--[[
# Element: Quest Indicator

Handles the visibility and updating of an indicator based on the unit's involvement in a quest.

## Widget

QuestIndicator - Any UI widget.

## Notes

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

## Examples

    -- Position and size
    local QuestIndicator = self:CreateTexture(nil, 'OVERLAY')
    QuestIndicator:SetSize(16, 16)
    QuestIndicator:SetPoint('TOPRIGHT', self)

    -- Register it with oUF
    self.QuestIndicator = QuestIndicator
--]]

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

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

    local element = self.QuestIndicator

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

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

    local isQuestBoss = UnitIsQuestBoss(unit)
    if(isQuestBoss) then
        element:Show()
    else
        element:Hide()
    end

    --[[ Callback: QuestIndicator:PostUpdate(isQuestBoss)
    Called after the element has been updated.

    * self        - the QuestIndicator element
    * isQuestBoss - indicates if the element is shown (boolean)
    --]]
    if(element.PostUpdate) then
        return element:PostUpdate(isQuestBoss)
    end
end

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

    * self  - the parent object
    * event - the event triggering the update (string)
    * ...   - the arguments accompanying the event
    --]]
    return (self.QuestIndicator.Override or Update) (self, ...)
end

local function ForceUpdate(element)
    return Path(element.__owner, 'ForceUpdate', element.__owner.unit)
end

local function Enable(self)
    local element = self.QuestIndicator
    if(element) then
        element.__owner = self
        element.ForceUpdate = ForceUpdate

        self:RegisterEvent('UNIT_CLASSIFICATION_CHANGED', Path)

        if(element:IsObjectType('Texture') and not element:GetTexture()) then
            element:SetTexture([[Interface\TargetingFrame\PortraitQuestBadge]])
        end

        return true
    end
end

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

        self:UnregisterEvent('UNIT_CLASSIFICATION_CHANGED', Path)
    end
end

oUF:AddElement('QuestIndicator', Path, Enable, Disable)
