/*
 * Copyright (C) 2025  Minecon724
 * Tweaks724 is licensed under the GNU General Public License. See the LICENSE.md file
 * in the project root for the full license text.
 */

package eu.m724.tweaks.motd;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.events.*;
import com.comphenix.protocol.reflect.StructureModifier;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonParser;
import eu.m724.tweaks.DebugLogger;
import eu.m724.tweaks.TweaksConfig;
import eu.m724.tweaks.TweaksModule;
import net.md_5.bungee.api.chat.TextComponent;
import net.md_5.bungee.chat.ComponentSerializer;
import net.minecraft.SharedConstants;
import net.minecraft.core.RegistryAccess;
import net.minecraft.network.chat.Component;
import net.minecraft.network.protocol.status.ServerStatus;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.Arrays;
import java.util.Optional;
import java.util.concurrent.ThreadLocalRandom;

public class MotdModule extends TweaksModule {
    private Component[] motds;

    @Override
    protected void onInit() {
        // TODO adding more MOTD features would require checking whether to enable set

        String motdSetName = TweaksConfig.getConfig().motdSet();
        String motdSetPath = "motd sets/" + motdSetName + ".txt";
        File motdSetsFile = new File(getPlugin().getDataFolder(), motdSetPath);

        // create "motd sets" directory
        motdSetsFile.getParentFile().mkdirs();

        // if this is a builtin set
        if (!motdSetsFile.exists() && getPlugin().hasResource(motdSetPath))
            getPlugin().saveResource(motdSetPath, false);

        if (!motdSetsFile.exists()) {
            throw new RuntimeException("MOTD set \"%s\" doesn't exist".formatted(motdSetName));
        }

        String fileContent;
        try {
            fileContent = Files.readString(motdSetsFile.toPath());
        } catch (IOException e) {
            throw new RuntimeException("Reading motd set", e);
        }

        // MOTDs are split with an empty line
        motds = Arrays.stream(fileContent.split("\n\n"))
                .map(entry -> {
                    entry = entry.strip();
                    JsonElement json = null;

                    try {
                        json = JsonParser.parseString(entry);
                        DebugLogger.finer("JSON line: %s...", entry.substring(0, Math.min(entry.length(), 10)));
                    } catch (JsonParseException e) {
                        DebugLogger.finer("JSON line: %s...", entry.substring(0, Math.min(entry.length(), 10)));
                    }

                    if (json == null) {
                        json = ComponentSerializer.toJson(TextComponent.fromLegacy(entry));
                    }

                    return Component.Serializer.fromJson(json, RegistryAccess.EMPTY);
                })
                .toArray(Component[]::new);

        onPacketSend(PacketType.Status.Server.SERVER_INFO, (event) -> {
            PacketContainer packet = event.getPacket();

            Component motd = motds[ThreadLocalRandom.current().nextInt(motds.length)];

            ServerStatus serverStatus = (ServerStatus) packet.getStructures().read(0).getHandle();

            /* this:
             * removes server mod prefix (Paper, Spigot, any brand)
             * hides players
             */
            ServerStatus newStatus = new ServerStatus(
                    motd,
                    Optional.empty(),
                    Optional.of(new ServerStatus.Version(
                            SharedConstants.getCurrentVersion().getName(),
                            SharedConstants.getProtocolVersion()
                    )),
                    serverStatus.favicon(),
                    false
            );

            packet.getStructures().write(0, new InternalStructure(newStatus, new StructureModifier<>(ServerStatus.class)));
        });
    }
}