--[[
# Element: Monk Stagger Bar

Handles the visibility and updating of the Monk's stagger bar.

## Widget

Stagger - A `StatusBar` used to represent the current stagger level.

## Notes

A default texture will be applied if the widget is a StatusBar and doesn't have a texture set.

## Options

.smoothing - Which smoothing method to use, defaults to Enum.StatusBarInterpolation.Immediate (number)

## Examples

    local Stagger = CreateFrame('StatusBar', nil, self)
    Stagger:SetSize(120, 20)
    Stagger:SetPoint('TOPLEFT', self, 'BOTTOMLEFT', 0, 0)

    -- Register with oUF
    self.Stagger = Stagger
--]]

local _, ns = ...
local oUF = ns.oUF
local Private = oUF.Private

local STATE = {}

local unitIsUnit = Private.unitIsUnit

-- sourced from Blizzard_FrameXMLBase/Constants.lua
local SPEC_MONK_BREWMASTER = _G.SPEC_MONK_BREWMASTER or 1

local POWER_TYPE_STAGGER = 'STAGGER'

-- percentages at which bar should change color
-- sourced from STAGGER_STATES in Blizzard_UnitFrame/MonkStaggerBar.lua
local STAGGER_YELLOW_TRANSITION = 0.3
local STAGGER_RED_TRANSITION = 0.6

-- table indices of bar colors
local STAGGER_GREEN_INDEX = 1
local STAGGER_YELLOW_INDEX = 2
local STAGGER_RED_INDEX = 3

local function UpdateColor(self, event, unit)
	if(unit and unit ~= self.__unit) then return end
	local element = self.Stagger

	local colors = self.colors.power[POWER_TYPE_STAGGER]
	local perc = STATE[element].cur / (STATE[element].max or 1)

	local color
	if(perc >= STAGGER_RED_TRANSITION) then
		color = colors and colors[STAGGER_RED_INDEX]
	elseif(perc > STAGGER_YELLOW_TRANSITION) then
		color = colors and colors[STAGGER_YELLOW_INDEX]
	else
		color = colors and colors[STAGGER_GREEN_INDEX]
	end

	if(color) then
		element:SetStatusBarColor(color:GetRGB())
	end

	--[[ Callback: Stagger:PostUpdateColor(color)
	Called after the element color has been updated.

	* self  - the Stagger element
	* color - the used ColorMixin-based object (table?)
	--]]
	if(element.PostUpdateColor) then
		element:PostUpdateColor(color)
	end
end

local function Update(self, event, unit)
	if(unit and unit ~= self.__unit) then return end

	local element = self.Stagger

	--[[ Callback: Stagger:PreUpdate()
	Called before the element has been updated.

	* self - the Stagger element
	--]]
	if(element.PreUpdate) then
		element:PreUpdate()
	end

	-- Blizzard code has nil checks for UnitStagger return
	local cur = UnitStagger('player') or 0
	local max = UnitHealthMax('player')

	element:SetMinMaxValues(0, max)
	element:SetValue(cur, element.smoothing)

	STATE[element].cur = cur
	STATE[element].max = max

	--[[ Callback: Stagger:PostUpdate(cur, max)
	Called after the element has been updated.

	* self - the Stagger element
	* cur  - the amount of staggered damage (number)
	* max  - the player's maximum possible health value (number)
	--]]
	if(element.PostUpdate) then
		element:PostUpdate(cur, max)
	end
end

local function Path(self, ...)
	--[[ Override: Stagger.Override(self, event, unit)
	Used to completely override the internal update function.

	* self  - the parent object
	* event - the event triggering the update (string)
	* unit  - the unit accompanying the event (string)
	--]]
	do
		(self.Stagger.Override or Update)(self, ...)
	end

	--[[ Override: Stagger.UpdateColor(self, event, unit)
	Used to completely override the internal function for updating the widgets' colors.

	* self  - the parent object
	* event - the event triggering the update (string)
	* unit  - the unit accompanying the event (string)
	--]]
	(self.Stagger.UpdateColor or UpdateColor) (self, ...)
end

local function Visibility(self, event, unit)
	local element = self.Stagger
	if(SPEC_MONK_BREWMASTER ~= C_SpecializationInfo.GetSpecialization() or UnitHasVehiclePlayerFrameUI('player')) then
		if(element:IsShown()) then
			element:Hide()
			self:UnregisterEvent('UNIT_AURA', Path)

			--[[ Callback: Stagger:PostVisibility(isVisible)
			Called after the element's visibility has been changed.

			* self      - the Stagger element
			* isVisible - the current visibility state of the element (boolean)
			--]]
			if(element.PostVisibility) then
				element:PostVisibility(false)
			end
		end
	else
		if(not element:IsShown()) then
			element:Show()
			self:RegisterEvent('UNIT_AURA', Path)

			if(element.PostVisibility) then
				element:PostVisibility(true)
			end
		end

		Path(self, event, unit)
	end
end

local function VisibilityPath(self, ...)
	--[[ Override: Stagger.OverrideVisibility(self, event, unit)
	Used to completely override the internal visibility toggling function.

	* self  - the parent object
	* event - the event triggering the update (string)
	* unit  - the unit accompanying the event (string)
	--]]
	(self.Stagger.OverrideVisibility or Visibility)(self, ...)
end

local function ForceUpdate(element)
	VisibilityPath(element.__owner, 'ForceUpdate', element.__owner.__unit)
end

local function Disable(self)
	local element = self.Stagger
	if(element) then
		element:Hide()

		self:UnregisterEvent('UNIT_AURA', Path)
		self:UnregisterEvent('UNIT_DISPLAYPOWER', VisibilityPath)
		self:UnregisterEvent('PLAYER_TALENT_UPDATE', VisibilityPath)

		MonkStaggerBar:RegisterEvent('PLAYER_ENTERING_WORLD')
		MonkStaggerBar:RegisterEvent('PLAYER_SPECIALIZATION_CHANGED')
		MonkStaggerBar:RegisterEvent('UNIT_DISPLAYPOWER')
		MonkStaggerBar:RegisterEvent('UNIT_EXITED_VEHICLE')
		MonkStaggerBar:RegisterEvent('UPDATE_VEHICLE_ACTIONBAR')
	end
end

local function Enable(self, unit)
	if(UnitClassBase('player') ~= 'MONK') then
		Disable(self)

		return false
	end

	local element = self.Stagger
	if(element and unitIsUnit(unit, 'player')) then
		element.__owner = self
		element.ForceUpdate = ForceUpdate

		STATE[element] = {}

		if(not element.smoothing) then
			element.smoothing = Enum.StatusBarInterpolation.Immediate
		end

		self:RegisterEvent('UNIT_DISPLAYPOWER', VisibilityPath)
		self:RegisterEvent('PLAYER_TALENT_UPDATE', VisibilityPath, true)

		if(element:IsObjectType('StatusBar') and not element:GetStatusBarTexture()) then
			element:SetStatusBarTexture([[Interface\TargetingFrame\UI-StatusBar]])
		end

		MonkStaggerBar:UnregisterEvent('PLAYER_ENTERING_WORLD')
		MonkStaggerBar:UnregisterEvent('PLAYER_SPECIALIZATION_CHANGED')
		MonkStaggerBar:UnregisterEvent('UNIT_DISPLAYPOWER')
		MonkStaggerBar:UnregisterEvent('UNIT_EXITED_VEHICLE')
		MonkStaggerBar:UnregisterEvent('UPDATE_VEHICLE_ACTIONBAR')

		-- do not change this without taking Visibility into account
		element:Hide()

		return true
	end
end

oUF:AddElement('Stagger', VisibilityPath, Enable, Disable)
