/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2019 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

var Class = require('../../utils/Class');
var Components = require('../components');
var GameObject = require('../GameObject');
var ModelViewProjection = require('../../renderer/webgl/pipelines/components/ModelViewProjection');
var ShaderRender = require('./ShaderRender');
var TransformMatrix = require('../components/TransformMatrix');

/**
 * @classdesc
 * A Shader Game Object.
 *
 * @class Shader
 * @extends Phaser.GameObjects.GameObject
 * @memberof Phaser.GameObjects
 * @constructor
 * @webglOnly
 * @since 3.17.0
 *
 * @extends Phaser.GameObjects.Components.Depth
 * @extends Phaser.GameObjects.Components.GetBounds
 * @extends Phaser.GameObjects.Components.Mask
 * @extends Phaser.GameObjects.Components.Origin
 * @extends Phaser.GameObjects.Components.Pipeline
 * @extends Phaser.GameObjects.Components.Size
 * @extends Phaser.GameObjects.Components.Transform
 * @extends Phaser.GameObjects.Components.Visible
 * @extends Phaser.GameObjects.Components.ScrollFactor
 *
 * @param {Phaser.Scene} scene - The Scene to which this Game Object belongs. A Game Object can only belong to one Scene at a time.
 * @param {number} x - The horizontal position of this Game Object in the world.
 * @param {number} y - The vertical position of this Game Object in the world.
 */
var Shader = new Class({

    Extends: GameObject,

    Mixins: [
        ModelViewProjection,
        Components.BlendMode,
        Components.Depth,
        Components.GetBounds,
        Components.Mask,
        Components.Origin,
        Components.Size,
        Components.Transform,
        Components.Visible,
        Components.ScrollFactor,
        ShaderRender
    ],

    initialize:

    function Shader (scene, x, y, width, height, vert, frag)
    {
        GameObject.call(this, scene, 'Shader');

        this.vertexCount = 0;
        this.vertexCapacity = 6;

        this.renderer = scene.sys.renderer;

        /**
         * The size in bytes of the vertex.
         * The attribute sizes all added together (2 + 2 + 1 + 4)
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#vertexSize
         * @type {integer}
         * @since 3.0.0
         */
        this.vertexSize = Float32Array.BYTES_PER_ELEMENT * 2;

        /**
         * The WebGL context this WebGL Pipeline uses.
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#gl
         * @type {WebGLRenderingContext}
         * @since 3.17.0
         */
        this.gl = this.renderer.gl;

        /**
         * Raw byte buffer of vertices.
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#vertexData
         * @type {ArrayBuffer}
         * @since 3.0.0
         */
        this.vertexData = new ArrayBuffer(this.vertexCapacity * this.vertexSize);

        /**
         * The handle to a WebGL vertex buffer object.
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#vertexBuffer
         * @type {WebGLBuffer}
         * @since 3.0.0
         */
        this.vertexBuffer = this.renderer.createVertexBuffer(this.vertexData.byteLength, this.gl.STREAM_DRAW);

        /**
         * The handle to a WebGL program
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#program
         * @type {WebGLProgram}
         * @since 3.0.0
         */
        this.program = this.renderer.createProgram(vert, frag);

        /**
         * Array of objects that describe the vertex attributes
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#attributes
         * @type {object}
         * @since 3.0.0
         */
        this.attributes = [
            {
                name: 'inPosition',
                size: 2,
                type: this.gl.FLOAT,
                normalized: false,
                offset: 0
            }
        ];

        /**
         * The primitive topology which the pipeline will use to submit draw calls
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#topology
         * @type {integer}
         * @since 3.0.0
         */
        this.topology = this.gl.TRIANGLES;

        /**
         * Uint8 view to the vertex raw buffer. Used for uploading vertex buffer resources
         * to the GPU.
         *
         * @name Phaser.Renderer.WebGL.WebGLPipeline#bytes
         * @type {Uint8Array}
         * @since 3.0.0
         */
        this.bytes = new Uint8Array(this.vertexData);

        /**
         * Float32 view of the array buffer containing the pipeline's vertices.
         *
         * @name Phaser.Renderer.WebGL.Pipelines.QuadShaderPipeline#vertexViewF32
         * @type {Float32Array}
         * @since 3.17.0
         */
        this.vertexViewF32 = new Float32Array(this.vertexData);

        /**
         * A temporary Transform Matrix, re-used internally during batching.
         *
         * @name Phaser.Renderer.WebGL.Pipelines.QuadShaderPipeline#_tempMatrix1
         * @private
         * @type {Phaser.GameObjects.Components.TransformMatrix}
         * @since 3.17.0
         */
        this._tempMatrix1 = new TransformMatrix();

        /**
         * A temporary Transform Matrix, re-used internally during batching.
         *
         * @name Phaser.Renderer.WebGL.Pipelines.QuadShaderPipeline#_tempMatrix2
         * @private
         * @type {Phaser.GameObjects.Components.TransformMatrix}
         * @since 3.17.0
         */
        this._tempMatrix2 = new TransformMatrix();

        /**
         * A temporary Transform Matrix, re-used internally during batching.
         *
         * @name Phaser.Renderer.WebGL.Pipelines.QuadShaderPipeline#_tempMatrix3
         * @private
         * @type {Phaser.GameObjects.Components.TransformMatrix}
         * @since 3.17.0
         */
        this._tempMatrix3 = new TransformMatrix();

        this.setPosition(x, y);
        this.setSize(width, height);
        this.setOrigin(0.5, 0.5);

        this.mvpInit();

        this.projOrtho(0, this.renderer.width, this.renderer.height, 0, -1000.0, 1000.0);
    },

    /**
     * Adds a description of vertex attribute to the pipeline
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#addAttribute
     * @since 3.2.0
     *
     * @param {string} name - Name of the vertex attribute
     * @param {integer} size - Vertex component size
     * @param {integer} type - Type of the attribute
     * @param {boolean} normalized - Is the value normalized to a range
     * @param {integer} offset - Byte offset to the beginning of the first element in the vertex
     *
     * @return {this} This WebGLPipeline instance.
     */
    addAttribute: function (name, size, type, normalized, offset)
    {
        this.attributes.push({
            name: name,
            size: size,
            type: this.renderer.glFormats[type],
            normalized: normalized,
            offset: offset
        });

        return this;
    },

    /**
     * Binds the pipeline resources, including programs, vertex buffers and binds attributes
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#bind
     * @since 3.0.0
     *
     * @return {this} This WebGLPipeline instance.
     */
    bind: function ()
    {
        var gl = this.gl;
        var vertexBuffer = this.vertexBuffer;
        var attributes = this.attributes;
        var program = this.program;
        var renderer = this.renderer;
        var vertexSize = this.vertexSize;

        renderer.setProgram(program);
        renderer.setVertexBuffer(vertexBuffer);

        for (var index = 0; index < attributes.length; index++)
        {
            var element = attributes[index];
            var location = gl.getAttribLocation(program, element.name);

            if (location >= 0)
            {
                gl.enableVertexAttribArray(location);
                gl.vertexAttribPointer(location, element.size, element.type, element.normalized, vertexSize, element.offset);
            }
            else if (location !== -1)
            {
                gl.disableVertexAttribArray(location);
            }
        }

        this.setFloat1('time', this.renderer.game.loop.time / 1000);
        this.setFloat2('resolution', this.width, this.height);
    },

    /**
     * Uploads the vertex data and emits a draw call
     * for the current batch of vertices.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#flush
     * @since 3.0.0
     *
     * @return {this} This WebGLPipeline instance.
     */
    flush: function ()
    {
        var gl = this.gl;
        var vertexCount = 6;
        var topology = this.topology;
        var vertexSize = this.vertexSize;

        gl.bufferSubData(gl.ARRAY_BUFFER, 0, this.bytes.subarray(0, vertexCount * vertexSize));

        gl.drawArrays(topology, 0, vertexCount);
    },

    /**
     * Renders a single quad using the current shader and then flushes the batch.
     *
     * @method Phaser.Renderer.WebGL.Pipelines.QuadShaderPipeline#draw
     * @since 3.17.0
     */
    draw: function ()
    {
        var xw = this.width;
        var yh = this.height;

        var vertexViewF32 = this.vertexViewF32;

        vertexViewF32[0] = 0;
        vertexViewF32[1] = 0;
        vertexViewF32[2] = 0;
        vertexViewF32[3] = yh;
        vertexViewF32[4] = xw;
        vertexViewF32[5] = yh;
        vertexViewF32[6] = 0;
        vertexViewF32[7] = 0;
        vertexViewF32[8] = xw;
        vertexViewF32[9] = yh;
        vertexViewF32[10] = xw;
        vertexViewF32[11] = 0;

        this.flush();
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat1
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {number} x - The new value of the `float` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat1: function (name, x)
    {
        this.renderer.setFloat1(this.program, name, x);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat2
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {number} x - The new X component of the `vec2` uniform.
     * @param {number} y - The new Y component of the `vec2` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat2: function (name, x, y)
    {
        this.renderer.setFloat2(this.program, name, x, y);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat3
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {number} x - The new X component of the `vec3` uniform.
     * @param {number} y - The new Y component of the `vec3` uniform.
     * @param {number} z - The new Z component of the `vec3` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat3: function (name, x, y, z)
    {
        this.renderer.setFloat3(this.program, name, x, y, z);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat4
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {number} x - X component of the uniform
     * @param {number} y - Y component of the uniform
     * @param {number} z - Z component of the uniform
     * @param {number} w - W component of the uniform
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat4: function (name, x, y, z, w)
    {
        this.renderer.setFloat4(this.program, name, x, y, z, w);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat1v
     * @since 3.13.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {Float32Array} arr - The new value to be used for the uniform variable.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat1v: function (name, arr)
    {
        this.renderer.setFloat1v(this.program, name, arr);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat2v
     * @since 3.13.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {Float32Array} arr - The new value to be used for the uniform variable.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat2v: function (name, arr)
    {
        this.renderer.setFloat2v(this.program, name, arr);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat3v
     * @since 3.13.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {Float32Array} arr - The new value to be used for the uniform variable.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat3v: function (name, arr)
    {
        this.renderer.setFloat3v(this.program, name, arr);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setFloat4v
     * @since 3.13.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {Float32Array} arr - The new value to be used for the uniform variable.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setFloat4v: function (name, arr)
    {
        this.renderer.setFloat4v(this.program, name, arr);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setInt1
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {integer} x - The new value of the `int` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setInt1: function (name, x)
    {
        this.renderer.setInt1(this.program, name, x);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setInt2
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {integer} x - The new X component of the `ivec2` uniform.
     * @param {integer} y - The new Y component of the `ivec2` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setInt2: function (name, x, y)
    {
        this.renderer.setInt2(this.program, name, x, y);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setInt3
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {integer} x - The new X component of the `ivec3` uniform.
     * @param {integer} y - The new Y component of the `ivec3` uniform.
     * @param {integer} z - The new Z component of the `ivec3` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setInt3: function (name, x, y, z)
    {
        this.renderer.setInt3(this.program, name, x, y, z);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setInt4
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {integer} x - X component of the uniform
     * @param {integer} y - Y component of the uniform
     * @param {integer} z - Z component of the uniform
     * @param {integer} w - W component of the uniform
     *
     * @return {this} This WebGLPipeline instance.
     */
    setInt4: function (name, x, y, z, w)
    {
        this.renderer.setInt4(this.program, name, x, y, z, w);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setMatrix2
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {boolean} transpose - Whether to transpose the matrix. Should be `false`.
     * @param {Float32Array} matrix - The new values for the `mat2` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setMatrix2: function (name, transpose, matrix)
    {
        this.renderer.setMatrix2(this.program, name, transpose, matrix);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setMatrix3
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {boolean} transpose - Whether to transpose the matrix. Should be `false`.
     * @param {Float32Array} matrix - The new values for the `mat3` uniform.
     *
     * @return {this} This WebGLPipeline instance.
     */
    setMatrix3: function (name, transpose, matrix)
    {
        this.renderer.setMatrix3(this.program, name, transpose, matrix);

        return this;
    },

    /**
     * Set a uniform value of the current pipeline program.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#setMatrix4
     * @since 3.2.0
     *
     * @param {string} name - The name of the uniform to look-up and modify.
     * @param {boolean} transpose - Should the matrix be transpose
     * @param {Float32Array} matrix - Matrix data
     *
     * @return {this} This WebGLPipeline instance.
     */
    setMatrix4: function (name, transpose, matrix)
    {
        this.renderer.setMatrix4(this.program, name, transpose, matrix);

        return this;
    },

    /**
     * Removes all object references in this WebGL Pipeline and removes its program from the WebGL context.
     *
     * @method Phaser.Renderer.WebGL.WebGLPipeline#destroy
     * @since 3.0.0
     *
     * @return {this} This WebGLPipeline instance.
     */
    destroy: function ()
    {
        var gl = this.gl;

        gl.deleteProgram(this.program);
        gl.deleteBuffer(this.vertexBuffer);

        delete this.program;
        delete this.vertexBuffer;
        delete this.gl;

        return this;
    }

});

module.exports = Shader;