using System.Collections.Generic;
using Escape_Room_Engine.Engine.Scripts.Modules;
using UnityEngine;

namespace Escape_Room_Engine.Engine.Scripts
{
    public class Space
    {
        /// <summary>
        /// The room relative (<i>RR</i>) dimensions of this space.
        /// </summary>
        internal readonly Dimensions rrDimensions;
        internal List<Module> Modules { get; } = new(2);
        
        private GameObject _spaceObject;

        internal Space(Dimensions rrDimensions, Passage entrance)
        {
            this.rrDimensions = rrDimensions;
            
            // connect the space to its passage
            entrance.ConnectTo(new DoorModule(this,
                ((DoorModuleDescription)entrance.fromOut.description).connectedDoorDescription));
            AddModule(entrance.toIn);
        }

        internal void AddModule(Module module)
        {
            Modules.Add(module);
        }

        internal void InstantiateSpace(Transform parent, string name)
        {
            _spaceObject = new GameObject($"Space {name}", typeof(MeshFilter), typeof(MeshRenderer));
            _spaceObject.transform.SetParent(parent, false);
            _spaceObject.transform.localPosition = new Vector3(rrDimensions.x, 0, rrDimensions.z);
            
            var meshFilter = _spaceObject.GetComponent<MeshFilter>();
            meshFilter.mesh = GenerateMesh();
            
            var meshRenderer = _spaceObject.GetComponent<MeshRenderer>();
            meshRenderer.material = Engine.DefaultEngine.roomMaterial;
            
            // instantiate all modules inside this space
            Modules.ForEach(module => module.InstantiateModule(_spaceObject.transform));
        }

        /// <summary>
        /// Convert a position relative to this space to one relative to the room.
        /// </summary>
        /// <param name="srPosition">The space relative (<i>SR</i>) position that should be converted to a room relative (<i>RR</i>) position.</param>
        /// <returns></returns>
        internal Vector2Int ToRoomRelative(Vector2Int srPosition) => srPosition + rrDimensions.Position;
        /// <summary>
        /// Convert a position relative to the room to one relative to this space.
        /// </summary>
        /// <param name="rrPosition">The room relative (<i>RR</i>) position that should be converted to a space relative (<i>SR</i>) position.</param>
        /// <returns></returns>
        internal Vector2Int ToSpaceRelative(Vector2Int rrPosition) => rrPosition - rrDimensions.Position;

        private Mesh GenerateMesh()
        {
            var mesh = new Mesh();

            mesh.vertices = new[]
            {
                new Vector3(0, 0, 0),
                new Vector3(rrDimensions.width, 0, 0),
                new Vector3(0, 0, rrDimensions.length),
                new Vector3(rrDimensions.width, 0, rrDimensions.length)
            };

            mesh.triangles = new[]
            {
                0, 2, 1,
                2, 3, 1
            };

            var normal = Vector3.up;
            mesh.normals = new[]
            {
                normal, normal, normal, normal
            };

            mesh.uv = new[]
            {
                new Vector2(0, 0),
                new Vector2(1, 0),
                new Vector2(0, 1),
                new Vector2(1, 1)
            };

            return mesh;
        }

        internal void Destroy()
        {
            Object.Destroy(_spaceObject);
        }
    }
}