/**
* @author       Richard Davey <rich@photonstorm.com>
* @author       Mat Groves (@Doormat23)
* @copyright    2016 Photon Storm Ltd.
* @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/

/**
* New version of PIXI.WebGLSpriteBatch
*
* @class Phaser.Renderer.Canvas
* @constructor
* @param {Phaser.Game} game - Game reference to the currently running game.
*/
Phaser.Renderer.WebGL.BatchManager = function (renderer)
{
    this.renderer = renderer;

    this.gl = null;

    this.vertSize = 5;

    //  Number of images in the BatchManager before it flushes
    this.size = 2000;

    //the total number of bytes in our batch
    // Including texture index:
    // position + uv + color + textureIndex
    // vec2 + vec2 + (char * 4) + float
    this.vertexSize = (4 * 2) + (4 * 2) + (4) + (4);

    var numVerts = this.vertexSize * this.size * 4;

    //this.size * 4 * 4 * this.vertSize;
    //the total number of indices in our batch
    var numIndices = this.size * 6;

    //  Holds the vertices
    this.vertices = new ArrayBuffer(numVerts);

    //  View on the vertices as a Float32Array
    this.positions = new Float32Array(this.vertices);

    //  View on the vertices as a Uint32Array
    this.colors = new Uint32Array(this.vertices);

    //  Holds the indices
    this.indices = new Uint16Array(numIndices);

    this.lastIndexCount = 0;

    for (var i = 0, j = 0; i < numIndices; i += 6, j += 4)
    {
        this.indices[i + 0] = j + 0;
        this.indices[i + 1] = j + 1;
        this.indices[i + 2] = j + 2;
        this.indices[i + 3] = j + 0;
        this.indices[i + 4] = j + 2;
        this.indices[i + 5] = j + 3;
    }

    this.currentTextureSource = null;

    // this.drawing = false;
    this.currentBatchSize = 0;
    this.dirty = true;
    this.textures = [];
    this.blendModes = [];
    this.shaders = [];
    this.sprites = [];
    // this.defaultShader = null;


    //  Let's Merge Sprite in here

    /**
     * The WebGL program.
     * @property program
     * @type Any
     */
    this.program = null;

    /**
    * The Default Vertex shader source.
    *
    * @property defaultVertexSrc
    * @type String
    */
    this.multivertexSrc = [
        'attribute vec2 aVertexPosition;',
        'attribute vec2 aTextureCoord;',
        'attribute vec4 aColor;',
        'attribute float aTextureIndex;',

        'uniform vec2 projectionVector;',
        'uniform vec2 offsetVector;',

        'varying vec2 vTextureCoord;',
        'varying vec4 vColor;',
        'varying float vTextureIndex;',

        'const vec2 center = vec2(-1.0, 1.0);',

        'void main(void) {',
        '   if (aTextureIndex > 0.0) gl_Position = vec4(0.0);',
        '   gl_Position = vec4( ((aVertexPosition + offsetVector) / projectionVector) + center, 0.0, 1.0);',
        '   vTextureCoord = aTextureCoord;',
        '   vColor = vec4(aColor.rgb * aColor.a, aColor.a);',
        '   vTextureIndex = aTextureIndex;',
        '}'
    ];

    this.vertexSrc = [
        'attribute vec2 aVertexPosition;',
        'attribute vec2 aTextureCoord;',
        'attribute vec4 aColor;',

        'uniform vec2 projectionVector;',

        'varying vec2 vTextureCoord;',
        'varying vec4 vColor;',

        'const vec2 center = vec2(-1.0, 1.0);',

        'void main(void) {',
        '   gl_Position = vec4((aVertexPosition / projectionVector) + center, 0.0, 1.0);',
        '   vTextureCoord = aTextureCoord;',
        '   vec3 color = mod(vec3(aColor.y / 65536.0, aColor.y / 256.0, aColor.y), 256.0) / 256.0;',
        '   vColor = vec4(color * aColor.x, aColor.x);',
        '}'
    ];

    /**
     * The fragment shader.
     * @property fragmentSrc
     * @type Array
     */
    this.multifragmentSrc = [
        'precision lowp float;',
        'varying vec2 vTextureCoord;',
        'varying vec4 vColor;',
        'varying float vTextureIndex;',
        'uniform sampler2D uSampler;',
        'void main(void) {',
        '   gl_FragColor = texture2D(uSampler, vTextureCoord) * vColor;',
        '}'
    ];

    this.fragmentSrc = [
        'precision mediump float;',
        'varying vec2 vTextureCoord;',
        'varying vec4 vColor;',
        'uniform sampler2D uSampler;',
        'void main(void) {',
        '   gl_FragColor = texture2D(uSampler, vTextureCoord) * vColor;',
        '}'
    ];

    /**
     * Uniform attributes cache.
     * @property attributes
     * @type Array
     * @private
     */
    this.attributes = [];

    /**
     * A local texture counter for multi-texture shaders.
     * @property textureCount
     * @type Number
     */
    this.textureCount = 0;

    //  @type {WebGLUniformLocation }
    this.uSampler;

    //  @type {WebGLUniformLocation }
    this.projectionVector;

    //  @type {WebGLUniformLocation }
    this.offsetVector;

    //  @type {GLint}
    this.colorAttribute;

    //  @type {GLint}
    this.aTextureIndex;

    //  @type {GLint}
    this.aVertexPosition;

    //  @type {GLint}
    this.aTextureCoord;

    //  @type {WebGLUniformLocation }
    this.translationMatrix;

    //  @type {WebGLUniformLocation }
    this.alpha;
};

Phaser.Renderer.WebGL.BatchManager.prototype.constructor = Phaser.Renderer.WebGL.BatchManager;

Phaser.Renderer.WebGL.BatchManager.prototype = {

    init: function ()
    {
        this.gl = this.renderer.gl;

        if (this.renderer.enableMultiTextureToggle)
        {
            this.initMultitexShader();
        }

        console.log('Compiled BatchManager Shader');

        // console.log(this.vertexSrc.join('\n'));
        // console.log(this.fragmentSrc.join('\n'));
        // console.log('compiling ...');

        var gl = this.gl;

        var program = this.renderer.compileProgram(this.vertexSrc, this.fragmentSrc);

        //  Set Shader
        gl.useProgram(program);

        //  Get and store the attributes
        this.aVertexPosition = gl.getAttribLocation(program, 'aVertexPosition');
        this.aTextureCoord = gl.getAttribLocation(program, 'aTextureCoord');
        this.colorAttribute = gl.getAttribLocation(program, 'aColor');
        // this.aTextureIndex = gl.getAttribLocation(program, 'aTextureIndex');

        //  Get and store the uniforms for the shader
        //  this part is different for multi-textures
        this.uSampler = gl.getUniformLocation(program, 'uSampler');

        //  vertex position
        gl.enableVertexAttribArray(0);

        //  texture coordinate
        gl.enableVertexAttribArray(1);

        //  color attribute
        gl.enableVertexAttribArray(2);

        //  texture index
        // gl.enableVertexAttribArray(3);

        //  The projection vector (middle of the game world)
        this.projectionVector = gl.getUniformLocation(program, 'projectionVector');
        // this.offsetVector = gl.getUniformLocation(program, 'offsetVector');

        this.program = program;

        //  setAttribs can also call this (which handles the enable array calls above)
        // this.attributes = [ this.aVertexPosition, this.aTextureCoord, this.colorAttribute, this.aTextureIndex ];
        this.attributes = [ this.aVertexPosition, this.aTextureCoord, this.colorAttribute ];

        //  Create a couple of buffers
        this.vertexBuffer = gl.createBuffer();
        this.indexBuffer = gl.createBuffer();

        //  65535 is max index, so 65535 / 6 = 10922.

        //  Upload the index data
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.indexBuffer);
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW);

        gl.bindBuffer(gl.ARRAY_BUFFER, this.vertexBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, this.vertices, gl.DYNAMIC_DRAW);
    },

    initMultiTextureShader: function ()
    {
        this.gl = this.renderer.gl;

        // var gl = this.gl;

        //  New Fragment Source ...

        /*
        if (this.renderer.enableMultiTextureToggle)
        {
            var dynamicIfs = '\tif (vTextureIndex == 0.0) gl_FragColor = texture2D(uSamplerArray[0], vTextureCoord) * vColor;\n';

            for (var index = 1; index < this.MAX_TEXTURES; ++index)
            {
                dynamicIfs += '\telse if (vTextureIndex == ' +
                    index + '.0) gl_FragColor = texture2D(uSamplerArray[' +
                    index + '], vTextureCoord) * vColor;\n';
            }

            //  Does this need the vTextureIndex varying? Doesn't look like it

            this.defaultShader = new Phaser.Filter(
                this.renderer.game,
                undefined,
                [
                    'precision lowp float;',
                    'varying vec2 vTextureCoord;',
                    'varying vec4 vColor;',
                    'varying float vTextureIndex;',
                    'uniform sampler2D uSamplerArray[' + this.MAX_TEXTURES + '];',
                    'void main(void) {',
                    dynamicIfs,
                    '\telse gl_FragColor = texture2D(uSamplerArray[0], vTextureCoord) * vColor;',
                    '}'
                ]);
        }
        else
        {
            //  Does this need the vTextureIndex varying? Doesn't look like it

            this.defaultShader = new Phaser.Filter(
                this.renderer.game,
                undefined,
                [
                    'precision lowp float;',
                    'varying vec2 vTextureCoord;',
                    'varying vec4 vColor;',
                    'varying float vTextureIndex;',
                    'uniform sampler2D uSampler;',
                    'void main(void) {',
                    '   gl_FragColor = texture2D(uSampler, vTextureCoord) * vColor;',
                    '}'
                ]);
        }
        */
    },

    begin: function ()
    {
        this.start();
    },

    start: function ()
    {
        this.dirty = true;
    },

    end: function ()
    {
        this.flush();
    },

    stop: function ()
    {
        this.flush();
        this.dirty = true;
    },

    render: function (src)
    {
        var frame = src.frame;
        var source = frame.source;

        //  Check TextureSource
        if (this.currentTextureSource !== source)
        // if (this.renderer.textureArray[source.glTextureIndex] !== source)
        {
            if (this.currentBatchSize > 0)
            {
                this.flush();
            }

            var gl = this.gl;

            gl.activeTexture(gl.TEXTURE0);
            // gl.activeTexture(gl.TEXTURE0 + source.glTextureIndex);
            gl.bindTexture(gl.TEXTURE_2D, source.glTexture);

            // this.renderer.textureArray[source.glTextureIndex] = source;
            this.currentTextureSource = source;
        }

        //  Check Batch Size
        if (this.currentBatchSize >= this.size)
        {
            this.flush();
            this.currentTextureSource = source;
        }

        //  MOVE ALL OF THIS INTO THE SPRITE / IMAGE WEBGL CLASSES? and just expose 'addVerts' here instead

        // Get the Texture UVs
        var uvs = frame.uvs;

        var aX = src.anchorX;
        var aY = src.anchorY;

        var w0, w1, h0, h1;

        /*
        if (texture.trim)
        {
            //  If the sprite is trimmed, add the extra space before transforming
            var trim = texture.trim;

            w1 = trim.x - (aX * trim.width);
            w0 = w1 + texture.crop.width;

            h1 = trim.y - (aY * trim.height);
            h0 = h1 + texture.crop.height;
        }
        else
        {
            w0 = (texture.frame.width) * (1 - aX);
            w1 = (texture.frame.width) * -aX;

            h0 = texture.frame.height * (1 - aY);
            h1 = texture.frame.height * -aY;
        }
        */

        w0 = (frame.width) * (1 - aX);
        w1 = (frame.width) * -aX;

        h0 = frame.height * (1 - aY);
        h1 = frame.height * -aY;

        var i = this.currentBatchSize * this.vertexSize;

        var resolution = source.resolution;
        var textureIndex = source.textureIndex;

        var wt = src.transform.world;

        var a = wt.a / resolution;
        var b = wt.b / resolution;
        var c = wt.c / resolution;
        var d = wt.d / resolution;
        var tx = wt.tx;
        var ty = wt.ty;

        // var cw = frame.cutWidth;
        // var ch = frame.cutHeight;

        /*
        if (texture.rotated)
        {
            var a0 = wt.a;
            var b0 = wt.b;
            var c0 = wt.c;
            var d0 = wt.d;
            var _w1 = w1;
            var _w0 = w0;

            // Offset before rotating
            tx = wt.c * ch + tx;
            ty = wt.d * ch + ty;
            
            // Rotate matrix by 90 degrees
            // We use precalculated values for sine and cosine of rad(90)
            a = a0 * 6.123233995736766e-17 + -c0;
            b = b0 * 6.123233995736766e-17 + -d0;
            c = a0 + c0 * 6.123233995736766e-17;
            d = b0 + d0 * 6.123233995736766e-17;

            // Update UV coordinates
            texture._updateUvsInverted();

            // Rotate dimensions
            w0 = h0;
            w1 = h1;
            h0 = _w0;
            h1 = _w1;
        }
        */

        //  These are just views into the same typed array
        var colors = this.colors;
        var positions = this.positions;

        // var tint = sprite.tint;
        var tint = 0xffffff;
        var color = (tint >> 16) + (tint & 0xff00) + ((tint & 0xff) << 16) + (src.worldAlpha * 255 << 24);

        if (this.renderer.roundPixels)
        {
            tx |= 0;
            ty |= 0;
        }

        //  Interleaved vert and color data
        //  The color passed here includes an applied tint *see bitwise ops above *
        //  Better to calculate that in the shader?

        //  Top Left vert (xy, uv, color)
        positions[i++] = a * w1 + c * h1 + tx;
        positions[i++] = d * h1 + b * w1 + ty;
        positions[i++] = uvs.x0;
        positions[i++] = uvs.y0;
        colors[i++] = color;
        positions[i++] = textureIndex;

        //  Top Right vert (xy, uv, color)
        positions[i++] = a * w0 + c * h1 + tx;
        positions[i++] = d * h1 + b * w0 + ty;
        positions[i++] = uvs.x1;
        positions[i++] = uvs.y1;
        colors[i++] = color;
        positions[i++] = textureIndex;

        //  Bottom Right vert (xy, uv, color)
        positions[i++] = a * w0 + c * h0 + tx;
        positions[i++] = d * h0 + b * w0 + ty;
        positions[i++] = uvs.x2;
        positions[i++] = uvs.y2;
        colors[i++] = color;
        positions[i++] = textureIndex;

        //  Bottom Left vert (xy, uv, color)
        positions[i++] = a * w1 + c * h0 + tx;
        positions[i++] = d * h0 + b * w1 + ty;
        positions[i++] = uvs.x3;
        positions[i++] = uvs.y3;
        colors[i++] = color;
        positions[i++] = textureIndex;

        this.sprites[this.currentBatchSize++] = src;
    },

    /*
    addVerts: function (uvs, wt, w0, h0, w1, h1, alpha, tint)
    {
        var a = wt.a;
        var b = wt.b;
        var c = wt.c;
        var d = wt.d;
        var tx = wt.tx;
        var ty = wt.ty;

        var verts = this.vertices;
        var i = this._size * 4 * this.vertSize;

        //  Top Left vert (xy, uv, color)
        verts[i++] = a * w1 + c * h1 + tx;
        verts[i++] = d * h1 + b * w1 + ty;
        verts[i++] = uvs.x0;
        verts[i++] = uvs.y0;
        verts[i++] = alpha;
        verts[i++] = tint[0];

        //  Top Right vert (xy, uv, color)
        verts[i++] = a * w0 + c * h1 + tx;
        verts[i++] = d * h1 + b * w0 + ty;
        verts[i++] = uvs.x1;
        verts[i++] = uvs.y1;
        verts[i++] = alpha;
        verts[i++] = tint[1];

        //  Bottom Right vert (xy, uv, color)
        verts[i++] = a * w0 + c * h0 + tx;
        verts[i++] = d * h0 + b * w0 + ty;
        verts[i++] = uvs.x2;
        verts[i++] = uvs.y2;
        verts[i++] = alpha;
        verts[i++] = tint[2];

        //  Bottom Left vert (xy, uv, color)
        verts[i++] = a * w1 + c * h0 + tx;
        verts[i++] = d * h0 + b * w1 + ty;
        verts[i++] = uvs.x3;
        verts[i++] = uvs.y3;
        verts[i++] = alpha;
        verts[i++] = tint[3];
    },
    */

    flush: function ()
    {
        // If the batch is length 0 then return as there is nothing to draw
        if (this.currentBatchSize === 0)
        {
            return;
        }

        var gl = this.gl;

        if (this.dirty)
        {
            //  Always dirty the first pass through
            //  but subsequent calls may be clean
            this.dirty = false;

            // bind the main texture
            gl.activeTexture(gl.TEXTURE0);

            // bind the buffers
            gl.bindBuffer(gl.ARRAY_BUFFER, this.vertexBuffer);
            gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.indexBuffer);

            //  set the projection vector (defaults to middle of game world on negative y)
            gl.uniform2f(this.projectionVector, this.renderer.projection.x, this.renderer.projection.y);

            //  vertex position
            gl.vertexAttribPointer(this.aVertexPosition, 2, gl.FLOAT, false, this.stride, 0);

            //  texture coordinate
            gl.vertexAttribPointer(this.aTextureCoord, 2, gl.FLOAT, false, this.stride, 8);

            //  color attribute
            gl.vertexAttribPointer(this.colorAttribute, 2, gl.FLOAT, false, this.stride, 16);

            //  texture index
            // gl.vertexAttribPointer(this.aTextureIndex, 2, gl.FLOAT, false, this.stride, 20);
        }

        //  Upload verts to the buffer
        if (this.currentBatchSize > (this.size * 0.5))
        {
            gl.bufferSubData(gl.ARRAY_BUFFER, 0, this.vertices);
        }
        else
        {
            gl.bindBuffer(gl.ARRAY_BUFFER, this.vertexBuffer);

            var view = this.positions.subarray(0, this.currentBatchSize * this.vertexSize);

            gl.bufferSubData(gl.ARRAY_BUFFER, 0, view);
        }

        var sprite;

        var start = 0;
        var currentSize = 0;

        var nextSource = null;

        var blend = 0;
        var nextBlend = null;

        for (var i = 0; i < this.currentBatchSize; i++)
        {
            sprite = this.sprites[i];

            nextBlend = sprite.blendMode;

            if (blend !== nextBlend)
            {

                //  Unrolled for speed
                /*
                if (nextBlend === this.renderer.blendModes.NORMAL)
                {
                    gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
                }
                else if (nextBlend === BlendModes.ADD)
                {
                    gl.blendFunc(gl.SRC_ALPHA, gl.DST_ALPHA);
                }
                else if (nextBlend === BlendModes.MULTIPLY)
                {
                    gl.blendFunc(gl.DST_COLOR, gl.ONE_MINUS_SRC_ALPHA);
                }
                else if (nextBlend === BlendModes.SCREEN)
                {
                    gl.blendFunc(gl.SRC_ALPHA, gl.ONE);
                }
                */
            }

            nextSource = sprite.frame.source;

            if (nextSource !== this.currentTextureSource)
            {
                if (currentSize > 0)
                {
                    this.renderBatch(this.currentTextureSource, currentSize, start);
                }

                start = i;
                currentSize = 0;
                this.currentTextureSource = nextSource;
            }

            currentSize++;
        }

        if (currentSize > 0)
        {
            this.renderBatch(this.currentTextureSource, currentSize, start);
        }

        //  Reset the batch
        this.currentBatchSize = 0;
    },

    renderBatch: function (source, size, startIndex)
    {
        if (size === 0)
        {
            return;
        }

        var gl = this.gl;

        if (source.glDirty)
        {
            if (!this.renderer.updateTexture(source))
            {
                //  If updateTexture returns false then we cannot render it, so bail out now
                return;
            }
        }

        gl.drawElements(gl.TRIANGLES, size * 6, gl.UNSIGNED_SHORT, startIndex * 6 * 2);

        this.renderer.drawCount++;
    },

    destroy: function ()
    {
        this.vertices = null;
        this.indices = null;

        this.gl.deleteBuffer(this.vertexBuffer);
        this.gl.deleteBuffer(this.indexBuffer);

        this.currentBaseTexture = null;

        this.renderer = null;
        this.gl = null;
    }

};