import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.security.MessageDigest;
import java.time.Duration;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * Mise à jour automatique des mods NeoGames : compare le dossier mods avec la liste du serveur (SHA-256) et ne télécharge que ce qui change.
 * Lancement : java Updater.java [dossier-mods] [url-de-base]   (aucune installation, juste Java). Hors ligne : ne bloque jamais le jeu.
 */
public class Updater {
    static final String DEFAULT_URL = "https://git.neofloodgames.fr/NeoFloodGames/oneblock-release/raw/branch/main/";

    public static void main(String[] a) {
        try {
            run(a);
        } catch (Exception e) {
            System.out.println("[NeoGames] Mise à jour impossible (" + e + ") : on lance avec les mods déjà présents.");
        }
    }

    static void run(String[] a) throws Exception {
        Path mods = Path.of(a.length > 0 ? a[0] : "mods");
        String base = a.length > 1 ? a[1] : System.getenv().getOrDefault("NEOGAMES_URL", DEFAULT_URL);
        if (!base.endsWith("/")) base += "/";
        Files.createDirectories(mods);
        HttpClient http = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(6)).followRedirects(HttpClient.Redirect.NORMAL).build();
        String manifest = new String(get(http, base + "manifest.txt"), StandardCharsets.UTF_8);
        List<String[]> files = new ArrayList<>();
        List<String> managed = new ArrayList<>();
        for (String line : manifest.split("\\R")) {
            line = line.trim();
            if (line.isEmpty()) continue;
            if (line.startsWith("#managed ")) { for (String p : line.substring(9).split("\\s+")) managed.add(p); continue; }
            if (line.startsWith("#")) continue;
            String[] p = line.split("\\s+", 3); // sha256 taille nom
            if (p.length == 3 && p[2].endsWith(".jar") && !p[2].contains("/") && !p[2].contains("\\")) files.add(p);
        }
        if (files.isEmpty()) throw new IOException("liste vide");
        Set<String> keep = new HashSet<>();
        int updated = 0;
        for (String[] f : files) {
            keep.add(f[2]);
            Path target = mods.resolve(f[2]);
            if (Files.exists(target) && sha256(Files.readAllBytes(target)).equals(f[0])) continue;
            System.out.println("[NeoGames] Téléchargement de " + f[2] + " (" + Long.parseLong(f[1]) / 1024 + " Ko)...");
            byte[] data = get(http, base + f[2]);
            if (!sha256(data).equals(f[0])) throw new IOException("fichier corrompu : " + f[2]);
            Path tmp = mods.resolve(f[2] + ".part");
            Files.write(tmp, data);
            Files.move(tmp, target, StandardCopyOption.REPLACE_EXISTING);
            updated++;
        }
        // anciennes versions des mods gérés (même préfixe, nom différent) : retirées pour éviter les doublons
        try (var s = Files.list(mods)) {
            for (Path p : (Iterable<Path>) s::iterator) {
                String n = p.getFileName().toString();
                if (!n.endsWith(".jar") || keep.contains(n)) continue;
                for (String pre : managed) if (n.startsWith(pre)) { Files.deleteIfExists(p); System.out.println("[NeoGames] Ancienne version retirée : " + n); break; }
            }
        }
        System.out.println(updated == 0 ? "[NeoGames] Mods à jour." : "[NeoGames] " + updated + " mod(s) mis à jour.");
    }

    static byte[] get(HttpClient http, String url) throws Exception {
        HttpResponse<byte[]> r = http.send(HttpRequest.newBuilder(URI.create(url)).timeout(Duration.ofSeconds(60)).build(), HttpResponse.BodyHandlers.ofByteArray());
        if (r.statusCode() != 200) throw new IOException("HTTP " + r.statusCode() + " sur " + url);
        return r.body();
    }

    static String sha256(byte[] data) throws Exception {
        StringBuilder sb = new StringBuilder();
        for (byte b : MessageDigest.getInstance("SHA-256").digest(data)) sb.append(String.format("%02x", b));
        return sb.toString();
    }
}