project_vollidioten_mod/src/main/java/ceratic/projectvollidioten/http/ResourcePackHttpServer.java

package ceratic.projectvollidioten.http;

import ceratic.projectvollidioten.config.GithubResourcePackConfig;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

import net.minecraft.server.MinecraftServer;

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.nio.file.Files;
import java.nio.file.Path;

public class ResourcePackHttpServer {
    private final HttpServer server;
    private final Path resourcePacksDir;
    private final String expectedFileName;
    private final int port;

    public ResourcePackHttpServer(MinecraftServer mcServer, String expectedFileName, int port) throws IOException {
        this.resourcePacksDir = mcServer.getRunDirectory().resolve("server-resource-packs");
        this.expectedFileName = expectedFileName;
        this.port = port;

        Files.createDirectories(resourcePacksDir);

        this.server = HttpServer.create(new InetSocketAddress("0.0.0.0", port), 0);
        this.server.createContext("/resourcepacks", new ResourcePackHandler());
        this.server.setExecutor(null); // Uses default executor
    }

    public void start() {
        server.start();
        System.out.println("[GithubRP] 🌐 HTTP server started on http://0.0.0.0:" + port + "/resourcepacks/");
    }

    public void stop() {
        server.stop(1);
        System.out.println("[GithubRP] 🌐 HTTP server stopped.");
    }

    // Returns URL clients should use — e.g. http://192.168.1.100:25585/resourcepacks/my-pack.zip
    public String getPackUrl() {
        // Try to get LAN IP (optional: replace with public IP if port-forwarded)
        String host = "127.0.0.1"; // fallback
        try {
            java.net.InetAddress addr = java.net.InetAddress.getLocalHost();
            if (!addr.isLoopbackAddress() && addr.isSiteLocalAddress()) {
                host = addr.getHostAddress();
            }
        } catch (Exception ignored) {}

        return String.format("http://%s:%d/resourcepacks/%s", host, port, expectedFileName);
    }

    private class ResourcePackHandler implements HttpHandler {
        @Override
        public void handle(HttpExchange exchange) throws IOException {
            String path = exchange.getRequestURI().getPath();
            String targetFile = path.substring("/resourcepacks/".length());

            // Security: only allow configured pack filename
            if (!targetFile.equals(expectedFileName)) {
                sendResponse(exchange, 403, "Forbidden: unknown resource pack");
                return;
            }

            Path packFile = resourcePacksDir.resolve(targetFile);
            if (!Files.exists(packFile) || !Files.isRegularFile(packFile)) {
                sendResponse(exchange, 404, "Resource pack not found");
                return;
            }

            // Set headers
            exchange.getResponseHeaders().set("Content-Type", "application/zip");
            exchange.getResponseHeaders().set("Content-Length", String.valueOf(Files.size(packFile)));
            exchange.getResponseHeaders().set("Cache-Control", "public, max-age=3600");
            exchange.getResponseHeaders().set("Access-Control-Allow-Origin", "*");

            // Send file
            exchange.sendResponseHeaders(200, 0); // chunked
            try (OutputStream os = exchange.getResponseBody();
                 var fis = Files.newInputStream(packFile)) {
                fis.transferTo(os);
            } catch (IOException e) {
                System.err.println("[GithubRP] Client disconnected during pack download.");
            }
        }

        private void sendResponse(HttpExchange exchange, int code, String msg) throws IOException {
            byte[] data = msg.getBytes(java.nio.charset.StandardCharsets.UTF_8);
            exchange.getResponseHeaders().set("Content-Type", "text/plain; charset=utf-8");
            exchange.sendResponseHeaders(code, data.length);
            exchange.getResponseBody().write(data);
            exchange.close();
        }
    }
}