using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Sirenix.OdinInspector;
using UnityEngine.AI;
using UnityEngine.Events;

[RequireComponent(typeof(NavMeshAgent))]
public class NavMeshComponent : MonoBehaviour
{
    [SerializeField]
    [ReadOnly]
    public int currentWaypointIndex = 0;

    [SerializeField]
    [ReadOnly]
    public WaypointsGroup waypointGroup;

    [SerializeField]
    [ReadOnly]
    private NavMeshAgent agent;

    [SerializeField]
    private UnityEvent<float> onVelocityChanged;

    private void Awake()
    {
        agent = GetComponent<NavMeshAgent>();
    }

    public void MoveTo(WaypointsGroup waypointGroup)
    {
        this.waypointGroup = waypointGroup;
        
        MoveToNext();
    }

    private void MoveToNext()
    {
        currentWaypointIndex++;
        agent.destination = waypointGroup.waypoints[currentWaypointIndex]
            .GetPosition();
    }

    private void Update()
    {
        var velocity = agent.velocity.magnitude / agent.speed;
        onVelocityChanged.Invoke(velocity);

        if (waypointGroup == null)
            return;

        if (ReachedDestinationOrGaveUp())
        {
            if (currentWaypointIndex != waypointGroup.waypoints.Count - 1)
            {
                MoveToNext();
            }
        }
    }

    private bool ReachedDestinationOrGaveUp()
    {
        if (agent.pathPending)
            return false;

        if (agent.remainingDistance > agent.stoppingDistance)
            return false;

        if (!(!agent.hasPath || agent.velocity.sqrMagnitude == 0f)) 
            return false;

        return true;
    }
}