/* $Id$ */

/** @file ai_rail.cpp Implementation of AIRail. */

#include "ai_rail.hpp"

#include "ai_object.hpp"

#include "ai_map.hpp"

#include "../../openttd.h"

#include "../../debug.h"

#include "../../rail_map.h"

#include "../../road_map.h"

#include "../../command_type.h"

#include "../../station_map.h"

#include "../../company_func.h"

#include "../../core/math_func.hpp"

#include "../../waypoint.h"

#include "../../newgrf.h"

#include "../../newgrf_generic.h"

#include "../../newgrf_station.h"

#include "../../newgrf_callbacks.h"

/* static */ bool AIRail::IsRailTile(TileIndex tile)

{

	if (!::IsValidTile(tile)) return false;

	return (::IsTileType(tile, MP_RAILWAY) && !::IsRailDepot(tile)) ||

			(::IsRailwayStationTile(tile) && !::IsStationTileBlocked(tile)) || ::IsLevelCrossingTile(tile);

}

/* static */ bool AIRail::IsLevelCrossingTile(TileIndex tile)

{

	if (!::IsValidTile(tile)) return false;

	return ::IsLevelCrossingTile(tile);

}

/* static */ bool AIRail::IsRailDepotTile(TileIndex tile)

{

	if (!::IsValidTile(tile)) return false;

	return ::IsRailDepotTile(tile);

}

/* static */ bool AIRail::IsRailStationTile(TileIndex tile)

{

	if (!::IsValidTile(tile)) return false;

	return ::IsRailwayStationTile(tile);

}

/* static */ bool AIRail::IsRailWaypointTile(TileIndex tile)

{

	if (!::IsValidTile(tile)) return false;

	return ::IsTileType(tile, MP_RAILWAY) && ::IsRailWaypointTile(tile);

}

/* static */ bool AIRail::IsRailTypeAvailable(RailType rail_type)

{

	if ((::RailType)rail_type < RAILTYPE_BEGIN || (::RailType)rail_type >= RAILTYPE_END) return false;

	return ::HasRailtypeAvail(_current_company, (::RailType)rail_type);

}

/* static */ AIRail::RailType AIRail::GetCurrentRailType()

{

	return (RailType)AIObject::GetRailType();

}

/* static */ void AIRail::SetCurrentRailType(RailType rail_type)

{

	if (!IsRailTypeAvailable(rail_type)) return;

	AIObject::SetRailType((::RailType)rail_type);

}

/* static */ bool AIRail::TrainCanRunOnRail(AIRail::RailType engine_rail_type, AIRail::RailType track_rail_type)

{

	if (!AIRail::IsRailTypeAvailable(engine_rail_type)) return false;

	if (!AIRail::IsRailTypeAvailable(track_rail_type)) return false;

	return ::IsCompatibleRail((::RailType)engine_rail_type, (::RailType)track_rail_type);

}

/* static */ bool AIRail::TrainHasPowerOnRail(AIRail::RailType engine_rail_type, AIRail::RailType track_rail_type)

{\

	if (!AIRail::IsRailTypeAvailable(engine_rail_type)) return false;

	if (!AIRail::IsRailTypeAvailable(track_rail_type)) return false;

	return ::HasPowerOnRail((::RailType)engine_rail_type, (::RailType)track_rail_type);

}

/* static */ AIRail::RailType AIRail::GetRailType(TileIndex tile)

{

	if (!AITile::HasTransportType(tile, AITile::TRANSPORT_RAIL)) return RAILTYPE_INVALID;

	return (RailType)::GetRailType(tile);

}

/* static */ bool AIRail::ConvertRailType(TileIndex start_tile, TileIndex end_tile, AIRail::RailType convert_to)

{

	EnforcePrecondition(false, ::IsValidTile(start_tile));

	EnforcePrecondition(false, ::IsValidTile(end_tile));

	EnforcePrecondition(false, IsRailTypeAvailable(convert_to));

	return AIObject::DoCommand(start_tile, end_tile, convert_to, CMD_CONVERT_RAIL);

}

/* static */ TileIndex AIRail::GetRailDepotFrontTile(TileIndex depot)

{

	if (!IsRailDepotTile(depot)) return INVALID_TILE;

	return depot + ::TileOffsByDiagDir(::GetRailDepotDirection(depot));

}

/* static */ AIRail::RailTrack AIRail::GetRailStationDirection(TileIndex tile)

{

	if (!IsRailStationTile(tile)) return RAILTRACK_INVALID;

	return (RailTrack)::GetRailStationTrack(tile);

}

/* static */ bool AIRail::BuildRailDepot(TileIndex tile, TileIndex front)

{

	EnforcePrecondition(false, tile != front);

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, ::IsValidTile(front));

	EnforcePrecondition(false, ::TileX(tile) == ::TileX(front) || ::TileY(tile) == ::TileY(front));

	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));

	uint entrance_dir = (::TileX(tile) == ::TileX(front)) ? (::TileY(tile) < ::TileY(front) ? 1 : 3) : (::TileX(tile) < ::TileX(front) ? 2 : 0);

	return AIObject::DoCommand(tile, AIObject::GetRailType(), entrance_dir, CMD_BUILD_TRAIN_DEPOT);

}

/* static */ bool AIRail::BuildRailStation(TileIndex tile, RailTrack direction, uint num_platforms, uint platform_length, bool join_adjacent)

{

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, direction == RAILTRACK_NW_SE || direction == RAILTRACK_NE_SW);

	EnforcePrecondition(false, num_platforms > 0 && num_platforms <= 0xFF);

	EnforcePrecondition(false, platform_length > 0 && platform_length <= 0xFF);

	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));

	uint32 p1 = GetCurrentRailType() | (platform_length << 16) | (num_platforms << 8);

	if (direction == RAILTRACK_NW_SE) p1 |= (1 << 4);

	if (!join_adjacent) p1 |= (1 << 24);

	return AIObject::DoCommand(tile, p1, INVALID_STATION << 16, CMD_BUILD_RAILROAD_STATION);

}

/* static */ bool AIRail::BuildNewGRFRailStation(TileIndex tile, RailTrack direction, uint num_platforms, uint platform_length, bool join_adjacent, CargoID cargo_id, IndustryType source_industry, IndustryType goal_industry, int distance, bool source_station)

{

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, direction == RAILTRACK_NW_SE || direction == RAILTRACK_NE_SW);

	EnforcePrecondition(false, num_platforms > 0 && num_platforms <= 0xFF);

	EnforcePrecondition(false, platform_length > 0 && platform_length <= 0xFF);

	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));

	uint32 p1 = GetCurrentRailType() | (platform_length << 16) | (num_platforms << 8);

	if (direction == RAILTRACK_NW_SE) p1 |= 1 << 4;

	if (!join_adjacent) p1 |= (1 << 24);

	const GRFFile *file;

	uint16 res = GetAiPurchaseCallbackResult(GSF_STATION, cargo_id, 0, source_industry, goal_industry, min(255, distance / 2), AICE_STATION_GET_STATION_ID, source_station ? 0 : 1, min(15, num_platforms) << 4 | min(15, platform_length), &file);

	uint32 p2 = INVALID_STATION << 16;

	if (res != CALLBACK_FAILED) {

		extern StationClass _station_classes[STAT_CLASS_MAX];

		const StationSpec *spec = GetCustomStationSpecByGrf(file->grfid, res);

		int index = -1;

		for (uint j = 0; j < _station_classes[spec->sclass].stations; j++) {

			if (spec == _station_classes[spec->sclass].spec[j]) {

				index = j;

				break;

			}

		}

		if (index == -1) {

			DEBUG(grf, 1, "%s returned an invalid station ID for 'AI construction/purchase selection (18)' callback", file->filename);

		} else {

			p2 |= spec->sclass | index << 8;

		}

	}

	return AIObject::DoCommand(tile, p1, p2, CMD_BUILD_RAILROAD_STATION);

}

/* static */ bool AIRail::RemoveRailStationTileRect(TileIndex tile, TileIndex tile2)

{

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, ::IsValidTile(tile2));

	return AIObject::DoCommand(tile, tile2, 0, CMD_REMOVE_FROM_RAILROAD_STATION);

}

/* static */ uint AIRail::GetRailTracks(TileIndex tile)

{

	if (!IsRailTile(tile)) return RAILTRACK_INVALID;

	if (IsRailWaypointTile(tile)) return ::GetRailWaypointBits(tile);

	if (IsRailStationTile(tile)) return ::TrackToTrackBits(::GetRailStationTrack(tile));

	if (IsLevelCrossingTile(tile)) return ::GetCrossingRailBits(tile);

	return ::GetTrackBits(tile);

}

/* static */ bool AIRail::BuildRailTrack(TileIndex tile, RailTrack rail_track)

{

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, rail_track != 0);

	EnforcePrecondition(false, (rail_track & ~::TRACK_BIT_ALL) == 0);

	EnforcePrecondition(false, KillFirstBit((uint)rail_track) == 0);

	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));

	return AIObject::DoCommand(tile, tile, GetCurrentRailType() | (FindFirstTrack((::TrackBits)rail_track) << 4), CMD_BUILD_RAILROAD_TRACK);

}

/* static */ bool AIRail::RemoveRailTrack(TileIndex tile, RailTrack rail_track)

{

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, ::IsTileType(tile, MP_RAILWAY) && ::IsPlainRailTile(tile));

	EnforcePrecondition(false, GetRailTracks(tile) & rail_track);

	EnforcePrecondition(false, KillFirstBit((uint)rail_track) == 0);

	return AIObject::DoCommand(tile, tile, GetCurrentRailType() | (FindFirstTrack((::TrackBits)rail_track) << 4), CMD_REMOVE_RAILROAD_TRACK);

}

/* static */ bool AIRail::AreTilesConnected(TileIndex from, TileIndex tile, TileIndex to)

{

	if (!IsRailTile(tile)) return false;

	if (from == to || AIMap::DistanceManhattan(from, tile) != 1 || AIMap::DistanceManhattan(tile, to) != 1) return false;

	if (to < from) ::Swap(from, to);

	if (tile - from == 1) {

		if (to - tile == 1) return (GetRailTracks(tile) & RAILTRACK_NE_SW) != 0;

		if (to - tile == ::MapSizeX()) return (GetRailTracks(tile) & RAILTRACK_NE_SE) != 0;

	} else if (tile - from == ::MapSizeX()) {

		if (tile - to == 1) return (GetRailTracks(tile) & RAILTRACK_NW_NE) != 0;

		if (to - tile == 1) return (GetRailTracks(tile) & RAILTRACK_NW_SW) != 0;

		if (to - tile == ::MapSizeX()) return (GetRailTracks(tile) & RAILTRACK_NW_SE) != 0;

	} else {

		return (GetRailTracks(tile) & RAILTRACK_SW_SE) != 0;

	}

	NOT_REACHED();

}

/**

 * Prepare the second parameter for CmdBuildRailroadTrack and CmdRemoveRailroadTrack. The direction

 * depends on all three tiles. Sometimes the third tile needs to be adjusted.

 */

static uint32 SimulateDrag(TileIndex from, TileIndex tile, TileIndex *to)

{

	int diag_offset = abs(abs((int)::TileX(*to) - (int)::TileX(tile)) - abs((int)::TileY(*to) - (int)::TileY(tile)));

	uint32 p2 = AIRail::GetCurrentRailType();

	if (::TileY(from) == ::TileY(*to)) {

		p2 |= (TRACK_X << 4);

		*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);

	} else if (::TileX(from) == ::TileX(*to)) {

		p2 |= (TRACK_Y << 4);

		*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);

	} else if (::TileY(from) < ::TileY(tile)) {

		if (::TileX(*to) < ::TileX(tile)) {

			p2 |= (TRACK_UPPER << 4);

		} else {

			p2 |= (TRACK_LEFT << 4);

		}

		if (diag_offset) {

			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);

		} else {

			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);

		}

	} else if (::TileY(from) > ::TileY(tile)) {

		if (::TileX(*to) < ::TileX(tile)) {

			p2 |= (TRACK_RIGHT << 4);

		} else {

			p2 |= (TRACK_LOWER << 4);

		}

		if (diag_offset) {

			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);

		} else {

			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);

		}

	} else if (::TileX(from) < ::TileX(tile)) {

		if (::TileY(*to) < ::TileY(tile)) {

			p2 |= (TRACK_UPPER << 4);

		} else {

			p2 |= (TRACK_RIGHT << 4);

		}

		if (!diag_offset) {

			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);

		} else {

			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);

		}

	} else if (::TileX(from) > ::TileX(tile)) {

		if (::TileY(*to) < ::TileY(tile)) {

			p2 |= (TRACK_LEFT << 4);

		} else {

			p2 |= (TRACK_LOWER << 4);

		}

		if (!diag_offset) {

			*to -= Clamp((int)::TileX(*to) - (int)::TileX(tile), -1, 1);

		} else {

			*to -= ::MapSizeX() * Clamp((int)::TileY(*to) - (int)::TileY(tile), -1, 1);

		}

	}

	return p2;

}

/* static */ bool AIRail::BuildRail(TileIndex from, TileIndex tile, TileIndex to)

{

	EnforcePrecondition(false, ::IsValidTile(from));

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, ::IsValidTile(to));

	EnforcePrecondition(false, ::DistanceManhattan(from, tile) == 1);

	EnforcePrecondition(false, ::DistanceManhattan(tile,to) >= 1);

	EnforcePrecondition(false, IsRailTypeAvailable(GetCurrentRailType()));

	int diag_offset = abs(abs((int)::TileX(to) - (int)::TileX(tile)) - abs((int)::TileY(to) - (int)::TileY(tile)));

	EnforcePrecondition(false, diag_offset <= 1 ||

			(::TileX(from) == ::TileX(tile) && ::TileX(tile) == ::TileX(to)) ||

			(::TileY(from) == ::TileY(tile) && ::TileY(tile) == ::TileY(to)));

	uint32 p2 = SimulateDrag(from, tile, &to);

	return AIObject::DoCommand(tile, to, p2, CMD_BUILD_RAILROAD_TRACK);

}

/* static */ bool AIRail::RemoveRail(TileIndex from, TileIndex tile, TileIndex to)

{

	EnforcePrecondition(false, ::IsValidTile(from));

	EnforcePrecondition(false, ::IsValidTile(tile));

	EnforcePrecondition(false, ::IsValidTile(to));

	EnforcePrecondition(false, ::DistanceManhattan(from, tile) == 1);

	EnforcePrecondition(false, ::DistanceManhattan(tile,to) >= 1);

	int diag_offset = abs(abs((int)::TileX(to) - (int)::TileX(tile)) - abs((int)::TileY(to) - (int)::TileY(tile)));

	EnforcePrecondition(false, diag_offset <= 1 ||

			(::TileX(from) == ::TileX(tile) && ::TileX(tile) == ::TileX(to)) ||

			(::TileY(from) == ::TileY(tile) && ::TileY(tile) == ::TileY(to)));

	if (!IsRailTypeAvailable(GetCurrentRailType())) SetCurrentRailType(GetRailType(tile));

	uint32 p2 = SimulateDrag(from, tile, &to);

	return AIObject::DoCommand(tile, to, p2, CMD_REMOVE_RAILROAD_TRACK);

}

/**

 * Contains information about the trackdir that belongs to a track when entering

 *   from a specific direction.

 */

struct AIRailSignalData {

	Track track;        //!< The track that will be taken to travel.

	Trackdir trackdir;  //!< The Trackdir belonging to that track.

	uint signal_cycles; //!< How many times the signal should be cycled in order to build it in the correct direction.

};

static const int NUM_TRACK_DIRECTIONS = 3; //!< The number of directions you can go when entering a tile.

/**

 * List information about the trackdir and number of needed cycles for building signals when

 *   entering a track from a specific direction. The first index is the difference between the

 *   TileIndex of the previous and current tile, where (-)MapSizeX is replaced with -2 / 2 and

 *   2 it added.

 */

static const AIRailSignalData _possible_trackdirs[5][NUM_TRACK_DIRECTIONS] = {

	{{TRACK_UPPER,   TRACKDIR_UPPER_E, 0}, {TRACK_Y,       TRACKDIR_Y_SE,    0}, {TRACK_LEFT,    TRACKDIR_LEFT_S,  1}},

	{{TRACK_RIGHT,   TRACKDIR_RIGHT_S, 1}, {TRACK_X,       TRACKDIR_X_SW,    1}, {TRACK_UPPER,   TRACKDIR_UPPER_W, 1}},

	{{INVALID_TRACK, INVALID_TRACKDIR, 0}, {INVALID_TRACK, INVALID_TRACKDIR, 0}, {INVALID_TRACK, INVALID_TRACKDIR, 0}},

	{{TRACK_LOWER,   TRACKDIR_LOWER_E, 0}, {TRACK_X,       TRACKDIR_X_NE,    0}, {TRACK_LEFT,    TRACKDIR_LEFT_N,  0}},

	{{TRACK_RIGHT,   TRACKDIR_RIGHT_N, 0}, {TRACK_Y,       TRACKDIR_Y_NW,    1}, {TRACK_LOWER,   TRACKDIR_LOWER_W, 1}}

};

/* static */ AIRail::SignalType AIRail::GetSignalType(TileIndex tile, TileIndex front)

{

	if (AIMap::DistanceManhattan(tile, front) != 1) return SIGNALTYPE_NONE;

	if (!::IsTileType(tile, MP_RAILWAY) || !::HasSignals(tile)) return SIGNALTYPE_NONE;

	int data_index = 2 + (::TileX(front) - ::TileX(tile)) + 2 * (::TileY(front) - ::TileY(tile));

	for (int i = 0; i < NUM_TRACK_DIRECTIONS; i++) {

		const Track &track = _possible_trackdirs[data_index][i].track;

		if (!(::TrackToTrackBits(track) & GetRailTracks(tile))) continue;

		if (!HasSignalOnTrack(tile, track)) continue;

		if (!HasSignalOnTrackdir(tile, _possible_trackdirs[data_index][i].trackdir)) continue;

		SignalType st = (SignalType)::GetSignalType(tile, track);

		if (HasSignalOnTrackdir(tile, ::ReverseTrackdir(_possible_trackdirs[data_index][i].trackdir))) st = (SignalType)(st | SIGNALTYPE_TWOWAY);

		return st;

	}

	return SIGNALTYPE_NONE;

}

/**

 * Check if signal_type is a valid SignalType.

 */

static bool IsValidSignalType(int signal_type)

{

	if (signal_type < AIRail::SIGNALTYPE_NORMAL || signal_type > AIRail::SIGNALTYPE_COMBO_TWOWAY) return false;

	if (signal_type > AIRail::SIGNALTYPE_PBS_ONEWAY && signal_type < AIRail::SIGNALTYPE_NORMAL_TWOWAY) return false;

	return true;

}

/* static */ bool AIRail::BuildSignal(TileIndex tile, TileIndex front, SignalType signal)

{

	EnforcePrecondition(false, AIMap::DistanceManhattan(tile, front) == 1)

	EnforcePrecondition(false, ::IsTileType(tile, MP_RAILWAY) && ::IsPlainRailTile(tile));

	EnforcePrecondition(false, ::IsValidSignalType(signal));

	Track track = INVALID_TRACK;

	uint signal_cycles;

	int data_index = 2 + (::TileX(front) - ::TileX(tile)) + 2 * (::TileY(front) - ::TileY(tile));

	for (int i = 0; i < NUM_TRACK_DIRECTIONS; i++) {

		const Track &t = _possible_trackdirs[data_index][i].track;

		if (!(::TrackToTrackBits(t) & GetRailTracks(tile))) continue;

		track = t;

		signal_cycles = _possible_trackdirs[data_index][i].signal_cycles;

		break;

	}

	EnforcePrecondition(false, track != INVALID_TRACK);

	uint p1 = track;

	if (signal < SIGNALTYPE_TWOWAY) {

		if (signal != SIGNALTYPE_PBS && signal != SIGNALTYPE_PBS_ONEWAY) signal_cycles++;

		p1 |= (signal_cycles << 15);

	}

	p1 |= ((signal >= SIGNALTYPE_TWOWAY ? signal ^ SIGNALTYPE_TWOWAY : signal) << 5);

	return AIObject::DoCommand(tile, p1, 0, CMD_BUILD_SIGNALS);

}

/* static */ bool AIRail::RemoveSignal(TileIndex tile, TileIndex front)

{

	EnforcePrecondition(false, AIMap::DistanceManhattan(tile, front) == 1)

	EnforcePrecondition(false, GetSignalType(tile, front) != SIGNALTYPE_NONE);

	Track track = INVALID_TRACK;

	int data_index = 2 + (::TileX(front) - ::TileX(tile)) + 2 * (::TileY(front) - ::TileY(tile));

	for (int i = 0; i < NUM_TRACK_DIRECTIONS; i++) {

		const Track &t = _possible_trackdirs[data_index][i].track;

		if (!(::TrackToTrackBits(t) & GetRailTracks(tile))) continue;

		track = t;

		break;

	}

	EnforcePrecondition(false, track != INVALID_TRACK);

	return AIObject::DoCommand(tile, track, 0, CMD_REMOVE_SIGNALS);

}