/*
 * Copyright (C) 2012-2020 CypherCore <http://github.com/CypherCore>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using Framework.Constants;
using Game.Entities;
using System;

namespace Game.Movement
{
    public class IdleMovementGenerator : MovementGenerator
    {
        public IdleMovementGenerator()
        {
            Mode = MovementGeneratorMode.Default;
            Priority = MovementGeneratorPriority.Normal;
            Flags = MovementGeneratorFlags.Initialized;
            BaseUnitState = 0;
        }

        public override void Initialize(Unit owner)
        {
            owner.StopMoving();
        }

        public override void Reset(Unit owner)
        {
            owner.StopMoving();
        }

        public override bool Update(Unit owner, uint diff)
        {
            return true;
        }

        public override void Deactivate(Unit owner) { }

        public override void Finalize(Unit owner, bool active, bool movementInform)
        {
            AddFlag(MovementGeneratorFlags.Finalized);
        }

        public override MovementGeneratorType GetMovementGeneratorType()
        {
            return MovementGeneratorType.Idle;
        }
    }

    public class RotateMovementGenerator : MovementGenerator
    {
        public RotateMovementGenerator(uint id, uint time, RotateDirection direction)
        {
            _id = id;
            _duration = time;
            _maxDuration = time;
            _direction = direction;

            Mode = MovementGeneratorMode.Default;
            Priority = MovementGeneratorPriority.Normal;
            Flags = MovementGeneratorFlags.InitializationPending;
            BaseUnitState = UnitState.Rotating;
        }

        public override void Initialize(Unit owner)
        {
            RemoveFlag(MovementGeneratorFlags.InitializationPending | MovementGeneratorFlags.Deactivated);
            AddFlag(MovementGeneratorFlags.Initialized);
            
            owner.StopMoving();

            /*
             *  TODO: This code should be handled somewhere else, like MovementInform
             *
             *  if (owner->GetVictim())
             *      owner->SetInFront(owner->GetVictim());
             *
             *  owner->AttackStop();
             */
        }

        public override void Reset(Unit owner)
        {
            RemoveFlag(MovementGeneratorFlags.Deactivated);
            Initialize(owner);
        }

        public override bool Update(Unit owner, uint diff)
        {
            if (owner == null)
                return false;

            float angle = owner.GetOrientation();
            angle += diff * MathFunctions.TwoPi / _maxDuration * (_direction == RotateDirection.Left ? 1.0f : -1.0f);
            angle = Math.Clamp(angle, 0.0f, MathF.PI * 2);

            MoveSplineInit init = new(owner);
            init.MoveTo(owner, false);
            if (!owner.GetTransGUID().IsEmpty())
                init.DisableTransportPathTransformations();

            init.SetFacing(angle);
            init.Launch();

            if (_duration > diff)
                _duration -= diff;
            else
            {
                AddFlag(MovementGeneratorFlags.InformEnabled);
                return false;
            } 

            return true;
        }

        public override void Deactivate(Unit owner)
        {
            AddFlag(MovementGeneratorFlags.Deactivated);
        }

        public override void Finalize(Unit owner, bool active, bool movementInform)
        {
            AddFlag(MovementGeneratorFlags.Finalized);

            if (movementInform && owner.IsCreature())
                owner.ToCreature().GetAI().MovementInform(MovementGeneratorType.Rotate, _id);
        }

        public override MovementGeneratorType GetMovementGeneratorType() { return MovementGeneratorType.Rotate; }

        uint _id;
        uint _duration;
        uint _maxDuration;
        RotateDirection _direction;
    }

    public class DistractMovementGenerator : MovementGenerator
    {
        public DistractMovementGenerator(uint timer, float orientation)
        {
            _timer = timer;
            _orientation = orientation;

            Mode = MovementGeneratorMode.Default;
            Priority = MovementGeneratorPriority.Highest;
            Flags = MovementGeneratorFlags.InitializationPending;
            BaseUnitState = UnitState.Distracted;
        }

        public override void Initialize(Unit owner)
        {
            RemoveFlag(MovementGeneratorFlags.InitializationPending | MovementGeneratorFlags.Deactivated);
            AddFlag(MovementGeneratorFlags.Initialized);

            // Distracted creatures stand up if not standing
            if (!owner.IsStandState())
                owner.SetStandState(UnitStandStateType.Stand);

            MoveSplineInit init = new(owner);
            init.MoveTo(owner, false);
            if (!owner.GetTransGUID().IsEmpty())
                init.DisableTransportPathTransformations();

            init.SetFacing(_orientation);
            init.Launch();
        }

        public override void Reset(Unit owner) 
        {
            RemoveFlag(MovementGeneratorFlags.Deactivated);
            Initialize(owner);
        }

        public override bool Update(Unit owner, uint diff)
        {
            if (owner == null)
                return false;

            if (diff > _timer)
            {
                AddFlag(MovementGeneratorFlags.InformEnabled);
                return false;
            }

            _timer -= diff;
            return true;
        }

        public override void Deactivate(Unit owner)
        {
            AddFlag(MovementGeneratorFlags.Deactivated);
        }

        public override void Finalize(Unit owner, bool active, bool movementInform)
        {
            AddFlag(MovementGeneratorFlags.Finalized);

            // TODO: This code should be handled somewhere else
            // If this is a creature, then return orientation to original position (for idle movement creatures)
            if (movementInform && HasFlag(MovementGeneratorFlags.InformEnabled) && owner.IsCreature())
            {
                float angle = owner.ToCreature().GetHomePosition().GetOrientation();
                owner.SetFacingTo(angle);
            }
        }

        public override MovementGeneratorType GetMovementGeneratorType() { return MovementGeneratorType.Distract; }

        uint _timer;
        float _orientation;
    }

    public class AssistanceDistractMovementGenerator : DistractMovementGenerator
    {
        public AssistanceDistractMovementGenerator(uint timer, float orientation) : base(timer, orientation)
        {
            Priority = MovementGeneratorPriority.Normal;
        }

        public override void Finalize(Unit owner, bool active, bool movementInform)
        {
            owner.ClearUnitState(UnitState.Distracted);
            owner.ToCreature().SetReactState(ReactStates.Aggressive);
        }

        public override MovementGeneratorType GetMovementGeneratorType() { return MovementGeneratorType.AssistanceDistract; }
    }
}