Backend/src/main/java/cc.fascinated/service/ServerService.java

package cc.fascinated.service;

import cc.fascinated.common.DNSUtils;
import cc.fascinated.common.EnumUtils;
import cc.fascinated.config.Config;
import cc.fascinated.exception.impl.BadRequestException;
import cc.fascinated.exception.impl.ResourceNotFoundException;
import cc.fascinated.model.cache.CachedMinecraftServer;
import cc.fascinated.model.dns.DNSRecord;
import cc.fascinated.model.dns.impl.ARecord;
import cc.fascinated.model.dns.impl.SRVRecord;
import cc.fascinated.model.server.JavaMinecraftServer;
import cc.fascinated.model.server.MinecraftServer;
import cc.fascinated.repository.MinecraftServerCacheRepository;
import lombok.extern.log4j.Log4j2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Base64;
import java.util.List;
import java.util.Optional;

@Service @Log4j2
public class ServerService {
    private static final String DEFAULT_SERVER_ICON = "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";

    private final MojangService mojangService;
    private final MinecraftServerCacheRepository serverCacheRepository;

    @Autowired
    public ServerService(MojangService mojangService, MinecraftServerCacheRepository serverCacheRepository) {
        this.mojangService = mojangService;
        this.serverCacheRepository = serverCacheRepository;
    }

    /**
     * Ping a server to get the server information.
     *
     * @param platformName the name of the platform
     * @param hostname the hostname of the server
     * @return the server
     */
    public CachedMinecraftServer getServer(String platformName, String hostname) {
        MinecraftServer.Platform platform = EnumUtils.getEnumConstant(MinecraftServer.Platform.class, platformName.toUpperCase());
        if (platform == null) {
            log.info("Invalid platform: {} for server {}", platformName, hostname);
            throw new BadRequestException("Invalid platform: %s".formatted(platformName));
        }
        int port = platform.getDefaultPort();
        if (hostname.contains(":")) {
            String[] parts = hostname.split(":");
            hostname = parts[0];
            try {
                port = Integer.parseInt(parts[1]);
            } catch (NumberFormatException e) {
                log.info("Invalid port: {} for server {}", parts[1], hostname);
                throw new BadRequestException("Invalid port: %s".formatted(parts[1]));
            }
        }
        String key = "%s-%s:%s".formatted(platformName, hostname, port);
        log.info("Getting server: {}:{}", hostname, port);

        // Check if the server is cached
        Optional<CachedMinecraftServer> cached = serverCacheRepository.findById(key);
        if (cached.isPresent() && Config.INSTANCE.isProduction()) {
                log.info("Server {}:{} is cached", hostname, port);
            return cached.get();
        }

        List<DNSRecord> records = new ArrayList<>(); // The resolved DNS records for the server

        SRVRecord srvRecord = platform == MinecraftServer.Platform.JAVA ? DNSUtils.resolveSRV(hostname) : null; // Resolve the SRV record
        if (srvRecord != null) { // SRV was resolved, use the hostname and port
            records.add(srvRecord); // Going to need this for later
            InetSocketAddress socketAddress = srvRecord.getSocketAddress();
            hostname = socketAddress.getHostName();
            port = socketAddress.getPort();
        }

        ARecord aRecord = DNSUtils.resolveA(hostname); // Resolve the A record so we can get the IPv4 address
        String ip = aRecord == null ? null : aRecord.getAddress(); // Get the IP address
        if (ip != null) { // Was the IP resolved?
            records.add(aRecord); // Going to need this for later
            log.info("Resolved hostname: {} -> {}", hostname, ip);
        }

        CachedMinecraftServer server = new CachedMinecraftServer(
                key,
                platform.getPinger().ping(hostname, ip, port, records.toArray(new DNSRecord[0])),
                System.currentTimeMillis()
        );

        // Check if the server is blocked by Mojang
        if (platform == MinecraftServer.Platform.JAVA) {
            ((JavaMinecraftServer) server.getServer()).setMojangBlocked(mojangService.isServerBlocked(hostname));
        }

        log.info("Found server: {}:{}", hostname, port);
        serverCacheRepository.save(server);
        server.setCached(-1); // Indicate that the server is not cached
        return server;
    }

    /**
     * Gets the server favicon.
     *
     * @param hostname the hostname of the server
     * @return the server favicon, null if not found
     */
    public byte[] getServerFavicon(String hostname) {
        String icon = null; // The server base64 icon
        try {
            JavaMinecraftServer.Favicon favicon = ((JavaMinecraftServer) getServer(MinecraftServer.Platform.JAVA.name(), hostname).getServer()).getFavicon();
            if (favicon != null) { // Use the server's favicon
                icon = favicon.getBase64();
                icon = icon.substring(icon.indexOf(",") + 1); // Remove the data type from the server icon
            }
        } catch (BadRequestException | ResourceNotFoundException ignored) {
            // Safely ignore these, we will use the default server icon
        }
        if (icon == null) { // Use the default server icon
            icon = DEFAULT_SERVER_ICON;
        }
        return Base64.getDecoder().decode(icon); // Return the decoded favicon
    }
}