/**
 * @author Mat Groves http://matgroves.com/
 */

 /**
 *
 * @class Strip
 * @extends DisplayObjectContainer
 * @constructor
 * @param texture {Texture} The texture to use
 * @param width {Number} the width
 * @param height {Number} the height
 *
 */
PIXI.Strip = function(texture)
{
    PIXI.DisplayObjectContainer.call( this );


    /**
     * The texture of the strip
     *
     * @property texture
     * @type Texture
     */
    this.texture = texture;

    // set up the main bits..
    this.uvs = new PIXI.Float32Array([0, 1,
                                      1, 1,
                                      1, 0,
                                      0, 1]);

    this.vertices = new PIXI.Float32Array([0, 0,
                                            100, 0,
                                            100, 100,
                                            0, 100]);

    this.colors = new PIXI.Float32Array([1, 1, 1, 1]);

    this.indices = new PIXI.Uint16Array([0, 1, 2, 3]);

    /**
     * Whether the strip is dirty or not
     *
     * @property dirty
     * @type Boolean
     */
    this.dirty = true;

    /**
     * The blend mode to be applied to the sprite. Set to PIXI.blendModes.NORMAL to remove any blend mode.
     *
     * @property blendMode
     * @type Number
     * @default PIXI.blendModes.NORMAL;
     */
    this.blendMode = PIXI.blendModes.NORMAL;

    /**
     * Triangles in canvas mode are automatically antialiased, use this value to force triangles to overlap a bit with each other.
     *
     * @property canvasPadding
     * @type Number
     */
    this.canvasPadding = 0;

    this.drawMode = PIXI.Strip.DrawModes.TRIANGLE_STRIP;

};

// constructor
PIXI.Strip.prototype = Object.create(PIXI.DisplayObjectContainer.prototype);
PIXI.Strip.prototype.constructor = PIXI.Strip;

PIXI.Strip.prototype._renderWebGL = function(renderSession)
{
    // if the sprite is not visible or the alpha is 0 then no need to render this element
    if(!this.visible || this.alpha <= 0)return;
    // render triangle strip..

    renderSession.spriteBatch.stop();

    // init! init!
    if(!this._vertexBuffer)this._initWebGL(renderSession);

    renderSession.shaderManager.setShader(renderSession.shaderManager.stripShader);

    this._renderStrip(renderSession);

    ///renderSession.shaderManager.activateDefaultShader();

    renderSession.spriteBatch.start();

    //TODO check culling
};

PIXI.Strip.prototype._initWebGL = function(renderSession)
{
    // build the strip!
    var gl = renderSession.gl;

    this._vertexBuffer = gl.createBuffer();
    this._indexBuffer = gl.createBuffer();
    this._uvBuffer = gl.createBuffer();
    this._colorBuffer = gl.createBuffer();

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

    gl.bindBuffer(gl.ARRAY_BUFFER, this._uvBuffer);
    gl.bufferData(gl.ARRAY_BUFFER,  this.uvs, gl.STATIC_DRAW);

    gl.bindBuffer(gl.ARRAY_BUFFER, this._colorBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, this.colors, gl.STATIC_DRAW);

    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this._indexBuffer);
    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW);
};

PIXI.Strip.prototype._renderStrip = function(renderSession)
{
    var gl = renderSession.gl;
    var projection = renderSession.projection,
        offset = renderSession.offset,
        shader = renderSession.shaderManager.stripShader;

    var drawMode = this.drawMode === PIXI.Strip.DrawModes.TRIANGLE_STRIP ? gl.TRIANGLE_STRIP : gl.TRIANGLES;

    // gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, mat4Real);

    renderSession.blendModeManager.setBlendMode(this.blendMode);


    // set uniforms
    gl.uniformMatrix3fv(shader.translationMatrix, false, this.worldTransform.toArray(true));
    gl.uniform2f(shader.projectionVector, projection.x, -projection.y);
    gl.uniform2f(shader.offsetVector, -offset.x, -offset.y);
    gl.uniform1f(shader.alpha, this.worldAlpha);

    if(!this.dirty)
    {

        gl.bindBuffer(gl.ARRAY_BUFFER, this._vertexBuffer);
        gl.bufferSubData(gl.ARRAY_BUFFER, 0, this.vertices);
        gl.vertexAttribPointer(shader.aVertexPosition, 2, gl.FLOAT, false, 0, 0);

        // update the uvs
        gl.bindBuffer(gl.ARRAY_BUFFER, this._uvBuffer);
        gl.vertexAttribPointer(shader.aTextureCoord, 2, gl.FLOAT, false, 0, 0);

        gl.activeTexture(gl.TEXTURE0);

        // check if a texture is dirty..
        if(this.texture.baseTexture._dirty[gl.id])
        {
            renderSession.renderer.updateTexture(this.texture.baseTexture);
        }
        else
        {
            // bind the current texture
            gl.bindTexture(gl.TEXTURE_2D, this.texture.baseTexture._glTextures[gl.id]);
        }

        // dont need to upload!
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this._indexBuffer);


    }
    else
    {

        this.dirty = false;
        gl.bindBuffer(gl.ARRAY_BUFFER, this._vertexBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, this.vertices, gl.STATIC_DRAW);
        gl.vertexAttribPointer(shader.aVertexPosition, 2, gl.FLOAT, false, 0, 0);

        // update the uvs
        gl.bindBuffer(gl.ARRAY_BUFFER, this._uvBuffer);
        gl.bufferData(gl.ARRAY_BUFFER, this.uvs, gl.STATIC_DRAW);
        gl.vertexAttribPointer(shader.aTextureCoord, 2, gl.FLOAT, false, 0, 0);

        gl.activeTexture(gl.TEXTURE0);

        // check if a texture is dirty..
        if(this.texture.baseTexture._dirty[gl.id])
        {
            renderSession.renderer.updateTexture(this.texture.baseTexture);
        }
        else
        {
            gl.bindTexture(gl.TEXTURE_2D, this.texture.baseTexture._glTextures[gl.id]);
        }

        // dont need to upload!
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this._indexBuffer);
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW);

    }
    //console.log(gl.TRIANGLE_STRIP)
    //
    //
    gl.drawElements(drawMode, this.indices.length, gl.UNSIGNED_SHORT, 0);


};



PIXI.Strip.prototype._renderCanvas = function(renderSession)
{
    var context = renderSession.context;

    var transform = this.worldTransform;

    var tx = (transform.tx * renderSession.resolution) + renderSession.shakeX;
    var ty = (transform.ty * renderSession.resolution) + renderSession.shakeY;

    if (renderSession.roundPixels)
    {
        context.setTransform(transform.a, transform.b, transform.c, transform.d, tx | 0, ty | 0);
    }
    else
    {
        context.setTransform(transform.a, transform.b, transform.c, transform.d, tx, ty);
    }

    if (this.drawMode === PIXI.Strip.DrawModes.TRIANGLE_STRIP)
    {
        this._renderCanvasTriangleStrip(context);
    }
    else
    {
        this._renderCanvasTriangles(context);
    }
};

PIXI.Strip.prototype._renderCanvasTriangleStrip = function(context)
{
    // draw triangles!!
    var vertices = this.vertices;
    var uvs = this.uvs;

    var length = vertices.length / 2;
    this.count++;

    for (var i = 0; i < length - 2; i++) {
        // draw some triangles!
        var index = i * 2;
        this._renderCanvasDrawTriangle(context, vertices, uvs, index, (index + 2), (index + 4));
    }
};

PIXI.Strip.prototype._renderCanvasTriangles = function(context)
{
    // draw triangles!!
    var vertices = this.vertices;
    var uvs = this.uvs;
    var indices = this.indices;

    var length = indices.length;
    this.count++;

    for (var i = 0; i < length; i += 3) {
        // draw some triangles!
        var index0 = indices[i] * 2, index1 = indices[i + 1] * 2, index2 = indices[i + 2] * 2;
        this._renderCanvasDrawTriangle(context, vertices, uvs, index0, index1, index2);
    }
};

PIXI.Strip.prototype._renderCanvasDrawTriangle = function(context, vertices, uvs, index0, index1, index2)
{
    var textureSource = this.texture.baseTexture.source;
    var textureWidth = this.texture.width;
    var textureHeight = this.texture.height;

    var x0 = vertices[index0], x1 = vertices[index1], x2 = vertices[index2];
    var y0 = vertices[index0 + 1], y1 = vertices[index1 + 1], y2 = vertices[index2 + 1];

    var u0 = uvs[index0] * textureWidth, u1 = uvs[index1] * textureWidth, u2 = uvs[index2] * textureWidth;
    var v0 = uvs[index0 + 1] * textureHeight, v1 = uvs[index1 + 1] * textureHeight, v2 = uvs[index2 + 1] * textureHeight;

    if (this.canvasPadding > 0) {
        var paddingX = this.canvasPadding / this.worldTransform.a;
        var paddingY = this.canvasPadding / this.worldTransform.d;
        var centerX = (x0 + x1 + x2) / 3;
        var centerY = (y0 + y1 + y2) / 3;

        var normX = x0 - centerX;
        var normY = y0 - centerY;

        var dist = Math.sqrt(normX * normX + normY * normY);
        x0 = centerX + (normX / dist) * (dist + paddingX);
        y0 = centerY + (normY / dist) * (dist + paddingY);

        //

        normX = x1 - centerX;
        normY = y1 - centerY;

        dist = Math.sqrt(normX * normX + normY * normY);
        x1 = centerX + (normX / dist) * (dist + paddingX);
        y1 = centerY + (normY / dist) * (dist + paddingY);

        normX = x2 - centerX;
        normY = y2 - centerY;

        dist = Math.sqrt(normX * normX + normY * normY);
        x2 = centerX + (normX / dist) * (dist + paddingX);
        y2 = centerY + (normY / dist) * (dist + paddingY);
    }

    context.save();
    context.beginPath();


    context.moveTo(x0, y0);
    context.lineTo(x1, y1);
    context.lineTo(x2, y2);

    context.closePath();

    context.clip();

    // Compute matrix transform
    var delta =  (u0 * v1)      + (v0 * u2)      + (u1 * v2)      - (v1 * u2)      - (v0 * u1)      - (u0 * v2);
    var deltaA = (x0 * v1)      + (v0 * x2)      + (x1 * v2)      - (v1 * x2)      - (v0 * x1)      - (x0 * v2);
    var deltaB = (u0 * x1)      + (x0 * u2)      + (u1 * x2)      - (x1 * u2)      - (x0 * u1)      - (u0 * x2);
    var deltaC = (u0 * v1 * x2) + (v0 * x1 * u2) + (x0 * u1 * v2) - (x0 * v1 * u2) - (v0 * u1 * x2) - (u0 * x1 * v2);
    var deltaD = (y0 * v1)      + (v0 * y2)      + (y1 * v2)      - (v1 * y2)      - (v0 * y1)      - (y0 * v2);
    var deltaE = (u0 * y1)      + (y0 * u2)      + (u1 * y2)      - (y1 * u2)      - (y0 * u1)      - (u0 * y2);
    var deltaF = (u0 * v1 * y2) + (v0 * y1 * u2) + (y0 * u1 * v2) - (y0 * v1 * u2) - (v0 * u1 * y2) - (u0 * y1 * v2);

    context.transform(deltaA / delta, deltaD / delta,
        deltaB / delta, deltaE / delta,
        deltaC / delta, deltaF / delta);

    context.drawImage(textureSource, 0, 0);
    context.restore();
};



/**
 * Renders a flat strip
 *
 * @method renderStripFlat
 * @param strip {Strip} The Strip to render
 * @private
 */
PIXI.Strip.prototype.renderStripFlat = function(strip)
{
    var context = this.context;
    var vertices = strip.vertices;

    var length = vertices.length/2;
    this.count++;

    context.beginPath();
    for (var i=1; i < length-2; i++)
    {
        // draw some triangles!
        var index = i*2;

        var x0 = vertices[index],   x1 = vertices[index+2], x2 = vertices[index+4];
        var y0 = vertices[index+1], y1 = vertices[index+3], y2 = vertices[index+5];

        context.moveTo(x0, y0);
        context.lineTo(x1, y1);
        context.lineTo(x2, y2);
    }

    context.fillStyle = '#FF0000';
    context.fill();
    context.closePath();
};

/*
PIXI.Strip.prototype.setTexture = function(texture)
{
    //TODO SET THE TEXTURES
    //TODO VISIBILITY

    // stop current texture
    this.texture = texture;
    this.width   = texture.frame.width;
    this.height  = texture.frame.height;
    this.updateFrame = true;
};
*/

/**
 * When the texture is updated, this event will fire to update the scale and frame
 *
 * @method onTextureUpdate
 * @param event
 * @private
 */

PIXI.Strip.prototype.onTextureUpdate = function()
{
    this.updateFrame = true;
};

/**
 * Returns the bounds of the mesh as a rectangle. The bounds calculation takes the worldTransform into account.
 *
 * @method getBounds
 * @param matrix {Matrix} the transformation matrix of the sprite
 * @return {Rectangle} the framing rectangle
 */
PIXI.Strip.prototype.getBounds = function(matrix)
{
    var worldTransform = matrix || this.worldTransform;

    var a = worldTransform.a;
    var b = worldTransform.b;
    var c = worldTransform.c;
    var d = worldTransform.d;
    var tx = worldTransform.tx;
    var ty = worldTransform.ty;

    var maxX = -Infinity;
    var maxY = -Infinity;

    var minX = Infinity;
    var minY = Infinity;

    var vertices = this.vertices;
    for (var i = 0, n = vertices.length; i < n; i += 2)
    {
        var rawX = vertices[i], rawY = vertices[i + 1];
        var x = (a * rawX) + (c * rawY) + tx;
        var y = (d * rawY) + (b * rawX) + ty;

        minX = x < minX ? x : minX;
        minY = y < minY ? y : minY;

        maxX = x > maxX ? x : maxX;
        maxY = y > maxY ? y : maxY;
    }

    if (minX === -Infinity || maxY === Infinity)
    {
        return PIXI.EmptyRectangle;
    }

    var bounds = this._bounds;

    bounds.x = minX;
    bounds.width = maxX - minX;

    bounds.y = minY;
    bounds.height = maxY - minY;

    // store a reference so that if this function gets called again in the render cycle we do not have to recalculate
    this._currentBounds = bounds;

    return bounds;
};

/**
 * Different drawing buffer modes supported
 *
 * @property
 * @type {{TRIANGLE_STRIP: number, TRIANGLES: number}}
 * @static
 */
PIXI.Strip.DrawModes = {
    TRIANGLE_STRIP: 0,
    TRIANGLES: 1
};
