import { Base64 } from './base64.js'
import { util } from './crypto.js'
import { HMAC } from './hmac.js'
import { SHA1 } from './sha1.js'

// 下面这3个信息必填
export const OSSUrl = 'https://zjeloong.oss-cn-hangzhou.aliyuncs.com/'
const OSSAccessKeyId = 'LTAI5tEo7FnNzc6ubbEdXhn8'
const OssAccesskeySercet= '8xdKsFQSwQXSXHMsU7vCmpxcXIt3dr';


const policyText = {
  "expiration": "2034-01-01T12:00:00.000Z", // 设置Policy的有效期，格式为UTC时间。如果Policy失效，将无法上传文件。
  "conditions": [
  ["content-length-range", 0, 1048576000] // 限制上传文件的大小，单位为字节，此处限制文件大小为1 GB。如果上传的文件大小超过此限制，文件将无法上传到OSS。如果未设置该限制，则默认文件大小最大为5 GB。
  ]
}

const policy = Base64.encode(JSON.stringify(policyText))
const bytes = HMAC(SHA1, policy, OssAccesskeySercet, { asBytes: true })
const signature = util.bytesToBase64(bytes)

// 生成文件名随机字符串
function random_string(len) {
　　const strLeng = len || 32;
　　const chars = 'ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678';   
　　const maxPos = chars.length;
　　let pwd = '';
　　for (let i = 0; i < strLeng; i++) {
    　　pwd += chars.charAt(Math.floor(Math.random() * maxPos));
    }
    return pwd;
}

// 获取文件后缀
function get_suffix(filename) {
    const pos = filename.lastIndexOf('.')
    let suffix = ''
    if (pos != -1) {
        suffix = filename.substring(pos)
    }
    return suffix;
}

// dir格式：'img/'
export const ossUpload = (filePath, name, dir) => {
  const key = dir + random_string(10) + get_suffix(name)
  return new Promise((resolve, reject) => {
    uni.uploadFile({
      url: OSSUrl,
      filePath,
      name: 'file',
      formData: {
        name,
        key,
        policy,
        OSSAccessKeyId,
        success_action_status: '200',
        signature
      },
      success: () => {
        resolve({success: true, data: OSSUrl + key})
      },
      fail: () => {
        reject({success: false, data: '上传失败'})
      }
    })
  })
}