using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;

namespace IStation.Extensions
{
    /// <summary>
    /// DateTime 拓展
    /// </summary>
    public static class DateTimeExtension
    {
        /// <summary>
        /// 获取周数
        /// </summary>
        public static int GetWeekOfYear(this DateTime dt)
        {
            GregorianCalendar gc = new GregorianCalendar();
            int weekOfYear = gc.GetWeekOfYear(dt, CalendarWeekRule.FirstDay, DayOfWeek.Monday);
            return weekOfYear;
        }

        /// <summary>
        /// 获取周一时间
        /// </summary>
        public static DateTime GetWeekFirst(this DateTime dt)
        {
            var dayOfWeek = dt.DayOfWeek;
            if (dayOfWeek == DayOfWeek.Sunday)
                return dt.AddDays(-6).Date;
            return dt.AddDays(1 - (int)dayOfWeek).Date;
        }

        /// <summary>
        /// 获取本周末
        /// </summary>
        public static DateTime GetWeekLast(this DateTime dt)
        {
            var dayOfWeek = dt.DayOfWeek;
            if (dayOfWeek == DayOfWeek.Sunday)
                return dt.Date;
            return dt.AddDays(7 - (int)dayOfWeek).Date;
        }

        /// <summary>
        /// 获取月初
        /// </summary>
        public static DateTime GetMonthFirst(this DateTime dt)
        {
            return new DateTime(dt.Year, dt.Month, 1);
        }

        /// <summary>
        /// /获取月末
        /// </summary>
        public static DateTime GetMonthLast(this DateTime dt)
        {
            var dt_temp = dt.AddMonths(1);
            return dt_temp.AddDays(-1).Date;
        }

        /// <summary>
        /// yyyy-MM-dd 格式字符串
        /// </summary>
        public static string ToStandardDateString(this DateTime dt)
        {
            var format = "yyyy-MM-dd";
            return dt.ToString(format);
        }

        /// <summary>
        /// HH:mm:ss 格式字符串
        /// </summary>
        public static string ToStandardTimeString(this DateTime dt)
        {
            var format = "HH:mm:ss";
            return dt.ToString(format);
        }

        /// <summary>
        /// yyyy-MM-dd HH:mm:ss 格式字符串
        /// </summary>
        public static string ToStandardString(this DateTime dt)
        {
            var format = "yyyy-MM-dd HH:mm:ss";
            return dt.ToString(format);
        }




    }
}