window.addEventListener('DOMContentLoaded', () => {

  /** 显示模式列表 */
  const DISPLAY_MODES = {
    data: {
      isDefault: true,
      label: '数据显示',
    },
    spectrum: {
      isDefault: false,
      label: '频谱显示',
    },
  };

  /** 分辨率配置选项 */
  const RESOLUTION_LIST = {
    '160x80': {
      isDefault: true,
      label: '160x80',
      lcdX: 160, lcdY: 80,
      showWidth: 320, showHeight: 240,
    },
    '320x172': {
      isDefault: false,
      label: '320x172',
      lcdX: 320, lcdY: 172,
      showWidth: 320, showHeight: 240,
    },
    '320x240': {
      isDefault: false,
      label: '320x240',
      lcdX: 320, lcdY: 240,
      showWidth: 320, showHeight: 240,
    },
  };

  /** @type {HTMLButtonElement} */
  const connectButton = document.getElementById('connect-button');

  /** @type {HTMLButtonElement} */
  const disconnectButton = document.getElementById('disconnect-button');

  /** @type {HTMLButtonElement} */
  const startButton = document.getElementById('start-button');

  /** @type {HTMLButtonElement} */
  const stopButton = document.getElementById('stop-button');

  /** @type {HTMLSelectElement} */
  const displayModeSelector = document.getElementById('display-mode-selector');

  /** @type {HTMLSelectElement} */
  const resolutionSelector = document.getElementById('resolution-selector');

  /** @type {HTMLCanvasElement} */
  const canvas = document.getElementById('canvas-element');
  const ctx = canvas.getContext('2d');

  /**
   * @desc 串口对象
   * @type {SerialPort}
   */
  let serialPort = null;

  /**
   * @desc 串口读取器
   * @type {ReturnType<typeof serialPort.readable.getReader>}
   */
  let serialReader = null;

  /**
   * @desc 串口写入器
   * @type {ReturnType<typeof serialPort.writable.getWriter>}
   */
  let serialWriter = null;

  /** 连接状态，0: 未连接, 1: 已连接 */
  let deviceState = 0;

  /** 渲染间隔，毫秒 */
  let renderInterval = 100;

  /** 发送间隔，毫秒 */
  let sendInterval = 100;

  /** 最后一次渲染的时间戳 */
  let lastRenderTime = 0;

  /** 最后一次发送的时间戳 */
  let lastSendTime = 0;

  /** 渲染循环 requestAnimationFrame ID */
  let renderAnimationId = null;

  /** 发送循环 requestAnimationFrame ID */
  let sendAnimationId = null;

  /**
   * @desc 显示模式
   * @type {keyof (typeof DISPLAY_MODES)}
   */
  let displayMode = 'data';

  // 音频相关变量

  /** @type {AudioContext} */
  let audioContext = null;

  /** @type {ReturnType<typeof audioContext.createAnalyser>} */
  let audioAnalyser = null;

  /** @type {number} */
  let audioBufferLength = null;

  /** @type {Uint8Array} */
  let audioDataArray = null;

  /** @type {ReturnType<typeof audioContext.createMediaStreamSource>} */
  let microphone = null;

  /** 音频是否已初始化 */
  let isAudioReady = false;

  // 显示参数
  let CANVAS_WIDTH = 0;  // 画布显示宽度
  let CANVAS_HEIGHT = 0; // 画布显示高度
  let LCD_WIDTH = 0;     // 设备实际宽度
  let LCD_HEIGHT = 0;    // 设备实际高度

  /** 数据文本渲染类 */
  class DataTextRender {

    constructor() {
      this.monitorData = {};
      this.font = '32px Arial';
    }

    updateDataText() {

      let date = new Date();

      this.monitorData = {
        row_1: {
          value: `${String(date.getFullYear()).padStart(2, '0')}-${String(date.getMonth() + 1).padStart(2, '0')}-${String(date.getDate()).padStart(2, '0')}`,
          label: '日期',
          unit: '',
          detail: '',
          color: '#FFFF00',
          icon: 'I',
        },
        row_2: {
          value: `${String(date.getHours()).padStart(2, '0')}:${String(date.getMinutes()).padStart(2, '0')}:${String(date.getSeconds()).padStart(2, '0')}`,
          label: '时间',
          unit: '',
          detail: '',
          color: '#00FFFF',
          icon: 'I',
        },
        row_3: {
          value: `${String(date.getFullYear()).padStart(2, '0')}-${String(date.getMonth() + 1).padStart(2, '0')}-${String(date.getDate()).padStart(2, '0')}`,
          label: '日期',
          unit: '',
          detail: '',
          color: '#FFFF00',
          icon: 'I',
        },
        row_4: {
          value: `${String(date.getHours()).padStart(2, '0')}:${String(date.getMinutes()).padStart(2, '0')}:${String(date.getSeconds()).padStart(2, '0')}`,
          label: '时间',
          unit: '',
          detail: '',
          color: '#00FFFF',
          icon: 'I',
        },
      };

      return this.monitorData;

    }

    formatDisplayText(key, showIcon = false) {

      let item = this.monitorData[key];

      if (!item) {
        return '';
      }

      let icon = showIcon ? `[${item.icon}] ` : '';
      let detail = item.detail || '';

      if (detail) {
        return `${icon}${item.label}: ${item.value}${item.unit} ${detail}`;
      } else {
        return `${icon}${item.label}: ${item.value}${item.unit}`;
      }

    }

    createDisplayImage() {

      // 更新数据
      this.updateDataText();

      // 清空画布
      ctx.fillStyle = 'black';
      ctx.fillRect(0, 0, CANVAS_WIDTH, CANVAS_HEIGHT);

      // 绘制网格布局
      this.drawGridLayout();

    }

    drawGridLayout() {

      let layouts = [
        { key: 'row_1', position: [10, 10] },
        { key: 'row_2', position: [10, 50] },
        { key: 'row_3', position: [10, 90] },
        { key: 'row_4', position: [10, 130] },
      ];

      ctx.font = this.font;
      ctx.textBaseline = 'top';
      ctx.textAlign = 'left';

      layouts.forEach(layout => {
        if (this.monitorData[layout.key]) {
          let item = this.monitorData[layout.key];
          let text = this.formatDisplayText(layout.key, false);
          ctx.fillStyle = item['color'];
          ctx.fillText(text, layout.position[0], layout.position[1]);
        }
      });

    }

  }

  /** 数据文本渲染实例 */
  const dataTextRender = new DataTextRender();

  /** 开始音频分析，初始化音频上下文和麦克风 */
  async function audioAnalyserStart() {
    try {

      // 创建音频上下文
      audioContext = new (window.AudioContext || window.webkitAudioContext)();

      // 请求麦克风访问
      let stream = await navigator.mediaDevices.getUserMedia({
        audio: true,
        video: false,
      });

      // 创建麦克风源
      microphone = audioContext.createMediaStreamSource(stream);

      // 创建分析器
      audioAnalyser = audioContext.createAnalyser();
      audioAnalyser.fftSize = 256;
      audioAnalyser.smoothingTimeConstant = 0.25;

      // 连接麦克风到分析器
      microphone.connect(audioAnalyser);

      // 获取分析器数据
      audioBufferLength = audioAnalyser.frequencyBinCount;
      audioDataArray = new Uint8Array(audioBufferLength);

      // 更新状态
      isAudioReady = true;

      console.info('音频初始化成功，音频分析已开始');

    } catch (error) {
      console.error('音频初始化失败:', error);
      isAudioReady = false;
    }
  }

  /** 停止音频分析 */
  function audioAnalyserStop() {

    if (audioContext) {
      audioContext.close();
      audioContext = null;
    }

    if (microphone) {
      microphone.disconnect();
      microphone = null;
    }

    if (audioAnalyser) {
      audioAnalyser.disconnect();
      audioAnalyser = null;
    }

    isAudioReady = false;

    console.info('音频分析已停止');

  }

  /** 将 32 位整数拆分为 4 个字节 */
  function convertDigitToInts(di) {
    return [(di >> 24) & 0xFF, (di >> 16) & 0xFF, (di >> 8) & 0xFF, di & 0xFF];
  }

  /**
   * @description 将 RGB565 颜色转换为 RGB 颜色
   * @param   {number} color565 RGB565 颜色值
   * @returns {number[]} RGB 颜色值数组，格式：`[r, g, b]`
   */
  function convertRgb565ToRgb(color565) {
    const r = ((color565 >> 11) & 0x1F) << 3;
    const g = ((color565 >> 5) & 0x3F) << 2;
    const b = (color565 & 0x1F) << 3;
    return [r, g, b];
  }

  /**
   * @description 将 RGB888 转换为 RGB565 格式
   * @param   {ImageData} imageData 包含 RGB888 数据的 ImageData 对象
   * @returns {number[]} 包含 RGB565 数据的数组
   */
  function convertRgb888ToRgb565(imageData) {

    let rgb565Array = [];

    for (let i = 0; i < imageData.data.length; i += 4) {
      let r = imageData.data[i];
      let g = imageData.data[i + 1];
      let b = imageData.data[i + 2];
      let rgb565 = ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3);
      rgb565Array.push(rgb565);
    }

    return rgb565Array;

  }

  /**
   * 对图像数据进行压缩处理，减少传输数据量
   * - 基于 `compaction.c` 中的 `MSN_compaction` 算法移植
   */
  function convertDisplayData(imageData = []) {

    let totalDataSize = imageData.length;
    let dataPerPage = 128;
    let hexUse = [];
    let dataIndex = 0;

    // -- 按页处理数据，每页 128 个像素 --

    let totalPages = Math.floor(totalDataSize / dataPerPage);

    for (let page = 0; page < totalPages; page++) {
      let i = 0;
      while (i < 128) {

        let a = 0;
        let a_data = imageData[dataIndex];

        // 统计第 1 种颜色的连续出现次数（最多 15 次）
        for (let s = 0; s < 15; s++) {
          if (i < 128 && a_data === imageData[dataIndex]) {
            a++;
            i++;
            dataIndex++;
          } else {
            break;
          }
        }

        let b = 0;
        let b_data = 0;

        // 统计第 2 种颜色的连续出现次数（最多 15 次）
        if (i < 128) {
          b_data = imageData[dataIndex];
          for (let s = 0; s < 15; s++) {
            if (i < 128 && b_data === imageData[dataIndex]) {
              b++;
              i++;
              dataIndex++;
            } else {
              break;
            }
          }
        }

        // 输出压缩数据：
        // [9, a*16+b, a_data 高字节, a_data 低字节, b_data 高字节, b_data 低字节]
        hexUse.push(9);
        hexUse.push(a * 16 + b);
        hexUse.push((a_data >> 8) & 0xFF);
        hexUse.push(a_data & 0xFF);
        hexUse.push((b_data >> 8) & 0xFF);
        hexUse.push(b_data & 0xFF);

      }
    }

    // -- 处理剩余数据 --

    let remainingDataSize = totalDataSize % dataPerPage;

    if (remainingDataSize !== 0) {

      let remainingData = imageData.slice(totalDataSize - remainingDataSize);

      // 补全数据到 128 字节
      while (remainingData.length < dataPerPage) {
        remainingData.push(0xFFFF);
      }

      let i = 0;
      let dataIndex = 0;

      while (i < 128) {

        let a = 0;
        let a_data = remainingData[dataIndex];

        for (let s = 0; s < 15; s++) {
          if (i < 128 && a_data === remainingData[dataIndex]) {
            a++;
            i++;
            dataIndex++;
          } else {
            break;
          }
        }

        let b = 0;
        let b_data = 0;

        if (i < 128) {
          b_data = remainingData[dataIndex];
          for (let s = 0; s < 15; s++) {
            if (i < 128 && b_data === remainingData[dataIndex]) {
              b++;
              i++;
              dataIndex++;
            } else {
              break;
            }
          }
        }

        hexUse.push(9);
        hexUse.push(a * 16 + b);
        hexUse.push((a_data >> 8) & 0xFF);
        hexUse.push(a_data & 0xFF);
        hexUse.push((b_data >> 8) & 0xFF);
        hexUse.push(b_data & 0xFF);

      }
    }

    return hexUse;

  }

  /** 设置 LCD 显示起始坐标 */
  function lcdSetDisplayXY(lcdD0 = 0, lcdD1 = 0) {
    let hexUse = [];
    hexUse.push(2);                       // LCD 多次写入命令
    hexUse.push(0);                       // 设置起始位置指令
    hexUse.push(Math.floor(lcdD0 / 256)); // X 坐标高字节
    hexUse.push(lcdD0 % 256);             // X 坐标低字节
    hexUse.push(Math.floor(lcdD1 / 256)); // Y 坐标高字节
    hexUse.push(lcdD1 % 256);             // Y 坐标低字节
    return hexUse;
  }

  /** 设置 LCD 显示区域大小 */
  function lcdSetDisplaySize(lcdD0 = 0, lcdD1 = 0) {
    let hexUse = [];
    hexUse.push(2);                       // LCD 多次写入命令
    hexUse.push(1);                       // 设置大小指令
    hexUse.push(Math.floor(lcdD0 / 256)); // 宽度高字节
    hexUse.push(lcdD0 % 256);             // 宽度低字节
    hexUse.push(Math.floor(lcdD1 / 256)); // 高度高字节
    hexUse.push(lcdD1 % 256);             // 高度低字节
    return hexUse;
  }

  /**
   * @description 设置 LCD 显示区域并准备写入数据
   * @param {number} lcdX - 显示区域起始 X 坐标
   * @param {number} lcdY - 显示区域起始 Y 坐标
   * @param {number} lcdW - 显示区域宽度
   * @param {number} lcdH - 显示区域高度
   */
  async function lcdSetDisplaySend(lcdX = 0, lcdY = 0, lcdW = 0, lcdH = 0) {

    let hexUse = [];

    hexUse.push(...lcdSetDisplayXY(lcdX, lcdY));
    hexUse.push(...lcdSetDisplaySize(lcdW, lcdH));
    hexUse.push(2); // LCD 多次写入命令
    hexUse.push(3); // 设置指令
    hexUse.push(7); // 载入地址
    hexUse.push(0, 0, 0);

    await sendData(hexUse);

  }

  /**
   * @description 监听串口数据
   * @param {typeof serialReader} reader
   * @param {TextDecoder}         decoder
   */
  async function listenSerialData(reader, decoder) {
    try {
      while (true) {

        let { value, done } = await reader.read();

        // 端口已关闭
        if (done) {
          console.info('串口已关闭');
          deviceState = 0;
          break;
        }

        // 处理接收到的数据
        let data = decoder.decode(value);

        console.debug('接收数据:', data);

        // 检测是否为 MSN 设备
        if (data.length > 5) {
          for (let n = 0; n < data.length - 5; n++) {
            if (data.charCodeAt(n) === 0) {
              if (data.substring(n + 1, n + 4) === 'MSN') {
                // 确认是 MSN 设备
                console.info('检测到 MSN 设备');
                deviceState = 1;
                // 检查是否收到连接确认
                if (data.substring(n + 1, n + 6) === 'MSNCN') {
                  console.info('MSN 设备连接完成');
                }
                break;
              }
            }
          }
        }

      }
    } catch (error) {
      console.error('读取串口数据失败:', error);
      deviceState = 0;
    }
  }

  /** 循环发送画布内容到设备 */
  async function sendCanvas(timestamp = 0) {

    // 限制发送频率
    if (timestamp - lastSendTime >= sendInterval) {

      // 更新时间戳
      lastSendTime = timestamp;

      // 未连接，结束后续处理
      if (!deviceState) {
        sendAnimationId = requestAnimationFrame(sendCanvas);
        return;
      }

      // 创建一个临时画布用于图像缩放
      let tempCanvas = document.createElement('canvas');
      let tempCtx = tempCanvas.getContext('2d');

      tempCanvas.width = LCD_WIDTH;
      tempCanvas.height = LCD_HEIGHT;

      // 将原始画布内容缩放到设备实际分辨率
      tempCtx.drawImage(canvas, 0, 0, LCD_WIDTH, LCD_HEIGHT);

      // 获取缩放后的图像数据
      let imageData = tempCtx.getImageData(0, 0, LCD_WIDTH, LCD_HEIGHT);

      // 转换为 RGB565 格式
      let rgb565 = convertRgb888ToRgb565(imageData);

      // 压缩数据
      let hexUse = convertDisplayData(rgb565);

      // 设置显示区域
      await lcdSetDisplaySend(0, 0, LCD_WIDTH, LCD_HEIGHT);

      // 发送数据到设备
      await sendData(hexUse);

    }

    // 循环发送
    sendAnimationId = requestAnimationFrame(sendCanvas);

  }

  /** 发送数据到设备 */
  async function sendData(dataArray = []) {

    if (!serialWriter) {
      return;
    }

    try {
      let data = new Uint8Array(dataArray);
      await serialWriter.write(data);
      console.debug('发送数据成功:', dataArray.length, '字节');
    } catch (error) {
      console.error('发送数据失败:', error);
    }

  }

  /** 发送文本到设备 */
  async function sendText(text = '') {

    if (!serialWriter) {
      return;
    }

    try {

      // 构建消息
      let data = new Uint8Array(text.length + 1);

      // 添加消息头
      data[0] = 0x00;

      // 处理消息内容
      for (let i = 0; i < text.length; i++) {
        data[i + 1] = text.charCodeAt(i);
      }

      await serialWriter.write(data);

      console.debug('发送文本成功:', text);

    } catch (error) {
      console.error('发送文本失败:', error);
    }

  }

  /** 循环渲染画布内容 */
  async function renderCanvas(timestamp = 0) {

    // 限制渲染频率
    if (timestamp - lastRenderTime >= renderInterval) {

      // 更新时间戳
      lastRenderTime = timestamp;

      // 更新画布内容
      switch (displayMode) {
        case 'data':
          await renderDataText();
          break;
        case 'spectrum':
          await renderAudioSpectrum();
          break;
        default:
          break;
      }

    }

    // 循环渲染
    renderAnimationId = requestAnimationFrame(renderCanvas);

  }

  /** 渲染音频频谱内容 */
  async function renderAudioSpectrum() {

    // 初始化音频
    if (!isAudioReady) {
      await audioAnalyserStart();
    }

    // 清空画布
    ctx.fillStyle = 'black';
    ctx.fillRect(0, 0, CANVAS_WIDTH, CANVAS_HEIGHT);

    if (!audioAnalyser) {
      ctx.fillStyle = 'white';
      ctx.font = '16px Arial';
      ctx.textAlign = 'center';
      ctx.fillText('音频未初始化', CANVAS_WIDTH / 2, CANVAS_HEIGHT / 2);
      return;
    }

    // 获取频谱数据
    audioAnalyser.getByteFrequencyData(audioDataArray);

    // 计算柱状图宽度和间距
    let barWidth = (CANVAS_WIDTH / audioBufferLength) * 2.5;
    let x = 0;

    // 绘制频谱柱状图
    for (let i = 0; i < audioBufferLength; i++) {

      // 计算柱状图高度
      let barHeight = (audioDataArray[i] / 255) * CANVAS_HEIGHT;

      // 生成渐变颜色
      let r = Math.floor((i / audioBufferLength) * 255);
      let g = Math.floor((audioDataArray[i] / 255) * 255);
      let b = 150;

      ctx.fillStyle = `rgb(${r}, ${g}, ${b})`;

      // 绘制柱状图
      ctx.fillRect(x, CANVAS_HEIGHT - barHeight, barWidth, barHeight);

      // 移动到下一个柱状图位置
      x += barWidth + 1;

    }

  }

  /** 渲染数据文本内容 */
  async function renderDataText() {

    // 更新画布内容
    dataTextRender.createDisplayImage();

  }

  // 初始化下拉选项
  (function () {

    let displayModeElements = [];
    let resolutionElements = [];

    // 显示模式
    for (let key in DISPLAY_MODES) {

      /** @type {typeof DISPLAY_MODES['data']} */
      let item = DISPLAY_MODES[key];
      let element = document.createElement('option');

      element.value = key;
      element.textContent = item.label;
      displayModeElements.push(element);

      if (item.isDefault) {
        element.selected = true;
      }

    }

    // 分辨率
    for (let key in RESOLUTION_LIST) {

      /** @type {typeof RESOLUTION_LIST['160x80']} */
      let item = RESOLUTION_LIST[key];
      let element = document.createElement('option');

      element.value = key;
      element.textContent = item.label;
      resolutionElements.push(element);

      if (item.isDefault) {

        element.selected = true;

        // 更新画布属性
        canvas.width = item.showWidth;
        canvas.height = item.showHeight;

        // 更新显示参数
        CANVAS_WIDTH = item.showWidth;
        CANVAS_HEIGHT = item.showHeight;
        LCD_WIDTH = item.lcdX;
        LCD_HEIGHT = item.lcdY;

      }

    }

    // 添加到下拉列表
    displayModeSelector.append.apply(displayModeSelector, displayModeElements);
    resolutionSelector.append.apply(resolutionSelector, resolutionElements);

  })();

  // 初始化事件
  (function () {

    // 点击连接设备按钮
    connectButton.addEventListener('click', async () => {
      try {

        // 请求用户授权访问串口设备
        serialPort = await navigator.serial.requestPort();

        // 打开串口
        await serialPort.open({
          baudRate: 115200,
          dataBits: 8,
          stopBits: 1,
          parity: 'none',
          flowControl: 'hardware',
        });

        const encoder = new TextEncoder();
        const decoder = new TextDecoder('gbk');

        serialReader = serialPort.readable.getReader();
        serialWriter = serialPort.writable.getWriter();

        // 开始监听串口数据
        listenSerialData(serialReader, decoder);

        console.info('MSN 设备连接中...');

        // 发送连接确认消息
        await sendText('MSNCN');

        // 连接成功后自动开始发送
        setTimeout(() => {
          if (!sendAnimationId) {
            console.info('自动开始发送');
            sendAnimationId = requestAnimationFrame(sendCanvas);
          }
        }, 100);

      } catch (error) {
        console.error('连接设备失败:', error);
      }
    });

    // 点击断开连接按钮
    disconnectButton.addEventListener('click', async () => {

      // 断开连接前自动停止发送
      if (sendAnimationId) {
        console.info('自动停止发送');
        cancelAnimationFrame(sendAnimationId);
        sendAnimationId = null;
      }

      if (serialReader) {
        await serialReader.cancel();
        serialReader.releaseLock();
        serialReader = null;
      }

      if (serialWriter) {
        await serialWriter.close();
        serialWriter.releaseLock();
        serialWriter = null;
      }

      if (serialPort) {
        await serialPort.close();
        serialPort = null;
      }

      deviceState = 0;
      console.info('断开连接成功');

    });

    // 点击开始渲染按钮
    startButton.addEventListener('click', () => {
      if (!renderAnimationId) {
        console.info('开始渲染');
        renderAnimationId = requestAnimationFrame(renderCanvas);
      }
    });

    // 点击停止渲染按钮
    stopButton.addEventListener('click', () => {

      // 停止循环渲染
      if (renderAnimationId) {
        console.info('停止渲染');
        cancelAnimationFrame(renderAnimationId);
        renderAnimationId = null;
      }

      // 停止音频分析
      audioAnalyserStop();

    });

    // 显示模式选择
    displayModeSelector.addEventListener('change', () => {

      displayMode = displayModeSelector.value;

      let info = DISPLAY_MODES[displayMode];

      if (info) {
        console.info(`显示模式切换成功: ${info.label}`);
      } else {
        console.error('显示模式切换失败：模式无效');
        displayMode = '';
        return;
      }

    });

    // 分辨率选择
    resolutionSelector.addEventListener('change', () => {

      let value = resolutionSelector.value;
      let config = RESOLUTION_LIST[value];

      // 更新画布属性
      canvas.width = CANVAS_WIDTH;
      canvas.height = CANVAS_HEIGHT;

      // 更新显示参数
      CANVAS_WIDTH = config.showWidth;
      CANVAS_HEIGHT = config.showHeight;
      LCD_WIDTH = config.lcdX;
      LCD_HEIGHT = config.lcdY;

      // 显示信息
      console.info(`分辨率切换成功：${value}`);

    });

  })();

});