/**
 * 格式化时间
 * @param {time} 时间
 * @param {cFormat} 格式
 * @return {String} 字符串
 * @example formatTime('2018-1-29', '{y}/{m}/{d} {h}:{i}:{s}') // -> 2018/01/29 00:00:00
 */
formatTime(time, cFormat) {
  if (arguments.length === 0) return null
  if ((time + '').length === 10) {
    time = +time * 1000
  }
  var format = cFormat || '{y}-{m}-{d} {h}:{i}:{s}', date
  if (typeof time === 'object') {
    date = time
  } else {
    date = new Date(time)
  }
  var formatObj = {
    y: date.getFullYear(),
    m: date.getMonth() + 1,
    d: date.getDate(),
    h: date.getHours(),
    i: date.getMinutes(),
    s: date.getSeconds(),
    a: date.getDay()
  }
  var time_str = format.replace(/{(y|m|d|h|i|s|a)+}/g, (result, key) => {
    var value = formatObj[key]
    if (key === 'a') return ['一', '二', '三', '四', '五', '六', '日'][value - 1]
    if (result.length > 0 && value < 10) {
      value = '0' + value
    }
    return value || 0
  })
  return time_str
}
/**
 * 返回指定长度的月份集合
 * @param {time} 时间
 * @param {len} 长度
 * @param {direction} 方向： 1: 前几个月; 2: 后几个月; 3:前后几个月 默认 3
 * @return {Array} 数组
 * @example  getMonths('2018-1-29', 6, 1) // -> ["2018-1", "2017-12", "2017-11", "2017-10", "2017-9", "2017-8", "2017-7"]
 */
getMonths(time, len, direction) {
  var mm = new Date(time).getMonth(),
    yy = new Date(time).getFullYear(),
    direction = isNaN(direction) ? 3 : direction,
    index = mm;
  var cutMonth = function(index) {
    if ( index <= len && index >= -len) {
      return direction === 1 ? formatPre(index).concat(cutMonth(++index)):
        direction === 2 ? formatNext(index).concat(cutMonth(++index)):formatCurr(index).concat(cutMonth(++index))
    }
    return []
  }
  var formatNext = function(i) {
    var y = Math.floor(i/12),
      m = i%12
    return [yy+y + '-' + (m+1)]
  }
  var formatPre = function(i) {
    var y = Math.ceil(i/12),
      m = i%12
    m = m===0 ? 12 : m
    return [yy-y + '-' + (13 - m)]
  }
  var formatCurr = function(i) {
    var y = Math.floor(i/12),
      yNext = Math.ceil(i/12),
      m = i%12,
      mNext = m===0 ? 12 : m
    return [yy-yNext + '-' + (13 - mNext),yy+y + '-' + (m+1)]
  }
  // 数组去重
  var unique = function(arr) {
    if ( Array.hasOwnProperty('from') ) {
      return Array.from(new Set(arr));
    }else{
      var n = {},r=[]; 
      for(var i = 0; i < arr.length; i++){
        if (!n[arr[i]]){
          n[arr[i]] = true; 
          r.push(arr[i]);
        }
      }
      return r;
    }
  }
  return direction !== 3 ? cutMonth(index) : unique(cutMonth(index).sort(function(t1, t2){
    return new Date(t1).getTime() - new Date(t2).getTime()
  }))
}
/**
 * 返回指定长度的天数集合
 * @param {time} 时间
 * @param {len} 长度
 * @param {direction} 方向： 1: 前几天; 2: 后几天; 3:前后几天 默认 3
 * @return {Array} 数组
 * @example date.getDays('2018-1-29', 6) // -> ["2018-1-26", "2018-1-27", "2018-1-28", "2018-1-29", "2018-1-30", "2018-1-31", "2018-2-1"]
 */
getDays(time, len, diretion) {
  var tt = new Date(time)
  var getDay = function(day) {
    var t = new Date(time)
    t.setDate(t.getDate() + day)
    var m = t.getMonth()+1
    return t.getFullYear()+'-'+m+'-'+t.getDate()
  }
  var arr = []
  if (diretion === 1) {
    for (var i = 1; i <= len; i++) {
      arr.unshift(getDay(-i))
    }
  }else if(diretion === 2) {
    for (var i = 1; i <= len; i++) {
      arr.push(getDay(i))
    }
  }else {
    for (var i = 1; i <= len; i++) {
      arr.unshift(getDay(-i))
    }
    arr.push(tt.getFullYear()+'-'+(tt.getMonth()+1)+'-'+tt.getDate())
    for (var i = 1; i <= len; i++) {
      arr.push(getDay(i))
    }
  }
  return diretion === 1 ? arr.concat([tt.getFullYear()+'-'+(tt.getMonth()+1)+'-'+tt.getDate()]) : 
    diretion === 2 ? [tt.getFullYear()+'-'+(tt.getMonth()+1)+'-'+tt.getDate()].concat(arr) : arr
}
/**
 * @param {s} 秒数
 * @return {String} 字符串 
 * @example formatHMS(3610) // -> 1h0m10s
 */
formatHMS (s) {
  var str = ''
  if (s > 3600) {
    str = Math.floor(s/3600)+'h'+Math.floor(s%3600/60)+'m'+s%60+'s'
  }else if(s > 60) {
    str = Math.floor(s/60)+'m'+s%60+'s'
  }else{
    str = s%60+'s'
  }
  return str
}
/*获取某月有多少天*/
getMonthOfDay (time) {
  var date = new Date(time)
  var year = date.getFullYear()
  var mouth = date.getMonth() + 1
  var days
  //当月份为二月时，根据闰年还是非闰年判断天数
  if (mouth == 2) {
    days = (year%4==0 && year%100==0 && year%400==0) || (year%4==0 && year%100!=0) ? 28 : 29
  } else if (mouth == 1 || mouth == 3 || mouth == 5 || mouth == 7 || mouth == 8 || mouth == 10 || mouth == 12) {
    //月份为：1,3,5,7,8,10,12 时，为大月.则天数为31；
    days = 31
  } else {
    //其他月份，天数为：30.
    days = 30
  }
  return days
}
/*获取某年有多少天*/
getYearOfDay (time) {
  var firstDayYear = this.getFirstDayOfYear(time);
  var lastDayYear = this.getLastDayOfYear(time);
  var numSecond = (new Date(lastDayYear).getTime() - new Date(firstDayYear).getTime())/1000;
  return Math.ceil(numSecond/(24*3600));
}
/*获取某年的第一天*/
getFirstDayOfYear (time) {
  var year = new Date(time).getFullYear();
  return year + "-01-01 00:00:00";
}
/*获取某年最后一天*/
getLastDayOfYear (time) {
  var year = new Date(time).getFullYear();
  var dateString = year + "-12-01 00:00:00";
  var endDay = this.getMonthOfDay(dateString);
  return year + "-12-" + endDay + " 23:59:59";
}
/*获取某个日期是当年中的第几天*/
getDayOfYear (time) {
  var firstDayYear = this.getFirstDayOfYear(time);
  var numSecond = (new Date(time).getTime() - new Date(firstDayYear).getTime())/1000;
  return Math.ceil(numSecond/(24*3600));
}
/*获取某个日期在这一年的第几周*/
getDayOfYearWeek (time) {
  var numdays = this.getDayOfYear(time);
  return Math.ceil(numdays / 7);
}