using System.Collections.Generic;
using UnityEngine;

public class EnemyMovement : MonoBehaviour
{
    #region Statication

    public static EnemyMovement instance;

    private void Awake()
    {
        if (instance != null && instance != this)
        {
            Destroy(gameObject);
            return;
        }
        instance = this;
    }

    #endregion
    private Queue<TileObject> allMovableTiles = new();
    private Queue<TileObject> currentMovableTiles = new();
    private Dictionary<TileObject, TileObject> currentPaths = new();
    
    public void PathfindToTarget(TileObject target, Enemy selectedEntity)
    {
        allMovableTiles.Clear();
        currentMovableTiles.Clear();
        currentPaths.Clear();
        GetTilesInRange(selectedEntity);
        TileObject requestedTile = GetPathToTarget(target, selectedEntity);
        selectedEntity.currentTile = requestedTile;
        selectedEntity.transform.position = requestedTile.transform.position;
    }
    private void GetTilesInRange(Enemy selectedEntity)
    {
        foreach (TileObject tileObject in selectedEntity.currentTile.neighbors)
        {
            if (!tileObject.blocked && !tileObject.hasUnit)
            {
                currentMovableTiles.Enqueue(tileObject);
                allMovableTiles.Enqueue(tileObject);
                currentPaths.Add(tileObject,  selectedEntity.currentTile);
            }
        }
        for (int i = 0; i < selectedEntity.maxMovement - 1; i++)
        {
            foreach (TileObject tileObject in currentMovableTiles.ToArray())
            {
                foreach (TileObject neighboringTiles in tileObject.neighbors)
                {
                    if (!neighboringTiles.blocked && !neighboringTiles.hasUnit)
                    {
                        currentMovableTiles.Enqueue(neighboringTiles);
                        currentPaths.TryAdd(neighboringTiles, tileObject);
                    }
                }
            }
        }
        foreach (TileObject tileObject in allMovableTiles.ToArray())
        {
            foreach (TileObject neighboringTiles in tileObject.neighbors)
            {
                if (!neighboringTiles.blocked && !neighboringTiles.hasUnit)
                {
                    allMovableTiles.Enqueue(neighboringTiles);
                    currentPaths.TryAdd(neighboringTiles, tileObject);
                }
            }
        }
    }

    private TileObject GetPathToTarget(TileObject target, Enemy selectedEntity)
    {
        TileObject currentTile = target; 
        List<TileObject> pathToTarget = new();
        TileObject pathTileInRange = null;
        while (currentTile != selectedEntity.currentTile)
        {
            pathToTarget.Add(currentTile);
            currentTile = currentPaths[currentTile];
        }

        for (int i = 0; i < pathToTarget.Count; i++)
        {
            if (currentMovableTiles.Contains(pathToTarget[i]))
            {
                pathTileInRange = pathToTarget[i];
                return pathTileInRange;
            }
        }
        List<TileObject> pathToRange = new();
        /*if (pathTileInRange != null)
        {
            while (pathTileInRange != selectedEntity.currentTile)
            {
                pathToTarget.Add(pathTileInRange);
                pathTileInRange = currentPaths[pathTileInRange];
            }
            return pathToRange;
        }*/
        return null;
    }
}