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

using UnityEngine;
using Pathfinding;

public class Ghost : MonoBehaviour {
    public Rigidbody2D body2D;
    // The point to move to
    public Vector3 targetPosition;
    private Seeker seeker;
    // The calculated path
    public Path path;
    // The max distance from the AI to a waypoint for it to continue to the next waypoint
    public float nextWaypointDistance = 3;
    // The waypoint we are currently moving towards
    private int currentWaypoint = 0;
    // How often to recalculate the path (in seconds)
    public float repathRate = 2f;
    private float lastRepath = -9999;
    public void Start () {
        seeker = GetComponent<Seeker>();

        body2D = GetComponent<Rigidbody2D> ();
        body2D.freezeRotation = true;

        targetPosition = GameObject.FindGameObjectWithTag ("Target").transform.position;
    }
    public void OnPathComplete (Path p) {
        Debug.Log("A path was calculated. Did it fail with an error? " + p.error);
        if (!p.error) {
            path = p;
            // Reset the waypoint counter so that we start to move towards the first point in the path
            currentWaypoint = 0;
        }
    }
    public void FixedUpdate () {
        if (Time.time - lastRepath > repathRate && seeker.IsDone()) {
            lastRepath = Time.time+ Random.value*repathRate*0.5f;
            // Start a new path to the targetPosition, call the the OnPathComplete function
            // when the path has been calculated (which may take a few frames depending on the complexity)
            Debug.Log("Seeker update");
            seeker.StartPath(transform.position, targetPosition, OnPathComplete);
        }
        if (path == null) {
            // We have no path to follow yet, so don't do anything
            return;
        }
        if (currentWaypoint > path.vectorPath.Count) return;
        if (currentWaypoint == path.vectorPath.Count) {
            Debug.Log("End Of Path Reached");
            currentWaypoint++;
            return;
        }
        // Direction to the next waypoint
        Vector3 dir = (path.vectorPath[currentWaypoint]-transform.position).normalized;
        body2D.velocity = dir;
        // The commented line is equivalent to the one below, but the one that is used
        // is slightly faster since it does not have to calculate a square root
        //if (Vector3.Distance (transform.position,path.vectorPath[currentWaypoint]) < nextWaypointDistance) {
        if ((transform.position-path.vectorPath[currentWaypoint]).sqrMagnitude < nextWaypointDistance*nextWaypointDistance) {
            Debug.Log("currentWayPoint: " + currentWaypoint);
            currentWaypoint++;
            return;
        }
    }
}