#include "creature_tracker.h"

#include <algorithm>
#include <ostream>
#include <utility>

#include "avatar.h"
#include "cata_assert.h"
#include "debug.h"
#include "flood_fill.h"
#include "map.h"
#include "mongroup.h"
#include "monster.h"
#include "mtype.h"
#include "npc.h"
#include "string_formatter.h"
#include "submap.h"
#include "type_id.h"

static const efftype_id effect_ridden( "ridden" );

#define dbg(x) DebugLog((x),D_GAME) << __FILE__ << ":" << __LINE__ << ": "

creature_tracker::creature_tracker() = default;

creature_tracker::~creature_tracker() = default;

shared_ptr_fast<monster> creature_tracker::find( const tripoint_abs_ms &pos ) const
{
    const auto iter = monsters_by_location.find( pos );
    if( iter != monsters_by_location.end() ) {
        const shared_ptr_fast<monster> &mon_ptr = iter->second;
        if( !mon_ptr->is_dead() ) {
            return mon_ptr;
        }
    }
    return nullptr;
}

int creature_tracker::temporary_id( const monster &critter ) const
{
    const auto iter = std::find_if( monsters_list.begin(), monsters_list.end(),
    [&]( const shared_ptr_fast<monster> &ptr ) {
        return ptr.get() == &critter;
    } );
    if( iter == monsters_list.end() ) {
        return -1;
    }
    return iter - monsters_list.begin();
}

shared_ptr_fast<monster> creature_tracker::from_temporary_id( const int id )
{
    if( static_cast<size_t>( id ) < monsters_list.size() ) {
        return monsters_list[id];
    } else {
        return nullptr;
    }
}

bool creature_tracker::add( const shared_ptr_fast<monster> &critter_ptr )
{
    cata_assert( critter_ptr );
    monster &critter = *critter_ptr;

    if( critter.type->id.is_null() ) { // Don't want to spawn null monsters o.O
        return false;
    }

    if( critter.type->has_flag( mon_flag_VERMIN ) ) {
        // Don't spawn vermin, they aren't implemented yet
        return false;
    }

    if( const shared_ptr_fast<monster> existing_mon_ptr = find( critter.get_location() ) ) {
        // We can spawn stuff on hallucinations, but we need to kill them first
        if( existing_mon_ptr->is_hallucination() ) {
            existing_mon_ptr->die( nullptr );
            // But don't remove - that would change the monster order and could segfault
        } else if( critter.is_hallucination() ) {
            return false;
        } else {
            debugmsg( "there's already a monster at %s", critter.get_location().to_string_writable() );
            return false;
        }
    }

    if( MonsterGroupManager::monster_is_blacklisted( critter.type->id ) ) {
        return false;
    }

    monsters_list.emplace_back( critter_ptr );
    monsters_by_location[critter.get_location()] = critter_ptr;
    return true;
}

size_t creature_tracker::size() const
{
    return monsters_list.size();
}

bool creature_tracker::update_pos( const monster &critter, const tripoint_abs_ms &old_pos,
                                   const tripoint_abs_ms &new_pos )
{
    if( critter.is_dead() ) {
        // find ignores dead critters anyway, changing their position in the
        // monsters_by_location map is useless.
        remove_from_location_map( critter );
        return true;
    }

    if( const shared_ptr_fast<monster> new_critter_ptr = find( new_pos ) ) {
        auto &othermon = *new_critter_ptr;
        if( othermon.is_hallucination() ) {
            othermon.die( nullptr );
        } else {
            debugmsg( "update_zombie_pos: wanted to move %s to %s, but new location already has %s",
                      critter.disp_name(), new_pos.to_string_writable(), othermon.disp_name() );
            return false;
        }
    }

    const auto iter = std::find_if( monsters_list.begin(), monsters_list.end(),
    [&]( const shared_ptr_fast<monster> &ptr ) {
        return ptr.get() == &critter;
    } );
    if( iter != monsters_list.end() ) {
        monsters_by_location.erase( old_pos );
        monsters_by_location[new_pos] = *iter;
        return true;
    } else {
        // We're changing the x/y/z coordinates of a zombie that hasn't been added
        // to the game yet. `add` will update monsters_by_location for us.
        debugmsg( "update_zombie_pos: no %s at %s (moving to %s)",
                  critter.disp_name(), old_pos.to_string_writable(), new_pos.to_string_writable() );
        // Rebuild cache in case the monster actually IS in the game, just bugged
        rebuild_cache();
        return false;
    }
}

void creature_tracker::remove_from_location_map( const monster &critter )
{
    const auto pos_iter = monsters_by_location.find( critter.get_location() );
    if( pos_iter != monsters_by_location.end() && pos_iter->second.get() == &critter ) {
        monsters_by_location.erase( pos_iter );
        return;
    }

    // When it's not in the map at its current location, it might still be there under,
    // another location, so look for it.
    const auto iter = std::find_if( monsters_by_location.begin(), monsters_by_location.end(),
    [&]( const decltype( monsters_by_location )::value_type & v ) {
        return v.second.get() == &critter;
    } );
    if( iter != monsters_by_location.end() ) {
        monsters_by_location.erase( iter );
    }
}

void creature_tracker::remove( const monster &critter )
{
    const auto iter = std::find_if( monsters_list.begin(), monsters_list.end(),
    [&]( const shared_ptr_fast<monster> &ptr ) {
        return ptr.get() == &critter;
    } );
    if( iter == monsters_list.end() ) {
        debugmsg( "Tried to remove invalid monster %s", critter.name() );
        return;
    }

    remove_from_location_map( critter );
    removed_.emplace( iter->get() );
    removed_this_turn_.emplace( *iter );
    monsters_list.erase( iter );
}

void creature_tracker::clear()
{
    monsters_list.clear();
    monsters_by_location.clear();
    removed_.clear();
    removed_this_turn_.clear();
    creatures_by_zone_and_faction_.clear();
    invalidate_reachability_cache();
}

void creature_tracker::rebuild_cache()
{
    monsters_by_location.clear();
    for( const shared_ptr_fast<monster> &mon_ptr : monsters_list ) {
        monsters_by_location[mon_ptr->get_location()] = mon_ptr;
    }
}

void creature_tracker::swap_positions( monster &first, monster &second )
{
    if( first.get_location() == second.get_location() ) {
        return;
    }

    if( first.get_reachable_zone() != second.get_reachable_zone() ) {
        invalidate_reachability_cache();
    }

    // Either of them may be invalid!
    const auto first_iter = monsters_by_location.find( first.get_location() );
    const auto second_iter = monsters_by_location.find( second.get_location() );
    // implied: first_iter != second_iter

    shared_ptr_fast<monster> first_ptr;
    if( first_iter != monsters_by_location.end() ) {
        first_ptr = first_iter->second;
        monsters_by_location.erase( first_iter );
    }

    shared_ptr_fast<monster> second_ptr;
    if( second_iter != monsters_by_location.end() ) {
        second_ptr = second_iter->second;
        monsters_by_location.erase( second_iter );
    }
    // implied: (first_ptr != second_ptr) or (first_ptr == nullptr && second_ptr == nullptr)

    const tripoint_abs_ms temp = second.get_location();
    second.spawn( first.get_location() );
    first.spawn( temp );

    // If the pointers have been taken out of the list, put them back in.
    if( first_ptr ) {
        monsters_by_location[first.get_location()] = first_ptr;
    }
    if( second_ptr ) {
        monsters_by_location[second.get_location()] = second_ptr;
    }
}

bool creature_tracker::kill_marked_for_death()
{
    // Important: `Creature::die` must not be called after creature objects (NPCs, monsters) have
    // been removed, the dying creature could still have a pointer (the killer) to another creature.
    bool monster_is_dead = false;
    // Copy the list so we can iterate the copy safely *and* add new monsters from within monster::die
    // This happens for example with blob monsters (they split into two smaller monsters).
    const auto copy = monsters_list;
    for( const shared_ptr_fast<monster> &mon_ptr : copy ) {
        cata_assert( mon_ptr );
        monster &critter = *mon_ptr;
        if( !critter.is_dead() ) {
            continue;
        }
        dbg( D_INFO ) << string_format( "cleanup_dead: critter at %s hp:%d %s",
                                        critter.get_location().to_string_writable(),
                                        critter.get_hp(), critter.name() );
        critter.die( nullptr );
        monster_is_dead = true;
    }

    return monster_is_dead;
}

void creature_tracker::remove_dead()
{
    // Can't use game::all_monsters() as it would not contain *dead* monsters.
    for( auto iter = monsters_list.begin(); iter != monsters_list.end(); ) {
        monster *const critter = iter->get();
        if( critter->is_dead() ) {
            remove_from_location_map( *critter );
            removed_.insert( critter );
            iter = monsters_list.erase( iter );
        } else {
            ++iter;
        }
    }
    removed_this_turn_.clear();
}

template<typename T>
T *creature_tracker::creature_at( const tripoint &p, bool allow_hallucination )
{
    return creature_at<T>( get_map().getglobal( p ), allow_hallucination );
}

template<typename T>
T *creature_tracker::creature_at( const tripoint_bub_ms &p, bool allow_hallucination )
{
    return creature_at<T>( get_map().getglobal( p ), allow_hallucination );
}

template<typename T>
T *creature_tracker::creature_at( const tripoint_abs_ms &p, bool allow_hallucination )
{
    if( const shared_ptr_fast<monster> mon_ptr = find( p ) ) {
        if( !allow_hallucination && mon_ptr->is_hallucination() ) {
            return nullptr;
        }
        // if we wanted to check for an NPC / player / avatar,
        // there is sometimes a monster AND an NPC/player there at the same time.
        // because the NPC/player etc may be riding that monster.
        // so only return the monster if we were actually looking for a monster.
        // otherwise, keep looking for the rider.
        // creature_at<creature> or creature_at() with no template will still default to returning monster first,
        // which is ok for the occasions where that happens.
        if( !mon_ptr->has_effect( effect_ridden ) || ( std::is_same<T, monster>::value ||
                std::is_same<T, Creature>::value || std::is_same<T, const monster>::value ||
                std::is_same<T, const Creature>::value ) ) {
            return dynamic_cast<T *>( mon_ptr.get() );
        }
    }
    if( !std::is_same<T, npc>::value && !std::is_same<T, const npc>::value ) {
        avatar &you = get_avatar();
        if( p == you.get_location() ) {
            return dynamic_cast<T *>( &you );
        }
    }
    for( auto &cur_npc : active_npc ) {
        if( cur_npc->get_location() == p && !cur_npc->is_dead() ) {
            return dynamic_cast<T *>( cur_npc.get() );
        }
    }
    return nullptr;
}

/** This is lazily evaluated on demand. Each creature in a zone is visited
 * as it flood fills, then the zone number is incremented. At the end all creatures in
 * the same zone will have the same zone number assigned, which can be used to have creatures in
 * different zones ignore each other very cheaply.
 */
void creature_tracker::flood_fill_zone( const Creature &origin )
{
    if( dirty_ ) {
        creatures_by_zone_and_faction_.clear();
        removed_.clear();
        zone_tick_ = zone_tick_ > 0 ? -1 : 1;
        zone_number_ = 1;
        dirty_ = false;
    }

    // This check insures we only flood fill when the target monster has an uninitialized zone,
    // or if it has a zone from last turn.  In other words it only triggers on
    // the first monster in a zone each turn. We can detect this because the sign
    // of the zone numbers changes on every invalidation.
    int old_zone = origin.get_reachable_zone();
    // Compare with zone_tick == old_zone && old_zone != 0
    if( old_zone * zone_tick_ > 0 ) {
        return;
    }

    map &map = get_map();
    ff::flood_fill_visit_10_connected( origin.pos_bub(),
    [&map]( const tripoint_bub_ms & loc, int direction ) {
        if( direction == 0 ) {
            return map.inbounds( loc ) && ( map.is_transparent_wo_fields( loc.raw() ) ||
                                            map.passable( loc ) );
        }
        if( direction == 1 ) {
            const maptile &up = map.maptile_at( loc );
            const ter_t &up_ter = up.get_ter_t();
            if( up_ter.id.is_null() ) {
                return false;
            }
            if( ( ( up_ter.movecost != 0 && up.get_furn_t().movecost >= 0 ) ||
                  map.is_transparent_wo_fields( loc.raw() ) ) &&
                ( up_ter.has_flag( ter_furn_flag::TFLAG_NO_FLOOR ) ||
                  up_ter.has_flag( ter_furn_flag::TFLAG_GOES_DOWN ) ) ) {
                return true;
            }
        }
        if( direction == -1 ) {
            const maptile &up = map.maptile_at( loc + tripoint_above );
            const ter_t &up_ter = up.get_ter_t();
            if( up_ter.id.is_null() ) {
                return false;
            }
            const maptile &down = map.maptile_at( loc );
            const ter_t &down_ter = up.get_ter_t();
            if( down_ter.id.is_null() ) {
                return false;
            }
            if( ( ( down_ter.movecost != 0 && down.get_furn_t().movecost >= 0 ) ||
                  map.is_transparent_wo_fields( loc.raw() ) ) &&
                ( up_ter.has_flag( ter_furn_flag::TFLAG_NO_FLOOR ) ||
                  up_ter.has_flag( ter_furn_flag::TFLAG_GOES_DOWN ) ) ) {
                return true;
            }
        }
        return false;
    },
    [this]( const tripoint_bub_ms & loc ) {
        Creature *creature = this->creature_at<Creature>( loc );
        if( creature ) {
            const int n = zone_number_ * zone_tick_;
            creatures_by_zone_and_faction_[n][creature->get_monster_faction()].push_back( creature );
            creature->set_reachable_zone( n );
        }
    } );
    if( zone_number_ == std::numeric_limits<int>::max() ) {
        zone_number_ = 1;
    } else {
        zone_number_++;
    }
}

template<typename T>
const T *creature_tracker::creature_at( const tripoint &p, bool allow_hallucination ) const
{
    return creature_at<T>( get_map().getglobal( p ), allow_hallucination );
}

template<typename T>
const T *creature_tracker::creature_at( const tripoint_bub_ms &p, bool allow_hallucination ) const
{
    return creature_at<T>( get_map().getglobal( p ), allow_hallucination );
}

template<typename T>
const T *creature_tracker::creature_at( const tripoint_abs_ms &p, bool allow_hallucination ) const
{
    return const_cast<creature_tracker *>( this )->creature_at<T>( p, allow_hallucination );
}

template const monster *creature_tracker::creature_at<monster>( const tripoint &, bool ) const;
template const monster *creature_tracker::creature_at<monster>( const tripoint_bub_ms &,
        bool ) const;
template const monster *creature_tracker::creature_at<monster>( const tripoint_abs_ms &,
        bool ) const;
template monster *creature_tracker::creature_at<monster>( const tripoint &, bool );
template monster *creature_tracker::creature_at<monster>( const tripoint_bub_ms &, bool );
template monster *creature_tracker::creature_at<monster>( const tripoint_abs_ms &, bool );
template const npc *creature_tracker::creature_at<npc>( const tripoint &, bool ) const;
template const npc *creature_tracker::creature_at<npc>( const tripoint_abs_ms &, bool ) const;
template npc *creature_tracker::creature_at<npc>( const tripoint &, bool );
template npc *creature_tracker::creature_at<npc>( const tripoint_abs_ms &, bool );
template const avatar *creature_tracker::creature_at<avatar>( const tripoint &, bool ) const;
template const avatar *creature_tracker::creature_at<avatar>( const tripoint_abs_ms &, bool ) const;
template avatar *creature_tracker::creature_at<avatar>( const tripoint &, bool );
template avatar *creature_tracker::creature_at<avatar>( const tripoint_abs_ms &, bool );
template const Character *creature_tracker::creature_at<Character>( const tripoint &, bool ) const;
template const Character *creature_tracker::creature_at<Character>( const tripoint_abs_ms &,
        bool ) const;
template Character *creature_tracker::creature_at<Character>( const tripoint &, bool );
template Character *creature_tracker::creature_at<Character>( const tripoint_abs_ms &, bool );
template const Creature *creature_tracker::creature_at<Creature>( const tripoint &, bool ) const;
template const Creature *creature_tracker::creature_at<Creature>( const tripoint_abs_ms &,
        bool ) const;
template Creature *creature_tracker::creature_at<Creature>( const tripoint &, bool );
template Creature *creature_tracker::creature_at<Creature>( const tripoint_bub_ms &, bool );
template Creature *creature_tracker::creature_at<Creature>( const tripoint_abs_ms &, bool );
