// deviceManager.js
let cachedVideoDevices = null;

export const getVideoDevices = async (forceRefresh = false) => {
  if (cachedVideoDevices && !forceRefresh) {
    return cachedVideoDevices;
  }

  try {
    if (!navigator.mediaDevices?.enumerateDevices) {
      throw new Error('MediaDevices API not supported');
    }

    const devices = await navigator.mediaDevices.enumerateDevices();
    cachedVideoDevices = devices
      .filter(device => device.kind === "videoinput")
      .map(device => ({
        label: device.label,
        id: device.deviceId,
        groupId: device.groupId // 添加更多有用信息
      }));
    
    return cachedVideoDevices;
  } catch (err) {
    console.error('Error enumerating devices:', err);
    throw err;
  }
};

// 监听设备变化
if (navigator.mediaDevices?.addEventListener) {
  navigator.mediaDevices.addEventListener('devicechange', () => {
    cachedVideoDevices = null; // 清除缓存
    // 可以在这里触发自定义事件或回调
  });
}

export const stopCamera = async(video) => {
  if(video == null) return;
  let stream = video.srcObject;
  if(stream==null) return;
  setTimeout(()=>{
    if (stream) {
      let tracks = stream.getTracks();
      tracks.forEach((x) => {
        x.stop();
      });
      video.srcObject = null;
    }
  },500);
};

export const stopStream = async(stream) => {
  if (stream) {
    let tracks = stream.getTracks();
    tracks.forEach((x) => {
      x.stop();
    });
  }
};

export const drawVideoToCanvas = (video,canvas) =>{
  canvas.width = canvas.offsetWidth;
  canvas.height = canvas.offsetHeight;

  // 绘制缩放后的视频帧
  const ctx = canvas.getContext('2d');
  ctx.imageSmoothingEnabled = false;
  ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
}

export const clearCanvas = (canvas) => {
    if(canvas == null) {
        console.error("Canvas element is null");
        return;
    }
    const context = canvas.getContext('2d');
    context.clearRect(0, 0, canvas.width, canvas.height);
}

export const captureImageFromVideo = (video) => {
    // 创建一个画布元素，设置画布尺寸为视频流的尺寸
  const canvas = document.createElement("canvas");
  // 设置画布大小与摄像大小一致
  canvas.width = video.videoWidth;
  canvas.height = video.videoHeight;
  // 获取画布上下文对象
  const ctx = canvas.getContext("2d");
  // 绘制当前视频帧到画布上
  ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
  // 将画布内容转为 Base64 数据
  const imageDataUrl = canvas.toDataURL("image/jpeg",0.8);
  return imageDataUrl;
}

export const captureBlobFromVideo = async (video) => {
    // 创建一个画布元素，设置画布尺寸为视频流的尺寸
  const canvas = document.createElement("canvas");
  // 设置画布大小与摄像大小一致
  canvas.width = video.videoWidth;
  canvas.height = video.videoHeight;
  // 获取画布上下文对象
  const ctx = canvas.getContext("2d");
  ctx.imageSmoothingEnabled = false;
  // 绘制当前视频帧到画布上
  ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
  const imageData = await new Promise(resolve => {
    canvas.toBlob(resolve, 'image/jpeg', 0.9);
  });
  return imageData;
}

export const createCanvasFromVideo = (video) => {
    // 创建一个画布元素，设置画布尺寸为视频流的尺寸
  const canvas = document.createElement("canvas");
  // 设置画布大小与摄像大小一致
  canvas.width = video.videoWidth;
  canvas.height = video.videoHeight;
  // 获取画布上下文对象
  const ctx = canvas.getContext("2d");
  // 绘制当前视频帧到画布上
  ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
  return ctx;
}