local Chorus = Chorus

local auraButtonEventProcessor = Chorus.auraButtonEventProcessor

local UnitAura = Chorus.test.UnitAura or UnitAura
local UnitExists = Chorus.test.UnitExists or UnitExists
local UnitIsConnected = Chorus.test.UnitIsConnected or UnitIsConnected

local SecureButton_GetUnit = Chorus.test.SecureButton_GetUnit or SecureButton_GetUnit

--[[ See `FrameXML/BuffFrame.lua:BUFF_MAX_DISPLAY`. ]]--
local BUFF_MAX_DISPLAY = BUFF_MAX_DISPLAY or 36
--[[ See `FrameXML/BuffFrame.lua:DEBUFF_MAX_DISPLAY`. ]]--
local DEBUFF_MAX_DISPLAY = DEBUFF_MAX_DISPLAY or 36

--[[ TODO Globalize special spells. ]]--
local auraWeightMap = {
	['Aimed Shot'] = 1,
	['Anti-Magic Shell'] = 2,
	['Avenging Wrath'] = 3,
	['Bladestorm'] = 3,
	['Blind'] = 3,
	['Chains of Ice'] = 1,
	['Cheap Shot'] = 1,
	['Concussion Blow'] = 1,
	['Cyclone'] = 3,
	['Deterrence'] = 3,
	['Disarm'] = 2,
	['Disarmed'] = 2,
	['Divine Plea'] = 1,
	['Divine Shield'] = 3,
	['Entangling Roots'] = 1,
	['Evasion'] = 2,
	['Evocation'] = 2,
	['Fear'] = 2,
	['Freezing Trap'] = 2,
	['Gnaw'] = 2,
	['Gouge'] = 2,
	['Grounding Totem Effect'] = 2,
	['Grounding Totem'] = 2,
	['Hammer of Justice'] = 1,
	['Hamstring'] = 1,
	['Hand of Freedom'] = 1,
	['Hand of Protection'] = 2,
	['Hand of Sacrifice'] = 1,
	['Hand of Salvation'] = 1,
	['Hex'] = 2,
	['Hibernation'] = 2,
	['Ice Block'] = 3,
	['Icebound Fortitude'] = 3,
	['Kidney Shot'] = 1,
	['Last Stand'] = 3,
	['Mind Control'] = 3,
	['Mortal Strike'] = 1,
	['Polymorph'] = 2,
	['Psychic Scream'] = 2,
	['Recklessness'] = 3,
	['Sacrifice'] = 2,
	['Sap'] = 3,
	['Seduction'] = 2,
	['Shield Block'] = 2,
	['Shield Wall'] = 3,
	['Sleep'] = 2,
	['Spell Reflection'] = 2,
	['Unstable Affliction'] = 2,
	['Wounding Poison'] = 1,
}

Chorus.auraWeightMap = auraWeightMap

local function getAuraWeight(unitDesignation, auraIndex, filter)
	local name, _, _, _, _, durationSec, owner = UnitAura(unitDesignation, auraIndex, filter)
	if not name then
		return 0
	end

	local specialPrio = auraWeightMap[name] or 0
	specialPrio = math.min(math.max(1, math.floor(math.abs(specialPrio))), 9)

	local durationIsLimited = 1
	if not durationSec or durationSec < 1 then
		durationIsLimited = 0
	end

	local ownerPrio = 1
	if 'player' == owner then
		ownerPrio = 2
	end

	local weight = 100000 * ownerPrio +
	               10000 * specialPrio +
		       durationIsLimited * (7201 - math.min(durationSec, 7200))
	return math.abs(math.floor(weight))
end

local function getAuraPriorityList(unitDesignation, filter)
	local t = {}
	local i = 0
	while (i < 8192) do
		i = i + 1
		local name = UnitAura(unitDesignation, i, filter)
		if not name then
			break
		end
		t[i] = i
	end

	table.sort(t, function(a, b)
		local p = getAuraWeight(unitDesignation, a, filter)
		local q = getAuraWeight(unitDesignation, b, filter)
		return p > q
	end)

	return t
end

local function auraFrameEventProcessor(self, eventCategory, ...)
	assert(self ~= nil)

	--[[ Optimization hack ]]--
	--[[ Make it use table value if it lags again. ]]--
	local unitDesignation = SecureButton_GetUnit(self) or 'none'
	assert(unitDesignation ~= nil)
	assert('string' == type(unitDesignation))
	unitDesignation = string.lower(strtrim(unitDesignation))
	assert(string.len(unitDesignation) >= 1)
	assert(string.len(unitDesignation) <= 256)

	if UnitExists(unitDesignation) and UnitIsConnected(unitDesignation) then
		self:Show()
	else
		self:Hide()
		return
	end

	if 'UNIT_AURA' == eventCategory then
		local u = select(1, ...)
		if u and 'string' == type(u) and unitDesignation ~= u then
			return
		end
	end

	--[[ Make it use table value if it lags again. ]]--
	local filter = SecureButton_GetAttribute(self, 'filter')
	assert(filter ~= nil)
	assert('string' == type(filter))
	filter = string.upper(strtrim(filter))
	assert(string.len(filter) >= 1)
	assert(string.len(filter) <= 256)

	local q = getAuraPriorityList(unitDesignation, filter)
	assert(q ~= nil)
	assert('table' == type(q))

	local i = 0
	local t = {self:GetChildren()}
	while (i < #q) do
		i = i + 1
		local b = t[i]
		if not b then
			break
		end
		assert(b ~= nil)

		local k = q[i]
		assert(k ~= nil)
		assert('number' == type(k))
		k = math.floor(math.abs(k))
		assert(k >= 0)
		b.index = k

		auraButtonEventProcessor(b, eventCategory, ...)
	end

	while (i < #t) do
		i = i + 1
		local b = t[i]
		assert(b ~= nil)
		b.index = 0

		auraButtonEventProcessor(b, eventCategory, ...)
	end
end

local function createEveryAuraButton(auraFrame)
	local self = auraFrame
	assert(self ~= nil)

	local n = self:GetName()
	assert(n ~= nil)

	local max = math.max(BUFF_MAX_DISPLAY or 36, DEBUFF_MAX_DISPLAY or 36) or 36
	local i = 0
	local w = math.max(self:GetWidth(), 30)
	local bmaxh = 30
	local x = 0
	local y = 0
	while (i < max) do
		i = i + 1

		local m = string.format('%sAuraButton%02d', n, i)
		local b = CreateFrame('FRAME', m, self, 'ChorusAuraButtonTemplate')
		b:SetPoint('TOPLEFT', x, -y)
		x = x + b:GetWidth()
		bmaxh = math.max(bmaxh, b:GetHeight())
		if x > w then
			x = 0
			y = y + bmaxh
		end
	end
end

function Chorus.auraFrameMain(self)
	assert(self ~= nil)

	--[[ `main` function is called on frame load. Frames declared in the
	XML descriptor are allocated before that. It is preferrable to use
	the XML descriptor for performance and separation of concerns. When
	no descendant frames were declared in this manner or another,
	fallback to allocating required aura buttons dynamically. ]]--

	local createAuraButtonsDynamically = nil == self:GetChildren()
	if createAuraButtonsDynamically then
		createEveryAuraButton(self)
	end

	self:RegisterEvent('PARTY_MEMBERS_CHANGED')
	self:RegisterEvent('PLAYER_FOCUS_CHANGED')
	self:RegisterEvent('PLAYER_LOGIN')
	self:RegisterEvent('PLAYER_TARGET_CHANGED')
	self:RegisterEvent('UNIT_AURA')

	--[[ Disable redundant aura updates. ]]--
	local t = {self:GetChildren()}
	local i = 0
	while (i < #t) do
		i = i + 1
		local b = t[i]
		if b then
			b:UnregisterEvent('UNIT_AURA')
		end
	end

	--[[ Optimization hack. This function call is expensive. Probably. ]]--
	self.unit = SecureButton_GetUnit(self)
	self.filter = SecureButton_GetAttribute(self, 'filter')

	self:SetScript('OnEvent', auraFrameEventProcessor)
	self:SetScript('OnShow', auraFrameEventProcessor)
end