SvgResourceManager.cs

using System.Collections.Concurrent;
using Gondwana.Assets;
using Microsoft.Extensions.Logging;
 
namespace Gondwana.Drawing;

public sealed class SvgResourceManager : IDisposable
{
    private static readonly Lazy<SvgResourceManager> _instance = new(() => new SvgResourceManager());
    private readonly ConcurrentDictionary<string, SvgResource> _svgResources = new();
    private bool _disposed;
 
    private SvgResourceManager()
    { }

    public static SvgResourceManager Instance => _instance.Value;

    public SvgResource LoadFromFile(string key, string path)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(key);
        ArgumentException.ThrowIfNullOrWhiteSpace(path);
 
        var resource = SvgResource.Load(path);
        return AddOrReplace(key, resource);
    }

    public List<SvgResource> LoadFromEngineAssetsFile(AssetsFile resourceFile)
    {
        ArgumentNullException.ThrowIfNull(resourceFile);
        var loaded = new List<SvgResource>();
 
        foreach (var entry in resourceFile.GetAllEntries())
        {
            if (entry.AssetType != AssetTypes.Svg || _svgResources.ContainsKey(entry.AssetName))
                continue;
 
            using var stream = resourceFile.Get(entry.AssetType, entry.AssetName);
            if (stream is null)
            {
                Engine.Logger.LogWarning("Failed to retrieve stream for SVG resource: {Key}", entry.AssetName);
                continue;
            }
 
            try
            {
                var svg = SvgResource.Load(stream);
                loaded.Add(AddOrReplace(entry.AssetName, svg));
            }
            catch (Exception ex)
            {
                Engine.Logger.LogError(ex, "Error loading SVG resource from asset file for key: {Key}", entry.AssetName);
                throw;
            }
        }
 
        return loaded;
    }

    public bool Contains(string key) => _svgResources.ContainsKey(key);

    public SvgResource? Get(string key) => _svgResources.TryGetValue(key, out var resource) ? resource : null;

    public Dictionary<string, SvgResource> GetAll() => _svgResources.ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

    public void Unload(string key)
    {
        if (_svgResources.TryRemove(key, out var resource))
            resource.Dispose();
    }

    public void Clear()
    {
        foreach (var resource in _svgResources.Values)
            resource.Dispose();
 
        _svgResources.Clear();
    }

    public void Dispose()
    {
        if (_disposed)
            return;
 
        Clear();
        _disposed = true;
    }
 
    private SvgResource AddOrReplace(string key, SvgResource resource)
    {
        if (_svgResources.TryGetValue(key, out var existing))
            existing.Dispose();
 
        _svgResources[key] = resource;
        return resource;
    }
}