using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Microsoft.Data.Sqlite;
using Xunit;
using ytLive.Helpers;
using ytLive.Models;
using ytLive.Services;
using ytLive.ViewModels;

namespace ytLive.Tests;

/// <summary>
/// Scene strip tile artwork (creator ruling 2026-10-10). A persisted scene tile
/// is stored as an Asset row; the preview pane keeps rendering each scene's
/// ORIGINAL background — the tiles never appear as preview backgrounds.
/// </summary>
[Collection("RealApp")]
public sealed class SceneThumbnailTests
{
    private readonly RealAppHost _app;

    public SceneThumbnailTests(RealAppHost app) => _app = app;

    [Fact]
    public void Strip_Shows_The_Persisted_Tile_And_The_Preview_Keeps_The_Original_Background()
    {
        _app.Run(() =>
        {
            EnvGuard? env = null;
            try
            {
                env = ArrangedDb(out var file);
                env.Apply();

                var tileAssetId = LayoutStore.Instance!.UpsertAsset(File.ReadAllBytes(file.TilePath), 320, 180);
                using (var connection = new SqliteConnection($"Data Source={env.DbPath}"))
                {
                    connection.Open();
                    using var cmd = connection.CreateCommand();
                    cmd.CommandText = "UPDATE Scene SET ThumbnailAssetId = $asset WHERE Name = $scene;";
                    cmd.Parameters.AddWithValue("$asset", tileAssetId);
                    cmd.Parameters.AddWithValue("$scene", SceneCatalog.Starting);
                    Assert.Equal(1, cmd.ExecuteNonQuery());
                }

                var vm = new MainViewModel();
                var starting = SceneByName(vm, SceneCatalog.Starting);

                Assert.False(string.IsNullOrWhiteSpace(starting.ThumbnailAssetId));

                // The strip tile is the seeded file (identity + dims prove it).
                var tile = ImageCache.Get(starting.ThumbnailAssetId);
                Assert.NotNull(tile);
                Assert.Same(tile, starting.Snapshot);
                Assert.Equal(320, starting.Snapshot!.PixelWidth);
                Assert.Equal(180, starting.Snapshot.PixelHeight);

                // The preview pane renders the scene's ORIGINAL background — never
                // the tile artwork.
                var originalBackground = ImageCache.Get(env.BackgroundIds[SceneCatalog.Starting]);
                Assert.NotNull(originalBackground);
                Assert.Same(originalBackground, vm.BackgroundImage);
                Assert.Same(originalBackground, vm.ActiveBackgroundImage);
                Assert.Same(originalBackground, MainViewModel.LoadBackgroundImage(starting));
                Assert.NotSame(tile, vm.BackgroundImage);

                // A scene without its own tile keeps its background art as the strip.
                var ending = SceneByName(vm, SceneCatalog.Ending);
                Assert.Null(ending.ThumbnailAssetId);
                Assert.Same(ImageCache.Get(env.BackgroundIds[SceneCatalog.Ending]), ending.Snapshot);

                // The mapping and the tile asset survive a save + reload (the
                // Save-time Asset prune must keep Scene.ThumbnailAssetId rows), and
                // a second load re-seeds nothing new (UpsertAsset is SHA256-keyed).
                vm.SaveLayoutNow();
                using (var reloaded = new LayoutStore(env.DbPath))
                {
                    var reloadedStarting = reloaded.Load().Single(s => s.Name == SceneCatalog.Starting);
                    Assert.Equal(starting.ThumbnailAssetId, reloadedStarting.ThumbnailAssetId);
                    Assert.NotNull(reloaded.GetAssetBytes(starting.ThumbnailAssetId));
                    Assert.Equal(1, CountAssetRows(env.DbPath, starting.ThumbnailAssetId));
                }

                var secondVm = new MainViewModel();
                Assert.Equal(starting.ThumbnailAssetId,
                    SceneByName(secondVm, SceneCatalog.Starting).ThumbnailAssetId);
            }
            finally
            {
                env?.Restore();
                env?.Dispose();
            }
        });
    }

    [Fact]
    public void Live_Staged_Mini_Shows_Its_Persisted_Tile_Not_The_Capture_Placeholder()
    {
        _app.Run(() =>
        {
            EnvGuard? env = null;
            try
            {
                env = ArrangedDb(out var file);
                env.Apply();

                var tileAssetId = LayoutStore.Instance!.UpsertAsset(File.ReadAllBytes(file.TilePath), 320, 180);
                using (var connection = new SqliteConnection($"Data Source={env.DbPath}"))
                {
                    connection.Open();
                    using var cmd = connection.CreateCommand();
                    cmd.CommandText = "UPDATE Scene SET ThumbnailAssetId = $asset WHERE Name = $scene;";
                    cmd.Parameters.AddWithValue("$asset", tileAssetId);
                    cmd.Parameters.AddWithValue("$scene", SceneCatalog.Live);
                    Assert.Equal(1, cmd.ExecuteNonQuery());
                }

                var vm = new MainViewModel();
                var live = SceneByName(vm, SceneCatalog.Live);
                Assert.False(string.IsNullOrWhiteSpace(live.ThumbnailAssetId));

                vm.StagedScene = live;
                // Minis never render captures; a seeded Live tile shows instead of
                // the green placeholder, while the preview still shows the background.
                Assert.Same(ImageCache.Get(live.ThumbnailAssetId), live.Snapshot);
                Assert.Same(ImageCache.Get(env.BackgroundIds[SceneCatalog.Live]), vm.BackgroundImage);
            }
            finally
            {
                env?.Restore();
                env?.Dispose();
            }
        });
    }

    [Fact]
    public void Staged_Scene_Tile_Shows_The_On_Air_Art_And_It_Follows_The_Scene_Swap()
    {
        _app.Run(() =>
        {
            EnvGuard? env = null;
            try
            {
                env = ArrangedDb(out var file);
                MainViewModel.OnAirSeedPath = file.OnAirPath;
                env.Apply();

                var vm = new MainViewModel();
                var starting = SceneByName(vm, SceneCatalog.Starting);
                var live = SceneByName(vm, SceneCatalog.Live);

                var onAir = ImageCache.Get(Services.LayoutStore.Instance!.GetOnAirImageId()!);
                Assert.NotNull(onAir);

                // The staged scene's tile (Starting at launch) shows the on-air art.
                Assert.Same(onAir, starting.Snapshot);
                // Unstaged scenes keep their own art, never the on-air image.
                Assert.NotSame(onAir, live.Snapshot);

                // Swapping scenes moves the on-air tile: staging Live swaps it across,
                // and Starting's tile returns to its own background art (no thumbnail).
                vm.StagedScene = live;
                Assert.Same(onAir, live.Snapshot);
                Assert.Same(ImageCache.Get(env.BackgroundIds[SceneCatalog.Starting]), starting.Snapshot);

                // The preview pane still renders the scene's ORIGINAL background —
                // the on-air art never leaks into the preview.
                Assert.Same(ImageCache.Get(env.BackgroundIds[SceneCatalog.Live]), vm.BackgroundImage);

                // Persistence: the on-air asset survives a save + reload (the Save
                // pruner must keep the OnAirImageAssetId setting's row), and a fresh
                // VM re-stamps it from the DB instead of re-importing.
                vm.SaveLayoutNow();
                using (var reloaded = new LayoutStore(env.DbPath))
                {
                    var id = reloaded.GetOnAirImageId();
                    Assert.NotNull(id);
                    Assert.NotNull(reloaded.GetAssetBytes(id));
                }
                var secondVm = new MainViewModel();
                Assert.Same(onAir, SceneByName(secondVm, SceneCatalog.Starting).Snapshot);
            }
            finally
            {
                env?.Restore();
                env?.Dispose();
            }
        });
    }

    [Fact]
    public void No_Seed_File_Means_No_Thumbnail_And_Background_Art_Fallback()
    {
        _app.Run(() =>
        {
            EnvGuard? env = null;
            try
            {
                env = ArrangedDb(out _);
                env.SeedPaths.Clear();
                env.Apply();

                var vm = new MainViewModel();
                foreach (var scene in vm.Scenes)
                {
                    Assert.Null(scene.ThumbnailAssetId);
                    Assert.Same(ImageCache.Get(env.BackgroundIds[scene.Name]), scene.Snapshot);
                }
            }
            finally
            {
                env?.Restore();
                env?.Dispose();
            }
        });
    }

    // ─── Fixture plumbing ───

    private static Scene SceneByName(MainViewModel vm, string name)
        => vm.Scenes.Single(s => s.Name == name);

    private static int CountAssetRows(string dbPath, string assetId)
    {
        using var connection = new SqliteConnection($"Data Source={dbPath}");
        connection.Open();
        using var cmd = connection.CreateCommand();
        cmd.CommandText = "SELECT COUNT(*) FROM Asset WHERE Id = $id;";
        cmd.Parameters.AddWithValue("$id", assetId);
        return Convert.ToInt32(cmd.ExecuteScalar());
    }

    /// <summary>Builds a temp DB whose every scene has a REAL background asset row.
    /// One throwaway VM creates the canonical scenes + heals their Backgrounds
    /// (the pack:// default-art stamp silently fails under the test host, so the
    /// contract is tested with an explicit background — the tile must never
    /// replace it). Seed paths start all-missing; the caller picks which scenes
    /// get a tile.</summary>
    private static EnvGuard ArrangedDb(out Files files)
    {
        files = new Files();
        var dbPath = Path.Combine(Path.GetTempPath(), $"ytLive-scenethumb-{Guid.NewGuid():N}.db");
        using (new LayoutStore(dbPath)) { }
        SqliteConnection.ClearAllPools();

        var env = new EnvGuard(dbPath, files);
        try
        {
            env.Apply();
            var builder = new MainViewModel();
            var backgroundIds = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
            var i = 0;
            foreach (var scene in builder.Scenes)
            {
                var bg = scene.Elements.OfType<Source>().FirstOrDefault(s => s.IsBackground);
                Assert.NotNull(bg);
                var bytes = files.NewBackgroundBytes(i++);
                var id = LayoutStore.Instance!.UpsertAsset(bytes, 320, 180);
                Assert.NotNull(id);
                bg!.AssetId = id;
                backgroundIds[scene.Name] = id;
            }
            builder.SaveLayoutNow();
            env.BackgroundIds = backgroundIds;
            return env;
        }
        catch
        {
            env.Restore();
            env.Dispose();
            throw;
        }
    }

    private sealed record EnvGuard : IDisposable
    {
        public string DbPath { get; }
        public Files Files { get; }
        public Dictionary<string, string> BackgroundIds { get; set; } = new(StringComparer.OrdinalIgnoreCase);
        public Dictionary<string, string> SeedPaths { get; }
        private readonly Dictionary<string, string> _originalPaths;
        private readonly string _originalOnAirPath;

        public EnvGuard(string dbPath, Files files)
        {
            DbPath = dbPath;
            Files = files;
            _originalPaths = new Dictionary<string, string>(MainViewModel.SceneThumbnailSeedPaths, StringComparer.OrdinalIgnoreCase);
            _originalOnAirPath = MainViewModel.OnAirSeedPath;
            SeedPaths = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
            MainViewModel.LayoutPathOverride = dbPath;
            MainViewModel.OnAirSeedPath = MissingPath();
            foreach (var path in _originalPaths)
                SeedPaths[path.Key] = MissingPath();
        }

        /// <summary>Writes the tests' chosen SeedPaths into the live map; any
        /// canonical scene not overridden stays pointing at a missing file.</summary>
        public void Apply()
        {
            MainViewModel.SceneThumbnailSeedPaths.Clear();
            foreach (var (key, value) in SeedPaths)
                MainViewModel.SceneThumbnailSeedPaths[key] = value;
        }

        public void Restore()
        {
            MainViewModel.SceneThumbnailSeedPaths.Clear();
            foreach (var (key, value) in _originalPaths)
                MainViewModel.SceneThumbnailSeedPaths[key] = value;
            MainViewModel.OnAirSeedPath = _originalOnAirPath;
            MainViewModel.LayoutPathOverride = null;
            SqliteConnection.ClearAllPools();
        }

        public void Dispose()
        {
            Files.Dispose();
            try { File.Delete(DbPath); } catch { }
        }
    }

    private sealed class Files : IDisposable
    {
        public string TilePath { get; }
        public string OnAirPath { get; }
        private readonly List<string> _paths = new();

        public Files()
        {
            TilePath = NewImage(320, 180, Brushes.Teal, Brushes.Red);
            OnAirPath = NewImage(320, 180, Brushes.SlateBlue, Brushes.White);
        }

        /// <summary>Distinct per-scene solid-color "original background".</summary>
        public byte[] NewBackgroundBytes(int index)
        {
            var colors = new[] { Brushes.ForestGreen, Brushes.OrangeRed, Brushes.DodgerBlue, Brushes.DarkOrchid, Brushes.SaddleBrown };
            var path = NewImage(320, 180, colors[index % colors.Length], Brushes.Black);
            return File.ReadAllBytes(path);
        }

        private string NewImage(int w, int h, Brush fill, Brush accent)
        {
            var path = Path.Combine(Path.GetTempPath(), $"ytLive-scenethumb-img-{Guid.NewGuid():N}.png");
            var dv = new DrawingVisual();
            using (var dc = dv.RenderOpen())
            {
                dc.DrawRectangle(fill, null, new Rect(0, 0, w, h));
                dc.DrawRectangle(accent, null, new Rect(24, 24, 64, 64));
            }
            var rtb = new RenderTargetBitmap(w, h, 96, 96, PixelFormats.Pbgra32);
            rtb.Render(dv);
            var encoder = new PngBitmapEncoder();
            encoder.Frames.Add(BitmapFrame.Create(rtb));
            using var fs = File.OpenWrite(path);
            encoder.Save(fs);
            _paths.Add(path);
            return path;
        }

        public void Dispose()
        {
            foreach (var path in _paths)
                try { File.Delete(path); } catch { }
        }
    }

    private static string MissingPath()
        => Path.Combine(Path.GetTempPath(), $"ytLive-no-such-{Guid.NewGuid():N}.png");
}