#include "ui_defs.lua"

Ui.weakRef = function(data)
    local weak = setmetatable({content=data}, {__mode="v"})
    return function() return weak.content end
end


Ui._ObjectHelpers = 
{
	addInnerChild = function(o, v, key)
		local helpers = Ui._ObjectHelpers
	
		o.children = o.children or {}
		table.insert(o.children, v)
		v.parent = o
		v._childIdx = #o.children
	
		local keyType = type(key)
		local nameToAdd = keyType == 'string' and key or v.id
		if nameToAdd and type(nameToAdd) == "string" and nameToAdd ~= "" then
			o[nameToAdd] = v
		end
		helpers.setRootRecursive(v, o)
		return v
	end,

	wrapDraw = function(obj)
	    obj.originalDraw = obj.draw

	    obj.draw = function(self)
	    	if self.onInputChanged then
	    		local curDevice = LastInputDevice()
	    		if curDevice ~= self.lastInputDevice then
	    			self.lastInputDevice = curDevice
	    			self:onInputChanged(curDevice)
	    		end
	    	end

	    	if not self.visible then
	    		return
	    	end

	    	if self.resizeToParent and self.parent then
	    		local hPad = (self.parent.padding and self.parent.padding.left + self.parent.padding.right or 0)
	    		local vPad = (self.parent.padding and self.parent.padding.top + self.parent.padding.bottom or 0)
	    		self.w = self.parent.w - hPad - (self.margin.left + self.margin.right)
	    		self.h = self.parent.h - vPad - (self.margin.top + self.margin.bottom)
	    	end

	    	UiPush()
		    	if self.ignoreNavigation then
		    		UiIgnoreNavigation()
		    	end

		    	self:onPreDraw()

				UiPush()
					UiColorFilter(unpack(self.colorFilter))

					self.w = self.w or 0
					self.h = self.h or 0
					if UiIsMouseInRect(self.w, self.h) and UiReceivesInput() then
						if not self.drawState.hovered then
							self:onMouseEnter()
						end
						self.drawState.hovered = true
						self:onHovered()
						if InputPressed("lmb") and not self.onPressedOverride then
							local x, y = UiGetCanvasMousePos()
							if UiIsInClipRegion(x, y) then
								self.drawState.pressed = true;
								self:onPressed()
							end
						elseif InputReleased("lmb") and self.drawState.pressed then
							self.drawState.pressed = false;
							self:onReleased()
						end
					elseif self.drawState.hovered then
						self.dbgmsg("MouseLeave for " .. tostring(self.id))
						self.drawState.hovered = false
						self:onMouseLeave()
					end
					if self.debug then
						--[[FIXME:Doesn't work very well because it doesn't take alignment into account, 
							so a more intrusive way to debug within the components themselves or find an 
							even better solution is needed.
						]]
						self:debugdraw(self.w,self.h)
					end
					self:originalDraw()
				UiPop()

				self:onPostDraw()
			UiPop()
	    end
	end,	

	tableFieldCopy = function(from, to, key)
		if to[key] ~= nil then
			for kk, vv in pairs(from[key]) do
				if type(vv) ~= 'table' then
					to[key][kk] = vv 
				else
					Ui._ObjectHelpers.tableFieldCopy(from[key], to[key], kk)
				end
			end
		else
			to[key] = from[key]
		end

		from[key] = nil
	end,

	isConfigurationField = function(fieldName, fieldValue)
		return type(fieldValue) == 'table' and not fieldValue._uiObjectFlag and fieldName ~= 'children'
	end,

	setRootRecursive = function(obj, r)
		rawset(obj, "root", r)

		if obj.children then
			for _, child in ipairs(obj.children) do
				Ui._ObjectHelpers.setRootRecursive(child, r)
			end
		end
	end,

	addToCreationWaitList = function(obj)
		local helpers = Ui._ObjectHelpers

		if not helpers.waitCreationList then
			helpers.waitCreationList = {}
		end
		table.insert(helpers.waitCreationList, obj)
	end,
}


Ui.Object = 
{
	debug = false,

	--base UI object should't be serialized
	nonserializable = true,

	new = function(self, innerObject)
		local helpers = Ui._ObjectHelpers

        local o = innerObject or {}
        o.drawState = o.drawState or { hovered = false; pressed = false; }

		local base
        if self == Ui.Object then
			base = {
				id = "UnnamedObject",
				x = 0,
				y = 0,
				w = 0,
				h = 0,
				visible = true,
				ignoreNavigation = false,
				margin = { top = 0, left = 0, right = 0, bottom = 0 },
				colorFilter = { 1, 1, 1, 1},
				resizeToParent = false,
				lastInputDevice = 0,
				signals = {},
				children = {},
				_uiObjectFlag = true,
				_isDrawWrapped = false,
			}
			setmetatable(base, { __index = Ui.Object })
		else
			base = self
		end
	
		-- Updates the base object using data from the innerObject.
		-- All data from innerObject is copied to the base;
		-- innerObject serves merely as a configuration.
		for k,v in pairs(o) do
			if type(v) == 'table' and v._uiObjectFlag then
				helpers.addInnerChild(base, v, k)
			elseif helpers.isConfigurationField(k, v) and type(base[k]) == 'table' then
				helpers.tableFieldCopy(o, base, k)
			else
				base[k] = v
			end
		end
	
		if not base._isDrawWrapped and base.draw then
			helpers.wrapDraw(base)
			base._isDrawWrapped = true
		end

		if base.onCreate then
			if helpers.isUiLoaded then
				base:onCreate()
			else
				helpers.addToCreationWaitList(base)
			end
		end

		if innerObject.onLanguageChanged then
			table.insert(Ui._UiObjectLangChangedListeners, Ui.weakRef(base))
		end
	
		return base
	end,
	
	append = function(self, child)
		return Ui._ObjectHelpers.addInnerChild(self, child)
	end,
    
	clear = function(self)
		self.children = {}
	end,

	inject = function(self, fields)
		local fieldsType  = type(fields)
		if  fieldsType == "string" then
			self[fields] = self:findById(fields)
		elseif fieldsType == "table" then
			for k, v in ipairs(fields) do
				self:inject(v)
			end
		end
	end,

	show = function(self, needsShow)
		self.visible = needsShow or true
	end,

	hide = function(self)
		self.visible = false
	end,

	getSize = function(self)
		return self.w, self.h
	end,
	
	getScaledSize = function(self)
		local sx, sy = UiGetScale()
		local w, h = self:getSize()
		local sw = (sx ~= 0) and w / sx or 0
		local sh = (sy ~= 0) and h / sy or 0

		return sw, sh
	end,

	size = function(self)
		local sw, sh = self:getScaledSize()
		return { w = sw, h = sh }
	end,

	dbgmsg = function(self, msg)
		--DebugPrint(msg)
	end,
	
	debugdraw = function(o, w, h)
		UiPush()
			local r,g,b = randomColor()
			o.debugColor = o.debugColor or Ui.Colorf(r,g,b,0.2)
			o.debugColor:set()
			UiRect(w,h)
		UiPop()
	end,

	findById = function(self, id)
		if self.id == id then
			return self
		end
	
		if self.children then
			for _, child in ipairs(self.children) do
				local found = child:findById(id)
				if found then
					return found
				end
			end
		end
	
		return nil
	end,

    apply = function(self, data)
        for k,v in pairs(data) do
            Ui._ObjectHelpers.tableFieldCopy(data, self, k)
        end
    end,

    connect = function(self, signal, target, slot)
        if not self.signals[signal] then
            self.signals[signal] = {}
        end

        self.signals[signal][slot] = {target, slot}
    end,

    emit = function(self, signal, ...)
        if self.signals[signal] then
            for _, slot in pairs(self.signals[signal]) do
				local o, m = unpack(slot)
				m(o,...)
            end
        end
    end,
	-----------------------------
---
-- @brief Synchronizes specific properties of a child component with its 
--        parent, implementing a simple data-binding mechanism. In its 
--        current implementation, only dimensions (width and height) are 
--        synchronized.
-- @param self Ui.Object: The child component whose properties are to be 
--        synchronized.
-- @note For future flexibility, consider passing an additional parameter 
--       listing the properties to be synchronized.
-- @usage Used in Ui.TextInput, where `fromParent` is invoked in the 
--        `onPreDraw` method to synchronize dimensions before rendering.
	fromParent = function(self)
		if self.parent then
			self.w = self.parent.w
			self.h = self.parent.h
		end
	end,

    -- EVENTS
	onPressed = function(self)
		self.dbgmsg("Pressed on object with id = "..tostring(self.id))
	end,
	onReleased = function(self)
		self.dbgmsg("Released on object with id = "..tostring(self.id))
	end,

	onHovered = function(self)
		self.dbgmsg("Hovered object with id = "..tostring(self.id))
	end,

	onMouseEnter = function(self)
		self.dbgmsg("Hovered object with id = "..tostring(self.id))
	end,

	onMouseLeave = function(self)
		self.dbgmsg("Hovered object with id = "..tostring(self.id))
	end,

	onPreDraw = function(self)
	end,

	onPostDraw = function(self)
	end
}


RegisterListenerTo("LanguageChanged", "__UiObjectLanguageChanged")

Ui._UiObjectLangChangedListeners = {}

function __UiObjectLanguageChanged(newLanguage)
	for _, v in ipairs(Ui._UiObjectLangChangedListeners) do
		if v() ~= nil then
			v():onLanguageChanged(newLanguage)
		end
	end
end


RegisterListenerTo("UiOnLoaded", "__UiOnLoaded")


function __UiOnLoaded()
	local helpers = Ui._ObjectHelpers
	helpers.isUiLoaded = true

	if not helpers.waitCreationList then
		return
	end

	for i=1,#helpers.waitCreationList do
		helpers.waitCreationList[i]:onCreate()
	end

	helpers.waitCreationList = {}
end