/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file yapf_type.hpp Types used by YAPF. */

#ifndef YAPF_TYPE_HPP
#define YAPF_TYPE_HPP

/* Enum used in PfCalcCost() to see why was the segment closed. */
enum EndSegmentReason {
	/* The following reasons can be saved into cached segment */
	ESR_DEAD_END = 0,      ///< track ends here
	ESR_RAIL_TYPE,         ///< the next tile has a different rail type than our tiles
	ESR_INFINITE_LOOP,     ///< infinite loop detected
	ESR_SEGMENT_TOO_LONG,  ///< the segment is too long (possible infinite loop)
	ESR_CHOICE_FOLLOWS,    ///< the next tile contains a choice (the track splits to more than one segments)
	ESR_DEPOT,             ///< stop in the depot (could be a target next time)
	ESR_WAYPOINT,          ///< waypoint encountered (could be a target next time)
	ESR_STATION,           ///< station encountered (could be a target next time)
	ESR_SAFE_TILE,         ///< safe waiting position found (could be a target)

	/* The following reasons are used only internally by PfCalcCost().
	 *  They should not be found in the cached segment. */
	ESR_PATH_TOO_LONG,     ///< the path is too long (searching for the nearest depot in the given radius)
	ESR_FIRST_TWO_WAY_RED, ///< first signal was 2-way and it was red
	ESR_LOOK_AHEAD_END,    ///< we have just passed the last look-ahead signal
	ESR_TARGET_REACHED,    ///< we have just reached the destination

	/* Special values */
	ESR_NONE = 0xFF,          ///< no reason to end the segment here
};

enum EndSegmentReasonBits {
	ESRB_NONE = 0,

	ESRB_DEAD_END          = 1 << ESR_DEAD_END,
	ESRB_RAIL_TYPE         = 1 << ESR_RAIL_TYPE,
	ESRB_INFINITE_LOOP     = 1 << ESR_INFINITE_LOOP,
	ESRB_SEGMENT_TOO_LONG  = 1 << ESR_SEGMENT_TOO_LONG,
	ESRB_CHOICE_FOLLOWS    = 1 << ESR_CHOICE_FOLLOWS,
	ESRB_DEPOT             = 1 << ESR_DEPOT,
	ESRB_WAYPOINT          = 1 << ESR_WAYPOINT,
	ESRB_STATION           = 1 << ESR_STATION,
	ESRB_SAFE_TILE         = 1 << ESR_SAFE_TILE,

	ESRB_PATH_TOO_LONG     = 1 << ESR_PATH_TOO_LONG,
	ESRB_FIRST_TWO_WAY_RED = 1 << ESR_FIRST_TWO_WAY_RED,
	ESRB_LOOK_AHEAD_END    = 1 << ESR_LOOK_AHEAD_END,
	ESRB_TARGET_REACHED    = 1 << ESR_TARGET_REACHED,

	/* Additional (composite) values. */

	/* What reasons mean that the target can be found and needs to be detected. */
	ESRB_POSSIBLE_TARGET = ESRB_DEPOT | ESRB_WAYPOINT | ESRB_STATION | ESRB_SAFE_TILE,

	/* What reasons can be stored back into cached segment. */
	ESRB_CACHED_MASK = ESRB_DEAD_END | ESRB_RAIL_TYPE | ESRB_INFINITE_LOOP | ESRB_SEGMENT_TOO_LONG | ESRB_CHOICE_FOLLOWS | ESRB_DEPOT | ESRB_WAYPOINT | ESRB_STATION | ESRB_SAFE_TILE,

	/* Reasons to abort pathfinding in this direction. */
	ESRB_ABORT_PF_MASK = ESRB_DEAD_END | ESRB_PATH_TOO_LONG | ESRB_INFINITE_LOOP | ESRB_FIRST_TWO_WAY_RED,
};

DECLARE_ENUM_AS_BIT_SET(EndSegmentReasonBits)

inline CStrA ValueStr(EndSegmentReasonBits bits)
{
	static const char * const end_segment_reason_names[] = {
		"DEAD_END", "RAIL_TYPE", "INFINITE_LOOP", "SEGMENT_TOO_LONG", "CHOICE_FOLLOWS",
		"DEPOT", "WAYPOINT", "STATION", "SAFE_TILE",
		"PATH_TOO_LONG", "FIRST_TWO_WAY_RED", "LOOK_AHEAD_END", "TARGET_REACHED"
	};

	CStrA out;
	out.Format("0x%04X (%s)", bits, ComposeNameT(bits, end_segment_reason_names, "UNK", ESRB_NONE, "NONE").Data());
	return out.Transfer();
}

#endif /* YAPF_TYPE_HPP */
