using System;
using RebootKit.Engine.Extensions;
using RebootKit.Engine.Main;
using RebootKit.Engine.Network;
using RebootKit.Engine.Simulation;
using RebootReality.jelycho.Player;
using Unity.Mathematics;
using UnityEngine;
using UnityEngine.AI;
using UnityEngine.Events;
using Logger = RebootKit.Engine.Foundation.Logger;

namespace RebootReality.jelycho.Enemies {
    public class ZombieActorData : IActorData {
        public void Serialize(NetworkBufferWriter writer) {
        }

        public void Deserialize(NetworkBufferReader reader) {
        }

        public int GetMaxBytes() {
            return 0;
        }
    }

    public class ZombieActor : Actor, IKillable {
        static readonly Logger s_Logger = new Logger(nameof(ZombieActor));

        static readonly int s_MovementSpeedHash = Animator.StringToHash("MovementSpeed");

        enum AIState {
            Idle,
            Dead,
            AttackBase,
            AttackCharacter,
            PanicEscape,
            Berserk
        }
        
        [SerializeField] Animator m_Animator;

        [SerializeField] NavMeshAgent m_NavAgent;

        [SerializeField] Collider[] m_RagdollColliders;
        [SerializeField] Rigidbody[] m_RagdollRigidbodies;
        [SerializeField] Collider[] m_Hitboxes;
        
        [SerializeField] float m_MaxAttackDistance = 1.0f;
        [SerializeField] float m_LoseInterestMinDistance = 10.0f;
        [SerializeField] ulong m_BaseDamage = 10;
        [SerializeField] float m_AttackDelay = 1.0f;

        AIState m_State = AIState.Idle;
        
        PlayerActor m_PlayerTarget;
        float m_NextAttackTimer;
        
        public UnityEvent died = new UnityEvent();

        //
        // @MARK: Unity callbacks
        //
        void Awake() {
            SetRagdollLocal(false);
        }
        
        //
        // @MARK: Actor
        //
        public override void OnClientTick(float deltaTime) {
            base.OnClientTick(deltaTime);

            if (!IsAlive()) {
                return;
            }
            
            float velXZ = m_NavAgent.velocity.With(y: 0).magnitude;
            m_Animator.SetFloat(s_MovementSpeedHash, velXZ);
        }

        public override void OnServerTick(float deltaTime) {
            base.OnServerTick(deltaTime);

            if (RR.World.Context is not WorldContext world) {
                s_Logger.Error("Invalid world context");
                return;
            }

            switch (m_State) {
            case AIState.Idle: {
                ServerTickIdle(deltaTime);
                break;
            }
            
            case AIState.AttackBase: {
                ServerTickAttackBase(deltaTime);
                break;
            }
            
            case AIState.AttackCharacter: {
                ServerTickAttackCharacter(deltaTime);
                break;
            }
            
            case AIState.PanicEscape: {
                break;
            }

            case AIState.Berserk: {
                ServerTickBerserk(deltaTime);
                break;
            }
            }
        }

        //
        // @MARK: Zombie
        //
        void ServerTickIdle(float dt) {
            (PlayerActor playerActor, float distSqToPlayer) = FindClosestPlayerActor(transform.position);
            if (playerActor == null || distSqToPlayer >= m_LoseInterestMinDistance * m_LoseInterestMinDistance) {
                return;
            }

            m_State = AIState.AttackCharacter;
            m_PlayerTarget = playerActor;
            
            s_Logger.Info($"Found player actor to attack: {m_PlayerTarget}");
            m_NavAgent.SetDestination(m_PlayerTarget.transform.position);
            m_NavAgent.isStopped = false;
        }
        
        void ServerTickAttackCharacter(float dt) {
            if (m_PlayerTarget == null || !m_PlayerTarget.IsAlive()) {
                SetIdleState();
                return;
            }
            
            float3 playerPos = m_PlayerTarget.transform.position;
            float3 zombiePos = transform.position;
            
            float distToPlayerSq = math.distancesq(playerPos, zombiePos);
            if (distToPlayerSq >= m_LoseInterestMinDistance * m_LoseInterestMinDistance) {
                SetIdleState();
                return;
            }
            
            if (distToPlayerSq <= m_MaxAttackDistance * m_MaxAttackDistance) {
                m_NextAttackTimer -= dt;
                if (m_NextAttackTimer <= 0.0f) {
                    m_Animator.CrossFade("Attack_0", 0.0f, 0);
                    m_NextAttackTimer = m_AttackDelay;
                }

                if (!m_NavAgent.isStopped) {
                    m_NavAgent.isStopped = true;
                }
                return;
            }
            
            float distFromDstToTargetSq = math.distancesq(playerPos, m_NavAgent.destination);
            if (distFromDstToTargetSq > 1.0f) {
                m_NavAgent.isStopped = false;
                m_NavAgent.SetDestination(m_PlayerTarget.transform.position);
            }
        }

        void ServerTickAttackBase(float dt) {
            
        }

        void ServerTickBerserk(float dt) {
            
        }
        
        void SetIdleState() {
            m_PlayerTarget = null;
            m_State = AIState.Idle;
        }

        void Die() {
            s_Logger.Info("Die");
            EnableRagdoll();

            m_State = AIState.Dead;
            died.Invoke();
        }

        (PlayerActor, float) FindClosestPlayerActor(float3 origin) {
            if (RR.World.Context is not WorldContext context) {
                return (null, -1.0f);
            }

            PlayerActor res = null;
            float closestDistanceSq = float.MaxValue;
            
            foreach (Actor actor in RR.Actors()) {
                if (actor is not PlayerActor playerActor) {
                    continue;
                }
                
                float distSq = math.distancesq(actor.transform.position, origin);
                if (distSq < closestDistanceSq) {
                    res = playerActor;
                    closestDistanceSq = distSq;
                }
            }

            return (res, closestDistanceSq);
        }

        //
        // @MARK: Actor
        //
        protected override IActorData CreateActorData() {
            return new ZombieActorData();
        }

        protected override void OnActorEventClient(ActorEvent actorEvent) {
            ZombieActorEvents zombieEvent = (ZombieActorEvents) actorEvent.EventID;

            switch (zombieEvent) {
            case ZombieActorEvents.EnableRagdoll: {
                SetRagdollLocal(true);
                break;
            }
            }
        }

        //
        // @MARK: Ragdoll
        //
        void EnableRagdoll() {
            SendActorEvent((byte)ZombieActorEvents.EnableRagdoll);
        }
        
        void SetRagdollLocal(bool active) {
            foreach (Collider ragdollCollider in m_RagdollColliders) {
                ragdollCollider.enabled = active;
            }

            foreach (Rigidbody ragdollRigidbody in m_RagdollRigidbodies) {
                ragdollRigidbody.isKinematic = !active;
            }

            m_Animator.enabled = !active;
            
            foreach (Collider hitbox in m_Hitboxes) {
                hitbox.enabled = !active;
            }
        }
        
        //
        // @MARK: IKillable
        //
        public ulong Health { get; private set; } = 100;

        public bool IsAlive() {
            return Health > 0;
        }

        public ulong OnHit(Actor attacker, ulong damage) {
            if (!RR.IsServer()) {
                s_Logger.Error("OnHit can only be called on the server.");
                return 0;
            }
            
            if (!IsAlive()) {
                return 0;
            }
            
            s_Logger.Info($"Hit: {damage}");

            damage = math.min(damage, Health);
            Health -= damage;
            if (Health <= 0) {
                Die();
                return damage;
            }

            return damage;
        }
    }

    enum ZombieActorEvents {
        None = 0x00,
        EnableRagdoll = 0x01
    }
}