using System;
using System.IO;
using System.Linq;
using Xunit;
using ytLive.Models;
using ytLive.Services;
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) { }
        }
    }

    /// <summary>
    /// The suggestion the creator is asked about before a stream, and the refusal that stops it coming
    /// back: raising is proposed only from five clean sessions above the 10% gap, applied only on a
    /// click, and "keep mine" suppresses that exact number for the tier.
    /// </summary>
    [Fact]
    public void A_suggested_rate_is_offered_between_sessions_and_only_a_click_applies_it()
    {
        var tempDb = Path.Combine(Path.GetTempPath(), $"llamacasty-rate-proposal-{Guid.NewGuid():N}.db");
        MainViewModel.LayoutPathOverride = tempDb;
        try
        {
            using (var seed = new LayoutStore(tempDb))
            {
                for (var i = 0; i < 5; i++)
                    seed.AppendRateHistory(new SessionRateResult("1080p60", "h264_nvenc", 15.0, 15.0, 0));
                Assert.Equal(5, seed.LoadRateHistory().Count);
            }

            var vm = new MainViewModel();
            vm.SelectedQuality = vm.QualityOptions.Single(tier => tier.Display == "1080p60");

            var historyCount = new LayoutStore(tempDb).LoadRateHistory().Count;

            // Offered, not applied: the rate is still the shipped default until the creator agrees.
            Assert.True(vm.HasRateProposal, $"history={historyCount}");
            Assert.Contains("15", vm.RateProposalText);
            Assert.Equal(12.0, vm.RatedMbps);

            vm.AcceptRateProposalCommand.Execute(null);
            Assert.Equal(15.0, vm.RatedMbps);
            Assert.False(vm.HasRateProposal);

            // Honest evidence now says 15 is what this line holds, so the same question stops being
            // asked: 15 is no longer 10% above the rate in use.
            var second = new MainViewModel();
            second.SelectedQuality = second.QualityOptions.Single(tier => tier.Display == "1080p60");
            Assert.False(second.HasRateProposal);

            // Back to 12 by hand: the evidence qualifies again, and this time the creator says no.
            second.RatedMbps = 12;
            second.SelectedQuality = second.QualityOptions.Single(tier => tier.Display == "1080p30");
            second.SelectedQuality = second.QualityOptions.Single(tier => tier.Display == "1080p60");
            Assert.True(second.HasRateProposal);

            second.DismissRateProposalCommand.Execute(null);
            Assert.False(second.HasRateProposal);
            Assert.Equal(12.0, second.RatedMbps);

            // Refusal is remembered against that number, so a fresh run stays quiet.
            var third = new MainViewModel();
            third.SelectedQuality = third.QualityOptions.Single(tier => tier.Display == "1080p60");
            Assert.False(third.HasRateProposal);
        }
        finally
        {
            MainViewModel.LayoutPathOverride = null;
            try { File.Delete(tempDb); } catch (IOException) { }
        }
    }
}