using Xunit;
using ytLive.Services;

namespace ytLive.Tests;

/// <summary>
/// Local recording filename rules (TASK 18):
/// <c>ty-&lt;yyyyMMdd&gt;-&lt;HHmm start&gt;-&lt;fff&gt;-&lt;hh2mm2 length&gt;.mp4</c>.
/// Recordings start with a <c>0000</c> length placeholder and are renamed on stop.
/// </summary>
public class RecordingFileTests
{
    /// <summary>Two instances started in the same minute must not compute the same
    /// path, or both ffmpeg processes write one file and the take is lost. The
    /// millisecond segment is what separates them (dev multi-instance, recording
    /// one instance with the other).</summary>
    [Fact]
    public void TwoStartsInTheSameMinute_ProduceDifferentNames()
    {
        var first = new DateTime(2026, 9, 27, 14, 54, 0, 123);
        var second = new DateTime(2026, 9, 27, 14, 54, 0, 456);

        Assert.NotEqual(RecordingFile.BuildStartName(first), RecordingFile.BuildStartName(second));
    }

    /// <summary>The ms segment must also survive the rename-on-stop, or the final
    /// name could collide with a different take started in the same minute.</summary>
    [Fact]
    public void MillisecondsSurviveTheRenameOnStop()
    {
        var start = new DateTime(2026, 9, 27, 14, 54, 0, 123);
        var name = RecordingFile.BuildFinalName(start, TimeSpan.FromMinutes(5));

        Assert.Equal("ty-20260927-1454-123-0005", name);
    }

    [Fact]
    public void BuildStartName_UsesDateHourAndMinute_WithZeroLength()
    {
        var start = new DateTime(2026, 8, 29, 14, 5, 0);
        Assert.Equal("ty-20260829-1405-000-0000", RecordingFile.BuildStartName(start));
    }

    [Fact]
    public void BuildStartName_PadsSingleDigitHourAndMinute()
    {
        var start = new DateTime(2026, 1, 2, 9, 7, 0);
        Assert.Equal("ty-20260102-0907-000-0000", RecordingFile.BuildStartName(start));
    }

    [Fact]
    public void BuildFinalName_ShortRecording_IsHhmmOfLength()
    {
        var start = new DateTime(2026, 8, 29, 14, 5, 0);
        var length = TimeSpan.FromMinutes(2);
        Assert.Equal("ty-20260829-1405-000-0002", RecordingFile.BuildFinalName(start, length));
    }

    [Fact]
    public void BuildFinalName_HourAndMinutes_ConcatenatesHh2Mm2()
    {
        var start = new DateTime(2026, 8, 29, 14, 5, 0);
        var length = new TimeSpan(1, 15, 0); // 1h 15m
        Assert.Equal("ty-20260829-1405-000-0115", RecordingFile.BuildFinalName(start, length));
    }

    [Fact]
    public void BuildFinalName_OverFlowHours_ShowsTotalHours()
    {
        var start = new DateTime(2026, 8, 29, 14, 5, 0);
        var length = new TimeSpan(12, 30, 0); // 12h 30m
        Assert.Equal("ty-20260829-1405-000-1230", RecordingFile.BuildFinalName(start, length));
    }
}