using System;
using Paca.Mobile.Core;
using Xunit;

namespace Paca.Tests.Core;

public class PlaybackSleepTimerEngineGateTests
{
    [Fact]
    public void Gate445_PlaybackSleepTimerEngine_CalculatesVolume_BeforeFade()
    {
        var total = TimeSpan.FromMinutes(30);
        var fade = TimeSpan.FromMinutes(5);
        var elapsed = TimeSpan.FromMinutes(10);

        var status = PlaybackSleepTimerEngine.Evaluate(elapsed, total, fade, FadeVolumeCurve.Linear);

        Assert.False(status.IsExpired);
        Assert.False(status.IsFading);
        Assert.Equal(1.0, status.VolumeFactor, 2);
    }

    [Fact]
    public void Gate446_PlaybackSleepTimerEngine_CalculatesVolume_DuringFade()
    {
        var total = TimeSpan.FromMinutes(30);
        var fade = TimeSpan.FromMinutes(10); // fade starts at 20m
        var elapsed = TimeSpan.FromMinutes(25); // halfway through 10m fade

        var statusLinear = PlaybackSleepTimerEngine.Evaluate(elapsed, total, fade, FadeVolumeCurve.Linear);
        Assert.True(statusLinear.IsFading);
        Assert.False(statusLinear.IsExpired);
        Assert.Equal(0.5, statusLinear.VolumeFactor, 2);

        var statusExp = PlaybackSleepTimerEngine.Evaluate(elapsed, total, fade, FadeVolumeCurve.Exponential);
        Assert.True(statusExp.VolumeFactor < 0.5); // exponential falls faster
    }

    [Fact]
    public void Gate447_PlaybackSleepTimerEngine_TriggersExpiry_AtOrPastTotal()
    {
        var total = TimeSpan.FromMinutes(30);
        var fade = TimeSpan.FromMinutes(5);

        var statusExact = PlaybackSleepTimerEngine.Evaluate(TimeSpan.FromMinutes(30), total, fade, FadeVolumeCurve.Linear);
        Assert.True(statusExact.IsExpired);
        Assert.Equal(0.0, statusExact.VolumeFactor);

        var statusPast = PlaybackSleepTimerEngine.Evaluate(TimeSpan.FromMinutes(35), total, fade, FadeVolumeCurve.Linear);
        Assert.True(statusPast.IsExpired);
        Assert.Equal(0.0, statusPast.VolumeFactor);
    }

    [Fact]
    public void Gate448_PlaybackSleepTimerEngine_BuildsFfmpegAfadeFilter()
    {
        var filter = PlaybackSleepTimerEngine.BuildFfmpegFadeOutFilter(totalSec: 1800, fadeDurationSec: 60);

        Assert.Equal("afade=t=out:st=1740:d=60", filter);
    }
}