/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "CreatureGroups.h"
#include "Creature.h"
#include "CreatureAI.h"
#include "DatabaseEnv.h"
#include "Log.h"
#include "Map.h"
#include "MotionMaster.h"
#include "ObjectMgr.h"

#define MAX_DESYNC 5.0f

FormationMgr::~FormationMgr()
{
    for (CreatureGroupInfoType::iterator itr = CreatureGroupMap.begin(); itr != CreatureGroupMap.end(); ++itr)
        delete itr->second;
}

FormationMgr* FormationMgr::instance()
{
    static FormationMgr instance;
    return &instance;
}

void FormationMgr::AddCreatureToGroup(ObjectGuid::LowType leaderGuid, Creature* creature)
{
    Map* map = creature->FindMap();
    if (!map)
        return;

    CreatureGroupHolderType::iterator itr = map->CreatureGroupHolder.find(leaderGuid);

    //Add member to an existing group
    if (itr != map->CreatureGroupHolder.end())
    {
        TC_LOG_DEBUG("entities.unit", "Group found: " UI64FMTD ", inserting %s, Group InstanceID %u", leaderGuid, creature->GetGUID().ToString().c_str(), creature->GetInstanceId());
        itr->second->AddMember(creature);
    }
    //Create new group
    else
    {
        TC_LOG_DEBUG("entities.unit", "Group not found: " UI64FMTD ". Creating new group.", leaderGuid);
        CreatureGroup* group = new CreatureGroup(leaderGuid);
        map->CreatureGroupHolder[leaderGuid] = group;
        group->AddMember(creature);
    }
}

void FormationMgr::RemoveCreatureFromGroup(CreatureGroup* group, Creature* member)
{
    TC_LOG_DEBUG("entities.unit", "Deleting member pointer to GUID: " UI64FMTD " from group " UI64FMTD, group->GetId(), member->GetSpawnId());
    group->RemoveMember(member);

    if (group->isEmpty())
    {
        Map* map = member->FindMap();
        if (!map)
            return;

        TC_LOG_DEBUG("entities.unit", "Deleting group with InstanceID %u", member->GetInstanceId());
        map->CreatureGroupHolder.erase(group->GetId());
        delete group;
    }
}

void FormationMgr::LoadCreatureFormations()
{
    uint32 oldMSTime = getMSTime();

    for (CreatureGroupInfoType::iterator itr = CreatureGroupMap.begin(); itr != CreatureGroupMap.end(); ++itr) // for reload case
        delete itr->second;
    CreatureGroupMap.clear();

    //Get group data
    QueryResult result = WorldDatabase.Query("SELECT leaderGUID, memberGUID, dist, angle, groupAI, point_1, point_2 FROM creature_formations ORDER BY leaderGUID");

    if (!result)
    {
        TC_LOG_ERROR("server.loading", ">>  Loaded 0 creatures in formations. DB table `creature_formations` is empty!");
        return;
    }

    uint32 count = 0;
    Field* fields;
    FormationInfo* group_member;

    do
    {
        fields = result->Fetch();

        //Load group member data
        group_member                        = new FormationInfo();
        group_member->leaderGUID            = fields[0].GetUInt64();
        ObjectGuid::LowType memberGUID      = fields[1].GetUInt64();
        group_member->groupAI               = fields[4].GetUInt32();
        group_member->point_1               = fields[5].GetUInt16();
        group_member->point_2               = fields[6].GetUInt16();
        //If creature is group leader we may skip loading of dist/angle
        if (group_member->leaderGUID != memberGUID)
        {
            group_member->follow_dist       = fields[2].GetFloat();
            group_member->follow_angle      = fields[3].GetFloat() * float(M_PI) / 180;
        }
        else
        {
            group_member->follow_dist       = 0;
            group_member->follow_angle      = 0;
        }

        // check data correctness
        {
            if (!sObjectMgr->GetCreatureData(group_member->leaderGUID))
            {
                TC_LOG_ERROR("sql.sql", "creature_formations table leader guid " UI64FMTD " incorrect (not exist)", group_member->leaderGUID);
                delete group_member;
                continue;
            }

            if (!sObjectMgr->GetCreatureData(memberGUID))
            {
                TC_LOG_ERROR("sql.sql", "creature_formations table member guid " UI64FMTD " incorrect (not exist)", memberGUID);
                delete group_member;
                continue;
            }
        }

        CreatureGroupMap[memberGUID] = group_member;
        ++count;
    }
    while (result->NextRow());

    TC_LOG_INFO("server.loading", ">> Loaded %u creatures in formations in %u ms", count, GetMSTimeDiffToNow(oldMSTime));
}

void CreatureGroup::AddMember(Creature* member)
{
    TC_LOG_DEBUG("entities.unit", "CreatureGroup::AddMember: Adding %s.", member->GetGUID().ToString().c_str());

    //Check if it is a leader
    if (member->GetSpawnId() == m_groupID)
    {
        TC_LOG_DEBUG("entities.unit", "%s is formation leader. Adding group.", member->GetGUID().ToString().c_str());
        m_leader = member;
    }

    m_members[member] = sFormationMgr->CreatureGroupMap.find(member->GetSpawnId())->second;
    member->SetFormation(this);
}

void CreatureGroup::RemoveMember(Creature* member)
{
    if (m_leader == member)
        m_leader = NULL;

    m_members.erase(member);
    member->SetFormation(NULL);
}

void CreatureGroup::MemberAttackStart(Creature* member, Unit* target)
{
    uint8 groupAI = sFormationMgr->CreatureGroupMap[member->GetSpawnId()]->groupAI;
    if (!groupAI)
        return;

    if (member == m_leader)
    {
        if (!(groupAI & FLAG_MEMBERS_ASSIST_LEADER))
            return;
    }
    else if (!(groupAI & FLAG_LEADER_ASSISTS_MEMBER))
        return;

    for (CreatureGroupMemberType::iterator itr = m_members.begin(); itr != m_members.end(); ++itr)
    {
        if (m_leader) // avoid crash if leader was killed and reset.
            TC_LOG_DEBUG("entities.unit", "GROUP ATTACK: group instance id %u calls member instid %u", m_leader->GetInstanceId(), member->GetInstanceId());

        Creature* other = itr->first;

        // Skip self
        if (other == member)
            continue;

        if (!other->IsAlive())
            continue;

        if (other->GetVictim())
            continue;

        if (((other != m_leader && (groupAI & FLAG_MEMBERS_ASSIST_LEADER)) || (other == m_leader && (groupAI & FLAG_LEADER_ASSISTS_MEMBER))) && other->IsValidAttackTarget(target))
            other->AI()->AttackStart(target);
    }
}

void CreatureGroup::FormationReset(bool dismiss)
{
    for (CreatureGroupMemberType::iterator itr = m_members.begin(); itr != m_members.end(); ++itr)
    {
        if (itr->first != m_leader && itr->first->IsAlive())
        {
            if (dismiss)
                itr->first->GetMotionMaster()->Initialize();
            else
                itr->first->GetMotionMaster()->MoveIdle();
            TC_LOG_DEBUG("entities.unit", "Set %s movement for member %s", dismiss ? "default" : "idle", itr->first->GetGUID().ToString().c_str());
        }
    }
    m_Formed = !dismiss;
}

void CreatureGroup::LeaderMoveTo(Position destination, uint32 id /*= 0*/, uint32 moveType /*= 0*/, bool orientation /*= false*/)
{
    //! To do: This should probably get its own movement generator or use WaypointMovementGenerator.
    //! If the leader's path is known, member's path can be plotted as well using formation offsets.
    if (!m_leader)
        return;

    float x = destination.GetPositionX(), y = destination.GetPositionY(), z = destination.GetPositionZ();

    float pathangle = std::atan2(m_leader->GetPositionY() - y, m_leader->GetPositionX() - x);

    for (CreatureGroupMemberType::iterator itr = m_members.begin(); itr != m_members.end(); ++itr)
    {
        Creature* member = itr->first;
        if (member == m_leader || !member->IsAlive() || member->GetVictim() || !(itr->second->groupAI & FLAG_IDLE_IN_FORMATION))
            continue;

        if (itr->second->point_1)
            if (m_leader->GetCurrentWaypointID() == itr->second->point_1 - 1 || m_leader->GetCurrentWaypointID() == itr->second->point_2 - 1)
                itr->second->follow_angle = float(M_PI) * 2 - itr->second->follow_angle;

        float angle = itr->second->follow_angle;
        float dist = itr->second->follow_dist;

        float dx = x + std::cos(angle + pathangle) * dist;
        float dy = y + std::sin(angle + pathangle) * dist;
        float dz = z;

        Trinity::NormalizeMapCoord(dx);
        Trinity::NormalizeMapCoord(dy);

        if (!member->IsFlying())
            member->UpdateGroundPositionZ(dx, dy, dz);

        Position point(dx, dy, dz, destination.GetOrientation());

        member->GetMotionMaster()->MoveFormation(id, point, moveType, !member->IsWithinDist(m_leader, dist + MAX_DESYNC), orientation);
        member->SetHomePosition(dx, dy, dz, pathangle);
    }
}