com.unity.multiplayer.samples.coop/Assets/BossRoom/Scripts/Server/Game/Action/ChaseAction.cs

using MLAPI;
using UnityEngine;

namespace BossRoom.Server
{
    public class ChaseAction : Action
    {
        private NetworkedObject m_Target;
        private ServerCharacterMovement m_Movement;

        private Vector3 m_CurrentTargetPos;

        public ChaseAction(ServerCharacter parent, ref ActionRequestData data, int level) : base(parent, ref data, level)
        {
        }


        /// <summary>
        /// Called when the Action starts actually playing (which may be after it is created, because of queueing). 
        /// </summary>
        /// <returns>false if the action decided it doesn't want to run after all, true otherwise. </returns>
        public override bool Start()
        {
            if (!HasValidTarget())
            {
                Debug.Log("Failed to start ChaseAction. The target entity  wasn't submitted or doesn't exist anymore");
                return false;
            }

            m_Target = MLAPI.Spawning.SpawnManager.SpawnedObjects[m_Data.TargetIds[0]];

            m_Movement = m_Parent.GetComponent<ServerCharacterMovement>();
            m_CurrentTargetPos = m_Target.transform.position;

            if (StopIfDone())
            {
                m_Parent.transform.LookAt(m_CurrentTargetPos); //even if we didn't move, snap to face the target!
                return false;
            }

            m_Movement.SetMovementTarget(m_Target.transform.position);
            return true;
        }

        /// <summary>
        /// Returns true if our ActionRequestData came with a valid target. For the ChaseAction, this is pretty liberal (could be friend or foe, could be
        /// dead or alive--just needs to be present). 
        /// </summary>
        private bool HasValidTarget()
        {
            return m_Data.TargetIds != null &&
                   m_Data.TargetIds.Length > 0 &&
                   MLAPI.Spawning.SpawnManager.SpawnedObjects.ContainsKey(m_Data.TargetIds[0]);
        }

        /// <summary>
        /// Tests to see if we've reached our target. Returns true if we've reached our target, false otherwise (in which case it also stops our movement). 
        /// </summary>
        private bool StopIfDone()
        {
            float distToTarget2 = (m_Parent.transform.position - m_Target.transform.position).sqrMagnitude;
            if ((m_Data.Amount * m_Data.Amount) > distToTarget2)
            {
                //we made it! we're done. 
                Cancel();
                return true;
            }

            return false;
        }

        /// <summary>
        /// Called each frame while the action is running. 
        /// </summary>
        /// <returns>true to keep running, false to stop. The Action will stop by default when its duration expires, if it has a duration set. </returns>
        public override bool Update()
        {
            if (StopIfDone()) { return false; }

            float targetMoved2 = (m_Target.transform.position - m_CurrentTargetPos).sqrMagnitude;
            if ((m_Data.Amount * m_Data.Amount) < targetMoved2)
            {
                //target has moved past our range tolerance. Must repath. 
                this.m_Movement.SetMovementTarget(m_Target.transform.position);
                m_CurrentTargetPos = m_Target.transform.position;
            }

            return true;
        }

        public override void Cancel()
        {
            m_Movement?.CancelMove();
        }

    }

}