using System;
using Amphora;
using UnitTestSharp;

namespace Konis.UnitTests
{
    public class FxTimeTests : TestFixture
    {
        private static Duration Seconds(double seconds)
        {
            return Duration.FromSeconds(seconds);
        }

        public class CtorTests : TestFixture
        {
            public void AssignsRealGameDtAndSpeed()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(0.5), speed: 2);

                CheckEqual(Seconds(0.25), time.Real);
                CheckEqual(Seconds(0.5), time.GameDt);
                CheckEqual(2.0, time.Speed);
            }

            public void APausedFrame_IsAllowed()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Duration.Zero, speed: 0);

                CheckEqual(Duration.Zero, time.GameDt);
                CheckEqual(0.0, time.Speed);
            }

            public void ZeroRealTime_IsAllowed()
            {
                CheckEqual(Duration.Zero, new FxTime(real: Duration.Zero, gameDt: Duration.Zero, speed: 1).Real);
            }

            public void NegativeRealTime_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Seconds(-0.1), gameDt: Duration.Zero, speed: 1);
            }

            public void InfiniteRealTime_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Duration.Forever, gameDt: Duration.Zero, speed: 1);
            }

            public void NegativeGameDt_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Seconds(0.1), gameDt: Seconds(-0.1), speed: 1);
            }

            public void InfiniteGameDt_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Seconds(0.1), gameDt: Duration.Forever, speed: 1);
            }

            public void NegativeSpeed_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Seconds(0.1), gameDt: Duration.Zero, speed: -1);
            }

            public void NaNSpeed_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Seconds(0.1), gameDt: Duration.Zero, speed: double.NaN);
            }

            public void InfiniteSpeed_Throws()
            {
                CheckThrow(typeof(ArgumentOutOfRangeException));
                new FxTime(real: Seconds(0.1), gameDt: Duration.Zero, speed: double.PositiveInfinity);
            }

            public void GameTimePassingAtSpeedZero_Throws()
            {
                CheckThrow(typeof(ArgumentException));
                new FxTime(real: Seconds(0.1), gameDt: Seconds(0.1), speed: 0);
            }
        }

        public class ElapsedTests : TestFixture
        {
            public void Real_IsTheRealTime()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(1), speed: 4);

                CheckEqual(Seconds(0.25), time.Elapsed(ClockBase.Real));
            }

            public void Real_IgnoresAPause()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Duration.Zero, speed: 0);

                CheckEqual(Seconds(0.25), time.Elapsed(ClockBase.Real));
            }

            public void Game_IsTheGameTime()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(1), speed: 4);

                CheckEqual(Seconds(1), time.Elapsed(ClockBase.Game));
            }

            public void Game_FreezesOnAPause()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Duration.Zero, speed: 0);

                CheckEqual(Duration.Zero, time.Elapsed(ClockBase.Game));
            }

            public void GameNormal_DividesOutTheSpeed()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(1), speed: 4);

                CheckEqual(Seconds(0.25), time.Elapsed(ClockBase.GameNormal));
            }

            public void GameNormal_AtNormalSpeed_IsTheGameTime()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(0.5), speed: 1);

                CheckEqual(Seconds(0.5), time.Elapsed(ClockBase.GameNormal));
            }

            public void GameNormal_BelowNormalSpeed_RunsLonger()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(0.5), speed: 0.5);

                CheckEqual(Seconds(1), time.Elapsed(ClockBase.GameNormal));
            }

            public void GameNormal_FreezesOnAPauseWithoutDividingByZero()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Duration.Zero, speed: 0);

                CheckEqual(Duration.Zero, time.Elapsed(ClockBase.GameNormal));
            }

            public void GameNormal_WithNoGameTimeAtNormalSpeed_IsZero()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Duration.Zero, speed: 1);

                CheckEqual(Duration.Zero, time.Elapsed(ClockBase.GameNormal));
            }

            public void AnUnknownBase_Throws()
            {
                var time = new FxTime(real: Seconds(0.25), gameDt: Seconds(1), speed: 1);

                CheckThrow(typeof(ArgumentOutOfRangeException));
                time.Elapsed((ClockBase)99);
            }
        }
    }
}