/*
 * 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 labelmaps_sl.cpp Code handling saving and loading of rail type label mappings */

#include "../stdafx.h"

#include "saveload.h"
#include "compat/labelmaps_sl_compat.h"

#include "saveload_internal.h"
#include "../station_map.h"
#include "../tunnelbridge_map.h"

#include "../safeguards.h"

static std::vector<RailTypeLabel> _railtype_list;

/**
 * Test if any saved rail type labels are different to the currently loaded
 * rail types. Rail types stored in the map will be converted if necessary.
 */
static void ConvertRailTypes()
{
	std::vector<RailType> railtype_conversion_map;
	bool needs_conversion = false;

	for (auto it = std::begin(_railtype_list); it != std::end(_railtype_list); ++it) {
		RailType rt = GetRailTypeByLabel(*it);
		if (rt == INVALID_RAILTYPE) {
			rt = RAILTYPE_RAIL;
		}

		railtype_conversion_map.push_back(rt);

		/* Conversion is needed if the rail type is in a different position than the list. */
		if (*it != 0 && rt != std::distance(std::begin(_railtype_list), it)) needs_conversion = true;
	}
	if (!needs_conversion) return;

	for (TileIndex t : Map::Iterate()) {
		switch (GetTileType(t)) {
			case MP_RAILWAY:
				SetRailType(t, railtype_conversion_map[GetRailType(t)]);
				break;

			case MP_ROAD:
				if (IsLevelCrossing(t)) {
					SetRailType(t, railtype_conversion_map[GetRailType(t)]);
				}
				break;

			case MP_STATION:
				if (HasStationRail(t)) {
					SetRailType(t, railtype_conversion_map[GetRailType(t)]);
				}
				break;

			case MP_TUNNELBRIDGE:
				if (GetTunnelBridgeTransportType(t) == TRANSPORT_RAIL) {
					SetRailType(t, railtype_conversion_map[GetRailType(t)]);
				}
				break;

			default:
				break;
		}
	}
}

void AfterLoadLabelMaps()
{
	ConvertRailTypes();
}

void ResetLabelMaps()
{
	_railtype_list.clear();
}

/** Container for a label for SaveLoad system */
struct LabelObject {
	uint32_t label;
};

static const SaveLoad _label_object_desc[] = {
	SLE_VAR(LabelObject, label, SLE_UINT32),
};

struct RAILChunkHandler : ChunkHandler {
	RAILChunkHandler() : ChunkHandler('RAIL', CH_TABLE) {}

	void Save() const override
	{
		SlTableHeader(_label_object_desc);

		LabelObject lo;

		for (RailType r = RAILTYPE_BEGIN; r != RAILTYPE_END; r++) {
			lo.label = GetRailTypeInfo(r)->label;

			SlSetArrayIndex(r);
			SlObject(&lo, _label_object_desc);
		}
	}

	void Load() const override
	{
		const std::vector<SaveLoad> slt = SlCompatTableHeader(_label_object_desc, _label_object_sl_compat);

		LabelObject lo;

		while (SlIterateArray() != -1) {
			SlObject(&lo, slt);
			_railtype_list.push_back((RailTypeLabel)lo.label);
		}
	}
};

static const RAILChunkHandler RAIL;
static const ChunkHandlerRef labelmaps_chunk_handlers[] = {
	RAIL,
};

extern const ChunkHandlerTable _labelmaps_chunk_handlers(labelmaps_chunk_handlers);