using JetBrains.Annotations;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

public class TilesOverlap : MonoBehaviour
{
    public bool UpdateRealTime;
    public bool DebugTiles;

    [HideInInspector] public List<Vector2> OverlapTiles { get; private set; }

    private List<Vector3> Vertices;
    private Mesh Mesh;

    public HashSet<Vector2> OverlapHashSet;

    private void Awake()
    {
        OverlapHashSet = new HashSet<Vector2>();
        Vertices = new List<Vector3>();

        Mesh = GetComponent<MeshFilter>().mesh;

        GetOverlap();

#if UNITY_EDITOR
        DebugOverlap();
#endif
    }


    private void Update()
    {
        if (UpdateRealTime)
        {
            GetOverlap();
#if UNITY_EDITOR
            DebugOverlap();
#endif
        }
    }

    private void GetOverlap()
    {
        Vertices = Mesh.vertices.ToList();
        
        if (OverlapHashSet.Count > 0)
            OverlapHashSet.Clear();
        
        for (int i = 0; i < Vertices.Count; i++)
        {
            var posV3 = transform.TransformPoint(Vertices[i]);

            //this accounts of negative transforms.
            //which i don't know if tiles are positive only.
            var posX = posV3.x < 0 ? posV3.x - 1 : posV3.x;
            var posY = posV3.z < 0 ? posV3.z - 1 : posV3.z;
            
            OverlapHashSet.Add(new Vector2((int)posX, (int)posY));
        }
        //returns as a list for easy manipulation if need be.
        OverlapTiles = OverlapHashSet.ToList();
    }

#if UNITY_EDITOR
    private void DebugOverlap()
    {
        if (DebugTiles)
        {   
            for (int i = 0; i < OverlapTiles.Count; i++)
            {
                Debug.Log(OverlapTiles[i]);
            }
        }
    }
#endif
}