<?php
namespace common\helpers;

use Yii;

/**
 * 日期助手类
 */
class DateHelper
{

    /**
     * 日期列表
     * @param string $beginDatetime 开始日期，日期时间格式，如2017-08-28 15:11:39
     * @param string $endDatetime 结束日期
     * @return array
     */
    public static function getDaily($beginDatetime, $endDatetime)
    {
        $beginTime = strtotime($beginDatetime);
        if (!$beginTime) {
            return [];
        }

        $endTime = strtotime($endDatetime);
        if (!$endTime) {
            return [];
        }

        $list = [];
        while ($beginTime <= $endTime) {
            $list[] = date('Y-m-d', $beginTime);
            $beginTime = strtotime('+1 days midnight', $beginTime);
        }

        return $list;
    }

    /**
     * 从昨天起，日期列表
     * @param string $date 日期，日期时间格式，如2017-08-28 15:11:39
     * @return array
     */
    public static function getDailyYesterday($date)
    {
        $now = strtotime(date("Y-m-d",strtotime('-1 days')));
        $start = strtotime($date);
        $temp = $start;
        $list = [];
        $i = 0;
        while ($now >= $temp) {
            $temp = strtotime("+$i days", $start);
            $list[] = date('Y-m-d', $temp);
            $i++;
        }

        return $list;
    }

    /**
     * 把时间戳转成日期时间格式
     * @param int $timestamp
     * @return string
     */
    public static function convertTime($timestamp)
    {
        $timestamp = (int) $timestamp;
        if (!$timestamp) {
            return '';
        }

        $datetime = date('Y-m-d H:i:s', $timestamp);
        if (!$datetime) {
            return '';
        }

        return $datetime;
    }
    
    /**
     * 把格式化的本地日期转成GMT/UTC（即0时区）的日期
     * 
     * $local_date = '2018-03-07 15:44:00';
     * 
     * date_default_timezone_set('Asia/Shanghai');
     * var_dump(date_default_timezone_get());
     * var_dump(convertDate($local_date));
     * 
     * date_default_timezone_set('UTC');
     * var_dump(date_default_timezone_get());
     * var_dump(convertDate($local_date));
     * 
     * @param string $local_date
     * @param int $timezone 参数$local_date对应的时区
     * @return string
     */
     public static function convertDateToGmt($local_date, $timezone = 8)
     {
         $time = strtotime(trim($local_date));
         if (!$time) {
             return $local_date;
         }
         
         $time = $time - $timezone * 3600;
         
         $date = date('Y-m-d H:i:s', $time);
         return $date;
     }
     
     /**
      * 等同于convertDateToGmt
      * @param string $local_date
      * @param int $timezone 参数$local_date对应的时区
      * @return string
      */
     public static function convertDateToUtc($local_date, $timezone = 8)
     {
         return static::convertDateToGmt($local_date, $timezone);
     }
     
     /**
      * 把GMT/UTC（即0时区）的日期转成格式化的本地日期
      * @param string $gmt_date
      * @param int $timezone
      * @return string
      */
     public static function convertDateToLocal($gmt_date, $timezone = 8)
     {
         $time = strtotime(trim($gmt_date));
         if (!$time) {
             return $gmt_date;
         }
         
         $time = $time + $timezone * 3600;
         
         $date = date('Y-m-d H:i:s', $time);
         return $date;
     }
     
}