MoveToPoint

using UnityEngine;
using System.Collections;

public class MoveToPoint : MonoBehaviour {

    public GameObject target;
    private NavMeshAgent navAgent;
    public bool followTarget, followFromStart;
    public bool randomTarget;
    private bool isRandomTargetSet = false;
    private bool isCalculatingPath = false;
    private Vector2 randomPos;
    public float randomPointRadius;

    // Use this for initialization
    void Start() {
        navAgent = gameObject.GetComponent<NavMeshAgent>();

        if (target && followFromStart) {
            navAgent.SetDestination(target.transform.position);
        }
    }

    void Update() {
        if (target && followTarget && !randomTarget) {
            navAgent.SetDestination(target.transform.position);
        }


        if (randomTarget) {
            if (!isRandomTargetSet && !isCalculatingPath) {
                StartCoroutine(setRandomTarget());
                isCalculatingPath = true;
            }
            else {
                if (Vector3.Distance(transform.position,  (Vector3)randomPos)<1) {
                    isRandomTargetSet = false;
                }
            }
        }

    }

    private IEnumerator setRandomTarget() {

        Vector2 randomPos = Random.insideUnitCircle * randomPointRadius + new Vector2(transform.position.x, transform.position.z);

        navAgent.SetDestination(randomPos);

        //Wait until the path is calculated
        while (navAgent.pathPending) {
            yield return 0;
        }

        //The newPos is not contained into the NavMesh, so try again
        if (navAgent.pathStatus == NavMeshPathStatus.PathInvalid) {
            StartCoroutine(setRandomTarget());
        }
        //The new position is valid
        else {

            isRandomTargetSet = true;
            isCalculatingPath = false;
        }
    }
}