using System.Collections.Generic;
using UnityEngine;
using Random = UnityEngine.Random;

namespace Escape_Room_Engine.Engine.Scripts
{
    public class Engine : MonoBehaviour
    {
        public static Engine DefaultEngine => FindObjectOfType<Engine>();

        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;

        public 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()
        {
            // 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 Passage();
            
            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 from)
        {
            var exit = new Passage();
            var space = new Space(GenerateSpaceDimensions(), from, exit);
            room.AddSpace(space, exit);
        }

        private Dimensions GenerateSpaceDimensions()
        {
            var xMin = Random.Range(0, playSpace.x - minRoomSize.x + 1);
            var xMax = Random.Range(xMin + minRoomSize.x, playSpace.x + 1);
            var yMin = Random.Range(0, playSpace.y - minRoomSize.y + 1);
            var yMax = Random.Range(yMin + minRoomSize.y, playSpace.y + 1);
            return new Dimensions(xMax - xMin, yMax - yMin, xMin, yMin);
        }

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