using System;
using UnityEngine;
using NodeCanvas.Framework;
using ParadoxNotion.Design;

using NavMeshAgent = UnityEngine.AI.NavMeshAgent;
using NavMesh = UnityEngine.AI.NavMesh;
using NavMeshHit = UnityEngine.AI.NavMeshHit;
using Random = UnityEngine.Random;

namespace NodeCanvas.Tasks.Actions
{

    [Category("Movement/Pathfinding")]
    [Description("Makes the agent wander randomly within the navigation map")]
    public class Wander : ActionTask<NavMeshAgent>
    {
        [Tooltip("The speed to wander with.")]
        public BBParameter<float> speed = 4;
        [Tooltip("The distance to keep from each wander point.")]
        public BBParameter<float> keepDistance = 0.1f;
        [Tooltip("A wander point can't be closer than this distance")]
        public BBParameter<float> minWanderDistance = 5;
        [Tooltip("A wander point can't be further than this distance")]
        public BBParameter<float> maxWanderDistance = 20;
        [Tooltip("If enabled, will keep wandering forever. If not, only one wander point will be performed.")]
        public bool repeat = true;
        [Tooltip("If enabled,will execute a move and exit")]
        public bool forget;

        private Vector3? lastPosition;

        protected override void OnExecute() {
            agent.speed = speed.value;
            DoWander();
        }

        protected override void OnUpdate() {
            if ( !agent.pathPending && agent.remainingDistance <= agent.stoppingDistance + keepDistance.value ) {
                if ( repeat ) {
                    DoWander();
                } else {
                    EndAction();
                }

                lastPosition = null;
            }
            else
            {
                if (forget)
                {
                    EndAction();
                }
            }
        }

        void DoWander() {
            if (agent.isOnNavMesh is false)
            {
                EndAction(false);
                return;
            }
            
            var min = minWanderDistance.value;
            var max = maxWanderDistance.value;
            min = Mathf.Clamp(min, 0.01f, max);
            max = Mathf.Clamp(max, min, max);
            var wanderPos = agent.transform.position;

            if (lastPosition.HasValue)
            {
                wanderPos = lastPosition.Value;
            }
            else
            {
                while ((wanderPos - agent.transform.position).magnitude < min)
                {
                    wanderPos = (Random.insideUnitSphere * max) + agent.transform.position;
                }
            }

            NavMeshHit hit;
            if ( NavMesh.SamplePosition(wanderPos, out hit, agent.height * 2, NavMesh.AllAreas) ) {
                try
                {
                    agent.SetDestination(hit.position);
                    lastPosition = hit.position;
                }
                catch (Exception e)
                {
                    Debug.LogWarning(agent.gameObject.name);
                    Debug.LogException(e);
                }
                
            }
        }

        protected override void OnPause() { OnStop(); }

        protected override void OnStop()
        {
            if (agent.gameObject.activeSelf && agent.isOnNavMesh)
            {
                if (forget is false)
                    agent.ResetPath();
            }
        }

        protected override void OnStop(bool interrupted)
        {
            base.OnStop(interrupted);
            if (interrupted)
            {
                lastPosition = null;
            }
        }
    }
}