using System;
using System.IO;
using System.Linq;
using Xunit;
using ytLive.Models;
using ytLive.ViewModels;

namespace ytLive.Tests;

/// <summary>
/// The creator's own video rate: per tier, clamped at the tier's YouTube minimum, persisted across
/// runs, and substituted into every consumer that builds encoder options.
///
/// <para>The rule that must never break: whatever the creator typed is what the encoder is asked to
/// hold, and no tier's minimum is quietly undercut.</para>
/// </summary>
[Collection("MainViewModelLayoutPath")]
public class RatedBitrateTests
{
    [Fact]
    public void The_creator_rate_is_per_tier_clamped_to_the_minimum_and_restored()
    {
        var tempDb = Path.Combine(Path.GetTempPath(), $"llamacasty-rate-{Guid.NewGuid():N}.db");
        MainViewModel.LayoutPathOverride = tempDb;
        try
        {
            var vm = new MainViewModel();
            var tier60 = vm.QualityOptions.Single(tier => tier.Display == "1080p60");
            var tier30 = vm.QualityOptions.Single(tier => tier.Display == "1080p30");
            vm.SelectedQuality = tier60;

            // Unset means the shipped default, not zero.
            Assert.Equal(tier60.Bitrate, vm.RatedMbps);

            // A creator who knows their line sets their own number, and the encoder sees it.
            vm.RatedMbps = 15;
            Assert.Equal(15, vm.RatedMbps);
            Assert.Equal(15, vm.EffectiveQuality(tier60).Bitrate);
            Assert.Equal(60, vm.EffectiveQuality(tier60).Fps);   // geometry stays the tier's

            // Below YouTube's minimum for the tier is not a legal target.
            vm.RatedMbps = 2;
            Assert.Equal(RateLadder.For(tier60).Minimum, vm.RatedMbps);

            // The other tier keeps its own value — one setting does not leak into the ladder.
            vm.SelectedQuality = tier30;
            Assert.Equal(tier30.Bitrate, vm.RatedMbps);
            vm.SelectedQuality = tier60;

            // And it survives a restart: the same profile, a fresh view model.
            var reloaded = new MainViewModel();
            reloaded.SelectedQuality = reloaded.QualityOptions.Single(tier => tier.Display == "1080p60");
            Assert.Equal(RateLadder.For(tier60).Minimum, reloaded.RatedMbps);
        }
        finally
        {
            MainViewModel.LayoutPathOverride = null;
            try { File.Delete(tempDb); } catch (IOException) { }
        }
    }
}