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

namespace TestConsoleApp
{
    internal class Program
    {
        static void Main(string[] args)
        {
            var dt1 = new DateTime(2026, 3, 29, 4, 0, 0);
            var dt2 = new DateTime(2026, 3, 29, 6, 0, 0);
            var dt3 = new DateTime(2026, 3, 29, 14, 0, 0);

            var dnt1 = DateAndTime.GetNow("", dt1);
            var dnt2 = DateAndTime.GetNow("", dt2);
            var dnt3 = DateAndTime.GetNow("", dt3);

            Console.WriteLine(string.Format("{0:yyyy-MM-dd} {1:yyyy-MM-dd} {2} {3:yyyy-MM-dd} {4}", dnt1.TwWorkDate, dnt1.TwCalendarDate, dnt1.TwTime, dnt1.LocalDate, dnt1.LocalTime));
            Console.WriteLine(string.Format("{0:yyyy-MM-dd} {1:yyyy-MM-dd} {2} {3:yyyy-MM-dd} {4}", dnt2.TwWorkDate, dnt2.TwCalendarDate, dnt2.TwTime, dnt2.LocalDate, dnt2.LocalTime));
            Console.WriteLine(string.Format("{0:yyyy-MM-dd} {1:yyyy-MM-dd} {2} {3:yyyy-MM-dd} {4}", dnt3.TwWorkDate, dnt3.TwCalendarDate, dnt3.TwTime, dnt3.LocalDate, dnt3.LocalTime));
            Console.WriteLine("按 ENTER 結束");
            Console.ReadLine();
        }
    }

    /// <summary>
    /// 30 小時制的日期類別
    /// </summary>
    public class DateAndTime
    {
        /// <summary>
        /// 台灣工作日期
        /// </summary>
        public DateTime TwWorkDate;

        /// <summary>
        /// 台灣日曆日期
        /// </summary>
        public DateTime TwCalendarDate;

        /// <summary>
        /// 台灣時間
        /// </summary>
        public string TwTime;

        /// <summary>
        /// 當地日期
        /// </summary>
        public DateTime LocalDate;

        /// <summary>
        /// 當地時間
        /// </summary>
        public string LocalTime;

        /// <summary>
        /// 時區名稱
        /// </summary>
        public string TimezoneName;

        /// <summary>
        /// 時區ID
        /// </summary>
        public string TimeZoneID;

        public DateAndTime(DateTime twWorkDate, DateTime twCalendarDate, string twTime, DateTime localDate, string localTime, string timezoneName, string timezoneID) : base()
        {
            this.TwWorkDate = twWorkDate;
            this.TwCalendarDate = twCalendarDate;
            this.TwTime = twTime;
            this.LocalDate = localDate;
            this.LocalTime = localTime;
            TimezoneName = timezoneName;
            TimeZoneID = timezoneID;
        }

        public static DateTime 轉換時區(string 時區, DateTime 日期, string 時間)
        {
            // 解析30小時制（小時可能 >= 24，表示跨入隔日凌晨）
            var parts = 時間.Split(':');
            var timeSpan = new TimeSpan(int.Parse(parts[0]), int.Parse(parts[1]), int.Parse(parts[2]));
            var sourceTime = 日期.Date.Add(timeSpan);

            if (string.IsNullOrEmpty(時區) || string.Compare(時區, "Taipei Standard Time") == 0)
            {
                return sourceTime;
            }

            // 重要：將 Kind 設為 Unspecified
            sourceTime = DateTime.SpecifyKind(sourceTime, DateTimeKind.Unspecified);

            // 轉換到目標時區
            var sourceZone = TimeZoneInfo.FindSystemTimeZoneById("Taipei Standard Time");
            var targetZone = TimeZoneInfo.FindSystemTimeZoneById(時區);

            var utcTime = TimeZoneInfo.ConvertTimeToUtc(sourceTime, sourceZone);
            var targetTime = TimeZoneInfo.ConvertTimeFromUtc(utcTime, targetZone);

            return targetTime;
        }

        public static DateAndTime GetNow(string bpeno, DateTime twNow)
        {
            string timezoneID = "Pacific Standard Time";
            string timezoneName = "美西";

            var twCalendarDate = twNow.Date;
            var twWorkDate = twNow.Date;
            var localNow = 轉換時區(timezoneID, twNow.Date, twNow.ToString("HH:mm:ss"));
            var localDate = localNow.Date;
            var twHourOffset = 0;
            var localHourOffset = 0;

            // 06:00 之前算前一天
            if (twNow.TimeOfDay < new TimeSpan(6, 0, 0))
            {
                twWorkDate = twWorkDate.AddDays(-1);
                twHourOffset = 24;
            }
            if (localNow.TimeOfDay < new TimeSpan(6, 0, 0))
            {
                localDate = localDate.AddDays(-1);
                localHourOffset = 24;
            }

            return new DateAndTime(
                twWorkDate,
                twCalendarDate,
                string.Format("{0:00}:{1:00}:{2:00}", twNow.TimeOfDay.Hours + twHourOffset, twNow.TimeOfDay.Minutes, twNow.Second),
                localDate,
                string.Format("{0:00}:{1:00}:{2:00}", localNow.TimeOfDay.Hours + localHourOffset, localNow.TimeOfDay.Minutes, localNow.Second),
                timezoneName,
                timezoneID
            );
        }

        public static DateAndTime GetNow(string bpeno)
        {
            var twNow = DateTime.UtcNow.AddHours(8);
            return GetNow(bpeno, twNow);
        }
    }
}