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

public class astar_vertex : MonoBehaviour
{
    public Transform VertexGroup;
    [SerializeField]
    public List<Vertex> nodes;

    Vertex startNode;
    Vertex endNode;

    public Transform startVisualizer;
    public Transform endVisualizer;
    public PathWalker walker;

    public List<Vertex> finalPath;
    void Start()
    {
        finalPath = new List<Vertex>();
        nodes = new List<Vertex>();
        foreach(Vertex vertex in VertexGroup.GetComponentsInChildren<Vertex>()){
            NodeData nodeData =  vertex.gameObject.AddComponent(typeof(NodeData)) as NodeData;
            nodes.Add(vertex);
        }
    }

    // Update is called once per frame
    void Update()
    {
        if(startNode != null){Debug.DrawLine(startVisualizer.position, startNode.transform.position);}
        if(endNode != null){Debug.DrawLine(endVisualizer.position, endNode.transform.position);}
        if(Input.GetKeyDown(KeyCode.E)){
            Vector2 startPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            startVisualizer.position = startPos;

            //get closest and reachable node to this location
            float minDist = Mathf.Infinity;

            foreach(Vertex node in nodes){
                if(Physics2D.Linecast(startPos, node.transform.position)){}else{
                    float distToNode = Vector2.Distance(node.transform.position, startPos);
                    if(distToNode < minDist){
                        minDist = distToNode;
                        startNode = node;
                    }
                }
            }
        }else if(Input.GetKeyDown(KeyCode.F)){
            Vector2 endPos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            endVisualizer.position = endPos;

            //get closest and reachable node to this location
            float minDist = Mathf.Infinity;

            foreach(Vertex node in nodes){
                if(Physics2D.Linecast(endPos, node.transform.position)){}else{
                    float distToNode = Vector2.Distance(node.transform.position, endPos);
                    if(distToNode < minDist){
                        minDist = distToNode;
                        endNode = node;
                    }
                }
            }
        }else if(Input.GetKeyDown(KeyCode.Return)){
            //Start Calculation
            StartCoroutine(Calculate());
        }else if(Input.GetKeyDown(KeyCode.I)){
            Recalculate();
        }else if(Input.GetKeyDown(KeyCode.S)){
            Recalculate();
            walker.pathNodes = new List<Transform>();
            walker.curIndex = 0;
            walker.pathNodes.Add(startNode.transform);
            for(int i = finalPath.Count-1; i >=0; i--){
                walker.pathNodes.Add(finalPath[i].transform);
            }
            walker.pathNodes.Add(endVisualizer);
        }

        if(finalPath.Count  > 1){
            for(int i = 1; i < finalPath.Count; i++){
                Debug.DrawLine(finalPath[i].transform.position, finalPath[i-1].transform.position, Color.green);
            }
        }
    }

    public void Recalculate(){
        DateTime startTime = DateTime.Now;
        foreach(Vertex node in nodes){
            node.GetComponent<NodeData>().Reset();
        }

        List<Vertex> open = new List<Vertex>();
        List<Vertex> close = new List<Vertex>();
        open.Add(startNode);
        bool foundPath = false;
        while(!foundPath){
            Vertex current = null;
            float lowestF = Mathf.Infinity;
            foreach(Vertex cell in open){
                if(cell.GetComponent<NodeData>().fCost < lowestF){
                    lowestF = cell.GetComponent<NodeData>().fCost;
                    current = cell;
                }
            }
            open.Remove(current);
            close.Add(current);

            if(current == endNode){foundPath=true; continue;}
            foreach(Vertex neighbour in current.neighbours){
                if(close.Contains(neighbour)){continue;}
                bool hasThisNeighbour = open.Contains(neighbour);
                if(neighbour.GetComponent<NodeData>().fCost < lowestF || !hasThisNeighbour){
                    calculateCellCost(neighbour.GetComponent<NodeData>());
                    if(neighbour.GetComponent<NodeData>().fCost < lowestF || neighbour.GetComponent<NodeData>().parent==null){ neighbour.GetComponent<NodeData>().parent = current;}
                    if(!hasThisNeighbour){open.Add(neighbour);}
                }
            }
           // yield return new WaitForSeconds(0.05f);
        }

        //sort
        bool pathCleared = false;
        Vertex parentCell = endNode;
        finalPath= new List<Vertex>();
        while(!pathCleared){

            if(parentCell == startNode){pathCleared=true; break;}
            finalPath.Add(parentCell);
            parentCell = parentCell.GetComponent<NodeData>().parent;
           // yield return new WaitForSeconds(0.1f);
        }

        Debug.Log("Calculation finished in " + (DateTime.Now - startTime).TotalMilliseconds + "ms");
    }

    IEnumerator Calculate(){
        DateTime startTime = DateTime.Now;
        foreach(Vertex node in nodes){
            node.GetComponent<NodeData>().Reset();
        }
        List<Vertex> open = new List<Vertex>();
        List<Vertex> close = new List<Vertex>();
        open.Add(startNode);
        bool foundPath = false;
        while(!foundPath){
            Vertex current = null;
            float lowestF = Mathf.Infinity;
            foreach(Vertex cell in open){
                if(cell.GetComponent<NodeData>().fCost < lowestF){
                    lowestF = cell.GetComponent<NodeData>().fCost;
                    current = cell;
                }
            }
            open.Remove(current);
            close.Add(current);

            if(current == endNode){foundPath=true; continue;}
            foreach(Vertex neighbour in current.neighbours){
                if(close.Contains(neighbour)){continue;}
                bool hasThisNeighbour = open.Contains(neighbour);
                if(neighbour.GetComponent<NodeData>().fCost < lowestF || !hasThisNeighbour){
                    calculateCellCost(neighbour.GetComponent<NodeData>());
                    if(neighbour.GetComponent<NodeData>().fCost < lowestF || neighbour.GetComponent<NodeData>().parent==null){ neighbour.GetComponent<NodeData>().parent = current;}
                    if(!hasThisNeighbour){open.Add(neighbour);}
                }
            }
           // yield return new WaitForSeconds(0.05f);
        }

        //sort
        bool pathCleared = false;
        Vertex parentCell = endNode;
        finalPath= new List<Vertex>();
        while(!pathCleared){

            if(parentCell == startNode){pathCleared=true; break;}
            finalPath.Add(parentCell);
            parentCell = parentCell.GetComponent<NodeData>().parent;
            yield return new WaitForSeconds(0.1f);
        }
        Debug.Log("Calculation finished in " + (DateTime.Now - startTime).Milliseconds + "ms");
    }

    

    bool calculateCellCost(NodeData cell){
        if((int)cell.fCost!=0){return false;}
        cell.hCost = Vector2.Distance(cell.transform.position, endNode.transform.position);
        cell.gCost = Vector2.Distance(cell.transform.position, startNode.transform.position);
        cell.fCost = cell.hCost + cell.gCost;

        return true;
    }


    void OnValidate(){
        if(VertexGroup !=null && VertexGroup.GetComponentInChildren<Vertex>()==null){VertexGroup = null; Debug.LogError("Please assigna a vertex group with vertecies as children");}
    }
}