// utils/media.js — 选图 + 压缩 + 上传云存储，返回 fileID
// 用法：const fileID = await chooseAndUpload('avatars')

/**
 * 选择一张图片（已压缩）并上传到云存储。
 * @param {string} prefix 云存储目录前缀，如 'avatars' / 'walk-photos'
 * @returns {Promise<string|null>} fileID（cloud://...）或 null
 */
function chooseAndUpload(prefix = 'uploads') {
  return new Promise((resolve) => {
    wx.chooseMedia({
      count: 1,
      mediaType: ['image'],
      sizeType: ['compressed'],
      sourceType: ['album', 'camera'],
      success: async (r) => {
        const temp = r.tempFiles && r.tempFiles[0] && r.tempFiles[0].tempFilePath;
        if (!temp) return resolve(null);
        wx.showLoading({ title: '上传中', mask: true });
        try {
          const up = await wx.cloud.uploadFile({
            cloudPath: `${prefix}/${Date.now()}-${Math.floor(Math.random() * 1e6)}.jpg`,
            filePath: temp,
          });
          resolve(up.fileID);
        } catch (e) {
          wx.showToast({ title: '上传失败', icon: 'none' });
          resolve(null);
        } finally {
          wx.hideLoading();
        }
      },
      fail: () => resolve(null),
    });
  });
}

module.exports = { chooseAndUpload };