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


namespace AriasServerUtils
{
    public static class TimeUtil
    {
        private static readonly Dictionary<char, int> TimeUnits = new()
        {
            { 's', 1 },        // seconds
            { 'm', 60 },       // minutes
            { 'h', 3600 },     // hours
            { 'd', 86400 },    // days
            { 'w', 604800 },   // weeks
            { 'M', 2592000 },  // months (approx. 30 days)
            { 'y', 31536000 }  // years (365 days)
        };

        public static long DecodeTimeNotation(string input)
        {
            if (string.IsNullOrWhiteSpace(input)) return 0;

            long totalSeconds = 0;
            int number = 0;

            foreach (char c in input)
            {
                if (char.IsDigit(c))
                {
                    number = number * 10 + (c - '0');
                }
                else if (TimeUnits.TryGetValue(c, out int unitSeconds))
                {
                    totalSeconds += number * unitSeconds;
                    number = 0;
                }
                else
                {
                    throw new FormatException($"Invalid time unit: {c}");
                }
            }

            return totalSeconds;
        }

        public static string EncodeTimeNotation(long seconds)
        {
            if (seconds <= 0) return "0s";

            var result = new List<string>();

            foreach (var (unit, unitSeconds) in TimeUnits.OrderByDescending(u => u.Value))
            {
                long value = seconds / unitSeconds;
                if (value > 0)
                {
                    result.Add($"{value}{unit}");
                    seconds %= unitSeconds;
                }
            }

            return string.Join("", result);
        }

        public static long GetUnixEpochTimestamp()
        {
            return DateTimeOffset.UtcNow.ToUnixTimeSeconds();
        }
    }
}