local addonName = ...

local EquippedItemLevel = CreateFrame("Frame")
_G[addonName] = EquippedItemLevel

local slots = {
	{ id = 1, frame = "CharacterHeadSlot" },
	{ id = 2, frame = "CharacterNeckSlot" },
	{ id = 3, frame = "CharacterShoulderSlot" },
	{ id = 5, frame = "CharacterChestSlot" },
	{ id = 6, frame = "CharacterWaistSlot" },
	{ id = 7, frame = "CharacterLegsSlot" },
	{ id = 8, frame = "CharacterFeetSlot" },
	{ id = 9, frame = "CharacterWristSlot" },
	{ id = 10, frame = "CharacterHandsSlot" },
	{ id = 11, frame = "CharacterFinger0Slot" },
	{ id = 12, frame = "CharacterFinger1Slot" },
	{ id = 13, frame = "CharacterTrinket0Slot" },
	{ id = 14, frame = "CharacterTrinket1Slot" },
	{ id = 15, frame = "CharacterBackSlot" },
	{ id = 16, frame = "CharacterMainHandSlot" },
	{ id = 17, frame = "CharacterSecondaryHandSlot" },
}

local itemLevels = {}
local updateQueued = false
local characterFrameHooked = false
local bagFrameHooks = {}
local equippedLowest, equippedHighest

local function GetCachedItemInfo(itemLink)
	if C_Item and C_Item.GetItemInfo then
		return C_Item.GetItemInfo(itemLink)
	end

	if GetItemInfo then
		return GetItemInfo(itemLink)
	end

	return nil
end

local function GetItemLevel(itemLink)
	if not itemLink then
		return nil
	end

	if C_Item and C_Item.GetDetailedItemLevelInfo then
		local level = C_Item.GetDetailedItemLevelInfo(itemLink)
		if level and level > 0 then
			return level
		end
	end

	local _, _, _, level = GetCachedItemInfo(itemLink)
	return level
end

local function GetGradientColor(level, lowest, highest)
	if lowest == highest then
		return 0, 1, 0
	end

	local progress = (level - lowest) / (highest - lowest)
	progress = math.max(0, math.min(1, progress))
	if progress <= 0.5 then
		return 1, progress * 2, 0
	end

	return 2 - progress * 2, 1, 0
end

local function IsGearItem(itemLink)
	if not itemLink then
		return false
	end

	local _, _, _, _, _, _, _, _, equipLocation = GetCachedItemInfo(itemLink)
	return equipLocation
		and equipLocation ~= ""
		and equipLocation ~= "INVTYPE_NON_EQUIP"
		and equipLocation ~= "INVTYPE_NON_EQUIP_IGNORE"
		and equipLocation ~= "INVTYPE_BAG"
		and equipLocation ~= "INVTYPE_TABARD"
end

local function CreateLabel(slot)
	local button = _G[slot.frame]
	if not button or button.EquippedItemLevelLabel then
		return
	end

	local label = button:CreateFontString(nil, "OVERLAY", "GameFontNormalSmall")
	label:SetPoint("BOTTOMRIGHT", button, "BOTTOMRIGHT", -2, 2)
	label:SetFont("Fonts\\FRIZQT__.TTF", 12, "OUTLINE")
	label:SetJustifyH("RIGHT")
	label:Hide()
	button.EquippedItemLevelLabel = label
end

function EquippedItemLevel:Update()
	updateQueued = false

	local lowest, highest
	for _, slot in ipairs(slots) do
		CreateLabel(slot)

		local itemLink = GetInventoryItemLink("player", slot.id)
		local level = GetItemLevel(itemLink)
		itemLevels[slot.id] = level

		if level then
			lowest = not lowest and level or math.min(lowest, level)
			highest = not highest and level or math.max(highest, level)
		end
	end

	equippedLowest, equippedHighest = lowest, highest

	for _, slot in ipairs(slots) do
		local button = _G[slot.frame]
		local label = button and button.EquippedItemLevelLabel
		local level = itemLevels[slot.id]

		if label and level and lowest and highest then
			local red, green, blue = GetGradientColor(level, lowest, highest)
			label:SetText(string.format("%.0f", level))
			label:SetTextColor(red, green, blue)
			label:Show()
		elseif label then
			label:Hide()
		end
	end

	self:UpdateBagLabels()
end

function EquippedItemLevel:QueueUpdate()
	if updateQueued then
		return
	end

	updateQueued = true
	C_Timer.After(0.1, function()
		EquippedItemLevel:Update()
	end)
end

function EquippedItemLevel:HookCharacterFrame()
	if characterFrameHooked or not CharacterFrame then
		return
	end

	CharacterFrame:HookScript("OnShow", function()
		EquippedItemLevel:QueueUpdate()
	end)
	characterFrameHooked = true
end

function EquippedItemLevel:UpdateBagButton(button)
	if not button or not button.GetBagID then
		return
	end

	local label = button.EquippedItemLevelBagLabel
	if not label then
		label = button:CreateFontString(nil, "OVERLAY", "GameFontNormalSmall")
		label:SetPoint("BOTTOMRIGHT", button, "BOTTOMRIGHT", -2, 2)
		label:SetFont("Fonts\\FRIZQT__.TTF", 11, "OUTLINE")
		label:SetJustifyH("RIGHT")
		button.EquippedItemLevelBagLabel = label
	end

	local bag, slot = button:GetBagID(), button:GetID()
	local itemLink = bag and slot and C_Container.GetContainerItemLink(bag, slot)
	local level = GetItemLevel(itemLink)
	if not level or not IsGearItem(itemLink) or not equippedLowest or not equippedHighest then
		label:Hide()
		return
	end

	local red, green, blue = GetGradientColor(level, equippedLowest, equippedHighest)
	label:SetText(string.format("%.0f", level))
	label:SetTextColor(red, green, blue)
	label:Show()
end

function EquippedItemLevel:UpdateContainerFrame(frame)
	if not frame then
		return
	end

	if frame.EnumerateValidItems then
		for _, button in frame:EnumerateValidItems() do
			self:UpdateBagButton(button)
		end
	elseif frame.Items then
		for _, button in ipairs(frame.Items) do
			self:UpdateBagButton(button)
		end
	end
end

function EquippedItemLevel:HookBagFrame(frame)
	if not frame or bagFrameHooks[frame] or not frame.Update then
		return
	end

	hooksecurefunc(frame, "Update", function(updatedFrame)
		EquippedItemLevel:UpdateContainerFrame(updatedFrame)
	end)
	bagFrameHooks[frame] = true
end

function EquippedItemLevel:UpdateBagLabels()
	local index = 1
	local frame = _G["ContainerFrame" .. index]
	while frame do
		self:HookBagFrame(frame)
		self:UpdateContainerFrame(frame)
		index = index + 1
		frame = _G["ContainerFrame" .. index]
	end

	if ContainerFrameCombinedBags then
		self:HookBagFrame(ContainerFrameCombinedBags)
		self:UpdateContainerFrame(ContainerFrameCombinedBags)
	end
end

local function AddTooltipItemLevel(tooltip, data)
	-- The same data is supplied for normal and comparison tooltips, including
	-- comparison panes that do not implement GameTooltip:GetItem().
	local itemReference = data and (data.hyperlink or data.id)
	if not itemReference or not IsGearItem(itemReference) then
		return
	end

	local level = GetItemLevel(itemReference)
	if not level then
		return
	end

	local red, green, blue = GetGradientColor(level, equippedLowest or level, equippedHighest or level)
	tooltip:AddDoubleLine("Item level", string.format("%.0f", level), 1, 0.82, 0, red, green, blue)
	tooltip:Show()
end

function EquippedItemLevel:OnEvent(event)
	if event == "PLAYER_LOGIN" then
		TooltipDataProcessor.AddTooltipPostCall(Enum.TooltipDataType.Item, AddTooltipItemLevel)

	end

	self:HookCharacterFrame()
	self:QueueUpdate()
end

EquippedItemLevel:RegisterEvent("PLAYER_LOGIN")
EquippedItemLevel:RegisterEvent("PLAYER_EQUIPMENT_CHANGED")
EquippedItemLevel:RegisterEvent("GET_ITEM_INFO_RECEIVED")
EquippedItemLevel:RegisterEvent("PLAYER_ENTERING_WORLD")
EquippedItemLevel:RegisterEvent("ADDON_LOADED")
EquippedItemLevel:RegisterEvent("BAG_UPDATE_DELAYED")
EquippedItemLevel:SetScript("OnEvent", EquippedItemLevel.OnEvent)