Bagshui/Components/Inventory.Cache.lua

-- Bagshui Inventory Prototype: Cache Management

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

  --- Primary cache management function that copies inventory contents into `self.inventory[bag][slot]`.
  ---
  --- Also responsible for deciding:
  --- * Whether resort/window update is required.
  --- * Item stock states (including saving/restoring when an items/bags are moved around).
  --- * If each empty slot is allowed to stack.
  --- * When toolbar icons that act on the inventory should be enabled (toolbar updates are performed in Inventory.layout.lua).
  function Inventory:UpdateCache()
    -- self:PrintDebug("UpdateCache()")

    -- Don't even try any updates until they're permitted.
    if not self.inventoryUpdateAllowed or not self.online then
      return
    end

    -- forceFullCacheUpdate should also satisfy any forceCacheUpdate condition.
    self.forceCacheUpdate = self.forceCacheUpdate or self.forceFullCacheUpdate

    -- If an update wasn't actually required, skip it.
    if not self.cacheUpdateNeeded and not self.forceCacheUpdate then
      return
    end

    -- If this was triggered by a bag change, wait for the next update.
    if self.lastEvent == "ITEM_LOCK_CHANGED" and BsUtil.TrueTableSize(self.lastUpdateLockedContainers) > 0 then
      BsUtil.TableClear(self.lastUpdateLockedContainers)
      -- Queuing another update here instead of completely ignoring to ensure that an update
      -- does happen eventually (and it should typically happen sooner than the delay here).
      self:QueueUpdate(0.1)
      return
    end

    self:PrintDebug("Updating inventory cache")

    -- We've passed the initial checks and can start preparing to update the cache.

    -- Reference to self.inventory[bagNum][slotNum].
    local item

    -- The `*Changes` variables are used to figure out what needs to occur be once this function has finished.

    -- New items added, items removed, counts changed, etc. Most commonly true of the three `*Changes` variables.
    local majorChanges = false
    -- Usually just means that an item has locked or unlocked.
    local cosmeticChanges = false
    -- Not currently used; used to be called `resort_suggested` in EngInventory. Leaving in case it comes in handy in the future.
    local minorChanges = false
    -- A slot's contents changed (anything beyond its locked state), so items need to be re-categorized.
    local itemChanges = false

    -- Track whether there are multiple partial stacks of the same item to decide whether the
    -- Restack button should be enabled.
    self.multiplePartialStacks = false

    -- Update this on every cache pass, since those happen fairly frequently.
    -- Used to determine whether change highlighting should be enabled.
    self.hasChanges = false

    -- Whether any item in the cache has the `_bagshuiPreventEmptySlotStack` property set to `true`
    -- Used by `ManageDryRun()` as a factor to determine whether `enableResortIcon` should be true.
    self.hasSlotsWithStackingPrevented = false

    -- Bag (outer loop) variables.
    local bagName, bagNumSlots, bagTexture, bagType, bagSlotLink, bagItemCode, bagInfo

    -- Slot (inner loop) variables.
    local itemReadable
    -- Used to compare current cache item and actual item now present in the slot
    local preCharges, preCount, preItemLink, preLocked, preItemString, preTooltip, nowCount, nowItemLink, nowLocked, nowCharges
    -- These two variables are used to maintain and restore from the stock state cache.
    -- (See Bagshui:PickupInventoryItem() for reasoning.)
    local shadowId, prevShadowId

    -- Reset tracking tables.
    if not self.lockOnlyChangedItems then
      self.lockOnlyChangedItems = {}
    end
    BsUtil.TableClear(self.lockOnlyChangedItems)
    BsUtil.TableClear(self.partialStacks)
    BsUtil.TableClear(self.emptyGenericContainerSlots)

    -- Identify any container changes triggered by moving bags between slots.
    if Bagshui.pickedUpBagSlotNum and Bagshui.putDownBagSlotNum then
      -- Container changes are only applicable if it's one of our containers.
      local pickedUpContainerId = self.inventoryIdsToContainerIds[Bagshui.pickedUpBagSlotNum]
      local putDownContainerId = self.inventoryIdsToContainerIds[Bagshui.putDownBagSlotNum]
      if pickedUpContainerId and putDownContainerId then
        self.pendingContainerChanges[pickedUpContainerId] = putDownContainerId
        self.pendingContainerChanges[putDownContainerId] = pickedUpContainerId
      end
    end
    local hasPendingContainerChanges = BsUtil.TrueTableSize(self.pendingContainerChanges) > 0

    -- Loop through bags.
    -- Using _bagIndex instead of _ as the throwaway variable for this loop because
    -- _ is used heavily within, and overwriting the loop variable can cause issues.
    for _bagIndex, bagNum in ipairs(self.containerIds) do
      -- Initialize bag cache if needed.
      if self.inventory[bagNum] == nil then
        self.inventory[bagNum] = {}
      end

      -- Get bag info.
      bagName = nil
      bagNumSlots = self:GetContainerNumSlots(bagNum) -- self:GetContainerNumSlots() intelligently handles this for for all container types.
      bagTexture = nil
      bagType = nil
      bagSlotLink = nil
      bagItemCode = nil
      if self.primaryContainer.id == bagNum then
        -- Can't pull primary container information from the API.
        bagName = self.primaryContainer.name
        bagTexture = self.primaryContainer.texture
        bagType = self.primaryContainer.name
      else
        bagName = _G.GetBagName(bagNum)
        bagSlotLink = _G.GetInventoryItemLink("player", _G.ContainerIDToInventoryID(bagNum))
        if bagSlotLink ~= nil then
          _, _, bagItemCode = string.find(bagSlotLink, "(%d+):")
          _, _, _, _, _, bagType, _, _, bagTexture = _G.GetItemInfo(bagItemCode)
        end
      end

      -- Keep track of whether this bag got locked to help coordinate bag change updates after it's unlocked.
      self.lastUpdateLockedContainers[bagNum] = _G.IsInventoryItemLocked(_G.ContainerIDToInventoryID(bagNum))

      -- No reason to store full texture paths since they're always in Interface\Icons.
      bagTexture = bagTexture

      -- self.containers[bagNum] always already exists in SavedVariables or has been
      -- initialized to {} during Inventory:Init().
      bagInfo = self.containers[bagNum]

      bagInfo.bagNum = bagNum

      -- Bag has changed or isn't initialized.
      if
        self.pendingContainerChanges[bagNum]
        or bagInfo.name ~= bagName
        or bagInfo.numSlots ~= bagNumSlots
        or bagInfo.texture ~= bagTexture
        or bagInfo.type ~= bagType
        or (
                    -- Need to check for numSlots > 0 to avoid constantly rebuilding container info for empty bag slots
bagInfo.numSlots > 0 and (not bagInfo.name or not bagInfo.type)
        )
        or self.initialInventoryUpdateNeeded
      then
        -- When the bag changes after startup, wipe its cache.
        if (bagInfo.numSlots or 0) > 0 and not self.initialInventoryUpdateNeeded then
          BsUtil.TableClear(self.inventory[bagNum])
        end
        bagInfo.name = bagName
        bagInfo.numSlots = bagNumSlots
        bagInfo.texture = bagTexture
        bagInfo.type = bagType

        -- isProfessionBag and genericType are used primarily for empty slot stacking.
        -- Anything that isn't a normal bag class and isn't the primary container
        -- is going to be considered a profession bag.
        bagInfo.isProfessionBag = (
          bagType ~= BsGameInfo.itemSubclasses["Container"]["Bag"] and bagType ~= self.primaryContainer.name
        )

        -- A bag's "generic type" is the the item class returned by GetItemInfo for profession
        -- bags or the localized version of "Bag" for any other bag and the primary container.
        bagInfo.genericType = bagInfo.isProfessionBag and bagInfo.type or BsGameInfo.itemSubclasses["Container"]["Bag"]

        -- Bag changes require a resort even if the window is visible.
        self.forceResort = true
      end

      -- Reset tracking of filled slots.
      self.containers[bagNum].slotsFilled = 0

      -- Make sure this bag has slots to process.
      if bagNumSlots > 0 then
        -- Prepare to stack empty slots (actual stacking is handled during UpdateWindow()).
        self:InitializeEmptySlotStackTracking(bagInfo)

        -- Time to go through all the bag slots and look at each item.
        for slotNum = 1, bagNumSlots do
          shadowId = nil
          prevShadowId = nil

          -- Initialize this slot in the cache when it doesn't exist yet.
          -- Using table.insert here to ensure table.getn() works correctly.
          if table.getn(self.inventory[bagNum]) < slotNum then
            table.insert(self.inventory[bagNum], {})
            BsItemInfo:InitializeItem(self.inventory[bagNum][slotNum])
          end

          item = self.inventory[bagNum][slotNum]

          -- Store previous information so we can determine whether changes occurred.
          preItemLink = item.itemLink
          preItemString = item.itemString
          preCharges = item.charges or 0
          preCount = item.count or 0
          preLocked = item.locked
          preTooltip = item.tooltip

          -- Get current item information.
          nowItemLink = _G.GetContainerItemLink(bagNum, slotNum)
          -- Ignoring quality (return value 4) from GetContainerItemInfo because
          -- it sometimes returns -1, which according to https://warcraft.wiki.gg/index.php?title=API_GetContainerItemInfo&oldid=2497880
          -- means it's somehow special (stackable, unique or a quest item).
          -- We'll obtain it from GetItemInfo() instead. (We also don't need
          -- texture since that will be obtained during ItemInfo:Get()).
          _, nowCount, nowLocked, _, itemReadable = _G.GetContainerItemInfo(bagNum, slotNum)
          -- The API returns 1/nil (or true/false), but the cache stores 1/0 (BS_ITEM_SKELETON.locked).
          -- Without this, `preLocked ~= nowLocked` was true (0 ~= nil) for every unlocked slot, so every
          -- cache update re-read item info and re-scanned the tooltip of every slot.
          nowLocked = (nowLocked and nowLocked ~= 0) and 1 or BS_ITEM_SKELETON.locked

          -- Update filled slot count for this container.
          if nowItemLink ~= nil then
            self.containers[bagNum].slotsFilled = self.containers[bagNum].slotsFilled + 1
          end

          -- If count was nil, set it to 0 so that the cache isn't constantly getting
          -- re-processed (otherwise preCount won't equal nowCount for empty slots).
          nowCount = nowCount or 0

          -- Assume there are no charges. This property will be filled either by Bagshui's
          -- native tooltip charges parsing in ItemInfo:GetTooltip() or just below
          -- if SuperWoW is loaded. Making item.charges not equal preCharges is also the
          -- trigger for native charges parsing when the item doesn't change.
          item.charges = 0
          nowCharges = 0

          -- Item charges from SuperWoW: move negative item counts, which indicate charges, into the charges field.
          if nowCount < 0 then
            nowCharges = math.abs(nowCount)
            item.charges = nowCharges
            nowCount = 1
          end

          -- ClassicAPI reports charges directly, so Bagshui doesn't have to depend on
          -- SuperWoW's negative item counts or tooltip parsing. Only ask for filled slots,
          -- and don't override charges already obtained above.
          -- (Note that C_Container.GetContainerItemInfo() reports a count of 1 for charged
          -- items, which is why the count above still comes from GetContainerItemInfo().)
          if nowCharges == 0 and nowItemLink ~= nil then
            local apiCharges = _G.C_Container.GetContainerItemCharges(bagNum, slotNum)
            apiCharges = apiCharges and tonumber(apiCharges)
            if apiCharges and apiCharges > 0 then
              nowCharges = apiCharges
              item.charges = apiCharges
            end
          end

          -- Only the locked state changed (an item was picked up, put down, or is moving between
          -- bags and bank): record it without re-reading item info or the tooltip, and without
          -- flagging the slot as changed for categorization. The window still redraws (see the
          -- `cosmeticChanges` check below) so the item turns gray/normal.
          if
            preLocked ~= nowLocked
            and preItemLink == nowItemLink
            and item.bagNum ~= nil
            and preCount == nowCount
            and preTooltip == item.tooltip
            and not self.initialInventoryUpdateNeeded
            and not self.pendingContainerChanges[bagNum]
            and not item._getItemInfoFailed
            and not self.forceFullCacheUpdate
          then
            item.locked = nowLocked
            self.lockOnlyChangedItems[item] = true
          -- Process item if there are changes.
          elseif
            preItemLink ~= nowItemLink -- Item has changed.
            or item.bagNum == nil -- AddItemBagInfo() hasn't been called on this slot yet.
            or preLocked ~= nowLocked -- Locked/unlocked.
            or preCount ~= nowCount -- Count has changed (changes to charges are checked separately).
            or preTooltip ~= item.tooltip
            or self.initialInventoryUpdateNeeded
            or self.pendingContainerChanges[bagNum]
            or item._getItemInfoFailed -- Item was flagged as requiring a refresh.
            or self.forceFullCacheUpdate -- Update even items that may not appear to need it.
          then
            -- Clear the failure flag (see explanation just below the call to ItemInfo:Get()).
            item._getItemInfoFailed = nil
            itemChanges = true

            -- Bag information is needed regardless of whether the slot is empty (bagNum, slotNum, bagType).
            -- This must happen before calling ItemInfo:Get() so that bagNum/slotNum are available.
            self:AddItemBagInfo(item, bagInfo)
            item.slotNum = slotNum

            -- Populate basic item information.
            if
              not BsItemInfo:Get(
                nowItemLink, -- itemIdentifier
                item, -- itemInfoTable
                false, -- initialize
                (preItemLink ~= nowItemLink), -- reinitialize
                false, -- forceIntoLocalGameCache
                self -- Inventory class instance
              )
            then
              -- If GetItemInfo() returns nil, ItemInfo:Get() will return false. When this occurs,
              -- bail and rely on cached inventory data until the next update attempt. This should only
              -- happen during the first second or two after login, so we do delay the initial inventory
              -- cache update to attempt to account for this. However, it's still safest to keep the
              -- check in place.

              -- Add a flag to this item's cache entry so we know that it absolutely has to be refreshed
              -- next time around.
              item._getItemInfoFailed = true
              return
            end

            -- Need to store different data for filled vs. empty slots.
            if item.itemString ~= nil then
              -- Slot contains an item.
              item.count = nowCount
              item.locked = nowLocked or BS_ITEM_SKELETON.locked
              item.readable = itemReadable or BS_ITEM_SKELETON.readable
              -- We got charges from GetContainerItemInfo() and need to restore
              -- because ItemInfo:Get() might have wiped them.
              if nowCharges > 0 then
                item.charges = nowCharges
              end
            else
              -- Slot is empty.
              BsItemInfo:InitializeEmptySlotItem(item)
              if self.containers[bagNum].isProfessionBag then
                item.name = item.bagType .. " " .. item.name
              end

              -- Slot has just become empty - don't allow it to collapse back
              -- into the stack until re-sorting occurs.
              if preItemLink ~= nowItemLink then
                item._bagshuiPreventEmptySlotStack = true
              end
            end

            -- Check for stock state changes.
            if
              item.itemString ~= nil
              and not self.freshCache
              -- Nothing has actually changed if the item was just picked up and put back down.
              and Bagshui.lastCursorItemUniqueId ~= BsItemInfo:GetUniqueItemId(item)
            then
              if item.itemString ~= preItemString and item.bagshuiDate == -1 then
                -- Item itself has changed, so flag it as new.
                item._proposedStockState = BS_ITEM_STOCK_STATE.NEW
                item._proposedDate = _G.time()

                -- Enable resorting because an item DID change.
                -- Even if the stock state change isn't approved, resort may be needed.
                majorChanges = true
              elseif item.itemString == preItemString and item.count ~= preCount and preCount ~= -1 then
                -- Item has not changed, but count did, so stock state needs to be updated.
                if item.count > preCount then
                  item._proposedStockState = BS_ITEM_STOCK_STATE.UP
                else
                  item._proposedStockState = BS_ITEM_STOCK_STATE.DOWN
                end
                item._proposedDate = _G.time()

                -- Also enable resorting since count is usually a sort property.
                -- This isn't dependent on the stock change being approved since the item
                -- slot count DID change, which can require a resort.
                majorChanges = true
              elseif
                self.initialInventoryUpdateNeeded
                and Bagshui.currentCharacterData.lastLogout
                and (item.bagshuiDate or 0) > 0
              then
                -- Just logged in, so move item dates forward by the amount of time since this
                -- character last logged out. This makes it so that only in-game time is counted.
                item.bagshuiDate = item.bagshuiDate + (_G.time() - Bagshui.currentCharacterData.lastLogout)
              end
            end
          elseif
            not BS_SUPER_WOW_LOADED
            and preCharges ~= item.charges
            -- Tooltip gets loaded earlier when a full cache update happens.
            and not self.forceFullCacheUpdate
          then
            -- None of the "big" changes happened to trigger a call to ItemInfo:Get(),
            -- but the item had some number of charges that we parsed from the tooltip
            -- previously, so we need to refresh it.
            -- (Normally the call to GetTooltip() happens automatically within ItemInfo:Get().)
            BsItemInfo:GetTooltip(item, self)
          end -- Item changes check.

          -- Add to empty slot tracking table. This list is rebuilt on every cache update, so it has
          -- to cover unchanged empty slots too (not just slots that changed in this update).
          -- See `Inventory:SwapBag()` comments regarding the exclusion of profession bags.
          if item.emptySlot == 1 and bagInfo.genericType == BsGameInfo.itemSubclasses["Container"]["Bag"] then
            table.insert(self.emptyGenericContainerSlots, item)
          end

          -- When charges has changed, a re-sort is probably needed.
          -- This check is here so that it works for both SuperWoW and native charges parsing.
          if item.charges ~= preCharges then
            majorChanges = true
          end

          -- Build "shadow" IDs for non-empty slots. (See comment above the declaration of shadowId for full explanation.)
          if item.emptySlot ~= 1 then
            shadowId = BsItemInfo:GetUniqueItemId(item)

            -- Determine whether a restoration of stock state is required.
            if self.pendingContainerChanges[bagNum] then
              -- Bag swap.
              prevShadowId = BsItemInfo:GetUniqueItemId(item, self.pendingContainerChanges[bagNum])
            elseif
              Bagshui.pickedUpItemBagNum
              and Bagshui.pickedUpItemSlotNum
              and self.myContainerIds[Bagshui.pickedUpItemBagNum]
              and Bagshui.putDownItemBagNum
              and Bagshui.putDownItemSlotNum
              and self.myContainerIds[Bagshui.putDownItemBagNum]
              and (
                (item.bagNum == Bagshui.pickedUpItemBagNum and item.slotNum == Bagshui.pickedUpItemSlotNum)
                or (item.bagNum == Bagshui.putDownItemBagNum and item.slotNum == Bagshui.putDownItemSlotNum)
              )
            then
              -- Item moved.
              if item.bagNum == Bagshui.pickedUpItemBagNum and item.slotNum == Bagshui.pickedUpItemSlotNum then
                prevShadowId = BsItemInfo:GetUniqueItemId(item, Bagshui.putDownItemBagNum, Bagshui.putDownItemSlotNum)
              else
                prevShadowId = BsItemInfo:GetUniqueItemId(item, Bagshui.pickedUpItemBagNum, Bagshui.pickedUpItemSlotNum)
              end
            end
          end

          -- Reasons to restore or clear the item stock state.
          if prevShadowId and self.shadowStockState[prevShadowId] then
            -- Restore stock state from the item's most recent location after a container move.
            -- (See Bagshui:PickupInventoryItem() for reasoning).
            item.bagshuiDate = (self.shadowBagshuiDate[prevShadowId] or 0)
            item.bagshuiStockState = self.shadowStockState[prevShadowId]
          elseif item.bagshuiDate == -1 then
            -- -1 means to clear the stock state.
            -- Among other things, this can be triggered by Inventory:ItemButton_OnClick().
            item.bagshuiDate = 0
            item.bagshuiStockState = BS_ITEM_STOCK_STATE.NO_CHANGE
          end

          -- Update partial stack tracking.
          if item.count < (tonumber(item.maxStackCount) or 0) then
            if self.partialStacks[item.id] == nil then
              self.partialStacks[item.id] = 1
            else
              self.partialStacks[item.id] = self.partialStacks[item.id] + 1
              self.multiplePartialStacks = true
            end
          end

          -- Item isn't assigned to a group, so resort is required.
          if item.bagshuiGroupId == "" then
            majorChanges = true
          end

          -- Locked status has changed, so an update is a good idea.
          if item.locked ~= preLocked then
            cosmeticChanges = true
          end

          -- Clean up any vestigial properties at startup.
          if self.initialInventoryUpdateNeeded then
            for key, _ in pairs(item) do
              if BS_ITEM_SKELETON[key] == nil then
                item[key] = nil
              end
            end
          end

          -- Update the "shadow" stock state cache, but only if all pending
          -- changes are cleared so that we don't overwrite anything too soon.
          -- (See Bagshui:PickupInventoryItem() for reasoning.)
          if shadowId and not hasPendingContainerChanges then
            self.shadowBagshuiDate[shadowId] = item.bagshuiDate
            self.shadowStockState[shadowId] = item.bagshuiStockState
          end

          -- Update item counts for use in stock state rectification.
          if item.itemString then
            if not self.postUpdateItemCounts[item.itemString] then
              self.postUpdateItemCounts[item.itemString] = 0
            end
            self.postUpdateItemCounts[item.itemString] = self.postUpdateItemCounts[item.itemString] + item.count
          end
        end -- Item slot loop within each bag.
      else
        -- There are no slots, so wipe the cache for this bag.
        -- self:PrintDebug("no slots in bag "..bagNum.." wiping cache")
        if table.getn(self.inventory[bagNum]) ~= 0 then
          majorChanges = true
        end
        BsUtil.TableClear(self.inventory[bagNum])
      end
    end -- Bag [container] loop.

    -- Post-update stock state rectification.
    -- Only allow changes to stock state when they make sense at an inventory level,
    -- not just because an individual slot changed.
    for _, container in pairs(self.inventory) do
      for _, item in pairs(container) do
        if
          item._proposedStockState
          and (
            (
                            -- Down: New count must be less than old count.
item._proposedStockState == BS_ITEM_STOCK_STATE.DOWN
              and self.postUpdateItemCounts[item.itemString] < (self.preUpdateItemCounts[item.itemString] or 0)
            )
            or (
                            -- New/Up: New count must be greater than old count.
item._proposedStockState ~= BS_ITEM_STOCK_STATE.DOWN
              and self.postUpdateItemCounts[item.itemString] > (self.preUpdateItemCounts[item.itemString] or 0)
            )
          )
        then
          -- self:PrintDebug(item.name .. " proposed " .. tostring(item._proposedStockState) .. " " .. tostring(self.preUpdateItemCounts[item.itemString]) .. " -> " .. tostring(self.postUpdateItemCounts[item.itemString]) .. " approved")
          item.bagshuiStockState = item._proposedStockState
          item.bagshuiDate = item._proposedDate
          -- elseif item._proposedStockState then
          -- self:PrintDebug(item.name .. " proposed " .. tostring(item._proposedStockState) .. " " .. tostring(self.preUpdateItemCounts[item.itemString]) .. " -> " .. tostring(self.postUpdateItemCounts[item.itemString]) .. " DENIED")
        end
        item._proposedStockState = nil
        item._proposedDate = nil
        item._allowStockStateChange = nil

        -- Update tracking of whether there are highlight-able items.
        if item.bagshuiStockState ~= BS_ITEM_STOCK_STATE.NO_CHANGE then
          self.hasChanges = true
        end

        -- Update tracking of empty slots peeled off the stack.
        if item._bagshuiPreventEmptySlotStack then
          self.hasSlotsWithStackingPrevented = true
        end
      end
    end
    -- This update cycle's post-update counts become next cycle's pre-update counts.
    BsUtil.TableCopy(self.postUpdateItemCounts, self.preUpdateItemCounts)
    BsUtil.TableClear(self.postUpdateItemCounts)

    -- Store resort/update status for use by Update() and friends in Inventory.Layout.lua.
    if majorChanges then
      self.resortNeeded = true
      self.windowUpdateNeeded = true
    elseif minorChanges then
      self.resortNeeded = self.resortNeeded or false
      self.windowUpdateNeeded = true
    elseif cosmeticChanges then
      self.windowUpdateNeeded = true
    end
    self.cacheChanged = (majorChanges or cosmeticChanges or minorChanges)
    -- Lock-only (cosmetic) changes redraw the window but don't need every item re-categorized.
    self.cacheNeedsCategorize = (majorChanges or minorChanges or itemChanges)
    -- Nothing but items locking/unlocking: Update() can refresh just those buttons.
    self.cacheOnlyLockChanges = (cosmeticChanges and not self.cacheNeedsCategorize) and true or false

    -- Make sure we don't do a full cache rebuild again.
    self.initialInventoryUpdateNeeded = false

    -- Item stock states can now be tracked.
    self.freshCache = false

    -- Reset cache flags.
    self.cacheUpdateNeeded = false
    self.forceCacheUpdate = false
    self.forceFullCacheUpdate = false

    -- Reset triggers for container-change based stock state restoration.
    -- (See Bagshui:PickupInventoryItem() for reasoning.)
    if hasPendingContainerChanges and Bagshui.pickedUpBagSlotNum and Bagshui.putDownBagSlotNum then
      Bagshui.pickedUpBagSlotNum = nil
      Bagshui.putDownBagSlotNum = nil
      BsUtil.TableClear(self.pendingContainerChanges)
    end

    -- Raise change event.
    if majorChanges or minorChanges or cosmeticChanges then
      Bagshui:RaiseEvent("BAGSHUI_INVENTORY_CACHE_UPDATE")
    end
  end

  --- Smart version of GetContainerNumSlots that will switch functions if it's
  --- a special container that requires a different function.
  ---@param bagNum integer Container number for which to get the slot count.
  ---@return integer bagSlotCount
  function Inventory:GetContainerNumSlots(bagNum)
    local bagNumSlotsFunction = _G.GetContainerNumSlots
    if self.primaryContainer.numSlotsFunction and self.primaryContainer.id == bagNum then
      bagNumSlotsFunction = self.primaryContainer.numSlotsFunction
    end
    return bagNumSlotsFunction(bagNum)
  end

  --- Add bag information to the given cache item.
  ---@param item table self.inventory cache entry.
  ---@param bagInfo table self.containers entry.
  ---@param isEmptySlotStack boolean? true if this slot
  function Inventory:AddItemBagInfo(item, bagInfo, isEmptySlotStack)
    item.bagNum = bagInfo.bagNum
    -- Empty slot stack proxy items expected to have their "generic type" as their bagType
    -- instead of the value returned by GetItemInfo() for the bag. This is needed
    -- so that profession bag slots can be named properly in InitializeEmptySlotItem().
    item.bagType = isEmptySlotStack and bagInfo.genericType or bagInfo.type
  end

  --- Prepare an entry in the emptySlotStacks table for to track the empty slot count for a given bag.
  ---@param bagInfo table self.containers entry.
  function Inventory:InitializeEmptySlotStackTracking(bagInfo)
    if not bagInfo.genericType then
      return
    end

    if not self.emptySlotStacks[bagInfo.genericType] then
      self.emptySlotStacks[bagInfo.genericType] = {}
    end

    -- Always re-initialize when called to ensure bag changes don't result in incorrect empty slot textures.
    BsItemInfo:InitializeItem(self.emptySlotStacks[bagInfo.genericType])
    self:AddItemBagInfo(self.emptySlotStacks[bagInfo.genericType], bagInfo, true)
    BsItemInfo:InitializeEmptySlotItem(self.emptySlotStacks[bagInfo.genericType], true)
  end
end)