using System;
using Paca.Core;
using Xunit;

namespace Paca.Tests.Core;

public class MediaBitrateEstimatorGateTests
{
    [Fact]
    public void Gate425_MediaBitrateEstimator_CalculatesTargetBitrates_Accurately()
    {
        // 100s, 25MB target, 128k audio, 3% container overhead
        long targetBytes = 25L * 1024 * 1024;
        var result = MediaBitrateEstimator.CalculateBitrate(100.0, targetBytes, audioBitrateKbps: 128, overheadPercent: 3.0);

        Assert.True(result.IsPossible);
        Assert.InRange(result.VideoBitrateKbps, 1850, 1950);
        Assert.Equal(128, result.AudioBitrateKbps);
    }

    [Fact]
    public void Gate426_MediaBitrateEstimator_HandlesImpossibleConstraint_Gracefully()
    {
        // 1000s, 1MB target (impossible with 128k audio)
        long targetBytes = 1L * 1024 * 1024;
        var result = MediaBitrateEstimator.CalculateBitrate(1000.0, targetBytes, audioBitrateKbps: 128);

        Assert.False(result.IsPossible);
        Assert.True(result.VideoBitrateKbps <= 64); // Fallback minimum
    }

    [Fact]
    public void Gate427_MediaBitrateEstimator_ProvidesPlatformPresets()
    {
        Assert.Equal(25L * 1024 * 1024, MediaBitrateEstimator.GetPlatformLimitBytes(TargetPlatformLimit.DiscordFree));
        Assert.Equal(16L * 1024 * 1024, MediaBitrateEstimator.GetPlatformLimitBytes(TargetPlatformLimit.WhatsAppVideo));
        Assert.Equal(20L * 1024 * 1024, MediaBitrateEstimator.GetPlatformLimitBytes(TargetPlatformLimit.EmailAttachment));
    }

    [Fact]
    public void Gate428_MediaBitrateEstimator_BuildsTwoPassFfmpegCommands()
    {
        var plan = new BitrateEstimationResult(true, 1800, 128, 25L * 1024 * 1024);
        var (pass1, pass2) = MediaBitrateEstimator.BuildTwoPassCommands("in.mp4", "out.mp4", plan);

        Assert.Contains("-b:v 1800k", pass1);
        Assert.Contains("-pass 1", pass1);
        Assert.Contains("-an", pass1);

        Assert.Contains("-b:v 1800k", pass2);
        Assert.Contains("-pass 2", pass2);
        Assert.Contains("-b:a 128k", pass2);
        Assert.Contains("\"out.mp4\"", pass2);
    }
}