/*
 * Copyright (C) 2005-2009 MaNGOS <http://getmangos.com/>
 *
 * Copyright (C) 2008-2009 Trinity <http://www.trinitycore.org/>
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "Creature.h"
#include "MapManager.h"
#include "RandomMovementGenerator.h"
#include "Traveller.h"
#include "ObjectAccessor.h"
#include "DestinationHolderImp.h"
#include "Map.h"
#include "Util.h"
#include "CreatureGroups.h"

#define RUNNING_CHANCE_RANDOMMV 20                                  //will be "1 / RUNNING_CHANCE_RANDOMMV"

template<>
bool
RandomMovementGenerator<Creature>::GetDestination(float &x, float &y, float &z) const
{
    if(i_destinationHolder.HasArrived())
        return false;

    i_destinationHolder.GetDestination(x, y, z);
    return true;
}

#ifdef MAP_BASED_RAND_GEN
#define rand_norm() creature.rand_norm()
#endif

template<>
void
RandomMovementGenerator<Creature>::_setRandomLocation(Creature &creature)
{
    float X,Y,Z,z,nx,ny,nz,ori,dist;

    creature.GetHomePosition(X, Y, Z, ori);

    z = creature.GetPositionZ();
    Map const* map = creature.GetBaseMap();

    // For 2D/3D system selection
    bool is_land_ok  = creature.canWalk();
    bool is_water_ok = creature.canSwim();
    bool is_air_ok   = creature.canFly();

    for(uint32 i = 0;; ++i)
    {

    const float angle = rand_norm()*(M_PI*2);
    const float range = rand_norm()*wander_distance;
    const float distanceX = range * cos(angle);
    const float distanceY = range * sin(angle);

    nx = X + distanceX;
    ny = Y + distanceY;

    // prevent invalid coordinates generation
    Trinity::NormalizeMapCoord(nx);
    Trinity::NormalizeMapCoord(ny);

    dist = (nx - X)*(nx - X) + (ny - Y)*(ny - Y);

    if(i == 5)
    {
        nz = Z;
        break;
    }

    if (is_air_ok) // 3D system above ground and above water (flying mode)
    {
        const float distanceZ = rand_norm() * sqrtf(dist)/2; // Limit height change
        nz = Z + distanceZ;
        float tz = map->GetHeight(nx, ny, nz-2.0f, false); // Map check only, vmap needed here but need to alter vmaps checks for height.
        float wz = map->GetWaterLevel(nx, ny);
        if (tz >= nz || wz >= nz)
            continue; // Problem here, we must fly above the ground and water, not under. Let's try on next tick
    }
    //else if (is_water_ok) // 3D system under water and above ground (swimming mode)
    else // 2D only
    {
        dist = dist>=100.0f ? 10.0f : sqrtf(dist); // 10.0 is the max that vmap high can check (MAX_CAN_FALL_DISTANCE)

        // The fastest way to get an accurate result 90% of the time.
        // Better result can be obtained like 99% accuracy with a ray light, but the cost is too high and the code is too long.
        nz = map->GetHeight(nx,ny,Z+dist-2.0f,false); // Map check
        if (fabs(nz-Z)>dist)
        {
            nz = map->GetHeight(nx,ny,Z-2.0f,true); // Vmap Horizontal or above
            if (fabs(nz-Z)>dist)
            {
                nz = map->GetHeight(nx,ny,Z+dist-2.0f,true); // Vmap Higher
                if (fabs(nz-Z)>dist)
                    continue; // let's forget this bad coords where a z cannot be find and retry at next tick
            }
        }
    }

    break;
    }

    Traveller<Creature> traveller(creature);
    creature.SetOrientation(creature.GetAngle(nx,ny));
    i_destinationHolder.SetDestination(traveller, nx, ny, nz);
    creature.addUnitState(UNIT_STAT_ROAMING);
    if (is_air_ok)
    {
        i_nextMoveTime.Reset(i_destinationHolder.GetTotalTravelTime());
    }
    //else if (is_water_ok) // Swimming mode to be done with more than this check
    else
    {
        i_nextMoveTime.Reset(urand(500+i_destinationHolder.GetTotalTravelTime(),5000+i_destinationHolder.GetTotalTravelTime()));
        creature.AddUnitMovementFlag(MOVEMENTFLAG_WALK_MODE);
    }

    //Call for creature group update
    if(creature.GetFormation() && creature.GetFormation()->getLeader() == &creature)
    {
        creature.GetFormation()->LeaderMoveTo(nx, ny, nz);
    }
}

template<>
void
RandomMovementGenerator<Creature>::Initialize(Creature &creature)
{
    if(!creature.isAlive())
        return;

    if(!wander_distance)
        wander_distance = creature.GetRespawnRadius();

    if(irand(0,RUNNING_CHANCE_RANDOMMV) > 0)
        creature.AddUnitMovementFlag(MOVEMENTFLAG_WALK_MODE);
    _setRandomLocation(creature);
}

template<>
void
RandomMovementGenerator<Creature>::Reset(Creature &creature)
{
    Initialize(creature);
}

template<>
void
RandomMovementGenerator<Creature>::Finalize(Creature &creature){}

template<>
bool
RandomMovementGenerator<Creature>::Update(Creature &creature, const uint32 &diff)
{
    if(creature.hasUnitState(UNIT_STAT_ROOT | UNIT_STAT_STUNNED | UNIT_STAT_DISTRACTED))
    {
        i_nextMoveTime.Update(i_nextMoveTime.GetExpiry());    // Expire the timer
        creature.clearUnitState(UNIT_STAT_ROAMING);
        return true;
    }

    i_nextMoveTime.Update(diff);

    if(i_destinationHolder.HasArrived() && !creature.IsStopped() && !creature.canFly())
        creature.clearUnitState(UNIT_STAT_ROAMING | UNIT_STAT_MOVE);

    if(!i_destinationHolder.HasArrived() && creature.IsStopped())
        creature.addUnitState(UNIT_STAT_ROAMING);

    CreatureTraveller traveller(creature);

    if( i_destinationHolder.UpdateTraveller(traveller, diff, true) )
    {
        if(i_nextMoveTime.Passed())
        {
            if(irand(0,RUNNING_CHANCE_RANDOMMV) > 0)
                creature.AddUnitMovementFlag(MOVEMENTFLAG_WALK_MODE);
            _setRandomLocation(creature);
        }
        else if(creature.isPet() && creature.GetOwner() && !creature.IsWithinDist(creature.GetOwner(),PET_FOLLOW_DIST+2.5f))
        {
           creature.RemoveUnitMovementFlag(MOVEMENTFLAG_WALK_MODE);
           _setRandomLocation(creature);
        }
    }
    return true;
}