using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using ytLive.Helpers;
using ytLive.Models;
using ytLive.ViewModels;

namespace ytLive.ViewModels;

public partial class MainViewModel
{
    internal static System.Windows.Media.Imaging.BitmapSource? LoadBackgroundImage(Scene scene)
    {
        var bg = scene.Elements.OfType<Source>().FirstOrDefault(s => s.IsBackground);
        if (bg != null && !bg.UseDefaultBackground
            && !string.IsNullOrWhiteSpace(bg.CustomBackgroundPath)
            && System.IO.File.Exists(bg.CustomBackgroundPath))
        {
            try
            {
                var bitmap = new System.Windows.Media.Imaging.BitmapImage();
                bitmap.BeginInit();
                bitmap.UriSource = new Uri(bg.CustomBackgroundPath);
                bitmap.CacheOption = System.Windows.Media.Imaging.BitmapCacheOption.OnLoad;
                bitmap.EndInit();
                bitmap.Freeze();
                return bitmap;
            }
            catch { /* fall through to AssetId */ }
        }
        if (bg != null && !string.IsNullOrWhiteSpace(bg.AssetId))
            return ImageCache.Get(bg.AssetId);
        return null;
    }

    private static BitmapSource CreatePlaceholderSnapshot(string sceneName)
    {
        var colors = new Dictionary<string, System.Windows.Media.Brush>(StringComparer.OrdinalIgnoreCase)
        {
            ["Starting"] = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromRgb(233, 69, 96)),
            ["Live"] = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromRgb(34, 197, 94)),
            ["BRB"] = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromRgb(234, 179, 8)),
            ["Chat"] = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromRgb(59, 130, 246)),
            ["Ending"] = new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromRgb(168, 85, 247)),
        };
        var brush = colors.TryGetValue(sceneName, out var c) ? c
            : new System.Windows.Media.SolidColorBrush(System.Windows.Media.Color.FromRgb(60, 60, 80));
        var dv = new System.Windows.Media.DrawingVisual();
        using (var ctx = dv.RenderOpen())
        {
            ctx.DrawRectangle(brush, null, new System.Windows.Rect(0, 0, 320, 180));
            var ft = new System.Windows.Media.FormattedText(
                sceneName,
                System.Globalization.CultureInfo.InvariantCulture,
                System.Windows.FlowDirection.LeftToRight,
                new System.Windows.Media.Typeface("Segoe UI"),
                18,
                System.Windows.Media.Brushes.White,
                96);
            ctx.DrawText(ft, new System.Windows.Point(160 - ft.Width / 2, 90 - ft.Height / 2));
        }
        var rtb = new System.Windows.Media.Imaging.RenderTargetBitmap(
            320, 180, 96, 96, System.Windows.Media.PixelFormats.Pbgra32);
        rtb.Render(dv);
        rtb.Freeze();
        return rtb;
    }

    // ─── Screen background capture (live desktop/game) ───

    private const string MonitorKeyPrefix = "monitor:";

    /// <summary>Every background-enabled scene has exactly one background, kept at index 0 (bottom layer).
    /// Returns null for a scene with <see cref="Scene.HasBackground"/> = false.</summary>
    internal static Source? EnsureBackground(Scene scene)
    {
        if (!scene.HasBackground) return null;
        var background = scene.Elements.OfType<Source>().FirstOrDefault(s => s.IsBackground);
        if (background != null) return background;

        background = CreateBackground(scene.Name);
        scene.Elements.Insert(0, background);
        return background;
    }

    /// <summary>The one Background row for a scene. Live gets the capture flavor
    /// (Show Desktop / monitor switch / fullscreen-game detect) falling back to
    /// live-background.jpg; every other screen is a static default-art layer.
    /// Both are named "Background" — the user never sees capture jargon here.</summary>
    internal static Source CreateBackground(string sceneName)
    {
        var isLive = SceneCatalog.Is(sceneName, SceneCatalog.Live);
        return new Source
        {
            Name = "Background",
            Type = isLive ? SourceType.DisplayCapture : SourceType.Background,
            IsBackground = true,
            IsEnabled = true,
            X = 0,
            Y = 0,
            Width = MasterFrameWidth,
            Height = MasterFrameHeight,
        };
    }

    /// <summary>Heals any loaded layout to the locked Background model: exactly
    /// one Background per canonical scene, correct flavor for the scene (static
    /// art everywhere, DisplayCapture on Live only), at index 0, named
    /// "Background". Duplicates and stale rows are dropped; missing ones seeded;
    /// non-canonical scenes get HasBackground=false and lose any backgrounds.</summary>
    internal static void NormalizeBackgrounds(IEnumerable<Scene> scenes)
    {
        foreach (var scene in scenes)
        {
            if (!SceneCatalog.HasBackground(scene.Name))
            {
                scene.HasBackground = false;
                foreach (var stale in scene.Elements.OfType<Source>().Where(s => s.IsBackground).ToList())
                    scene.Elements.Remove(stale);
                continue;
            }

            scene.HasBackground = true;
            var isLive = SceneCatalog.Is(scene.Name, SceneCatalog.Live);
            var wantedType = isLive ? SourceType.DisplayCapture : SourceType.Background;

            var candidates = scene.Elements.OfType<Source>().Where(s => s.IsBackground).ToList();
            var keep = candidates.FirstOrDefault(b => b.Type == wantedType) ?? candidates.FirstOrDefault();

            foreach (var extra in candidates.Where(b => !ReferenceEquals(b, keep)))
                scene.Elements.Remove(extra);

            if (keep == null)
            {
                keep = CreateBackground(scene.Name);
                scene.Elements.Insert(0, keep);
            }

            // Source.Type's setter derives IsBackground from the enum, so a
            // flavor correction must re-assert the flag afterwards.
            if (keep.Type != wantedType)
            {
                keep.Type = wantedType;
                keep.IsBackground = true;
            }

            keep.Name = "Background";
            keep.IsEnabled = true;

            var index = scene.Elements.IndexOf(keep);
            if (index > 0)
                scene.Elements.Move(index, 0);
        }
    }

    // Only the Live screen's background is a real-time surface. Every other
    // lookup below (auto-capture, focus hooks, refresh) must ignore the static
    // default-art rows so they can never start a desktop capture session.
    private IEnumerable<Source> AllBackgrounds()
        => Scenes.Where(s => SceneCatalog.Is(s.Name, SceneCatalog.Live))
            .SelectMany(s => s.Elements.OfType<Source>().Where(x => x.IsBackground));
}