/// <reference path="../../_definitions.ts" />

module Phaser.Renderer.Canvas {

    export class TilemapRenderer {

        constructor(game: Phaser.Game) {
            this.game = game;
        }

        /**
         * The essential reference to the main game object
         */
        public game: Phaser.Game;

        //  Local rendering related temp vars to help avoid gc spikes through constant var creation
        private _ga: number = 1;
        private _dx: number = 0;
        private _dy: number = 0;
        private _dw: number = 0;
        private _dh: number = 0;
        private _tx: number = 0;
        private _ty: number = 0;
        private _tl: number = 0;
        private _maxX: number = 0;
        private _maxY: number = 0;
        private _startX: number = 0;
        private _startY: number = 0;
        private _columnData;

        /**
         * Render a tilemap to a specific camera.
         * @param camera {Camera} The camera this tilemap will be rendered to.
         */
        public render(camera: Phaser.Camera, tilemap: Phaser.Tilemap): boolean {

            //  Loop through the layers

            this._tl = tilemap.layers.length;

            for (var i = 0; i < this._tl; i++)
            {
                if (tilemap.layers[i].visible == false || tilemap.layers[i].alpha < 0.1)
                {
                    continue;
                }

                var layer: TilemapLayer = tilemap.layers[i];

                //  Work out how many tiles we can fit into our camera and round it up for the edges
                this._maxX = this.game.math.ceil(camera.width / layer.tileWidth) + 1;
                this._maxY = this.game.math.ceil(camera.height / layer.tileHeight) + 1;

                //  And now work out where in the tilemap the camera actually is
                this._startX = this.game.math.floor(camera.worldView.x / layer.tileWidth);
                this._startY = this.game.math.floor(camera.worldView.y / layer.tileHeight);

                //  Tilemap bounds check
                if (this._startX < 0)
                {
                    this._startX = 0;
                }

                if (this._startY < 0)
                {
                    this._startY = 0;
                }

                if (this._maxX > layer.widthInTiles)
                {
                    this._maxX = layer.widthInTiles;
                }

                if (this._maxY > layer.heightInTiles)
                {
                    this._maxY = layer.heightInTiles;
                }

                if (this._startX + this._maxX > layer.widthInTiles)
                {
                    this._startX = layer.widthInTiles - this._maxX;
                }

                if (this._startY + this._maxY > layer.heightInTiles)
                {
                    this._startY = layer.heightInTiles - this._maxY;
                }

                //  Finally get the offset to avoid the blocky movement
                //this._dx = (camera.screenView.x * layer.transform.scrollFactor.x) - (camera.worldView.x * layer.transform.scrollFactor.x);
                //this._dy = (camera.screenView.y * layer.transform.scrollFactor.y) - (camera.worldView.y * layer.transform.scrollFactor.y);
                //this._dx = (camera.screenView.x * this.scrollFactor.x) + this.x - (camera.worldView.x * this.scrollFactor.x);
                //this._dy = (camera.screenView.y * this.scrollFactor.y) + this.y - (camera.worldView.y * this.scrollFactor.y);
                this._dx = 0;
                this._dy = 0;

                this._dx += -(camera.worldView.x - (this._startX * layer.tileWidth));
                this._dy += -(camera.worldView.y - (this._startY * layer.tileHeight));

                this._tx = this._dx;
                this._ty = this._dy;

                //  Alpha
                if (layer.texture.alpha !== 1)
                {
                    this._ga = layer.texture.context.globalAlpha;
                    layer.texture.context.globalAlpha = layer.texture.alpha;
                }

                for (var row = this._startY; row < this._startY + this._maxY; row++)
                {
                    this._columnData = layer.mapData[row];

                    for (var tile = this._startX; tile < this._startX + this._maxX; tile++)
                    {
                        if (layer.tileOffsets[this._columnData[tile]])
                        {
                            layer.texture.context.drawImage(
                                layer.texture.texture,
                                layer.tileOffsets[this._columnData[tile]].x,
                                layer.tileOffsets[this._columnData[tile]].y,
                                layer.tileWidth,
                                layer.tileHeight,
                                this._tx,
                                this._ty,
                                layer.tileWidth,
                                layer.tileHeight
                                );

                        }

                        this._tx += layer.tileWidth;

                    }

                    this._tx = this._dx;
                    this._ty += layer.tileHeight;

                }

                if (this._ga > -1)
                {
                    layer.texture.context.globalAlpha = this._ga;
                }
            }

            return true;

        }

    }

}