using System;
using System.Globalization;

using DFEngine.Server;

namespace DFEngine.Content.Game
{
	public class GameTime
	{
		public static readonly GameTime Zero = new GameTime(DateTime.MinValue, TimeSpan.Zero, TimeSpan.Zero);

		public DateTime Time { get; }

		public TimeSpan Elapsed { get; }
		public TimeSpan TotalElapsed { get; }

		public GameTime()
			: this(DateTime.Now, TimeSpan.Zero, TimeSpan.Zero)
		{
		}

		public GameTime(DateTime time)
			: this(time, TimeSpan.Zero, TimeSpan.Zero)
		{
		}

		public GameTime(DateTime time, TimeSpan elapsed)
			: this(time, elapsed, TimeSpan.Zero)
		{
		}

		public GameTime(DateTime time, TimeSpan elapsed, TimeSpan totalElapsed)
		{
			this.Time = time;
			this.Elapsed = elapsed;
			this.TotalElapsed = totalElapsed;
		}

		public TimeSpan Subtract(GameTime time)
		{
			return Subtract(time.Time);
		}

		public TimeSpan Subtract(DateTime time)
		{
			return this.Time.Subtract(time);
		}

		public static GameTime Now()
		{
			return ServerMainBase.InternalInstance.CurrentTime;
		}

		public GameTime AddMilliseconds(double amount)
		{
			return new GameTime(Time.AddMilliseconds(amount), Elapsed, TotalElapsed);
		}

		public override bool Equals(object obj)
		{
			return this == obj as GameTime;
		}

		public override int GetHashCode() => Time.GetHashCode() + Elapsed.GetHashCode() + TotalElapsed.GetHashCode();

		public override string ToString() => Time.ToString(CultureInfo.CurrentCulture);

		public static explicit operator GameTime(DateTime value)
		{
			return new GameTime(value, TimeSpan.Zero, TimeSpan.Zero);
		}

		public static bool operator ==(GameTime v1, GameTime v2)
		{
			if ((object)v1 == null)
				return (object)v2 == null;

			return v2 != null && v1.Time == v2.Time && v1.Elapsed == v2.Elapsed && v1.TotalElapsed == v2.TotalElapsed;
		}

		public static bool operator !=(GameTime v1, GameTime v2)
		{
			return !(v1 == v2);
		}

		public static bool operator >=(GameTime v1, GameTime v2)
		{
			if ((object)v1 == null)
				return (object)v2 == null;

			return v1.Time >= v2.Time;
		}

		public static bool operator <=(GameTime v1, GameTime v2)
		{
			if ((object)v1 == null)
				return (object)v2 == null;

			return v1.Time <= v2.Time;
		}

		public static bool operator >(GameTime v1, GameTime v2)
		{
			if ((object)v1 == null)
				return (object)v2 == null;

			return v1.Time > v2.Time;
		}

		public static bool operator <(GameTime v1, GameTime v2)
		{
			if ((object)v1 == null)
				return (object)v2 == null;

			return v1.Time < v2.Time;
		}

		public static GameTime operator +(GameTime v1, GameTime v2)
		{
			return new GameTime(v1.Time, v1.Elapsed + v2.Elapsed, v1.TotalElapsed + v2.TotalElapsed);
		}

		public static GameTime operator -(GameTime v1, GameTime v2)
		{
			TimeSpan elapsed = v2.Elapsed > v1.Elapsed ? TimeSpan.Zero : v1.Elapsed - v2.Elapsed,
				totalElapsed = v2.TotalElapsed > v1.TotalElapsed ? TimeSpan.Zero : v1.TotalElapsed - v2.TotalElapsed;

			return new GameTime(v1.Time, elapsed, totalElapsed);
		}

		public static bool operator >=(GameTime v1, DateTime v2)
		{
			if ((object)v1 == null)
				return false;
			return v1.Time >= v2;
		}

		public static bool operator <=(GameTime v1, DateTime v2)
		{
			if ((object)v1 == null)
				return false;
			return v1.Time <= v2;
		}

		public static bool operator >(GameTime v1, DateTime v2)
		{
			if ((object)v1 == null)
				return false;
			return v1.Time > v2;
		}

		public static bool operator <(GameTime v1, DateTime v2)
		{
			if ((object)v1 == null)
				return false;
			return v1.Time < v2;
		}

		public static bool operator >=(DateTime v1, GameTime v2)
		{
			return v1 >= v2.Time;
		}

		public static bool operator <=(DateTime v1, GameTime v2)
		{
			return v1 <= v2.Time;
		}

		public static bool operator >(DateTime v1, GameTime v2)
		{
			return v1 > v2.Time;
		}

		public static bool operator <(DateTime v1, GameTime v2)
		{
			return v1 < v2.Time;
		}
	}
}