// 中國 東8區   韓國 東9區  印度 東5.5區
export const getNewDate = function({ date, zone }) { // date 日期格式  zone 時區
  var timezone = zone || 8; //目標時區時間
  var dates = date || new Date()
  var offset_GMT = dates.getTimezoneOffset(); // Date中時間和格林威治的時間差，單位為分鐘
  var nowDate = dates.getTime(); // Date中時間距 1970 年 1 月 1 日午夜（GMT 時間）之間的毫秒數
  var targetDate = new Date(nowDate + offset_GMT * 60 * 1000 + timezone * 60 * 60 * 1000);
  // console.log(`東${timezone}區現在是：` + targetDate)
  return targetDate
}

export const toTimestamp = function(time, zone) { // time 可以為時間戳，可為日期
  if (!time) return null
  if (arguments.length === 0) {
    return null
  }
  let date
  if (typeof time === 'object') {
    date = time
  } else {
    if ((typeof time === 'string')) {
      if ((/^[0-9]+$/.test(time))) {
        // support "1548221490638"
        time = parseInt(time)
      } else {
        // support safari
        // https://stackoverflow.com/questions/4310953/invalid-date-in-safari
        time = time.replace(new RegExp(/-/gm), '/')
      }
    }

    if ((typeof time === 'number') && (time.toString().length === 10)) {
      time = time * 1000
    }
    date = new Date(time)
  }
  date = getNewDate({ date, zone })
  return date.getTime()
}

export function parseTime(time, cFormat, zone) { // time 可以為時間戳，可為日期
  if (!time) return null
  if (arguments.length === 0) {
    return null
  }
  const format = cFormat || '{y}-{m}-{d} {h}:{i}:{s}'
  let date
  if (typeof time === 'object') {
    date = time
  } else {
    if ((typeof time === 'string')) {
      if ((/^[0-9]+$/.test(time))) {
        // support "1548221490638"
        time = parseInt(time)
      } else {
        // support safari
        // https://stackoverflow.com/questions/4310953/invalid-date-in-safari
        time = time.replace(new RegExp(/-/gm), '/')
      }
    }

    if ((typeof time === 'number') && (time.toString().length === 10)) {
      time = time * 1000
    }
    date = new Date(time)
  }
  date = getNewDate({ date, zone })
  const formatObj = {
    y: date.getFullYear(),
    m: date.getMonth() + 1,
    d: date.getDate(),
    h: date.getHours(),
    i: date.getMinutes(),
    s: date.getSeconds(),
    a: date.getDay()
  }
  const time_str = format.replace(/{([ymdhisa])+}/g, (result, key) => {
    const value = formatObj[key]
    // Note: getDay() returns 0 on Sunday
    if (key === 'a') { return ['日', '一', '二', '三', '四', '五', '六'][value ] }
    return value.toString().padStart(2, '0')
  })
  return time_str
}

/**
 * @param {number} time
 * @param {string} option
 * @returns {string}
 */
export function formatTime(time, option) { // time 時間戳 option
  if (('' + time).length === 10) {
    time = parseInt(time) * 1000
  } else {
    time = +time
  }
  const d = new Date(time)
  const now = Date.now()

  const diff = (now - d) / 1000

  if (diff < 30) {
    return '剛剛'
  } else if (diff < 3600) {
    // less 1 hour
    return Math.ceil(diff / 60) + '分鐘前'
  } else if (diff < 3600 * 24) {
    return Math.ceil(diff / 3600) + '小時前'
  } else if (diff < 3600 * 24 * 2) {
    return '1天前'
  }
  if (option) {
    return parseTime(time, option)
  } else {
    return (
      d.getMonth() +
      1 +
      '月' +
      d.getDate() +
      '日' +
      d.getHours() +
      '時' +
      d.getMinutes() +
      '分'
    )
  }
}