using System.Collections.Generic;

using RobocraftX.Blocks;
using RobocraftX.Common;
using Svelto.DataStructures;
using Svelto.ECS;

using GamecraftModdingAPI.Engines;

namespace GamecraftModdingAPI.Blocks
{
	public class BlockEngine : IApiEngine
	{
		public string Name { get; } = "GamecraftModdingAPIBlockGameEngine";

		public EntitiesDB entitiesDB { set; private get; }

		public bool isRemovable => false;

		public void Dispose()
		{
		}

		public void Ready()
		{
		}

		public Block[] GetConnectedBlocks(EGID blockID)
		{
			if (!BlockExists(blockID)) return new Block[0];
			Stack<uint> cubeStack = new Stack<uint>();
			FasterList<uint> cubesToProcess = new FasterList<uint>();
			ConnectedCubesUtility.TreeTraversal.GetConnectedCubes(entitiesDB, blockID.entityID, cubeStack, cubesToProcess, (in GridConnectionsEntityStruct g) => { return false; });
			var ret = new Block[cubesToProcess.count];
			for (int i = 0; i < cubesToProcess.count; i++)
				ret[i] = new Block(cubesToProcess[i]);
			return ret;
		}

		/// <summary>
		/// Get a struct of a block. Can be used to set properties.
		/// When only querying parameters, use the other overload for convenience.
		/// </summary>
		/// <param name="blockID"></param>
		/// <param name="def"></param>
		/// <typeparam name="T"></typeparam>
		/// <returns></returns>
		public ref T GetBlockInfo<T>(EGID blockID, ref T def) where T : struct, IEntityComponent
		{
			if (entitiesDB.Exists<T>(blockID))
				return ref entitiesDB.QueryEntity<T>(blockID);
			return ref def;
		}

		/// <summary>
		/// Get a struct of a block. Can only be used to retrieve information.
		/// Use the overload with a default parameter to get the struct by reference to set values.
		/// </summary>
		/// <param name="blockID">The block's EGID</param>
		/// <typeparam name="T">The struct's type to get</typeparam>
		/// <returns>A copy of the struct or null</returns>
		public T? GetBlockInfo<T>(EGID blockID) where T : struct, IEntityComponent
		{
			if (entitiesDB.Exists<T>(blockID))
				return entitiesDB.QueryEntity<T>(blockID);
			return null;
		}

		public bool BlockExists(EGID id)
		{
			return entitiesDB.Exists<DBEntityStruct>(id);
		}

		public bool GetBlockInfoExists<T>(EGID blockID) where T : struct, IEntityComponent
		{
			return entitiesDB.Exists<T>(blockID);
		}

#if DEBUG
		public EntitiesDB GetEntitiesDB()
		{
			return entitiesDB;
		}
#endif
	}
}