local PANEL = {}

AccessorFunc( PANEL, "m_fAnimSpeed",	"AnimSpeed" )
AccessorFunc( PANEL, "vCamPos",			"CamPos" )
AccessorFunc( PANEL, "fFOV",			"FOV" )
AccessorFunc( PANEL, "vLookatPos",		"LookAt" )
AccessorFunc( PANEL, "aLookAngle",		"LookAng" )
AccessorFunc( PANEL, "colAmbientLight",	"AmbientLight" )
AccessorFunc( PANEL, "colColor",		"Color" )
AccessorFunc( PANEL, "bAnimated",		"Animated" )

function PANEL:Init()

	self.Entities = {}
	self.LastPaint = 0
	self.DirectionalLight = {}
	self.FarZ = 4096

	self:SetCamPos( Vector( 50, 50, 50 ) )
	self:SetLookAt( Vector( 0, 0, 40 ) )
	self:SetFOV( 70 )

	self:SetText( "" )
	self:SetAnimSpeed( 0.5 )
	self:SetAnimated( false )

	self:SetAmbientLight( Color( 50, 50, 50 ) )

	self:SetDirectionalLight( BOX_TOP, Color( 255, 255, 255 ) )
	self:SetDirectionalLight( BOX_FRONT, Color( 255, 255, 255 ) )

	self:SetColor( Color( 255, 255, 255, 255 ) )

end

function PANEL:SetDirectionalLight( iDirection, color )
	self.DirectionalLight[ iDirection ] = color
end

function PANEL:AddModel( strModelName )

	-- Note: Not in menu dll
	if ( !ClientsideModel ) then return end

    self.Entities[#self.Entities+1] = ClientsideModel(strModelName, RENDER_GROUP_OPAQUE_ENTITY)
	if ( !IsValid( self.Entities[#self.Entities] ) ) then return end

	self.Entities[#self.Entities]:SetNoDraw( true )
	self.Entities[#self.Entities]:SetIK( false )

end

function PANEL:DrawModel()

	local curparent = self
	local rightx = self:GetWide()
	local leftx = 0
	local topy = 0
	local bottomy = self:GetTall()
	local previous = curparent
	while( curparent:GetParent() != nil ) do
		curparent = curparent:GetParent()
		local x, y = previous:GetPos()
		topy = math.Max( y, topy + y )
		leftx = math.Max( x, leftx + x )
		bottomy = math.Min( y + previous:GetTall(), bottomy + y )
		rightx = math.Min( x + previous:GetWide(), rightx + x )
		previous = curparent
	end
	render.SetScissorRect( leftx, topy, rightx, bottomy, true )

    for k,v in pairs(self.Entities) do
    	local ret = self:PreDrawModel( v )
    	if ( ret != false ) then
    		v:DrawModel()
    		self:PostDrawModel( v )
    	end
    end

	render.SetScissorRect( 0, 0, 0, 0, false )

end

function PANEL:PreDrawModel( ent )
	return true
end

function PANEL:PostDrawModel( ent )

end

function PANEL:Paint( w, h )
    for k,v in pairs(self.Entities) do
    	if ( !IsValid( v ) ) then continue end

    	local x, y = self:LocalToScreen( 0, 0 )

    	self:LayoutEntity( v )

    	local ang = self.aLookAngle
    	if ( !ang ) then
    		ang = ( self.vLookatPos - self.vCamPos ):Angle()
    	end

    	cam.Start3D( self.vCamPos, ang, self.fFOV, x, y, w, h, 5, self.FarZ )

    	render.SuppressEngineLighting( true )
    	render.SetLightingOrigin( v:GetPos() )
    	render.ResetModelLighting( self.colAmbientLight.r / 255, self.colAmbientLight.g / 255, self.colAmbientLight.b / 255 )
    	render.SetColorModulation( self.colColor.r / 255, self.colColor.g / 255, self.colColor.b / 255 )
    	render.SetBlend( ( self:GetAlpha() / 255 ) * ( self.colColor.a / 255 ) )

    	for i = 0, 6 do
    		local col = self.DirectionalLight[ i ]
    		if ( col ) then
    			render.SetModelLighting( i, col.r / 255, col.g / 255, col.b / 255 )
    		end
    	end

    	self:DrawModel()

    	render.SuppressEngineLighting( false )
    	cam.End3D()

    	self.LastPaint = RealTime()
    end
end

--[[
function PANEL:StartScene( name )

	if ( IsValid( self.Scene ) ) then
		self.Scene:Remove()
	end

	self.Scene = ClientsideScene( name, self.Entity )

end
]]

function PANEL:LayoutEntity( Entity )

	--
	-- This function is to be overriden
	--

	if ( self.bAnimated ) then
		self:RunAnimation()
	end
	Entity:SetAngles( Angle( 0, RealTime() * 10 % 360, 0 ) )

end

function PANEL:OnRemove()
	for k,v in pairs(self.Entities) do
        v:Remove()
        self.Entities[k] = nil
    end
end

derma.DefineControl( "DModelPanel", "A panel containing a model", PANEL, "DModelPanel" )