using Hi.Disp;
using Hi.Geom;
using Hi.Native;
using System.Collections.Concurrent;

namespace Hi.Webapi.Services
{
    /// <summary>
    /// Singleton Service for managing <see cref="DispEngine"/>.
    /// </summary>
    public class RenderingService : IDisposable
    {
		/// <summary>
		/// Engine Dictionary.
		/// Key is sessionID.
		/// </summary>
		public ConcurrentDictionary<string, DispEngine> EngineDictionary { get; } = new();
		ILogger<RenderingService> Logger { get; }
		private bool disposedValue;

		public RenderingService(ILogger<RenderingService> logger)
        {
            Logger = logger;
        }

        /// <summary>
        /// 創建或獲取一個 DispEngine 實例
        /// </summary>
        public DispEngine GetOrCreateEngine(string sessionId)
        {
            return EngineDictionary.GetOrAdd(sessionId, id =>
            {
                Logger.LogInformation($"創建新的 DispEngine，SessionId: {id}");
                var engine = new DispEngine();
                engine.BackgroundColor = new Vec3d(0.1, 0.1, 0.5);
                engine.BackgroundOpacity = 0.1;
                return engine;
            });
        }

        /// <summary>
        /// 移除指定的 DispEngine
        /// </summary>
        public bool RemoveEngine(string sessionId)
        {
            if (EngineDictionary.TryRemove(sessionId, out var engine))
            {
                Logger.LogInformation($"移除 DispEngine，SessionId: {sessionId}");
                
                try
                {
                    // 停止渲染
                    engine.IsVisible = false;
                    
                    // 釋放資源
                    engine.Dispose();
                }
                catch (Exception ex)
                {
                    Logger.LogError(ex, $"清理 DispEngine 時發生錯誤，SessionId: {sessionId}");
                }
                
                return true;
            }
            return false;
        }

        /// <summary>
        /// 獲取當前活動的引擎數量
        /// </summary>
        public int GetActiveEngineCount() => EngineDictionary.Count;
		/// <inheritdoc/>
		protected virtual void Dispose(bool disposing)
		{
			if (!disposedValue)
			{
				if (disposing)
				{
                    foreach (var kvp in EngineDictionary)
                    {
                        try
                        {
                            kvp.Value.IsVisible = false;
                            kvp.Value.Dispose();
                        }
                        catch (Exception ex)
                        {
                            Logger.LogError(ex, $"Dispose 時清理引擎錯誤，SessionId: {kvp.Key}");
                        }
                    }
                    EngineDictionary.Clear();
                }

                disposedValue = true;
			}
		}
		/// <inheritdoc/>
		public void Dispose()
		{
			Dispose(disposing: true);
			GC.SuppressFinalize(this);
		}
        
    }
}