using System.Collections.Generic;
using System.Linq;
using ytLive.Models;
using ytLive.Services;

namespace ytLive.ViewModels;

public partial class MainViewModel
{
    private readonly TextOverlayRenderer _textOverlayRenderer = new();
    private readonly HashSet<Source> _wiredTextOverlays = new();

    private void UpdateConfiguredTextOverlays()
    {
        var sources = Scenes.SelectMany(scene => scene.Elements).OfType<Source>()
            .Where(source => source.Type == SourceType.TextOverlay).ToArray();
        RetainTextOverlaySubscriptions();
        _textOverlayRenderer.Retain(sources);
        foreach (var source in sources)
        {
            if (source.Width <= 0) source.Width = 900;
            if (source.Height <= 0) source.Height = 140;
            WireTextOverlaySource(source);
            _textOverlayRenderer.UpdatePreview(source);
        }
    }

    private void WireTextOverlaySource(Source source)
    {
        if (_wiredTextOverlays.Add(source))
            source.PropertyChanged += OnElementPropertyChanged;
    }

    private void UpdateTextOverlayPreview(Source source) => _textOverlayRenderer.UpdatePreview(source);

    private void RemoveTextOverlayPreview(Source source)
    {
        if (_wiredTextOverlays.Remove(source))
            source.PropertyChanged -= OnElementPropertyChanged;
        _textOverlayRenderer.Remove(source);
    }

    private void RetainTextOverlaySubscriptions()
    {
        var active = Scenes.SelectMany(scene => scene.Elements).OfType<Source>()
            .Where(source => source.Type == SourceType.TextOverlay).ToHashSet();
        foreach (var source in _wiredTextOverlays.ToArray())
            if (!active.Contains(source))
                RemoveTextOverlayPreview(source);
    }

    private void OnTextOverlayPropertyChanged(Source source, string? propertyName)
    {
        if (propertyName is nameof(Source.TextContent) or nameof(Source.TextFontFamily)
            or nameof(Source.TextFontSize) or nameof(Source.TextColor) or nameof(Source.TextBold)
            or nameof(Source.TextItalic) or nameof(Source.TextUnderline) or nameof(Source.TextAlignment)
            or nameof(Source.Width) or nameof(Source.Height))
            UpdateTextOverlayPreview(source);
    }

}