/*
 * WorldEdit, a Minecraft world manipulation toolkit
 * Copyright (C) sk89q <http://www.sk89q.com>
 * Copyright (C) WorldEdit team and contributors
 *
 * This program 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.sk89q.worldedit.world.registry;

import com.google.common.io.Resources;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;
import com.sk89q.worldedit.math.Vector3;
import com.sk89q.worldedit.util.gson.VectorAdapter;
import com.sk89q.worldedit.util.io.ResourceLoader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nullable;
import java.io.IOException;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Provides item data based on the built-in item database that is bundled
 * with WorldEdit.
 *
 * <p>A new instance cannot be created. Use {@link #getInstance()} to get
 * an instance.</p>
 *
 * <p>The data is read from a JSON file that is bundled with WorldEdit. If
 * reading fails (which occurs when this class is first instantiated), then
 * the methods will return {@code null}s for all items.</p>
 */
public class BundledItemData {

    private static final Logger log = LoggerFactory.getLogger(BundledItemData.class);
    private static BundledItemData INSTANCE;

    private final Map<String, ItemEntry> idMap = new HashMap<>();

    /**
     * Create a new instance.
     */
    private BundledItemData() {
        try {
            loadFromResource();
        } catch (Throwable e) {
            log.warn("Failed to load the built-in item registry", e);
        }
    }

    /**
     * Attempt to load the data from file.
     *
     * @throws IOException thrown on I/O error
     */
    private void loadFromResource() throws IOException {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.registerTypeAdapter(Vector3.class, new VectorAdapter());
        Gson gson = gsonBuilder.create();
        URL url = ResourceLoader.getResource(BundledItemData.class,"items.json");
        if (url == null) {
            throw new IOException("Could not find items.json");
        }
        String data = Resources.toString(url, Charset.defaultCharset());
        List<ItemEntry> entries = gson.fromJson(data, new TypeToken<List<ItemEntry>>() {}.getType());

        for (ItemEntry entry : entries) {
            idMap.put(entry.id, entry);
        }
    }

    /**
     * Return the entry for the given item ID.
     *
     * @param id the ID
     * @return the entry, or null
     */
    @Nullable
    public ItemEntry findById(String id) {
        // If it has no namespace, assume minecraft.
        if (!id.contains(":")) {
            id = "minecraft:" + id;
        }
        return idMap.get(id);
    }

    /**
     * Get a singleton instance of this object.
     *
     * @return the instance
     */
    public static BundledItemData getInstance() {
        if (INSTANCE == null) {
            INSTANCE = new BundledItemData();
        }
        return INSTANCE;
    }

    public static class ItemEntry {
        private String id;
        private String unlocalizedName;
        public String localizedName;
        private int maxDamage;
        private int maxStackSize;
    }

}
