/*
 * Tencent is pleased to support the open source community by making vap available.
 *
 * Copyright (C) 2020 THL A29 Limited, a Tencent company.  All rights reserved.
 *
 * Licensed under the MIT License (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 *
 * http://opensource.org/licenses/MIT
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions and
 * limitations under the License.
 */
import {VapConfig} from "./type";
import VapFrameParser from './vap-frame-parser';
import * as glUtil from './gl-util';
import VapVideo from './video';

let clearTimer = null;
let instances = {};
const PER_SIZE = 9;

function computeCoord(x:number, y:number, w:number, h:number, vw:number, vh:number) {
  // leftX rightX bottomY topY
  return [x / vw, (x + w) / vw, (vh - y - h) / vh, (vh - y) / vh]
}

export default class WebglRenderVap extends VapVideo {
  constructor(options:VapConfig) {
    super(options);
    this.insType = this.options.type;
    if (instances[this.insType]) {
      this.instance = instances[this.insType]
    } else {
      this.instance = instances[this.insType] = {}
    }
    this.textures = [];
    this.buffers = [];
    this.shaders = [];
    this.init();
  }

  private insType;
  private textures;
  private buffers;
  private shaders;
  private vapFrameParser;
  private resources;
  private instance;
  private program;
  private videoTexture;
  private aPosition;
  private aTexCoord;
  private aAlphaTexCoord;
  private _imagePos;

  async init() {
    this.setCanvas();
    if (this.options.config) {
      try {
        this.vapFrameParser = await new VapFrameParser(this.options.config, this.options).init();
        this.resources = this.vapFrameParser.srcData;
      } catch (e) {
        console.error('[Alpha video] parse vap frame error.', e);
      }
    }
    this.resources = this.resources || {};
    this.initWebGL();
    this.play();
  }
  setCanvas() {
    let canvas = this.instance.canvas;
    const { width, height } = this.options;
    if (!canvas) {
      canvas = this.instance.canvas = document.createElement('canvas');
    }
    canvas.width = width;
    canvas.height = height;
    this.container.appendChild(canvas);
  }

  initWebGL() {
    const { canvas } = this.instance;
    let { gl, vertexShader, fragmentShader, program } = this.instance;
    if (!canvas) {
      return
    }
    if (!gl) {
      this.instance.gl = gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');
      gl.disable(gl.BLEND);
      gl.blendFuncSeparate(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA, gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
      gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
    }

    // 清除界面，解决同类型type切换MP4时，第一帧是上一个mp4最后一帧的问题
    gl.clear(gl.COLOR_BUFFER_BIT);

    if (gl) {
      gl.viewport(0, 0, canvas.width, canvas.height);
      if (!vertexShader) {
        vertexShader = this.instance.vertexShader = this.initVertexShader();
      }
      if (!fragmentShader) {
        fragmentShader = this.instance.fragmentShader = this.initFragmentShader();
      }
      if (!program) {
        program = this.instance.program = glUtil.createProgram(gl, vertexShader, fragmentShader);
      }
      this.program = program;
      this.initTexture();
      this.initVideoTexture();
      return gl;
    }
  }

  /**
   * 顶点着色器
   */
  initVertexShader() {
    const { gl } = this.instance;
    return glUtil.createShader(
      gl,
      gl.VERTEX_SHADER,
      `attribute vec2 a_position; // 接受顶点坐标
             attribute vec2 a_texCoord; // 接受纹理坐标
             attribute vec2 a_alpha_texCoord; // 接受纹理坐标
             varying vec2 v_alpha_texCoord; // 接受纹理坐标
             varying   vec2 v_texcoord; // 传递纹理坐标给片元着色器
             void main(void){
                gl_Position = vec4(a_position, 0.0, 1.0); // 设置坐标
                v_texcoord = a_texCoord; // 设置纹理坐标
                v_alpha_texCoord = a_alpha_texCoord; // 设置纹理坐标
             }`
    );
  }

  /**
   * 片元着色器
   */
  initFragmentShader() {
    const { gl } = this.instance;
    const bgColor = `vec4(texture2D(u_image_video, v_texcoord).rgb, texture2D(u_image_video,v_alpha_texCoord).r);`;
    const textureSize = gl.getParameter(gl.MAX_TEXTURE_IMAGE_UNITS) - 1;
    // const textureSize =0
    let sourceTexure = '';
    let sourceUniform = '';
    if (textureSize > 0) {
      const imgColor = [];
      const samplers = [];
      for (let i = 0; i < textureSize; i++) {
        imgColor.push(
          `if(ndx == ${i + 1}){
                        color = texture2D(u_image${i + 1},uv);
                    }`
        )
        samplers.push(`uniform sampler2D u_image${i + 1};`)
      }

      sourceUniform = `
            ${samplers.join('\n')}
            uniform float image_pos[${textureSize * PER_SIZE}];
            vec4 getSampleFromArray(int ndx, vec2 uv) {
                vec4 color;
                ${imgColor.join(' else ')}
                return color;
            }
            `;
      sourceTexure = `
            vec4 srcColor,maskColor;
            vec2 srcTexcoord,maskTexcoord;
            int srcIndex;
            float x1,x2,y1,y2,mx1,mx2,my1,my2; //显示的区域

            for(int i=0;i<${textureSize * PER_SIZE};i+= ${PER_SIZE}){
                if ((int(image_pos[i]) > 0)) {
                  srcIndex = int(image_pos[i]);
    
                    x1 = image_pos[i+1];
                    x2 = image_pos[i+2];
                    y1 = image_pos[i+3];
                    y2 = image_pos[i+4];
                    
                    mx1 = image_pos[i+5];
                    mx2 = image_pos[i+6];
                    my1 = image_pos[i+7];
                    my2 = image_pos[i+8];
    
    
                    if (v_texcoord.s>x1 && v_texcoord.s<x2 && v_texcoord.t>y1 && v_texcoord.t<y2) {
                        srcTexcoord = vec2((v_texcoord.s-x1)/(x2-x1),(v_texcoord.t-y1)/(y2-y1));
                         maskTexcoord = vec2(mx1+srcTexcoord.s*(mx2-mx1),my1+srcTexcoord.t*(my2-my1));
                         srcColor = getSampleFromArray(srcIndex,srcTexcoord);
                         maskColor = texture2D(u_image_video, maskTexcoord);
                         srcColor.a = srcColor.a*(maskColor.r);
                      
                         bgColor = vec4(srcColor.rgb*srcColor.a,srcColor.a) + (1.0-srcColor.a)*bgColor;
                      
                    }   
                }
            }
            `;
    }

    const fragmentSharder = `
        precision lowp float;
        varying vec2 v_texcoord;
        varying vec2 v_alpha_texCoord;
        uniform sampler2D u_image_video;
        ${sourceUniform}
        
        void main(void) {
            vec4 bgColor = ${bgColor}
            ${sourceTexure}
            // bgColor = texture2D(u_image[0], v_texcoord);
            gl_FragColor = bgColor;
        }
        `;
    return glUtil.createShader(gl, gl.FRAGMENT_SHADER, fragmentSharder)
  }

  initTexture() {
    const { gl } = this.instance;
    let i = 1;
    if (!this.vapFrameParser || !this.vapFrameParser.srcData) {
      return
    }
    const resources = this.vapFrameParser.srcData;
    for (const key in resources) {
      const resource = resources[key];
      this.textures.push(glUtil.createTexture(gl, i, resource.img));
      const sampler = gl.getUniformLocation(this.program, `u_image${i}`);
      gl.uniform1i(sampler, i);
      this.vapFrameParser.textureMap[resource.srcId] = i++;
    }
    const dumpTexture = gl.createTexture();
    gl.activeTexture(gl.TEXTURE0);
    gl.bindTexture(gl.TEXTURE_2D, dumpTexture);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);

    this.videoTexture = glUtil.createTexture(gl, i);
    const sampler = gl.getUniformLocation(this.program, `u_image_video`);
    gl.uniform1i(sampler, i);
  }

  initVideoTexture() {
    const { gl } = this.instance;
    const vertexBuffer = gl.createBuffer();
    this.buffers.push(vertexBuffer);
    if (!this.vapFrameParser || !this.vapFrameParser.config || !this.vapFrameParser.config.info) {
      return
    }
    const info = this.vapFrameParser.config.info;
    const ver = [];
    const { videoW: vW, videoH: vH } = info;
    const [rgbX, rgbY, rgbW, rgbH] = info.rgbFrame;
    const [aX, aY, aW, aH] = info.aFrame;
    const rgbCoord = computeCoord(rgbX, rgbY, rgbW, rgbH, vW, vH);
    const aCoord = computeCoord(aX, aY, aW, aH, vW, vH);
    ver.push(...[-1, 1, rgbCoord[0], rgbCoord[3], aCoord[0], aCoord[3]]);
    ver.push(...[1, 1, rgbCoord[1], rgbCoord[3], aCoord[1], aCoord[3]]);
    ver.push(...[-1, -1, rgbCoord[0], rgbCoord[2], aCoord[0], aCoord[2]]);
    ver.push(...[1, -1, rgbCoord[1], rgbCoord[2], aCoord[1], aCoord[2]]);
    const view = new Float32Array(ver);
    gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, view, gl.STATIC_DRAW);

    this.aPosition = gl.getAttribLocation(this.program, 'a_position');
    gl.enableVertexAttribArray(this.aPosition);
    this.aTexCoord = gl.getAttribLocation(this.program, 'a_texCoord');
    gl.enableVertexAttribArray(this.aTexCoord);
    this.aAlphaTexCoord = gl.getAttribLocation(this.program, 'a_alpha_texCoord');
    gl.enableVertexAttribArray(this.aAlphaTexCoord);
    // 将缓冲区对象分配给a_position变量、a_texCoord变量
    const size = view.BYTES_PER_ELEMENT;
    gl.vertexAttribPointer(this.aPosition, 2, gl.FLOAT, false, size * 6, 0); // 顶点着色器位置
    gl.vertexAttribPointer(this.aTexCoord, 2, gl.FLOAT, false, size * 6, size * 2); // rgb像素位置
    gl.vertexAttribPointer(this.aAlphaTexCoord, 2, gl.FLOAT, false, size * 6, size * 4); // rgb像素位置
  }

  drawFrame(_, info) {
    const gl = this.instance.gl;
    if (!gl) {
      super.drawFrame(_, info);
      return
    }
    gl.clear(gl.COLOR_BUFFER_BIT);
    if (this.vapFrameParser) {
      const timePoint = (info && info.mediaTime >= 0) ? info.mediaTime : this.video.currentTime
      const frame = Math.floor(timePoint * this.options.fps);
      const frameData = this.vapFrameParser.getFrame(frame);
      let posArr = [];

      if (frameData && frameData.obj) {
        frameData.obj.forEach((frame, index) => {
          posArr[posArr.length] = +this.vapFrameParser.textureMap[frame.srcId];

          const info = this.vapFrameParser.config.info;
          const { videoW: vW, videoH: vH } = info;
          const [x, y, w, h] = frame.frame;
          const [mX, mY, mW, mH] = frame.mFrame;
          const coord = computeCoord(x, y, w, h, vW, vH);
          const mCoord = computeCoord(mX, mY, mW, mH, vW, vH);
          posArr = posArr.concat(coord).concat(mCoord);
        })
      }
      //
      const size = (gl.getParameter(gl.MAX_TEXTURE_IMAGE_UNITS) - 1) * PER_SIZE;
      posArr = posArr.concat(new Array(size - posArr.length).fill(0));
      this._imagePos = this._imagePos || gl.getUniformLocation(this.program, 'image_pos');
      gl.uniform1fv(this._imagePos, new Float32Array(posArr));
    }
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, gl.RGB, gl.UNSIGNED_BYTE, this.video); // 指定二维纹理方式
    gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
    super.drawFrame(_, info);
  }

  destroy() {
    const { canvas, gl } = this.instance;
    if (this.textures && this.textures.length) {
      for (let i = 0; i < this.textures.length; i++) {
        gl.deleteTexture(this.textures[i]);
      }
    }
    if (canvas) {
      canvas.parentNode && canvas.parentNode.removeChild(canvas);
    }
    // glUtil.cleanWebGL(gl, this.shaders, this.program, this.textures, this.buffers)
    super.destroy();
    this.clearMemoryCache();
  }

  clearMemoryCache() {
    if (clearTimer) {
      clearTimeout(clearTimer);
    }

    clearTimer = setTimeout(() => {
      instances = {};
    }, 30 * 60 * 1000);
  }
}