local E, L, V, P, G = unpack(ElvUI); --Import: Engine, Locales, PrivateDB, ProfileDB, GlobalDB

--Cache global variables
--Lua functions
local abs, floor, min, max = math.abs, math.floor, math.min, math.max
local match = string.match
--WoW API / Variables
local GetCVar, SetCVar = GetCVar, SetCVar

local scale

function E:UIScale(event)
	local width = E.screenwidth
	local height = E.screenheight

	local uiScaleCVar = GetCVar("uiScale")
	if uiScaleCVar then
		E.global.uiScale = uiScaleCVar
	end

	local minScale = E.global.general.minUiScale or 0.64
	if E.global.general.autoScale then
		scale = max(minScale, min(1.15, 768/height))
	else
		scale = max(minScale, min(1.15, E.global.uiScale or (height > 0 and (768/height)) or UIParent:GetScale()))
	end

	if width < 1600 then
			E.lowversion = true
	elseif width >= 3840 and E.global.general.eyefinity then
		-- because some user enable bezel compensation, we need to find the real width of a single monitor.
		-- I don't know how it really work, but i'm assuming they add pixel to width to compensate the bezel. :P

		-- HQ resolution
		if width >= 9840 then width = 3280 end										-- WQSXGA
		if width >= 7680 and width < 9840 then width = 2560 end					-- WQXGA
		if width >= 5760 and width < 7680 then width = 1920 end					-- WUXGA & HDTV
		if width >= 5040 and width < 5760 then width = 1680 end					-- WSXGA+

		-- adding height condition here to be sure it work with bezel compensation because WSXGA+ and UXGA/HD+ got approx same width
		if width >= 4800 and width < 5760 and height == 900 then width = 1600 end	-- UXGA & HD+

		-- low resolution screen
		if width >= 4320 and width < 4800 then width = 1440 end					-- WSXGA
		if width >= 4080 and width < 4320 then width = 1360 end					-- WXGA
		if width >= 3840 and width < 4080 then width = 1224 end					-- SXGA & SXGA (UVGA) & WXGA & HDTV

		-- yep, now set ElvUI to lower resolution if screen #1 width < 1600
		if width < 1600 then
			E.lowversion = true
		end

		-- register a constant, we will need it later for launch.lua
		E.eyefinity = width
	end

	E.mult = 768/height/scale
	E.Spacing = E.PixelMode and 0 or E.mult
	E.Border = (E.PixelMode and E.mult or E.mult*2)

	if E.global.general.autoScale then
		--Set UIScale, NOTE: SetCVar for UIScale can cause taints so only do this when we need to..
		if E.Round and event == "PLAYER_LOGIN" and (E:Round(UIParent:GetScale(), 5) ~= E:Round(scale, 5)) then
			SetCVar("useUiScale", 1)
			SetCVar("uiScale", scale)
		end

		--SetCVar for UI scale only accepts value as low as 0.64, so scale UIParent if needed
		if scale < 0.64 then
			UIParent:SetScale(scale)
		end
	end

	if event == "PLAYER_LOGIN" or (event == "CVAR_UPDATE" and arg1 == "USE_UISCALE") then
		--Resize E.UIParent if Eyefinity is on.
		if E.eyefinity then
			-- if autoscale is off, find a new width value of E.UIParent for screen #1.
			if not E.global.general.autoScale or height > 1200 then
				local h = UIParent:GetHeight()
				local ratio = height / h
				local w = width / ratio

				width = w
				height = h
			end
			--[[Eyefinity Test mode
				Resize the E.UIParent to be smaller than it should be, all objects inside should relocate.
				Dragging moveable frames outside the box and reloading the UI ensures that they are saving position correctly.
			]]
		else
			width = UIParent:GetWidth()
			height = UIParent:GetHeight()
		end

		E.UIParent:SetWidth(width)
		E.UIParent:SetHeight(height)
		E.UIParent:ClearAllPoints()
		E.UIParent:SetAllPoints(UIParent)

		E.diffGetLeft = E:Round(abs(UIParent:GetLeft() - E.UIParent:GetLeft()))
		E.diffGetRight = E:Round(abs(UIParent:GetRight() - E.UIParent:GetRight()))
		E.diffGetTop = E:Round(abs(UIParent:GetTop() - E.UIParent:GetTop()))
		E.diffGetBottom = E:Round(abs(UIParent:GetBottom() - E.UIParent:GetBottom()))

		local change
		if E.Round then
			change = abs((E:Round(UIParent:GetScale(), 5) * 100) - (E:Round(scale, 5) * 100))
		end

		if event == "CVAR_UPDATE" and arg1 == "USE_UISCALE" and change and change > 1 then
			if E.global.general.autoScale then
				E:StaticPopup_Show("FAILED_UISCALE")
			else
				E:StaticPopup_Show("CONFIG_RL")
			end
		end

		self:UnregisterEvent("PLAYER_LOGIN")
	end
end

-- pixel perfect script of custom ui scale.
function E:Scale(x)
	return E.mult*floor(x/E.mult+.5)
end