using Dictionary = Godot.Collections.Dictionary;

public partial class Workshop : Area3D
{
	/// <summary> Returns whether this workshop is owned by the local player. </summary>
	public bool IsLocal => this.IsAuthority();

	/// <summary> Gets the peer ID of the player owning this workshop. </summary>
	public int PeerId => GetMultiplayerAuthority();

	/// <summary> Gets the player that owns this workshop. </summary>
	public Player Player => Game.Players.ByPeerId(PeerId);

	[Export] public Node Objects { get; private set; }


	public void Clear()
	{
		// TODO: This is very ugly please send help.
		var manager = this.GetNodeOrThrow<ItemManager>(nameof(ItemManager));
		manager.TrackedItems.Clear();

		foreach (var obj in Objects.GetChildren()) {
			if (obj is Item) {
				Objects.RemoveChild(obj);
				obj.QueueFree();
			}

			if (obj.GetNodeOrNull(nameof(Grid)) is Grid g)
				foreach (var child in g.GetChildren().OfType<Item>()) {
					g.RemoveChild(child);
					child.QueueFree();
				}

			// TODO: Do we need to do recursion here?
		}
	}

	public void FromDictionary(Dictionary dict)
	{
		// TODO: File information shouldn't be handled by this.
		var version = dict["version"].AsInt32();
		if (version != 0) throw new Exception($"Unknown version '{version}'");

		Clear();

		var manager = this.GetNodeOrThrow<ItemManager>(nameof(ItemManager));
		var objectsDict = dict["objects"].AsGodotDictionary<string, Dictionary>();
		foreach (var (childName, childDict) in objectsDict)
			FromDictionary(manager, Objects, childName, childDict);
	}

	static void FromDictionary(ItemManager manager, Node parent, string name, Dictionary dict)
	{
		Node node;

		if (dict.ContainsKey("scene")) {
			var sceneName = dict["scene"].AsString();
			var scene = ResourceLoader.Load<PackedScene>(sceneName, "PackedScene");

			var item = scene.Instantiate<Item>();
			item.Name = name;
			item.Transform = ArrayToTransform(dict["transform"].AsFloat32Array());
			parent.AddChild(item);
			manager.Add(item);

			node = item;
		} else {
			node = parent.GetNodeOrThrow<Node>(name);
		}

		if (dict.ContainsKey("grid")) {
			var grid = node.GetNodeOrThrow<Grid>(nameof(Grid));

			var gridDict = dict["grid"].AsGodotDictionary<string, Dictionary>();
			foreach (var (childName, childDict) in gridDict)
				FromDictionary(manager, grid, childName, childDict);
		}
	}

	public Dictionary ToDictionary()
	{
		var result = new Dictionary {
			["version"] = 0,
		};

		var objects = new Dictionary();
		foreach (var child in Objects.GetChildren())
			objects[child.Name] = ToDictionary(child);
		result["objects"] = objects;

		return result;
	}

	// TODO: Rework the way object are loaded / saved.
	// Since it will be likely that objects will have varying data
	// associated with them, only save the scene / object ID and let
	// the object itself handle loading and saving its data.
	static Dictionary ToDictionary(Node node)
	{
		var result = new Dictionary();

		if (node is Item item) {
			result["scene"] = item.SceneFilePath;
			result["transform"] = TransformToArray(item.Transform);
		}

		var grid = new Dictionary();
		if (node.GetNodeOrNull(nameof(Grid)) is Grid g)
			foreach (var child in g.GetChildren().OfType<Item>())
				grid[child.Name] = ToDictionary(child);
		if (grid.Count > 0)
			result["grid"] = grid;

		return result;
	}

	public void SaveToFile(string path)
	{
		using var file = FileAccess.Open(path, FileAccess.ModeFlags.Write)
			?? throw new Exception($"Failed to open '{path}' for writing: {FileAccess.GetOpenError()}");
		file.StoreString(Json.Stringify(ToDictionary()));
	}

	public void LoadFromFile(string path)
	{
		using var file = FileAccess.Open(path, FileAccess.ModeFlags.Read)
			?? throw new Exception($"Failed to open '{path}' for reading: {FileAccess.GetOpenError()}");
		var json = file.GetLine();

		var dict = Json.ParseString(json).AsGodotDictionary();
		FromDictionary(dict);
	}


	static float[] TransformToArray(Transform3D t)
		=> [ t[0, 0], t[1, 0], t[2, 0],
		     t[0, 1], t[1, 1], t[2, 1],
		     t[0, 2], t[1, 2], t[2, 2],
		     t[3, 0], t[3, 1], t[3, 2] ];

	static Transform3D ArrayToTransform(float[] a)
		=> new(a[ 0], a[ 1], a[ 2],
		       a[ 3], a[ 4], a[ 5],
		       a[ 6], a[ 7], a[ 8],
		       a[ 9], a[10], a[11]);
}