using SepCore.CustomUtility;
using SepCore.Definition;
using UnityEngine;

namespace SepCore.Entity
{
    public class MeleeEnemy : EnemyBase
    {
        private float _sqrAttackRange;
        private EnemyStateType enemyState = EnemyStateType.Idle;
        private TargetableObject _targetableTarget;

        #region Lifecycle

        protected override void OnShow(object userData)
        {
            base.OnShow(userData);

            _sqrAttackRange = AttackRange * AttackRange;
            enemyState = EnemyStateType.Idle;
            _targetableTarget = null;
        }

        protected override void OnUpdate(float elapseSeconds, float realElapseSeconds)
        {
            base.OnUpdate(elapseSeconds, realElapseSeconds);

            UpdateAttackState(elapseSeconds);
        }

        protected override void OnHide(bool isShutdown, object userData)
        {
            _targetableTarget = null;
            enemyState = EnemyStateType.Idle;

            base.OnHide(isShutdown, userData);
        }

        #endregion

        public override void SetTarget(Transform target)
        {
            base.SetTarget(target);
            _targetableTarget = target != null ? target.GetComponent<TargetableObject>() : null;
        }

        private void UpdateAttackState(float elapseSeconds)
        {
            switch (enemyState)
            {
                case EnemyStateType.Idle:
                    Movement.SetMove(false);
                    if (HasValidTarget())
                    {
                        TransitionTo(EnemyStateType.Seek);
                    }

                    break;
                case EnemyStateType.Seek:
                    if (!HasValidTarget())
                    {
                        TransitionTo(EnemyStateType.Idle);
                        return;
                    }

                    if (IsTargetInRange())
                    {
                        TransitionTo(EnemyStateType.Chase);
                        return;
                    }

                    Movement.SetMove(true);
                    Movement.SetDirection(GetTargetDirection());
                    break;
                case EnemyStateType.Chase:
                    if (!HasValidTarget())
                    {
                        TransitionTo(EnemyStateType.Idle);
                        return;
                    }

                    Movement.SetMove(false);
                    if (!IsTargetInRange())
                    {
                        TransitionTo(EnemyStateType.Seek);
                        return;
                    }

                    if (_canAttack)
                    {
                        ResetAttackCooldown(AttackCooldown);
                        TransitionTo(EnemyStateType.Attack);
                    }

                    break;
            }
        }

        private void TransitionTo(EnemyStateType newState)
        {
            enemyState = newState;

            if (enemyState == EnemyStateType.Chase)
            {
                Movement.SetMove(false);
            }

            if (enemyState == EnemyStateType.Attack)
            {
                Movement.SetMove(false);
                ExecuteAttack();
                TransitionTo(EnemyStateType.Chase);
            }
        }

        private bool HasValidTarget()
        {
            if (_target == null) return false;

            if (_targetableTarget == null || _targetableTarget.CachedTransform != _target)
            {
                _targetableTarget = _target.GetComponent<TargetableObject>();
            }

            return _targetableTarget != null && _targetableTarget.Available && !_targetableTarget.IsDead;
        }

        private bool IsTargetInRange()
        {
            if (_target == null) return false;

            Vector3 delta = _target.position - CachedTransform.position;
            delta.y = 0f;
            return delta.sqrMagnitude <= _sqrAttackRange;
        }

        private void ExecuteAttack()
        {
            if (!HasValidTarget() || !IsTargetInRange()) return;

            ImpactData targetImpactData = _targetableTarget.GetImpactData();
            ImpactData selfImpactData = GetImpactData();
            if (AIUtility.GetRelation(selfImpactData.Camp, targetImpactData.Camp) == RelationType.Friendly)
            {
                return;
            }

            int damage = AIUtility.CalcDamageHP(AttackDamage, null, targetImpactData.DefenseStat,
                targetImpactData.DodgeStat);
            _targetableTarget.ApplyDamage(this, damage);
        }
    }
}