using Jint;
using Jint.Native;
using Progrart.Core.Graphics;
using Progrart.Core.Storage;
using System.Diagnostics;

namespace Progrart.Core.JSExecution
{
	public class ProgrartExecutor : IDisposable
	{
		public ExecutionEngine engine;
		public Dictionary<string, object> ObjectPool = new();
		public IStorageProvider StorageProvider;
		public ProgrartExecutor(IStorageProvider storageProvider)
		{
			engine = new ExecutionEngine();
			SetupCalls();
			StorageProvider = storageProvider;
		}
		public void SetupCalls()
		{
			Jint.Native.Json.JsonSerializer serializer = new Jint.Native.Json.JsonSerializer(engine.Engine);
			engine.Engine.SetValue("log", new Action<JsValue>((v) =>
			{
				if (v is JsObject obj)
				{
					Trace.WriteLine(serializer.Serialize(obj));
				}
				else
					Trace.WriteLine(v);
			}));
			engine.Engine.SetValue("require", (string str) =>
			{
				require(str, () =>
				{
					if (str.IndexOf(".") < 0)
					{
						require(str + ".progrart", () => 
						{
							require(str + ".js", () =>
							{
								throw new Exception("Module not found: " + str);
							});
						});
					}
					else
					{
						throw new Exception("Module not found: " + str);
					}
				});
			});
			engine.Engine.SetValue("visual_root", visual_root);
			engine.Engine.SetValue("line", line);
			engine.Engine.SetValue("rectangle", rectangle);
			engine.Engine.SetValue("rectangle", rectangle);
			engine.Engine.SetValue("oval", oval);
			engine.Engine.SetValue("triangle", triangle);
			engine.Engine.SetValue("path", path);
			engine.Engine.SetValue("path_element", path_element);
			engine.Engine.SetValue("circle", circle);
			engine.Engine.SetValue("color4", color4);
			engine.Engine.SetValue("color3", color3);
			engine.Engine.SetValue("text", text);
			engine.Engine.SetValue("color_hex", color_hex);
			engine.Engine.SetValue("linear_gradient", linear_gradient);
			engine.Engine.SetValue("radial_gradient", radial_gradient);
		}

		private void require(string str, Action onNoFound)
		{
			var task = StorageProvider.TryOpenRead(str);
			task.Wait();
			var stream = task.GetAwaiter().GetResult();
			if (stream is null)
			{
				onNoFound();
				return;
			}
			using var sr = new StreamReader(stream);
			engine.Engine.Execute(sr.ReadToEnd());
		}

		public JsObject color4(JsNumber r, JsNumber g, JsNumber b, JsNumber a)
		{
			return ProgrartFunctions.color(engine.Engine
				, r.AsNumber()
				, g.AsNumber()
				, b.AsNumber()
				, a.AsNumber()
				);
		}
		public JsObject color3(JsNumber r, JsNumber g, JsNumber b)
		{
			return ProgrartFunctions.color(engine.Engine
				, r.AsNumber()
				, g.AsNumber()
				, b.AsNumber()
				);
		}
		float colorFloat(byte b) => ((float)b / (float)byte.MaxValue);
		public JsObject color_hex(JsString colorString)
		{
			byte[] bytes = Convert.FromHexString(colorString.AsString());
			if (bytes.Length == 3)
				return ProgrartFunctions.color(engine.Engine
					, colorFloat(bytes[0])
					, colorFloat(bytes[1])
					, colorFloat(bytes[2])
					);
			else
				if (bytes.Length == 4)
					return ProgrartFunctions.color(engine.Engine
					, colorFloat(bytes[0])
					, colorFloat(bytes[1])
					, colorFloat(bytes[2])
					, colorFloat(bytes[3])
					);
				else throw new FormatException($"{colorString.AsString()} is not a recognizable color string!");
		}
		public JsObject visual_root()
		{
			return ProgrartFunctions.CreateVisualRoot(this);
		}
		public JsObject line() => ProgrartFunctions.CreateElement<Line>(this);
		public JsObject rectangle() => ProgrartFunctions.CreateElement<Rectangle>(this);
		public JsObject roundrect() => ProgrartFunctions.CreateElement<RoundRectangle>(this);
		public JsObject path_element() => ProgrartFunctions.CreateElement<PathElement>(this);
		public JsObject path() => ProgrartFunctions.CreateElement<Graphics.Path>(this);
		public JsObject circle() => ProgrartFunctions.CreateElement<Circle>(this);
		public JsObject oval() => ProgrartFunctions.CreateElement<Oval>(this);
		public JsObject triangle() => ProgrartFunctions.CreateElement<Triangle>(this);
		public JsObject text() => ProgrartFunctions.CreateElement<Text>(this);

		public RenderContext RenderImage(int Scale, string script, ExecuteArguments arguments)
		{
			float width = 1;
			float height = 1;
			engine.Symbols = arguments.data;
			engine.Execute(script);
			if (engine.Engine.GetValue("Width") is JsNumber js_width)
			{
				width = (float)(js_width.AsNumber());
			}
			if (engine.Engine.GetValue("Height") is JsNumber js_height)
			{
				height = (float)(js_height.AsNumber());
			}
			RenderContext renderContext = new((int)(width * Scale), (int)(height * Scale), StorageProvider)
			{
				LogicalW = width,
				LogicalH = height
			};
			ImageRoot imageRoot = new ImageRoot();
			var img = engine.Engine.Call("main");
			if (ObjectPool[$"{img.Get("id")}"] is BaseElement element)
				imageRoot.Add(element);
			imageRoot.Render(renderContext);
			renderContext.canvas.Flush();
			return renderContext;
		}
		public string RegisterObject(object obj)
		{
			string v = $"{obj.GetHashCode()}";
			ObjectPool[v] = obj;
			return v;
		}
		public JsObject linear_gradient() => ProgrartFunctions.linear_gradient(engine.Engine);
		public JsObject radial_gradient() => ProgrartFunctions.radial_gradient(engine.Engine);
		public void Dispose()
		{
			engine.Dispose();
		}
	}
}