local _G = ShaguTweaks.GetGlobalEnv()

-- Central capability layer for ClassicAPI / SuperWoW integration.
-- Keep feature checks here so individual modules don't scatter DLL-specific
-- detection logic all over the codebase.
ShaguTweaks.API = ShaguTweaks.API or {}
local API = ShaguTweaks.API

API.classicapi_version = tonumber(_G.CLASSIC_API_VERSION) or 0
API.classicapi = type(_G.C_NamePlate) == "table"
  or type(_G.C_Spell) == "table"
  or type(_G.C_UnitAuras) == "table"
  or type(_G.UnitGUID) == "function"

API.nameplates = type(_G.C_NamePlate) == "table"
  and type(_G.C_NamePlate.GetNamePlateForUnit) == "function"

API.casts = type(_G.C_Spell) == "table"
  and type(_G.C_Spell.UnitCastingInfo) == "function"
  and type(_G.C_Spell.UnitChannelInfo) == "function"

API.auras = type(_G.C_UnitAuras) == "table"
  and type(_G.C_UnitAuras.GetAuraDataByIndex) == "function"
  and type(_G.C_UnitAuras.GetDebuffDataByIndex) == "function"

API.spellinfo = type(_G.GetSpellInfo) == "function"

API.inventory = type(_G.C_Container) == "table"
  and type(_G.C_Container.GetContainerNumFreeSlots) == "function"

API.itemprice = type(_G.C_Item) == "table"
  and type(_G.C_Item.GetItemSellPriceByID) == "function"

API.merchant = type(_G.C_MerchantFrame) == "table"
  and type(_G.C_MerchantFrame.GetNumJunkItems) == "function"
  and type(_G.C_MerchantFrame.SellAllJunkItems) == "function"

API.playerstate = type(_G.IsMounted) == "function"
  and type(_G.Dismount) == "function"
  and type(_G.GetShapeshiftFormID) == "function"
  and type(_G.CancelShapeshiftForm) == "function"

API.unitguid = type(_G.UnitGUID) == "function"

API.chatidentity = type(_G.GetCurrentChatGUID) == "function"
  and type(_G.GetPlayerInfoByGUID) == "function"

API.playercache = type(_G.C_PlayerCache) == "table"
  and type(_G.C_PlayerCache.GetPlayerInfoByName) == "function"

-- SuperWoW remains optional. It can still provide useful extra cast/GUID
-- information, but ClassicAPI is the primary compatibility layer.
API.superwow = type(_G.SpellInfo) == "function"
  and type(_G.CombatLogAdd) == "function"

API.GetNamePlateForUnit = function(unit)
  if API.nameplates then
    return _G.C_NamePlate.GetNamePlateForUnit(unit)
  end
end

API.UnitCastingInfo = function(unit)
  if API.casts then
    return _G.C_Spell.UnitCastingInfo(unit)
  end
end

API.UnitChannelInfo = function(unit)
  if API.casts then
    return _G.C_Spell.UnitChannelInfo(unit)
  end
end

-- ShaguTweaks' castbar modules use the old 1.12-compatible seven-value shape.
-- Keep that public shape while sourcing the data from ClassicAPI first.
API.GetCastInfo = function(unit)
  if not API.casts then return end

  local name, displayName, texture, startTime, endTime, isTradeSkill,
    castID, notInterruptible, spellID = _G.C_Spell.UnitCastingInfo(unit)

  -- Remote channels seen after they started can have metadata but no timing.
  -- Castbars require start/end times, so only expose complete timing data here.
  if not name or not startTime or not endTime then return end

  return name, "", displayName or "", texture, startTime, endTime,
    isTradeSkill, castID, notInterruptible, spellID
end

API.GetChannelInfo = function(unit)
  if not API.casts then return end

  local name, displayName, texture, startTime, endTime, isTradeSkill,
    notInterruptible, spellID = _G.C_Spell.UnitChannelInfo(unit)

  if not name or not startTime or not endTime then return end

  return name, "", displayName or "", texture, startTime, endTime,
    isTradeSkill, notInterruptible, spellID
end

API.GetAuraDataByIndex = function(unit, index, filter)
  if API.auras then
    return _G.C_UnitAuras.GetAuraDataByIndex(unit, index, filter)
  end
end

API.GetDebuffDataByIndex = function(unit, index)
  if API.auras then
    return _G.C_UnitAuras.GetDebuffDataByIndex(unit, index)
  end
end

API.GetCurrentChatGUID = function()
  if API.chatidentity then
    return _G.GetCurrentChatGUID()
  end
end

API.GetPlayerInfoByGUID = function(guid)
  if API.chatidentity and guid then
    return _G.GetPlayerInfoByGUID(guid)
  end
end

-- Read-only bridge to ClassicAPI's optional persistent player cache.
-- ShaguTweaks never enables that cache or its visible-object scanner itself.
API.GetCachedPlayerInfoByName = function(name)
  if API.playercache and name then
    return _G.C_PlayerCache.GetPlayerInfoByName(name)
  end
end

API.GetSpellInfo = function(spell, bookType)
  if API.spellinfo then
    return _G.GetSpellInfo(spell, bookType)
  end
end

API.GetContainerNumFreeSlots = function(bag)
  if API.inventory then
    return _G.C_Container.GetContainerNumFreeSlots(bag)
  end
  return 0, 0
end

-- Returns the live vendor sell price in copper when the client has the item
-- cached. ClassicAPI warms uncached item data itself and returns nil until the
-- cache fill completes.
API.GetItemSellPriceByID = function(itemID)
  if API.itemprice and itemID then
    return _G.C_Item.GetItemSellPriceByID(itemID)
  end
end

local function GetVendorPriceCache()
  ShaguTweaks_cache = ShaguTweaks_cache or {}
  ShaguTweaks_cache["vendor_prices"] = ShaguTweaks_cache["vendor_prices"] or {}
  return ShaguTweaks_cache["vendor_prices"]
end

-- Persist only prices that add something to the original static database:
-- new Turtle/custom items or prices changed by Turtle WoW. This keeps the
-- per-character SavedVariables cache very small.
API.RememberVendorPrice = function(itemID)
  if not API.itemprice or type(itemID) ~= "number" then return end

  local price = API.GetItemSellPriceByID(itemID)
  if not price or price <= 0 then return end

  local learned = GetVendorPriceCache()
  local legacy = ShaguTweaks.SellValueLegacyDB or ShaguTweaks.SellValueDB
  local legacyPrice = legacy and legacy[itemID]

  if not legacyPrice or legacyPrice ~= price then
    learned[itemID] = price
  else
    -- Drop a now-redundant learned value if the bundled database caught up.
    learned[itemID] = nil
  end

  -- If the ClassicAPI proxy is already active, make this confirmed live value
  -- immediately available without another lookup during the current session.
  if ShaguTweaks.SellValueLegacyDB and ShaguTweaks.SellValueDB then
    rawset(ShaguTweaks.SellValueDB, itemID, price)
  end

  return price
end

-- Vendor Values keeps its original static database as the final fallback.
-- Resolution order is: current ClassicAPI value -> learned persistent value ->
-- bundled ShaguTweaks database.
API.PrepareVendorValues = function()
  if not API.itemprice or not ShaguTweaks.SellValueDB or ShaguTweaks.SellValueLegacyDB then
    return
  end

  local legacy = ShaguTweaks.SellValueDB
  local learned = GetVendorPriceCache()
  local live = {}

  setmetatable(live, {
    __index = function(tab, itemID)
      if type(itemID) ~= "number" then
        return legacy[itemID]
      end

      local price = API.GetItemSellPriceByID(itemID)
      if price and price > 0 then
        if not legacy[itemID] or legacy[itemID] ~= price then
          learned[itemID] = price
        else
          learned[itemID] = nil
        end

        rawset(tab, itemID, price)
        return price
      end

      local remembered = learned[itemID]
      if remembered and remembered > 0 then
        return remembered
      end

      return legacy[itemID]
    end
  })

  ShaguTweaks.SellValueLegacyDB = legacy
  ShaguTweaks.SellValueDB = live

  -- Vendor Values intentionally suppresses its own tooltip price while a
  -- merchant is open because the default UI already shows it there. Learn the
  -- ClassicAPI price from bag/merchant tooltips anyway so new Turtle items are
  -- available immediately after closing the merchant and after /reload.
  if not API.vendorprice_tooltip_hooks then
    API.vendorprice_tooltip_hooks = true

    local HookSetBagItem = GameTooltip.SetBagItem
    function GameTooltip.SetBagItem(self, container, slot)
      if MerchantFrame and MerchantFrame:IsShown() then
        local link = GetContainerItemLink(container, slot)
        local itemID = link and ShaguTweaks.GetItemIDFromLink(link)
        if itemID then API.RememberVendorPrice(itemID) end
      end
      return HookSetBagItem(self, container, slot)
    end

    local HookSetMerchantItem = GameTooltip.SetMerchantItem
    function GameTooltip.SetMerchantItem(self, merchantIndex)
      local link = GetMerchantItemLink(merchantIndex)
      local itemID = link and ShaguTweaks.GetItemIDFromLink(link)
      if itemID then API.RememberVendorPrice(itemID) end
      return HookSetMerchantItem(self, merchantIndex)
    end
  end
end

API.GetNumJunkItems = function()
  if API.merchant then
    return _G.C_MerchantFrame.GetNumJunkItems()
  end
  return 0
end

API.SellAllJunkItems = function()
  if API.merchant then
    return _G.C_MerchantFrame.SellAllJunkItems()
  end
end

API.IsMounted = function()
  return API.playerstate and _G.IsMounted() or false
end

API.Dismount = function()
  if API.playerstate then return _G.Dismount() end
end

API.GetShapeshiftFormID = function()
  if API.playerstate then return _G.GetShapeshiftFormID() end
  return 0
end

API.CancelShapeshiftForm = function()
  if API.playerstate then return _G.CancelShapeshiftForm() end
end

API.UnitGUID = function(unit)
  if API.unitguid then
    return _G.UnitGUID(unit)
  end
end