the empty slot stack items. Should only be called with `true` once per window update.
  function Inventory:ResetEmptySlotStackCounts(resetBagsRepresented)
    for _, emptySlotStack in pairs(self.emptySlotStacks) do
      emptySlotStack.count = 0
      emptySlotStack.displayed = false
      if resetBagsRepresented then
        BsUtil.TableClear(emptySlotStack._bagsRepresented)
      end
    end
  end

  --- Loop through all items in a group and add their counts to the appropriate empty
  --- slot stack using `UpdateEmptySlotStackCount()`
  ---@param groupId number ID of group to count empty slots for.
  function Inventory:CountEmptySlots(groupId)
    self:ResetEmptySlotStackCounts()
    for _, item in pairs(self.groupItems[groupId]) do
      self:UpdateEmptySlotStackCount(item)
    end
  end

  --- Has the user hidden this bag's items (right-click or Ctrl+Click on its bag button)?
  ---@param bagNum number
  ---@return boolean
  function Inventory:IsBagHidden(bagNum)
    local settingName = Bagshui.config.HideBagSettings[bagNum]
    return settingName ~= nil and self.settings[settingName] == true
  end

  --- Should this bag's items be left out of the window right now?
  --- Same exceptions as individually hidden items: Edit Mode, Show Hidden, and a locked bag highlight.
  ---@param bagNum number
  ---@return boolean
  function Inventory:IsBagHiddenInLayout(bagNum)
    return not self.editMode
      and not self.showHidden
      and self.highlightItemsInContainerLocked ~= bagNum
      and self:IsBagHidden(bagNum)
  end

  --- Determine whether a slot is empty, and if so, add 1 to the appropriate per-bag-type empty slot stack.
  ---@param item table Bagshui inventory cache entry.
  ---@return boolean # true if the item is an empty slot.
  function Inventory:UpdateEmptySlotStackCount(item)
    -- Only increment the count for slots that are empty AND not temporarily prevented from stacking.
    if item.emptySlot == 1 and not item._bagshuiPreventEmptySlotStack then
      -- Empty slots in bags the user has hidden don't count toward any stack.
      if self:IsBagHiddenInLayout(item.bagNum) then
        return true
      end
      -- genericType SHOULD be filled in, but let's just be sure.
      local genericBagType = self.containers[item.bagNum].genericType or BsGameInfo.itemSubclasses.Container.Bag
      -- Increment the count.
      self.emptySlotStacks[genericBagType].count = self.emptySlotStacks[genericBagType].count + 1
      -- Record that the bag containing this item is represented by this stack
      -- (used during container mouseover slot highlighting).
      self.emptySlotStacks[genericBagType]._bagsRepresented[item.bagNum] = true
      -- Return true so calling functions can know the item is an empty slot.
      return true
    end
    return false
  end

  --- Return the number of items in a group that will be visible, accounting for stacked slots and hidden items.
  --- Also updates `self.hasHiddenItems`.
  ---@param groupId number ID of group to get the number of items for.
  ---@param zeroUnlessHasItemsInBagNum number? Return 0 unless the group has items that are in the specified bag number -- in that case, return the normal count.
  ---@return integer visibleItemCount
  function Inventory:GetGroupItemCountForLayout(groupId, zeroUnlessHasItemsInBagNum)
    -- No items.
    if not self.groupItems[groupId] then
      return 0
    end

    -- Quickly return real count when we're in Edit Mode since nothing can be hidden.
    if self.editMode then
      return table.getn(self.groupItems[groupId])
    end

    -- Slot stacking / item hiding is enabled, so prepare for more complex counting.
    local visibleItemCount = 0
    local itemVisible
    local hasEmptySlots = false
    local hasItemsInFilterBag = false

    -- We'll be using the permanent self.emptySlotStacks items, so reset their counts first.
    self:ResetEmptySlotStackCounts()

    -- Count up the number of visible items while figuring out if there are any empty slots or hidden items.
    for _, item in ipairs(self.groupItems[groupId]) do
      -- Assume the item will be counted
      itemVisible = true

      -- Have we found an item in the bag that will require a full count to be returned?
      if zeroUnlessHasItemsInBagNum and item.bagNum == zeroUnlessHasItemsInBagNum then
        hasItemsInFilterBag = true
      end

      -- Empty slot stacks and hidden items.
      if self:IsBagHiddenInLayout(item.bagNum) then
        -- This item is in a bag the user has hidden. Mark that hidden items exist so the
        -- toolbar's Show Hidden button is enabled.
        self.hasHiddenItems = true
        itemVisible = false
      elseif self:UpdateEmptySlotStackCount(item) then
        -- This is an empty slot stack, which we know because in addition to
        -- updating the appropriate empty slot stack proxy item in self.emptySlotsStacks,
        -- UpdateEmptySlotStackCount() returns true if the given item is an empty slot.
        if self.emptySlotStackingAllowed then
          itemVisible = false
          hasEmptySlots = true
        end
      elseif self.hideItems[item.id] then
        -- Hidden items.
        -- We need to update hasHiddenItems even if we're not actually hiding this item so that the toolbar icon will be enabled.
        self.hasHiddenItems = true
        -- Need to count the item when in Edit Mode or hidden items are shown.
        itemVisible = (self.editMode or self.showHidden or self.highlightItemsInContainerLocked == item.bagNum)
      end

      -- Increment count if visible.
      if itemVisible then
        visibleItemCount = visibleItemCount + 1
      end
    end

    -- Add 1 for each empty slot stack that contains 1 or more slots.
    if hasEmptySlots then
      for _, emptySlotStack in pairs(self.emptySlotStacks) do
        if emptySlotStack.count > 0 then
          visibleItemCount = visibleItemCount + 1
        end
      end
    end

    -- We were asked for a full count ONLY If this group has items in a specific bag.
    if zeroUnlessHasItemsInBagNum and not hasItemsInFilterBag then
      return 0
    end

    return visibleItemCount
  end

  --- Prepare a layout table to be used by `ShowFrameInNextPosition()`.
  ---@param positioningTableName string Identifier for this positioning table that will also be passed to `ShowFrameInNextPosition()`.
  ---@param frameXSpacing number Horizontal space between frames.
  ---@param frameYSpacing number Vertical space between frames.
  ---@param initialAnchorToFrame table Frame to which the first frame should be attached.
  ---@param initialXOffset number Horizontal space between initialAnchorToFrame and first frame.
  ---@param initialYOffset number Vertical space between initialAnchorToFrame and first frame.
  function Inventory:InitFramePositioningTable(
    positioningTableName,
    frameXSpacing,
    frameYSpacing,
    initialAnchorToFrame,
    initialXOffset,
    initialYOffset
  )
    -- Set up positioning variable storage.
    -- The table doesn't need to be cleared if it already exists because all its values will be reset below.
    if self.positioningTables[positioningTableName] == nil then
      self.positioningTables[positioningTableName] = {}
    end
    local positioningTable = self.positioningTables[positioningTableName]

    -- Define anchor points and spacing.
    positioningTable.anchorXPoint = self.settings.windowContentAlignment
    positioningTable.anchorLeft = positioningTable.anchorXPoint == "LEFT"
    positioningTable.anchorToPointXRowStart = "TOP" .. positioningTable.anchorXPoint
    positioningTable.anchorToPointXSubsequent = "BOTTOM" .. BsUtil.FlipAnchorPoint(positioningTable.anchorXPoint)
    positioningTable.frameXSpacing = frameXSpacing
    positioningTable.frameYSpacing = frameYSpacing

    -- Track the current row so we know when to move to a new one.
    positioningTable.currentRow = nil

    -- Each time we move to a new row, this is the frame the first element of the new row will anchor to.
    positioningTable.firstVisibleFrameInPreviousRow = nil

    -- The very first frame anchors to the bottom corner of the given frame.
    positioningTable.anchorPoint = "BOTTOM" .. positioningTable.anchorXPoint
    positioningTable.initialAnchorToFrame = initialAnchorToFrame
    positioningTable.anchorToFrame = initialAnchorToFrame
    positioningTable.anchorToPoint = positioningTable.anchorPoint

    -- These are the initial values for X and Y offsets.
    positioningTable.anchorXOffset = initialXOffset
    positioningTable.anchorYOffset = initialYOffset
  end

  --- Helper function for `UpdateWindow()` to manage the process of displaying the grid of
  --- groups and items within those groups at the correct location.
  ---@param positioningTableName string Identifier for this positioning table that was prepared in `InitFramePositioningTable()`.
  ---@param rowNum number Current row number.
  ---@param frame table Frame to display.
  ---@param width number Frame width.
  ---@param height number? Frame height (will use width if not specified).
  ---@param scale number? Frame scale.
  function Inventory:ShowFrameInNextPosition(positioningTableName, rowNum, frame, width, height, scale)
    local positioningTable = self.positioningTables[positioningTableName]

    assert(
      positioningTable,
      "Inventory:ShowFrameInNextPosition(): Positioning table '"
        .. tostring(positioningTableName)
        .. "' has not been initialized; must call InitFramePositioningTable() first!"
    )

    -- self:PrintDebug(
    -- 	"Showing " .. frame:GetName() .. " for row " .. rowNum
    -- 	.. "\nAnchor point:" .. positioningTable.anchorPoint
    -- 	.. "\nAnchor frame:" .. positioningTable.anchorToFrame:GetName()
    -- 	.. "\nAnchor frame point:" .. positioningTable.anchorToPoint
    -- 	.. "\nX offset:" .. (positioningTable.anchorLeft and -positioningTable.anchorXOffset or positioningTable.anchorXOffset)
    -- 	.. "\nY offset:" .. positioningTable.anchorYOffset
    -- 	.. "\nWidth" .. width
    -- 	.. "\nHeight" .. height
    -- 	.. "\nScale" .. tostring(scale)
    -- )

    -- Is this a new row?
    -- nil check is so this only happens once we're above the first row.
    if positioningTable.currentRow ~= nil and positioningTable.currentRow ~= rowNum then
      -- Anchor to the first frame in the previous row.
      positioningTable.anchorToFrame = positioningTable.firstVisibleFrameInPreviousRow
      positioningTable.anchorToPoint = positioningTable.anchorToPointXRowStart
      positioningTable.anchorXOffset = 0
      -- First frame in the row needs to be higher up.
      positioningTable.anchorYOffset = positioningTable.frameYSpacing
    end

    -- Display the frame.
    self:SizeAndShowFrame(
      frame,
      positioningTable.anchorPoint,
      positioningTable.anchorToFrame,
      positioningTable.anchorToPoint,
      positioningTable.anchorLeft and -positioningTable.anchorXOffset or positioningTable.anchorXOffset,
      positioningTable.anchorYOffset,
      width,
      height,
      scale,
      -positioningTable.frameXSpacing -- HitRectInsets
    )

    -- The next element in a row always anchors to the previous one.
    positioningTable.anchorToFrame = frame

    -- When we move to a new row, update positioning variables to the proper state for anchoring within the same row.
    if positioningTable.currentRow ~= rowNum then
      -- Update the row number of the tracking variable so we know we've found the first visible element in this row.
      positioningTable.currentRow = rowNum
      -- Change the anchor point for subsequent frames.
      positioningTable.anchorToPoint = positioningTable.anchorToPointXSubsequent
      -- Subsequent frames in this row will be spaced using the frameXSpacing set by InitFramePositioningTable().
      positioningTable.anchorXOffset = -positioningTable.frameXSpacing
      -- Subsequent frames in this same row should be at the same vertical offset.
      positioningTable.anchorYOffset = 0
      -- Keep a note of the first frame int this row because the first frame in the next row will anchor to it.
      positioningTable.firstVisibleFrameInPreviousRow = frame
    end
  end

  -- SizeAndShowFrame() gets called a LOT so let's reuse variables to cut down on garbage collection.
  local sizeAndShow_frame, sizeAndShow_finalScale, sizeAndShow_inverseScale, sizeAndShow_sizeWasSetViaScaling

  --- Display the given frame at the specified position and size.
  ---@param frameObjOrName table|string Frame or name of frame.
  ---@param frameAttachPoint string Point on `frameObjOrName` that should be be attached.
  ---@param attachToFrame table|string Frame to which `frameObjOrName` should be attached.
  ---@param attachToPoint string Point on `attachToFrame` to which `frameObjOrName` should be attached..
  ---@param xOffset number? Horizontal offset for `frameObjOrName` (negative for left).
  ---@param yOffset number? Vertical offset for `frameObjOrName` (negative for down).
  ---@param width number Width of the frame.
  ---@param height number? Height of the frame (will use width if not specified).
  ---@param scale number? Scaling factor (0 - 1) that should be applied to the frame.
  ---@param hitRectInsets number? Hit rectangle insets to should be applied to the frame.
  function Inventory:SizeAndShowFrame(
    frameObjOrName,
    frameAttachPoint,
    attachToFrame,
    attachToPoint,
    xOffset,
    yOffset,
    width,
    height,
    scale,
    hitRectInsets
  )
    -- Get the frame object.
    sizeAndShow_frame = frameObjOrName
    if type(frameObjOrName) == "string" then
      sizeAndShow_frame = _G[frameObjOrName]
    end

    assert(
      sizeAndShow_frame ~= nil,
      "Invalid frame '" .. tostring(frameObjOrName) .. "' provided to SizeAndShowFrame()."
    )

    -- When an item slot button is sized by calling SetItemButtonSize, calling SetWidth/SetHeight isn't necessary.
    sizeAndShow_sizeWasSetViaScaling = false

    -- Item slot buttons should always be sized by scaling if possible, so do it automatically.
    if
      not scale
      and sizeAndShow_frame.bagshuiData
      and sizeAndShow_frame.bagshuiData.type == BS_UI_ITEM_BUTTON_TYPE.ITEM
    then
      scale = self.ui:SetItemButtonSize(sizeAndShow_frame, width)
      sizeAndShow_sizeWasSetViaScaling = scale ~= nil
    end

    -- We need to know both the scale factor to apply to the frame and the inverse scale,
    -- because SetPoint() uses the frame scale for offsets, so we need to un-scale the offsets.
    sizeAndShow_finalScale = scale or 1
    sizeAndShow_inverseScale = 1 / sizeAndShow_finalScale

    -- Normal behavior -- set height, width, and scale.
    if not sizeAndShow_sizeWasSetViaScaling then
      sizeAndShow_frame:SetWidth(width)
      sizeAndShow_frame:SetHeight(height or width)
      sizeAndShow_frame:SetScale(sizeAndShow_finalScale)
    end

    -- Move frame to the specified point.
    sizeAndShow_frame:ClearAllPoints()
    sizeAndShow_frame:SetPoint(
      frameAttachPoint,
      attachToFrame,
      attachToPoint,
      xOffset * sizeAndShow_inverseScale,
      yOffset * sizeAndShow_inverseScale
    )

    -- Adjust hit rectangle insets.
    if hitRectInsets then
      sizeAndShow_frame:SetHitRectInsets(hitRectInsets, hitRectInsets, hitRectInsets, hitRectInsets)
    end

    sizeAndShow_frame:Show()

    -- For some reason, an initial call to GetTop() is sometimes necessary to prevent it
    -- from returning nil later.
    sizeAndShow_frame:GetTop()
  end

  --- Automatically select the next Group Move Target based on groupMoveTargetCount,
  --- creating it if needed, then display using `ShowFrameInNextPosition()`
  ---@param width number Desired width of the group move target.
  ---@param height number Desired height of the group move target.
  ---@param uiRowNum number Current row number within the UI layout.
  ---@param layoutRowNum number Current layout/structure row number that the group move target should act on.
  ---@param layoutColumnNum number Current layout/structure column number that the group move target should act on.
  ---@param insertType BS_INVENTORY_LAYOUT_DIRECTION Whether the roup move target should act on rows or columns.
  function Inventory:ShowNextGroupMoveTarget(width, height, uiRowNum, layoutRowNum, layoutColumnNum, insertType)
    -- Increment count of targets and create a new one if needed.
    self.groupMoveTargetCount = self.groupMoveTargetCount + 1
    self.ui:CreateGroupMoveTarget(self.groupMoveTargetCount)

    local groupMoveTarget = self.ui.frames.groupMoveTargets[self.groupMoveTargetCount]

    -- Snag the button within the group move target frame so we can resize it and set properties.
    local button = self.ui.frames.groupMoveTargets[self.groupMoveTargetCount].bagshuiData.button

    -- This information will be pulled when the group move target button is clicked.
    button.bagshuiData.insert = insertType
    button.bagshuiData.rowNum = layoutRowNum
    button.bagshuiData.columnNum = layoutColumnNum

    -- Select button offsets based on whether the group is horizontal or vertical (start by assuming vertical).
    local xOffsetLeft = BsSkin.groupMoveTargetAnchorOffset
    local xOffsetRight = xOffsetLeft
    local yOffset = BsSkin.groupMoveTargetLongDimensionSubtraction
    if width > height then
      -- This one is horizontal.
      xOffsetRight = -(BsSkin.groupMoveTargetLongDimensionSubtraction + BsSkin.groupMoveTargetThinDimension + 1)
      xOffsetLeft = xOffsetRight - BsSkin.groupMoveTargetAnchorOffset * 2
      yOffset = -BsSkin.groupMoveTargetAnchorOffset
    end

    -- Set button offsets so the move target is visually shorter than the height/width of the groups.
    button:SetPoint("TOPLEFT", groupMoveTarget, "TOPLEFT", -xOffsetLeft, -yOffset)
    button:SetPoint("BOTTOMRIGHT", groupMoveTarget, "BOTTOMRIGHT", xOffsetRight, yOffset)

    -- Display the frame.
    self:ShowFrameInNextPosition("UpdateWindow", uiRowNum, groupMoveTarget, width, height)
  end

  --- Update free/available slot counts. Subclasses should override for special bag bar stuff.
  function Inventory:UpdateBagBar()
    local showBagUsage = self.settings.bagUsageAlwaysShow
    local showUsageSummary = false

    -- We always need to do one loop through the bag buttons to refresh the appearance and make some decisions.
    for _, bagSlotButton in ipairs(self.ui.buttons.bagSlots) do
      -- Set button textures -- necessary for them to be correct when viewing another character's inventory.
      _G.SetItemButtonTexture(bagSlotButton, self.containers[bagSlotButton.bagshuiData.bagNum].texture)

      -- Locked highlight border.
      if self.highlightItemsInContainerLocked == bagSlotButton.bagshuiData.bagNum then
        bagSlotButton.bagshuiData.buttonComponents.border:SetBackdropBorderColor(
          BS_COLOR.ITEM_SLOT_HIGHLIGHT[1],
          BS_COLOR.ITEM_SLOT_HIGHLIGHT[2],
          BS_COLOR.ITEM_SLOT_HIGHLIGHT[3],
          BsSkin.itemSlotBorderContainerHighlightOpacity
        )
        bagSlotButton.bagshuiData.buttonComponents.innerGlow:SetVertexColor(
          BS_COLOR.ITEM_SLOT_HIGHLIGHT[1],
          BS_COLOR.ITEM_SLOT_HIGHLIGHT[2],
          BS_COLOR.ITEM_SLOT_HIGHLIGHT[3],
          BsSkin.itemSlotInnerGlowOpacity + 0.2
        )
        bagSlotButton.bagshuiData.highlightBorderApplied = true
      elseif self.highlightItemsInContainerLocked ~= bagSlotButton.bagshuiData.bagNum then
        bagSlotButton.bagshuiData.buttonComponents.border:SetBackdropBorderColor(
          BsSkin.itemSlotBorderDefaultColor.r,
          BsSkin.itemSlotBorderDefaultColor.g,
          BsSkin.itemSlotBorderDefaultColor.b,
          BsSkin.itemSlotBorderOpacity
        )
        bagSlotButton.bagshuiData.buttonComponents.innerGlow:SetVertexColor(0, 0, 0, 0)
        bagSlotButton.bagshuiData.highlightBorderApplied = false
      end

      -- Offline icon texture opacity.
      bagSlotButton.bagshuiData.buttonComponents.iconTexture:SetVertexColor(
        BS_COLOR.ITEM_SLOT_STATE_NORMAL[1],
        BS_COLOR.ITEM_SLOT_STATE_NORMAL[2],
        BS_COLOR.ITEM_SLOT_STATE_NORMAL[3],
        (not self.online and BsSkin.itemSlotTextureOfflineOpacity or 1)
          -- Dim bags whose items are hidden.
          * (self:IsBagHidden(bagSlotButton.bagshuiData.bagNum) and 0.4 or 1)
      )

      -- Overall button opacity.
      bagSlotButton:SetAlpha(
        self.editMode and 0.2
          -- When an item in the inventory is moused over, we want to dim everything but the container it's in.
          or (
            self.hoveredItem
            and (
              (
                                      -- Empty slot stack.
self.hoveredItem._bagsRepresented
                    and self.hoveredItem._bagsRepresented[bagSlotButton.bagshuiData.bagNum]
                  -- Normal item.
                  or self.hoveredItem.bagNum == bagSlotButton.bagshuiData.bagNum
                )
                and 1
              or 0.4
            )
          )
          -- When the container highlight is locked on, dim other bags.
          or ((self.highlightItemsInContainerLocked and self.highlightItemsInContainerLocked ~= bagSlotButton.bagshuiData.bagNum) and 0.7)
          -- No item currently hovered.
          or 1
      )

      -- Display free space information when the mouse is over any button.
      if bagSlotButton.bagshuiData.mouseIsOver then
        showBagUsage = true
        showUsageSummary = true
      end
    end

    -- Also display free space information when the mouse is over the summary area.
    if self.alwaysShowUsageSummary or self.ui.frames.spaceSummary.bagshuiData.mouseIsOver then
      showUsageSummary = true
    end

    -- Cancel free space display in Edit Mode.
    if self.editMode then
      showBagUsage = false
      showUsageSummary = false
    end

    -- Width of bag space summary text area to the right of the bag bar that will be added
    -- to the overall bag bar width.
    local summaryWidth = 0

    -- Reset space tracking - don't need to worry about whether the table members
    -- are initialized because that's handled below. Here we're only iterating over
    -- what already exists.
    for _, spaceInfo in pairs(self.containerSpace) do
      spaceInfo.available = 0
      spaceInfo.used = 0
      spaceInfo.total = 0
    end
    self.availableSlots, self.usedSlots, self.totalSlots = 0, 0, 0

    -- Gether free space information.
    for _, bagSlotButton in ipairs(self.ui.buttons.bagSlots) do
      -- Step through bag slot buttons and determine available/used/total space.
      local container = self.containers[bagSlotButton.bagshuiData.bagNum]
      local available, used = 0, 0
      local slotText = ""
      if container.numSlots > 0 then
        used = container.slotsFilled
        if container.slotsFilled < container.numSlots then
          available = container.numSlots - used
          slotText = string.format("%s/%s", used, container.numSlots)
        else
          slotText = L.Full
        end
      end
      if showBagUsage then
        bagSlotButton.bagshuiData.buttonComponents.stock:SetText(slotText)
        bagSlotButton.bagshuiData.buttonComponents.stock:Show()
      else
        bagSlotButton.bagshuiData.buttonComponents.stock:Hide()
      end

      local genericType = container.genericType or BsGameInfo.itemSubclasses["Container"]["Bag"]

      -- Initialize space tracking if needed.
      if not self.containerSpace[genericType] then
        self.containerSpace[genericType] = {
          available = 0,
          used = 0,
          total = 0,
        }
      end

      -- Update calculations.
      local spaceInfo = self.containerSpace[genericType]
      spaceInfo.available = spaceInfo.available + available
      spaceInfo.used = spaceInfo.used + used
      spaceInfo.total = spaceInfo.total + container.numSlots
      self.availableSlots = self.availableSlots + available
      self.usedSlots = self.usedSlots + used
      self.totalSlots = self.totalSlots + container.numSlots
    end

    -- Figure out what to display in the summary based on settings.

    local textParts = BsUtil.Split(self.settings.bagUsageFormat, "_")

    local mainText = tostring(textParts[1] == "Used" and self.usedSlots or self.availableSlots)
    local miniText = mainText
    local subText
    if textParts[2] then
      if textParts[2] == "Total" then
        subText = self.totalSlots
      elseif textParts[3] == "Total" then
        subText =
          string.format("%s/%s", (textParts[2] == "Used" and self.usedSlots or self.availableSlots), self.totalSlots)
        -- miniText = miniText .. " (" .. subText .. ")"
      end
    end

    if showUsageSummary then
      self.ui.frames.spaceSummary.bagshuiData.text:SetText(mainText)
      self.ui.frames.spaceSummary.bagshuiData.text:SetTextColor(
        self.settings.groupLabelDefault[1],
        self.settings.groupLabelDefault[2],
        self.settings.groupLabelDefault[3],
        self.settings.groupLabelDefault[4]
      )
      self.ui.frames.miniSpaceSummaryBottom.bagshuiData.text:SetText(miniText)
      self.ui.frames.miniSpaceSummaryBottom.bagshuiData.text:SetTextColor(
        self.settings.groupLabelDefault[1],
        self.settings.groupLabelDefault[2],
        self.settings.groupLabelDefault[3],
        self.settings.groupLabelDefault[4]
      )
      self.ui.frames.miniSpaceSummaryTop.bagshuiData.text:SetText(miniText)
      self.ui.frames.miniSpaceSummaryTop.bagshuiData.text:SetTextColor(
        self.settings.groupLabelDefault[1],
        self.settings.groupLabelDefault[2],
        self.settings.groupLabelDefault[3],
        self.settings.groupLabelDefault[4]
      )
      if subText then
        self.ui.frames.spaceSummary.bagshuiData.text:ClearAllPoints()
        self.ui.frames.spaceSummary.bagshuiData.text:SetPoint("BOTTOM", self.ui.frames.spaceSummary, "CENTER", 0, -2)
        self.ui.frames.spaceSummary.bagshuiData.subtext:SetText(subText)
        self.ui.frames.spaceSummary.bagshuiData.subtext:SetTextColor(
          self.settings.groupLabelDefault[1],
          self.settings.groupLabelDefault[2],
          self.settings.groupLabelDefault[3],
          self.settings.groupLabelDefault[4]
        )
        self.ui.frames.spaceSummary.bagshuiData.subtext:Show()
        self.ui.frames.miniSpaceSummaryBottom.bagshuiData.subtext:SetText(subText)
        self.ui.frames.miniSpaceSummaryBottom.bagshuiData.subtext:SetTextColor(
          self.settings.groupLabelDefault[1],
          self.settings.groupLabelDefault[2],
          self.settings.groupLabelDefault[3],
          self.settings.groupLabelDefault[4]
        )
        self.ui.frames.miniSpaceSummaryBottom.bagshuiData.subtext:Show()
        self.ui.frames.miniSpaceSummaryTop.bagshuiData.subtext:SetText(subText)
        self.ui.frames.miniSpaceSummaryTop.bagshuiData.subtext:SetTextColor(
          self.settings.groupLabelDefault[1],
          self.settings.groupLabelDefault[2],
          self.settings.groupLabelDefault[3],
          self.settings.groupLabelDefault[4]
        )
        self.ui.frames.miniSpaceSummaryTop.bagshuiData.subtext:Show()
      else
        self.ui.frames.spaceSummary.bagshuiData.subtext:Hide()
        self.ui.frames.spaceSummary.bagshuiData.text:ClearAllPoints()
        self.ui.frames.spaceSummary.bagshuiData.text:SetPoint("CENTER", self.ui.frames.spaceSummary, "CENTER")
        self.ui.frames.miniSpaceSummaryBottom.bagshuiData.subtext:Hide()
        self.ui.frames.miniSpaceSummaryBottom.bagshuiData.subtext:SetText("")
        self.ui.frames.miniSpaceSummaryTop.bagshuiData.subtext:Hide()
        self.ui.frames.miniSpaceSummaryTop.bagshuiData.subtext:SetText("")
      end

      -- Resize and show/hide.
      summaryWidth = math.max(
        self.ui.frames.spaceSummary.bagshuiData.text:GetStringWidth(),
        self.ui.frames.spaceSummary.bagshuiData.subtext:GetStringWidth()
      )
      self.ui.frames.spaceSummary:SetWidth(summaryWidth)
      self.ui.frames.spaceSummary:SetAlpha(1) -- Reversing the SetAlpha(0) call that happens when we hide the summary.

      self.ui.frames.miniSpaceSummaryBottom:SetWidth(
        self.ui.frames.miniSpaceSummaryBottom.bagshuiData.text:GetStringWidth()
          + self.ui.frames.miniSpaceSummaryBottom.bagshuiData.subtext:GetStringWidth()
          + 2
      )
      self.ui.frames.miniSpaceSummaryTop:SetWidth(
        self.ui.frames.miniSpaceSummaryTop.bagshuiData.text:GetStringWidth()
          + self.ui.frames.miniSpaceSummaryTop.bagshuiData.subtext:GetStringWidth()
          + 2
      )
    else
      -- Hide space summary.
      self.ui.frames.spaceSummary:SetAlpha(0) -- Using SetAlpha() instead of Hide() so it's still responsive to mouseover.
    end

    -- Set the Bag Bar to the correct width.
    self.ui.frames.bagBar:SetWidth(
      self.ui.frames.bagBar.bagshuiData.baseWidth
        + (math.max(summaryWidth, 15) * self.ui.frames.spaceSummary:GetScale())
        + 10 -- Buffer so nothing gets cut off.
    )
  end

  --- Enable/disable/highlight toolbar buttons as appropriate.
  function Inventory:UpdateToolbar()
    local toolbarButtons = self.ui.buttons.toolbar

    -- Resort icon.
    self:SetToolbarButtonState(
      toolbarButtons.resort,
      nil,
      (
        self.enableResortIcon
        or (
                    -- Docked inventory needs resorting.
self.dockedInventory and self.dockedInventory.enableResortIcon
        )
      )
    )

    -- Restack icon.
    self:SetToolbarButtonState(
      toolbarButtons.restack,
      nil,
      (
        self.multiplePartialStacks
        -- Items can go into a matching specialty bag.
        or self.specialtyMovesAvailable
        or (self.dockedInventory and self.dockedInventory.specialtyMovesAvailable)
        or (
                    -- Docked inventory has needs restack.
self.dockedInventory and self.dockedInventory.multiplePartialStacks
        )
      )
    )

    -- Show/Hide icon.
    self:SetToolbarButtonState(
      toolbarButtons.showHide,
      nil,
      (self.hasHiddenGroups or self.hasHiddenItems) and not self.editMode,
      self.showHidden,
      L.Toolbar_Hide_TooltipTitle,
      L.Toolbar_Show_TooltipTitle
    )

    -- Highlight Changes icon.
    self:SetToolbarButtonState(
      toolbarButtons.highlightChanges,
      nil,
      self.highlightChangesEnabled and not self.editMode,
      self.highlightChanges,
      L.Toolbar_UnHighlightChanges_TooltipTitle,
      L.Toolbar_HighlightChanges_TooltipTitle
    )

    -- Character icon.
    self:SetToolbarButtonState(
      toolbarButtons.character,
      nil,
      table.getn(BsCharacterData.characterIdList) > 1, -- Only enable when there's more than one character.
      self.activeCharacterId ~= Bagshui.currentCharacterId
    )

    -- Lock highlights for inventories when they're open.
    for inventoryType, _ in self:OtherInventoryTypesInToolbarIconOrder(true) do
      self:SetToolbarButtonState(toolbarButtons[inventoryType], nil, true, Bagshui.components[inventoryType]:Visible())
    end
    -- Catalog.
    self:SetToolbarButtonState(toolbarButtons.catalog, nil, true, BsCatalog:Visible())

    -- Refresh toolbar button colors in case they've changed.
    for _, button in pairs(toolbarButtons) do
      self.ui:SetIconButtonColors(button)
    end

    -- State buttons.
    self:SetToolbarButtonState(toolbarButtons.offline, not self.online)
    self:SetToolbarButtonState(toolbarButtons.error, (string.len(self.errorText or "") > 0))
    self:SetToolbarButtonState(toolbarButtons.editMode, self.editMode, nil, self.editMode)

    -- Error button needs its tooltip updated.
    toolbarButtons.error.bagshuiData.tooltipText = self.errorText

    -- Update status text.
    if self.editMode then
      -- Show active Structure profile name when editing.
      self.ui.text.status:SetText(
        NORMAL_FONT_COLOR_CODE
          .. string.format(L.Symbol_Colon, L.Profile_Structure)
          .. FONT_COLOR_CODE_CLOSE
          .. " "
          .. BsProfiles:GetName(self.settings.profileStructure)
      )
      self.ui.frames.status:Show()
      -- Move the offline character name into the tooltip in edit mode.
      toolbarButtons.offline.bagshuiData.tooltipText = GRAY_FONT_COLOR_CODE
        .. self.activeCharacterId
        .. FONT_COLOR_CODE_CLOSE
    else
      self.ui.text.status:SetText(self.activeCharacterId)
      if self.activeCharacterId ~= Bagshui.currentCharacterId then
        self.ui.frames.status:Show()
      else
        self.ui.frames.status:Hide()
      end
      -- Don't need the offline character name in the tooltip normally.
      toolbarButtons.offline.bagshuiData.tooltipText = nil
    end

    -- Money frame.
    if self.settings.showMoney then
      self.ui.frames.money:Show()
      self.ui.frames.money:SetAlpha(self.editMode and 0.2 or 1)
      -- Use label colors for money text.
      for _, text in pairs(self.ui.frames.money.bagshuiData.texts) do
        text:SetTextColor(
          self.settings.groupLabelDefault[1],
          self.settings.groupLabelDefault[2],
          self.settings.groupLabelDefault[3],
          self.settings.groupLabelDefault[4]
        )
      end
    else
      self.ui.frames.money:Hide()
    end

    -- Hearthstone button.
    if self.hearthButton and self.settings.showFooter and self.settings.showHearthstone and self.hearthstoneItemRef then
      toolbarButtons.hearthstone:Show()

      -- Display cooldown.
      local cooldownStart, cooldownDuration, isOnCooldown =
        _G.GetContainerItemCooldown(self.hearthstoneItemRef.bagNum, self.hearthstoneItemRef.slotNum)
      self.ui:SetIconButtonCooldown(toolbarButtons.hearthstone, cooldownStart, cooldownDuration, isOnCooldown)
    else
      toolbarButtons.hearthstone:Hide()
    end

    -- Clam (open container) button.
    self:SetToolbarButtonState(
      toolbarButtons.clam,
      (self.clamButton and self.settings.showClam or false),
      (
        self.hasOpenables
        and not self.editMode
        -- Don't allow at Bank because UseContainerItem() moves the item
        -- instead of opening it.
        and not Bagshui.components.Bank.atBank
        -- Avoid messing with item highlighting during a pending sale.
        and not self.itemPendingSale
      )
    )

    -- Disenchant button.
    self:SetToolbarButtonState(
      toolbarButtons.disenchant,
      (
        self.disenchantButton
          and BsCharacter.spellNamesToIds[toolbarButtons.disenchant.bagshuiData.spellName]
          and self.settings.showDisenchant
        or false
      ),
      not self.editMode
    )

    -- Pick Lock button.
    self:SetToolbarButtonState(
      toolbarButtons.pickLock,
      (
        self.pickLockButton
          and BsCharacter.spellNamesToIds[toolbarButtons.pickLock.bagshuiData.spellName]
          and self.settings.showPickLock
        or false
      ),
      not self.editMode
    )

    -- Utilization summaries.
    if
      self.alwaysShowUsageSummary
      and (not self.settings.showFooter or (self.settings.showFooter and not self.settings.showBagBar))
    then
      if self.settings.showFooter then
        self.ui.frames.miniSpaceSummaryBottom:Show()
        self.ui.frames.miniSpaceSummaryTop:Hide()
      else
        self.ui.frames.miniSpaceSummaryBottom:Hide()
        self.ui.frames.miniSpaceSummaryTop:Show()
      end
    else
      self.ui.frames.miniSpaceSummaryBottom:Hide()
      self.ui.frames.miniSpaceSummaryTop:Hide()
    end

    -- Re-anchor all toolbar widgets based on visibility.
    self:UpdateToolbarAnchoring("topLeftToolbar", "LEFT")
    self:UpdateToolbarAnchoring("topRightToolbar", "RIGHT")
    self:UpdateToolbarAnchoring("bottomRightToolbar", "RIGHT")

    -- Disable unusable stuff in Edit Mode.
    local editModeState = self.editMode and "Disable" or "Enable"
    -- Hearthstone
    if self.hearthButton then
      self.ui.buttons.toolbar.hearthstone[editModeState](self.ui.buttons.toolbar.hearthstone)
    end
    -- Search
    self.ui.buttons.toolbar.search[editModeState](self.ui.buttons.toolbar.search)

    -- Parent toolbar needs to sync state.
    if self.dockedToInventory then
      self.dockedToInventory:UpdateToolbar()
    end
  end

  --- Control the state and appearance of a toolbar button.
  ---@param button table Button object.
  ---@param visible boolean? Whether the button should be displayed.
  ---@param enable boolean? Whether the button should be enabled.
  ---@param lockHighlight boolean? Whether the button should be highlighted.
  ---@param lockedHighlightTooltip string? Tooltip title to display when the button highlight is locked.
  ---@param unlockedHighlightTooltip string? Tooltip title to display when the button highlight is unlocked.
  function Inventory:SetToolbarButtonState(
    button,
    visible,
    enable,
    lockHighlight,
    lockedHighlightTooltip,
    unlockedHighlightTooltip
  )
    if visible == nil then
      visible = true
    end
    button[visible and "Show" or "Hide"](button)

    if button.Enable then
      if enable == nil then
        enable = true
      end
      button[enable and "Enable" or "Disable"](button)
    end

    if button.LockHighlight then
      if lockHighlight then
        if lockedHighlightTooltip then
          button.bagshuiData.tooltipTitle = lockedHighlightTooltip
        end
        button:LockHighlight()
      else
        if unlockedHighlightTooltip then
          button.bagshuiData.tooltipTitle = unlockedHighlightTooltip
        end
        button:UnlockHighlight()
      end
    end

    -- Update tooltip if it's visible so that text stays current.
    if
      button.bagshuiData.isIconButton
      and button.bagshuiData.mouseIsOver
      and BsIconButtonTooltip:IsVisible()
      and BsIconButtonTooltip:IsOwned(button)
    then
      self.ui:ShowIconButtonTooltip(button, 0)
    end
  end

  --- Toolbar icons need their anchors updated based on what's shown.
  ---@param widgetOrderTable string Name of table in `self.ui.ordering`, which is an array of WoW UI widgets, in display order. Can also include numbers as spacing directives that override the default.
  ---@param anchorPoint "LEFT"|"RIGHT" Place to anchor each widget. This point will be anchored to the opposing point of the previous widget.
  function Inventory:UpdateToolbarAnchoring(widgetOrderTable, anchorPoint)
    local widgetList = self.ui.ordering[widgetOrderTable]
    local invert = (anchorPoint == "RIGHT" and -1 or 1)
    local defaultOffset = invert * BsSkin.toolbarSpacing
    local nextOffset

    -- Go through the list of widgets in order, but skip the first one since
    -- that's only there as the left/rightmost anchor.
    for widgetPosition = 2, table.getn(widgetList) do
      local widget = widgetList[widgetPosition]
      -- Ignore spacing directives when finding widgets.
      if type(widget) == "table" and widget:IsShown() then
        -- Assume default spacing, adjusted if customized for the widget.
        nextOffset = defaultOffset + (widget.bagshuiData and widget.bagshuiData.autoLayoutXOffset or 0)
        -- Walk backwards through the list of widgets and anchor to the first visible one.
        for anchorPosition = widgetPosition - 1, 1, -1 do
          if type(widgetList[anchorPosition]) ~= "table" then
            -- Spacing directive found. Use this instead of the default.
            if type(widgetList[anchorPosition]) == "number" then
              nextOffset = widgetList[anchorPosition]
            end
          else
            -- Check visibility and update anchoring.
            local anchorButton = widgetList[anchorPosition]
            if anchorButton:IsShown() then
              widget:SetPoint(anchorPoint, anchorButton, BsUtil.FlipAnchorPoint(anchorPoint), nextOffset, 0)
              break
            end
          end
        end -- Inner anchor finding loop.
      end
    end -- Widget iteration.
  end

  --- It seems like the client doesn't always catch situations where frames move out from
  --- under the cursor. When empty slots are expanded/collapsed, that's exactly what happens, so
  --- we have to manually hide the tooltip (handled in `ItemButton_OnClick()`) and we also need to determine
  --- if the mouse is over an item button **after** the UI is redrawn. To do that, `UpdateWindow()` queues a
  --- call to this function on the next frame update. Then we can evaluate whether the mouse is present,
  --- and if so, update the UI to reflect that.
  --- This is also an issue when picking up and putting down Categories/Groups/Items in Edit Mode,
  --- where we manually hide tooltips and need to make them reappear when something is put back down.
  function Inventory:ItemSlotAndGroupMouseOverCheck()
    local mouseOverFound = false
    for _, button in self.ui.buttons.itemSlots do
      -- The IsVisible() check is needed because item slot frames that are hidden will still return true for MouseIsOver().
      if _G.MouseIsOver(button) and button:IsVisible() then
        self:ItemButton_OnEnter(button)
        mouseOverFound = true
        break
      end
    end
    if self.editMode and not mouseOverFound then
      for _, group in self.ui.frames.groups do
        if _G.MouseIsOver(group) and group:IsVisible() then
          self:Group_OnEnter(group)
        end
      end
    end
  end

  --- Look through the inventory cache to find and record references to any special items.
  --- Currently only used for the Hearthstone.
  function Inventory:FindSpecialItems()
    -- Reset Hearthstone item tracking.
    self.hearthstoneItemRef = nil
    self.hideItems[BS_INVENTORY_HEARTHSTONE_ITEM_ID] = (
      self.hearthButton
      and self.settings.showHearthstone
      and self.settings.showFooter
    ) or nil

    for _, bagContents in pairs(self.inventory) do
      for __, item in ipairs(bagContents) do
        -- Check for Hearthstone.
        if self.hearthButton and item.id == BS_INVENTORY_HEARTHSTONE_ITEM_ID then
          self.hearthstoneItemRef = item
        end
      end
    end
  end

  --- Toggle an inventory class property.
  --- Used to display/hide hidden items, enable/disable highlighting of changes,
  --- maybe more in the future?
  ---@param propertyName any
  function Inventory:ToggleProperty(propertyName)
    if not propertyName then
      return
    end
    _G.PlaySound("igMainMenuOptionCheckBox" .. (self[propertyName] and "Off" or "On"))
    self[propertyName] = not self[propertyName]
    self:ForceUpdateWindow()

    if self.dockedInventory then
      self.dockedInventory:ToggleProperty(propertyName)
    end
  end
end)