using System;
using System.Collections.Generic;
using Escape_Room_Engine.Engine.Scripts.Modules;
using UnityEngine;
using Logger = Escape_Room_Engine.Engine.Scripts.Utilities.Logger;
using LogType = Escape_Room_Engine.Engine.Scripts.Utilities.LogType;
using Random = UnityEngine.Random;

namespace Escape_Room_Engine.Engine.Scripts
{
    public class Engine : MonoBehaviour
    {
        public static Engine DefaultEngine
        {
            get
            {
                if (_foundEngine == null)
                {
                    _foundEngine = FindObjectOfType<Engine>();
                }
                return _foundEngine;
            }
        }
        private static Engine _foundEngine;

        public Material roomMaterial;

        [Tooltip("The minimum size that should be allowed for rooms.")] public Vector2Int minRoomSize;
        [Tooltip("The size of the physical play space available to the engine.")] public Vector2Int playSpace;

        private int NumberOfRooms => _rooms.Count;

        private readonly List<Room> _rooms = new(1);
        private GameObject _playSpaceOrigin;

        private void Start()
        {
            _playSpaceOrigin = new GameObject("Play Space Origin");
            _playSpaceOrigin.transform.SetParent(transform);
            _playSpaceOrigin.transform.localPosition = new Vector3(-playSpace.x / 2f, 0, -playSpace.y / 2f);
        }

        public void GenerateRoom()
        {
            Logger.Log("Generating room...", LogType.RoomGeneration);
            
            // get the last entrance from the newest room or create a spawn passage with no entrance door for where the player will start
            var entrance = NumberOfRooms > 0 ? _rooms[0].exit : new SpawnPassage();
            
            var room = new Room(entrance);
            _rooms.Add(room);
            
            GenerateSpace(room, entrance); // TODO: rooms with more than one space
            room.InstantiateRoom(_playSpaceOrigin.transform, (_rooms.Count - 1).ToString());
        }

        private void GenerateSpace(Room room, Passage entrance)
        {
            Logger.Log("Generating space...", LogType.RoomGeneration);
            
            // create space
            var rrDimensions = GenerateSpaceDimensions(entrance.rrPosition);
            var space = new Space(rrDimensions, entrance);
            
            // add exit
            var exitDoor = new DoorModule(DoorType.Exit, space);
            exitDoor.Place(new Vector2Int(
                Random.Range(0, rrDimensions.width),
                Random.Range(0, rrDimensions.length)
            ));
            var exit = new Passage(exitDoor);
            space.AddModule(exitDoor);
            
            room.AddSpace(space, exit);
        }

        /// <summary>
        /// Generate space dimensions that fit the required size constraints and cover the position of the entrance.
        /// </summary>
        /// <param name="entranceRrPosition">The room relative (<i>RR</i>) position of the entrance.</param>
        /// <returns>The generated room relative (<i>RR</i>) dimensions.</returns>
        private Dimensions GenerateSpaceDimensions(Vector2Int entranceRrPosition)
        {
            var xMin = Utilities.Utilities.RandomInclusive(
                0,
                Math.Min(entranceRrPosition.x, playSpace.x - minRoomSize.x)
                );
            var xMax = Utilities.Utilities.RandomInclusive(
                Math.Max(entranceRrPosition.x, xMin + minRoomSize.x),
                playSpace.x
                );
            var zMin = Utilities.Utilities.RandomInclusive(
                0,
                Math.Min(entranceRrPosition.y, playSpace.y - minRoomSize.y)
                );
            var zMax = Utilities.Utilities.RandomInclusive(
                Math.Max(entranceRrPosition.y, zMin + minRoomSize.y),
                playSpace.y
                );

            var dimensions = new Dimensions(xMax - xMin, zMax - zMin, xMin, zMin);
            
            Logger.Log($"Generated space dimensions {dimensions}", LogType.RoomGeneration);
            
            return dimensions;
        }

        public void HideOldestRoom()
        {
            if (NumberOfRooms > 0)
            {
                _rooms[NumberOfRooms - 1].roomObject.SetActive(false);
            }
        }

        /// <summary>
        /// Dispose of the oldest room to save resources.
        /// </summary>
        public void DisposeOldestRoom()
        {
            if (NumberOfRooms > 0)
            {
                _rooms[NumberOfRooms - 1].Destroy();
                _rooms.RemoveAt(NumberOfRooms - 1);
            }
        }
    }
}