using System;
using System.Diagnostics;

using ACE.Entity.Enum;

namespace ACE.Server.WorldObjects
{
    partial class Creature
    {
        protected const double monsterTickInterval = 0.2;

        public double NextMonsterTickTime;

        private bool firstUpdate = true;

        /// <summary>
        /// Primary dispatch for monster think
        /// </summary>
        public void Monster_Tick(double currentUnixTime)
        {
            if (IsChessPiece && this is GamePiece gamePiece)
            {
                // faster than vtable?
                gamePiece.Tick(currentUnixTime);
                return;
            }

            if (IsPassivePet && this is Pet pet)
            {
                pet.Tick(currentUnixTime);
                return;
            }

            NextMonsterTickTime = currentUnixTime + monsterTickInterval;

            if (!IsAwake)
            {
                if (MonsterState == State.Return)
                    MonsterState = State.Idle;

                if (IsFactionMob || HasFoeType)
                    FactionMob_CheckMonsters();

                return;
            }

            if (IsDead) return;

            if (EmoteManager.IsBusy) return;

            HandleFindTarget();

            CheckMissHome();    // tickrate?

            if (AttackTarget == null && MonsterState != State.Return)
            {
                Sleep();
                return;
            }

            if (MonsterState == State.Return)
            {
                Movement();
                return;
            }

            var combatPet = this as CombatPet;

            var creatureTarget = AttackTarget as Creature;

            if (creatureTarget != null && (creatureTarget.IsDead || (combatPet == null && !IsVisibleTarget(creatureTarget))))
            {
                FindNextTarget();
                return;
            }

            if (firstUpdate)
            {
                if (CurrentMotionState.Stance == MotionStance.NonCombat)
                    DoAttackStance();

                if (IsAnimating)
                {
                    //PhysicsObj.ShowPendingMotions();
                    PhysicsObj.update_object();
                    return;
                }

                firstUpdate = false;
            }

            // select a new weapon if missile launcher is out of ammo
            var weapon = GetEquippedWeapon();
            /*if (weapon != null && weapon.IsAmmoLauncher)
            {
                var ammo = GetEquippedAmmo();
                if (ammo == null)
                    SwitchToMeleeAttack();
            }*/

            if (weapon == null && CurrentAttack != null && CurrentAttack == CombatType.Missile)
            {
                EquipInventoryItems(true);
                DoAttackStance();
                CurrentAttack = null;
            }

            // decide current type of attack
            if (CurrentAttack == null)
            {
                CurrentAttack = GetNextAttackType();
                MaxRange = GetMaxRange();

                //if (CurrentAttack == AttackType.Magic)
                //MaxRange = MaxMeleeRange;   // FIXME: server position sync
            }

            if (PhysicsObj.IsSticky)
                UpdatePosition(false);

            // get distance to target
            var targetDist = GetDistanceToTarget();
            //Console.WriteLine($"{Name} ({Guid}) - Dist: {targetDist}");

            if (CurrentAttack != CombatType.Missile)
            {
                if (targetDist > MaxRange || (!IsFacing(AttackTarget) && !IsSelfCast()))
                {
                    // turn / move towards
                    if (!IsTurning && !IsMoving)
                        StartTurn();
                    else
                        Movement();
                }
                else
                {
                    // perform attack
                    if (AttackReady())
                        Attack();
                }
            }
            else
            {
                if (IsTurning || IsMoving)
                {
                    Movement();
                    return;
                }

                if (!IsFacing(AttackTarget))
                {
                    StartTurn();
                }
                else if (targetDist <= MaxRange)
                {
                    // perform attack
                    if (AttackReady())
                        Attack();
                }
                else
                {
                    // monster switches to melee combat immediately,
                    // if target is beyond max range?

                    // should ranged mobs only get CurrentTargets within MaxRange?
                    //Console.WriteLine($"{Name}.MissileAttack({AttackTarget.Name}): targetDist={targetDist}, MaxRange={MaxRange}, switching to melee");
                    TrySwitchToMeleeAttack();
                }
            }

            // pets drawing aggro
            if (combatPet != null)
                combatPet.PetCheckMonsters();
        }
    }
}