local T, C, L = unpack(ShestakUI)
if C.unitframe.enable ~= true or C.unitframe.plugins_fader ~= true then return end

----------------------------------------------------------------------------------------
--	Based on oUF_Fader(by Slakah)
----------------------------------------------------------------------------------------
local _, ns = ...
local oUF = ns.oUF

local strmatch, gmatch = string.match, string.gmatch
local objects, addon = {}, CreateFrame("Frame")

-- Events
local events = setmetatable({
	Combat = "PLAYER_REGEN_ENABLED:PLAYER_REGEN_DISABLED",
	PlayerTarget = "PLAYER_TARGET_CHANGED",
	PlayerHostileTarget = "PLAYER_TARGET_CHANGED",
	UnitTarget = "UNIT_TARGET",
	UnitHostileTarget = "UNIT_TARGET",
	Resting = "PLAYER_UPDATE_RESTING",
	Flying = "UNIT_FLAGS",
	PlayerTaxi = "UNIT_FLAGS",
	UnitTaxi = "UNIT_FLAGS",
	PlayerMaxHealth = "UNIT_HEALTH",
	UnitMaxHealth = "UNIT_HEALTH",
	PlayerMaxMana = "UNIT_POWER_UPDATE",
	UnitMaxMana = "UNIT_POWER_UPDATE",
	Stealth = "UPDATE_STEALTH",
	PlayerNotMaxHealth = "UNIT_HEALTH",
	PlayerNotMaxMana = "UNIT_POWER_UPDATE",
	Casting = "UNIT_SPELLCAST_START:UNIT_SPELLCAST_FAILED:UNIT_SPELLCAST_STOP:UNIT_SPELLCAST_INTERRUPTED:UNIT_SPELLCAST_CHANNEL_START:UNIT_SPELLCAST_CHANNEL_STOP",
	Arena = "ZONE_CHANGED_NEW_AREA",
	Instance = "PLAYER_ENTERING_WORLD",
}, {__index = function(events, k)
	local cond = strmatch(k, "not(.+)")
	assert(rawget(events, cond), format("Missing event for condition %s", k))
	events[k] = events[cond]
	return events[cond]
end})

-- Conditions
local conditions = setmetatable({
	PlayerHostileTarget = function() return UnitCanAttack("player", "target") end,
	UnitHostileTarget = function(_, unit) return unit and UnitCanAttack(unit, unit.."target") end,
	PlayerTarget = function() return UnitExists("target") end,
	UnitTarget = function(_, unit) return unit and UnitExists(unit.."target") end,
	PlayerTaxi = function() return UnitOnTaxi("player") end,
	UnitTaxi = function(_, unit) return unit and UnitOnTaxi(unit) end,
	UnitMaxHealth = function(_, unit) return unit and (not UnitIsDeadOrGhost(unit) or UnitIsFeignDeath(unit)) and UnitHealth(unit) == UnitHealthMax(unit) end,
	PlayerMaxHealth = function(_, unit) return unit and not UnitIsDeadOrGhost("player") and UnitHealth("player") == UnitHealthMax("player") end,
	UnitMaxMana = function(_, unit) return unit and not (not UnitIsDeadOrGhost(unit) or UnitIsFeignDeath(unit)) and UnitPower(unit) == UnitPowerMax(unit) end,
	PlayerMaxMana = function(_, unit) return unit and not UnitIsDeadOrGhost("player") and UnitPower("player") == UnitPowerMax("player") end,
	Stealth = IsStealthed,
	Flying = IsFlying,
	Resting = IsResting,
	Combat = InCombatLockdown,
	PlayerNotMaxHealth = function(_, unit) return unit and UnitHealth("player") ~= UnitHealthMax("player") end,
	PlayerNotMaxMana = function(_, unit)
		local _, powerTypeString = UnitPowerType("player")
		if powerTypeString ~= "RAGE" and powerTypeString ~= "RUNIC_POWER" then
			return unit and UnitPower("player") ~= UnitPowerMax("player")
		end
	end,
	Casting = function(_, unit) return unit and (UnitCastingInfo(unit) or UnitChannelInfo(unit)) end,
	Arena = function(_, unit) return unit and GetZonePVPInfo() == "arena" end,
	Instance = function(_, unit) return unit and IsInInstance() == true end,
}, {__index = function(t, k)
	local cond = strmatch(k, "not(.+)")
	assert(rawget(t, cond), format("Missing condition %s", k))
	t[k] = function(...)
		return not t[cond](...)
	end
	return t[k]
end})

function addon:RegisterCondition(name, func, event)
	assert(type(name) == "string", format("Bad argument #1 to \"RegisterCondition\" (string expected, got %s)", type(name)))
	assert(type(func) == "function", format("Bad argument #2 to \"RegisterCondition\" (function expected, got %s)", type(func)))
	assert(type(event) == "string", format("Bad argument #3 to \"RegisterCondition\" (string expected, got %s)", type(event)))

	conditions[name] = func
	events[name] = event
end

-- Update the Alpha or obj
local function UpdateAlpha(obj)
	local alpha
	for _, tbl in ipairs(obj.Fader) do
		for cond, condalpha in pairs(tbl) do
			if conditions[cond](obj, obj.unit) then
				alpha = not alpha and condalpha or condalpha > alpha and condalpha or alpha
			end
		end
		if alpha then
			break
		end
	end

	alpha = alpha or obj.NormalAlpha
	if obj.Range then
		obj.inRangeAlpha = alpha
		obj.outsideRangeAlpha = alpha * obj.outsideRangeAlphaPerc
	end

	obj:SetAlpha(alpha)
	obj:SetScript("OnEnter", function(self) self:SetAlpha(1) UnitFrame_OnEnter(obj) end)
	obj:SetScript("OnLeave", function(self) self:SetAlpha(alpha) UnitFrame_OnLeave(obj) end)
end

local t = 0
local function OnUpdate(addon, el) -- I do this because it's easier than passing events to conditions
	t = t + el
	if t > 0.1 then
		t = 0
		for _, v in ipairs(objects) do
			UpdateAlpha(v)
		end
		addon:Hide()
	end
end

oUF:RegisterInitCallback(
	function(obj)
		local F = obj.Fader
		if F then
			for _, tbl in ipairs(F) do
				for name in pairs(tbl) do
					for event in gmatch(events[name], "[^:]+") do
						addon:RegisterEvent(event)
					end
				end
			end

			obj.NormalAlpha = obj.NormalAlpha or obj:GetAlpha()
			obj.outsideRangeAlphaPerc = obj.outsideRangeAlphaPerc or obj.outsideRangeAlpha
			UpdateAlpha(obj)
			objects[#objects + 1] = obj
		end
	end
)
addon:SetScript("OnEvent", addon.Show)
addon:SetScript("OnUpdate", OnUpdate)

addon.Conditions = conditions
addon.Events = events
oUF.Fader = addon