using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class astar : MonoBehaviour
{
    [Header("Grid Information")]
    public float width;
    public float height;
    public Color gridBoundsVisualizeColor = Color.red;
    public GameObject cellGameObject;
    public Transform cellsParent;
    public cellData[,] cells;
    public Vector2Int targetCellId;
    public Vector2Int startCellId;
    void Start()
    {
        StartCoroutine(generateCells());
    }

    IEnumerator generateCells(){
        //Generate cells in grid
        float cellSize = cellGameObject.transform.localScale.x;
        Vector2 cellStartPosition = new Vector2( transform.position.x - width /2f, transform.position.y - height /2f) 
                                    + new Vector2(cellSize/2f, cellSize/2f);

        

        int horizontalCellCount = (int)(width / cellSize);
        int verticalCellCount = (int)(height / cellSize);
        cells = new cellData[horizontalCellCount,verticalCellCount];
        for(int x= 0; x < horizontalCellCount; x++){
            for(int y = 0; y < verticalCellCount; y++){
                Vector2 cellSpawnPos = cellStartPosition + new Vector2(cellSize * x, cellSize *y );
                GameObject cell = Instantiate(cellGameObject, cellSpawnPos , Quaternion.identity);
                cell.GetComponent<cellData>().x = x;
                cell.GetComponent<cellData>().y = y;
                cell.transform.parent = cellsParent;
                
                //isObstacle?
                cell.GetComponent<cellData>().setObstacle(Physics2D.BoxCast(cell.transform.position, cell.transform.localScale/2f, 0 ,Vector2.zero));
                //cell.GetComponent<cellData>().setObstacle(Physics2D.CircleCast(cellSpawnPos,cellSize /2f,Vector2.zero));

                //cells.Add(cell.GetComponent<cellData>());
                cells[x,y] = cell.GetComponent<cellData>();
                yield return new WaitForSeconds(0.001f);
            }
        }
    }

    // Update is called once per frame
    Coroutine calculator = null;
    void Update()
    {
        if(Input.GetKeyDown(KeyCode.E)){
            Vector2 worldPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);

            Vector2Int closestCellId = getClosestCell(worldPos);
            if(startCellId.magnitude >=0){cells[startCellId.x,startCellId.y].setObstacle();}
            startCellId = closestCellId;
            cells[startCellId.x, startCellId.y].GetComponent<SpriteRenderer>().color = Color.red;
        }else if(Input.GetKeyDown(KeyCode.F)){
            Vector2 worldPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            if(targetCellId.magnitude >=0){cells[targetCellId.x,targetCellId.y].setObstacle();}
            Vector2Int closestCell = getClosestCell(worldPos);
            targetCellId = closestCell;
            cells[targetCellId.x, targetCellId.y].GetComponent<SpriteRenderer>().color = Color.blue;
        }else if(Input.GetKeyDown(KeyCode.Return)){
            if(calculator != null){StopCoroutine(calculator); resetCellsCost();}
            Debug.Log("Starting calculation");
            calculator = StartCoroutine(Calculate());
        }
    }

    public Vector2Int getClosestCell(Vector2 worldPos){
        float minDist = Mathf.Infinity;
        cellData closestCell = null;
        foreach(cellData cell in cells){
            if(cell.isObstacle){continue;}
            float DistToCell = Vector3.Distance(worldPos, cell.transform.position);
            if(DistToCell < minDist){
                minDist = DistToCell;
                closestCell = cell;
            }
        }

        return closestCell;
    }


    void OnDrawGizmos(){
        //Gizmos.Color = gridBoundsVisualizeColor;
        Gizmos.color = gridBoundsVisualizeColor;
        Gizmos.DrawWireCube(transform.position, new Vector3(width, height, 0));
    }

    IEnumerator Calculate(){
        bool foundPath = false;
        Vector2Int closeCellId = startCellId;
        while(!foundPath){
            calculateCellCost(cells[closeCellId.x,closeCellId.y]);
            for(int x = -1; x <= 1; x++){
                for(int y=-1; y <= 1; y++){
                    int targetX = closeCellId.x +x;
                    int targetY = closeCellId.y +y;
                    if(cells.GetLength(0) < targetX || targetX < 0 || targetY < 0 || cells.GetLength(1) < targetY){continue;}
                    calculateCellCost(cells[targetX,targetY]);
                }
            }
            
           // cellsToCalculate.Remove(cell);
            yield return new WaitForSeconds(0.01f);
        }
    }

    void calculateCellCost(cellData cell){
        if(cell.fCost==0){return;}
        float hCost = Vector2.Distance(cell.transform.position, cells[targetCellId.x, targetCellId.y].transform.position);
        float gCost = Vector2.Distance(cell.transform.position, cells[startCellId.x, startCellId.y].transform.position);
        float fCost = hCost + gCost;

        cell.setCellCost(gCost, hCost, fCost);
    }

    public void resetCellsCost(){
        foreach(cellData cell in cells){
            cell.resetCost();
        }
    }
}