using AIMachineTools;
using System.Collections;
using UnityEngine;

public class FollowState : State
{
    private static FollowState _instance; //only declared once

    private FollowState() //set instance to itself
    {
        if (_instance != null)
        {
            return;
        }

        _instance = this;
    }

    public static FollowState instance //creates the instance of the first state if it does not exist
    {
        get
        {
            if (_instance == null)
            {
                new FollowState();
            }

            return _instance;
        }
    }

    public override IEnumerator InState(AIMachine owner)
    {
        owner.RemoveMarker();

        while (owner.botMachine.currentState == FollowState.instance)
        {
            if (!owner.disabled)
            {
                if (Vector3.Angle(owner.transform.forward, owner.playerObject.transform.position - owner.transform.position) < 15)
                {
                    owner.thisAgent.SetDestination(owner.playerObject.transform.position);

                    //if the distance to the target is less than the follow distance, stop moving
                    if (Vector3.Distance(owner.transform.position, owner.playerObject.transform.position) <= owner.followDistance)
                    {
                        owner.thisAgent.SetDestination(owner.transform.position);
                    }
                }
                else
                    RotateBody(owner, owner.playerObject.transform.position);

                GameObject targetEnemy = owner.followTarget.GetComponent<PlayerCallForHelp>().GetEnemy();

                if (targetEnemy != null && owner.enemyObject == null) //if follow target has target and this bot does not, set the target to the follow targets target
                {
                    owner.canSeeEnemy = true;
                    owner.enemyObject = targetEnemy;
                    owner.botMachine.ChangeState(ChaseState.instance);
                    yield break;
                }

                //if the bot sees an enemy that is in attack distance, attack it
                if (owner.canSeeEnemy && owner.enemyObject != null && Vector3.Distance(owner.transform.position, owner.enemyObject.transform.position) <= owner.attackDistance)
                {
                    owner.botMachine.ChangeState(AttackState.instance);
                    yield break;
                }
            }
            else //if the bot is disabled, tell it to stop moving
            {
                owner.thisAgent.SetDestination(owner.transform.position);
            }

            yield return null;
        }
    }

    private void RotateBody(AIMachine _owner, Vector3 navPoint) //called to have the bot rotate to face the waypoint before navigating to it
    {
        //declare variables that will be used to determine how to move the bot
        Quaternion targetRot = Quaternion.LookRotation(navPoint - _owner.transform.position);

        //rotate the bot over time to face the enemy
        _owner.transform.rotation = Quaternion.RotateTowards(_owner.transform.rotation, targetRot, Time.deltaTime * _owner.bodyRotateSpeed);

        //set the bots y euler angle so that it only moves on that transform
        _owner.transform.localEulerAngles = new Vector3(0, _owner.transform.localEulerAngles.y, 0);
    }

}