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

import java.io.IOException;
import java.io.OutputStream;
import java.io.InputStream;
import java.net.InetSocketAddress;
import java.nio.charset.StandardCharsets;
import java.util.*;

public class RestApiServer {

    // Key yang diizinkan
    private static final String VALID_KEY = "K7tfZuRT1MLmNsftNWK9FUlGZHL4oPIa";

    // start single port
    public static void start(int port) {
        try {
            HttpServer server = HttpServer.create(new InetSocketAddress(port), 0);

            server.createContext("/mid/bifast/inqAccount", new InqAccountHandler());

            server.setExecutor(null);
            System.out.println("✅ Dummy BI-Fast REST listening on http://0.0.0.0:" + port);
            server.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // start multiple ports
    public static void start(int[] ports) {
        for (int port : ports) {
            new Thread(() -> start(port), "restapi-" + port).start();
        }
    }

    // Handler untuk BI-Fast
    static class InqAccountHandler implements HttpHandler {
        @Override
        public void handle(HttpExchange exchange) throws IOException {
            if (!"POST".equalsIgnoreCase(exchange.getRequestMethod())) {
                exchange.sendResponseHeaders(405, -1); // Method Not Allowed
                return;
            }

            // cek key dari header atau query
            String clientKey = exchange.getRequestHeaders().getFirst("key");
            if (clientKey == null) {
                clientKey = getQueryParam(exchange.getRequestURI().getQuery(), "key");
            }

            // if (!VALID_KEY.equals(clientKey)) {
            //     String resp = "{\"rsp\":\"401\",\"rspdesc\":\"Unauthorized - Invalid key\"}";
            //     writeResponse(exchange, 401, resp);
            //     return;
            // }

            // baca body manual (karena Java 8 belum ada readAllBytes)
            InputStream is = exchange.getRequestBody();
            StringBuilder sb = new StringBuilder();
            byte[] buffer = new byte[1024];
            int len;
            while ((len = is.read(buffer)) != -1) {
                sb.append(new String(buffer, 0, len, StandardCharsets.UTF_8));
            }
            String requestBody = sb.toString();

            // ambil id dari body kalau ada (sederhana, tanpa parser JSON)
            String clientId = null;
            if (requestBody.contains("\"id\"")) {
                int idx = requestBody.indexOf("\"id\"");
                int colon = requestBody.indexOf(":", idx);
                if (colon > 0) {
                    int start = requestBody.indexOf("\"", colon);
                    int end = requestBody.indexOf("\"", start + 1);
                    if (start > 0 && end > start) {
                        clientId = requestBody.substring(start + 1, end);
                    }
                }
            }

            // response dummy
            String resp = "{"
                    + "\"wsref\":\"000716949164\","
                    + "\"rsp\":\"000\","
                    + "\"rspdesc\":\"Transaction Success (POST)\","
                    + "\"id\":\"" + (clientId != null ? clientId : "AKTE NO.23") + "\","
                    + "\"idType\":\"03\","
                    + "\"residentStatus\":\"Y\","
                    + "\"townName\":\"0391\","
                    + "\"name\":\"NASABAH POST\","
                    + "\"type\":\"D\""
                    + "}";

            writeResponse(exchange, 200, resp);
        }
    }

    private static void writeResponse(HttpExchange exchange, int status, String resp) throws IOException {
        exchange.getResponseHeaders().add("Content-Type", "application/json");
        exchange.sendResponseHeaders(status, resp.getBytes(StandardCharsets.UTF_8).length);
        try (OutputStream os = exchange.getResponseBody()) {
            os.write(resp.getBytes(StandardCharsets.UTF_8));
        }
    }

    // helper ambil query param
    private static String getQueryParam(String query, String key) {
        if (query == null) return null;
        for (String pair : query.split("&")) {
            String[] kv = pair.split("=");
            if (kv.length == 2 && kv[0].equals(key)) {
                return kv[1];
            }
        }
        return null;
    }
}