const formatTime = date => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = date.getDate()
  const hour = date.getHours()
  const minute = date.getMinutes()
  const second = date.getSeconds()
  return (
    [year, month, day].map(formatNumber).join('/') +
    ' ' +
    [hour, minute, second].map(formatNumber).join(':')
  )
}

const formatNumber = n => {
  n = n.toString()
  return n[1] ? n : '0' + n
}

const fsm = wx.getFileSystemManager()
const FILE_BASE_NAME = 'tmp_base64src'

const base64src = function (base64data) {
  return new Promise((resolve, reject) => {
    const [, format, bodyData] = /data:image\/(\w+);base64,(.*)/.exec(base64data) || []
    if (!format) {
      reject(new Error('ERROR_BASE64SRC_PARSE'))
    }
    const filePath = `${wx.env.USER_DATA_PATH}/${FILE_BASE_NAME}.${format}`
    const buffer = wx.base64ToArrayBuffer(bodyData)
    fsm.writeFile({
      filePath,
      data: buffer,
      encoding: 'binary',
      success() {
        resolve(filePath)
      },
      fail() {
        reject(new Error('ERROR_BASE64SRC_WRITE'))
      },
    })
  })
}

module.exports = {
  formatTime: formatTime,
  base64src,
}