using System;
using System.Collections.Generic;

namespace CoreCms.Net.Utility.Helper
{
    /// <summary>
    /// 时段工具类
    /// </summary>
    public static class TimeSlotHelper
    {
        #region 时段常量定义

        /// <summary>
        /// 凌晨时段
        /// </summary>
        public const int DAWN = 0;

        /// <summary>
        /// 上午时段
        /// </summary>
        public const int MORNING = 1;

        /// <summary>
        /// 下午时段
        /// </summary>
        public const int AFTERNOON = 2;

        /// <summary>
        /// 晚上时段
        /// </summary>
        public const int EVENING = 3;

        #endregion

        #region 时段时间范围

        /// <summary>
        /// 时段开始小时配置
        /// </summary>
        private static readonly Dictionary<int, int> SlotStartHours = new Dictionary<int, int>
        {
            { DAWN, 0 },        // 凌晨 00:00
            { MORNING, 6 },     // 上午 06:00
            { AFTERNOON, 12 },  // 下午 12:00
            { EVENING, 18 }     // 晚上 18:00
        };

        /// <summary>
        /// 时段结束小时配置（23点59分需要特殊处理）
        /// </summary>
        private static readonly Dictionary<int, int> SlotEndHours = new Dictionary<int, int>
        {
            { DAWN, 5 },        // 凌晨 05:59
            { MORNING, 11 },    // 上午 11:59
            { AFTERNOON, 17 },  // 下午 17:59
            { EVENING, 23 }     // 晚上 23:59
        };

        /// <summary>
        /// 时段名称配置
        /// </summary>
        private static readonly Dictionary<int, string> SlotNames = new Dictionary<int, string>
        {
            { DAWN, "凌晨" },
            { MORNING, "上午" },
            { AFTERNOON, "下午" },
            { EVENING, "晚上" }
        };

        #endregion

        #region 公共方法

        /// <summary>
        /// 根据时间获取时段类型
        /// </summary>
        /// <param name="time">时间</param>
        /// <returns>时段类型：0=凌晨，1=上午，2=下午，3=晚上</returns>
        public static int GetTimeSlotType(DateTime time)
        {
            int hour = time.Hour;

            if (hour >= 0 && hour < 6)
                return DAWN;
            else if (hour >= 6 && hour < 12)
                return MORNING;
            else if (hour >= 12 && hour < 18)
                return AFTERNOON;
            else
                return EVENING;
        }

        /// <summary>
        /// 根据时段类型获取时段名称
        /// </summary>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>时段名称</returns>
        public static string GetTimeSlotName(int timeSlotType)
        {
            return SlotNames.ContainsKey(timeSlotType) ? SlotNames[timeSlotType] : "未知时段";
        }

        /// <summary>
        /// 获取时段的起止时间
        /// </summary>
        /// <param name="date">日期</param>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>起止时间元组 (开始时间, 结束时间)</returns>
        public static (DateTime startTime, DateTime endTime) GetTimeRange(DateTime date, int timeSlotType)
        {
            if (!SlotStartHours.ContainsKey(timeSlotType))
            {
                throw new ArgumentException($"无效的时段类型：{timeSlotType}");
            }

            // 使用日期的Date部分，确保从00:00:00开始
            var dayStart = date.Date;

            // 计算开始时间
            var startHour = SlotStartHours[timeSlotType];
            var startTime = dayStart.AddHours(startHour);

            // 计算结束时间（设置为该时段最后一分钟的最后一秒）
            var endHour = SlotEndHours[timeSlotType];
            var endTime = dayStart.AddHours(endHour).AddMinutes(59).AddSeconds(59);

            return (startTime, endTime);
        }

        /// <summary>
        /// 获取时段的起止时间（返回分离的开始和结束时间）
        /// </summary>
        /// <param name="date">日期</param>
        /// <param name="timeSlotType">时段类型</param>
        /// <param name="startTime">输出参数：开始时间</param>
        /// <param name="endTime">输出参数：结束时间</param>
        public static void GetTimeRange(DateTime date, int timeSlotType, out DateTime startTime, out DateTime endTime)
        {
            var range = GetTimeRange(date, timeSlotType);
            startTime = range.startTime;
            endTime = range.endTime;
        }

        /// <summary>
        /// 校验时间是否在指定时段内
        /// </summary>
        /// <param name="time">要校验的时间</param>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>是否在时段内</returns>
        public static bool ValidateTimeSlot(DateTime time, int timeSlotType)
        {
            var (startTime, endTime) = GetTimeRange(time.Date, timeSlotType);
            return time >= startTime && time <= endTime;
        }

        /// <summary>
        /// 获取所有时段类型列表
        /// </summary>
        /// <returns>时段类型列表</returns>
        public static List<int> GetAllTimeSlotTypes()
        {
            return new List<int> { DAWN, MORNING, AFTERNOON, EVENING };
        }

        /// <summary>
        /// 获取所有时段信息（类型和名称）
        /// </summary>
        /// <returns>时段信息字典</returns>
        public static Dictionary<int, string> GetAllTimeSlots()
        {
            return new Dictionary<int, string>(SlotNames);
        }

        /// <summary>
        /// 判断时段类型是否有效
        /// </summary>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>是否有效</returns>
        public static bool IsValidTimeSlotType(int timeSlotType)
        {
            return timeSlotType >= DAWN && timeSlotType <= EVENING;
        }

        /// <summary>
        /// 获取时段的时间范围描述
        /// </summary>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>时间范围描述，如"00:00-05:59"</returns>
        public static string GetTimeRangeDescription(int timeSlotType)
        {
            if (!SlotStartHours.ContainsKey(timeSlotType))
            {
                return "未知时段";
            }

            var startHour = SlotStartHours[timeSlotType];
            var endHour = SlotEndHours[timeSlotType];

            return $"{startHour:D2}:00-{endHour:D2}:59";
        }

        /// <summary>
        /// 获取完整的时段描述
        /// </summary>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>完整描述，如"凌晨(00:00-05:59)"</returns>
        public static string GetFullTimeSlotDescription(int timeSlotType)
        {
            var name = GetTimeSlotName(timeSlotType);
            var range = GetTimeRangeDescription(timeSlotType);
            return $"{name}({range})";
        }

        /// <summary>
        /// 检查两个时段是否有重叠
        /// </summary>
        /// <param name="date">日期</param>
        /// <param name="slot1">时段1</param>
        /// <param name="slot2">时段2</param>
        /// <returns>是否重叠</returns>
        public static bool IsTimeSlotOverlap(DateTime date, int slot1, int slot2)
        {
            // 同一时段必然重叠
            if (slot1 == slot2)
                return true;

            var (start1, end1) = GetTimeRange(date, slot1);
            var (start2, end2) = GetTimeRange(date, slot2);

            // 判断时间段是否重叠
            return start1 < end2 && start2 < end1;
        }

        /// <summary>
        /// 获取当前时段类型
        /// </summary>
        /// <returns>当前时段类型</returns>
        public static int GetCurrentTimeSlotType()
        {
            return GetTimeSlotType(DateTime.Now);
        }

        /// <summary>
        /// 判断指定时段是否已过去
        /// </summary>
        /// <param name="date">日期</param>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>是否已过去</returns>
        public static bool IsTimeSlotPassed(DateTime date, int timeSlotType)
        {
            var (startTime, endTime) = GetTimeRange(date, timeSlotType);
            return DateTime.Now > endTime;
        }

        /// <summary>
        /// 判断指定时段是否正在进行中
        /// </summary>
        /// <param name="date">日期</param>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>是否正在进行中</returns>
        public static bool IsTimeSlotCurrent(DateTime date, int timeSlotType)
        {
            var (startTime, endTime) = GetTimeRange(date, timeSlotType);
            var now = DateTime.Now;
            return now >= startTime && now <= endTime;
        }

        /// <summary>
        /// 判断指定时段是否在未来
        /// </summary>
        /// <param name="date">日期</param>
        /// <param name="timeSlotType">时段类型</param>
        /// <returns>是否在未来</returns>
        public static bool IsTimeSlotFuture(DateTime date, int timeSlotType)
        {
            var (startTime, endTime) = GetTimeRange(date, timeSlotType);
            return DateTime.Now < startTime;
        }

        #endregion
    }
}