/*
 * Minecraft Forge
 * Copyright (c) 2016-2019.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation version 2.1
 * of the License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package net.minecraftforge.userdev;

import cpw.mods.modlauncher.api.INameMappingService;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;

import static net.minecraftforge.fml.loading.LogMarkers.CORE;

import cpw.mods.modlauncher.api.INameMappingService.Domain;

public class MCPNamingService implements INameMappingService {
    private static final Logger LOGGER = LogManager.getLogger();
    private HashMap<String, String> methods;
    private HashMap<String, String> fields;

    @Override
    public String mappingName() {
        return "srgtomcp";
    }

    @Override
    public String mappingVersion() {
        return "1234";
    }

    @Override
    public Map.Entry<String, String> understanding() {
        return Pair.of("srg", "mcp");
    }

    @Override
    public BiFunction<Domain, String, String> namingFunction() {
        return this::findMapping;
    }

    private String findMapping(final Domain domain, final String srgName) {
        switch (domain) {
            case CLASS:
                return srgName;
            case FIELD:
                return findFieldMapping(srgName);
            case METHOD:
                return findMethodMapping(srgName);
        }
        return srgName;
    }

    private String findMethodMapping(final String origin) {
        if (methods == null) {
            HashMap<String,String> tmpmethods = new HashMap<>(1000);
            loadMappings("methods.csv", tmpmethods::put);
            methods = tmpmethods;
            LOGGER.debug(CORE, "Loaded {} method mappings from methods.csv", methods.size());
        }
        return methods.getOrDefault(origin, origin);
    }

    private String findFieldMapping(final String origin) {
        if (fields == null) {
            HashMap<String,String> tmpfields = new HashMap<>(1000);
            loadMappings("fields.csv", tmpfields::put);
            fields = tmpfields;
            LOGGER.debug(CORE, "Loaded {} field mappings from fields.csv", fields.size());
        }
        return fields.getOrDefault(origin, origin);
    }


    private static void loadMappings(final String mappingFileName, BiConsumer<String, String> mapStore)
    {
        URL path = ClassLoader.getSystemResource(mappingFileName); //We EXPLICITLY go throught the SystemClassLoader here because this is dev-time only. And will be on the root classpath.
        if (path == null)
            return;

        try (BufferedReader reader = new BufferedReader(new InputStreamReader(path.openStream())))
        {
            reader.lines().skip(1).map(e -> e.split(",")).forEach(e -> mapStore.accept(e[0], e[1]));
        }
        catch (IOException e1)
        {
            LOGGER.error(CORE, "Error reading mappings", e1);
        }
    }
}
