using System.Reflection;

using Harmony;
using RobocraftX.Blocks;
using RobocraftX.Blocks.Ghost;
using RobocraftX.Character.Camera;
using RobocraftX.Character.Factories;
using RobocraftX.Common;
using RobocraftX.Players;
using Svelto.ECS;
using uREPL;

using GamecraftModdingAPI.Commands;
using GamecraftModdingAPI.Utility;

namespace GamecraftModdingAPI.Blocks
{
    public class RemovalEngine : IApiEngine
    {
        private static IEntityFunctions _entityFunctions;
        private static MachineGraphConnectionEntityFactory _connectionFactory;

        public bool RemoveBlock(EGID target)
        {
            if (!entitiesDB.Exists<MachineGraphConnectionsEntityStruct>(target))
                return false;
            var connections = entitiesDB.QueryEntity<MachineGraphConnectionsEntityStruct>(target);
            for (int i = connections.connections.Length - 1; i >= 0; i--)
                _connectionFactory.RemoveConnection(connections, i, entitiesDB);
            _entityFunctions.RemoveEntity<BlockEntityDescriptor>(target);
            return true;
        }

        /// <summary>
        /// Returns the block the player is currently looking at.
        /// </summary>
        /// <param name="playerId">The player's ID</param>
        /// <param name="maxDistance">The maximum distance from the player (default is the player's building reach)</param>
        /// <returns>The block's EGID or null if not found</returns>
        public EGID? GetBlockUnderCursor(uint playerId, float maxDistance = -1f)
        {
            if (!entitiesDB.TryQueryMappedEntities<CharacterCameraRayCastEntityStruct>(
                CameraExclusiveGroups.CameraGroup, out var mapper))
                return null;
            mapper.TryGetEntity(playerId, out CharacterCameraRayCastEntityStruct rayCast);
            float distance = maxDistance < 0
                ? GhostBlockUtils.GetBuildInteractionDistance(entitiesDB, rayCast)
                : maxDistance;
            if (rayCast.hit && rayCast.distance <= distance)
                return rayCast.hitEgid;
            return null;
        }

        public void Ready()
        {
            CommandManager.AddCommand(new SimpleCustomCommandEngine(() =>
            {
                var block = GetBlockUnderCursor(LocalPlayerIDUtility.GetLocalPlayerID(entitiesDB));
                if (block.HasValue)
                {
                    RemoveBlock(block.Value);
                    Log.Output("Removed block.");
                }
                else
                    Log.Output("No block found where you're looking at.");
            }, "removeCube", "Removes the cube you're looking at."));
        }

        public EntitiesDB entitiesDB { get; set; }

        public void Dispose()
        {
        }

        public string Name { get; } = "GamecraftModdingAPIRemovalGameEngine";

        [HarmonyPatch]
        public class FactoryObtainerPatch
        {
            static void Postfix(IEntityFunctions entityFunctions,
                MachineGraphConnectionEntityFactory machineGraphConnectionEntityFactory)
            {
                _entityFunctions = entityFunctions;
                _connectionFactory = machineGraphConnectionEntityFactory;
                Logging.MetaDebugLog("Requirements injected.");
            }

            static MethodBase TargetMethod(HarmonyInstance instance)
            {
                return AccessTools.TypeByName("RobocraftX.CR.MachineEditing.RemoveBlockEngine").GetConstructors()[0];
            }
        }
    }
}