// Spark IM HTTP + TCP demo against production.
// javac docs/clients/SparkImClient.java && java -cp docs/clients SparkImClient
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.zip.GZIPInputStream;
import javax.net.ssl.SNIHostName;
import javax.net.ssl.SSLParameters;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;

public final class SparkImClient {
	static final String API = "https://sparkapi.wyrs365.com";
	static final String IM_HOST = "sparkim.wyrs365.com";
	static final int IM_PORT = 443;
	static final int HDR = 23;
	static final long DEVICE_ID = 7;

	public static void main(String[] args) throws Exception {
		String login = httpPost(API + "/v1/auth/login",
				"{\"email\":\"test01@spark.com\",\"verify_code\":\"000000\",\"device_id\":"
						+ DEVICE_ID + ",\"device_type\":\"android\",\"device_name\":\"demo\"}");
		System.out.println("LOGIN " + login);
		if (!login.contains("\"code\":\"0\"")) {
			return;
		}
		String token = jsonString(login, "access_token");

		SSLSocketFactory factory = (SSLSocketFactory) SSLSocketFactory.getDefault();
		SSLSocket socket = (SSLSocket) factory.createSocket();
		SSLParameters params = socket.getSSLParameters();
		params.setServerNames(List.of(new SNIHostName(IM_HOST)));
		socket.setSSLParameters(params);
		socket.connect(new InetSocketAddress(IM_HOST, IM_PORT), 10_000);
		socket.startHandshake();
		DataOutputStream out = new DataOutputStream(socket.getOutputStream());
		DataInputStream in = new DataInputStream(socket.getInputStream());

		String auth = "{\"token\":\"" + token + "\",\"device_id\":" + DEVICE_ID
				+ ",\"app_version\":\"1.0.0\",\"language\":\"zh-CN\"}";
		write(out, 1, 1, auth);
		System.out.println("AUTH " + read(in));
		write(out, 2, 2, "");
		System.out.println("HB " + read(in));
		write(out, 4, 3, "{\"peer_id\":1,\"client_msg_id\":\"demo-1\",\"content\":{\"t\":1,\"text\":{\"body\":\"hi\"}}}");
		System.out.println("SEND " + read(in));
		socket.close();
	}

	static void write(DataOutputStream out, int cmd, int seq, String body) throws IOException {
		byte[] b = body.getBytes(StandardCharsets.UTF_8);
		ByteBuffer buf = ByteBuffer.allocate(HDR + b.length);
		buf.putShort((short) 0x5350).put((byte) 1).putShort((short) cmd).putShort((short) 0)
				.putLong(0).putInt(seq).putInt(b.length).put(b);
		out.write(buf.array());
		out.flush();
	}

	static String read(DataInputStream in) throws IOException {
		byte[] h = in.readNBytes(HDR);
		if (h.length < HDR) {
			throw new IOException("short header");
		}
		ByteBuffer buf = ByteBuffer.wrap(h);
		if (buf.getShort() != 0x5350) {
			throw new IOException("magic");
		}
		buf.get();
		int cmd = buf.getShort() & 0xffff;
		int flags = buf.getShort() & 0xffff;
		buf.getLong();
		int seq = buf.getInt();
		int n = buf.getInt();
		byte[] body = in.readNBytes(n);
		if ((flags & 1) != 0) {
			body = gunzip(body);
		}
		return "cmd=" + cmd + " seq=" + seq + " " + new String(body, StandardCharsets.UTF_8);
	}

	static byte[] gunzip(byte[] body) throws IOException {
		try (GZIPInputStream gz = new GZIPInputStream(new ByteArrayInputStream(body));
				ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
			gz.transferTo(bos);
			return bos.toByteArray();
		}
	}

	static String httpPost(String url, String json) throws IOException {
		URL u = URI.create(url).toURL();
		HttpURLConnection c = (HttpURLConnection) u.openConnection();
		c.setRequestMethod("POST");
		c.setDoOutput(true);
		c.setRequestProperty("Content-Type", "application/json");
		c.setRequestProperty("X-Language", "zh-CN");
		c.setRequestProperty("X-App-Version", "1.0.0");
		try (OutputStream os = c.getOutputStream()) {
			os.write(json.getBytes(StandardCharsets.UTF_8));
		}
		int code = c.getResponseCode();
		InputStream is = code >= 400 ? c.getErrorStream() : c.getInputStream();
		try (InputStream in = is) {
			return new String(in.readAllBytes(), StandardCharsets.UTF_8);
		}
	}

	static String jsonString(String env, String key) {
		int i = env.indexOf("\"" + key + "\"");
		int colon = env.indexOf(':', i);
		int a = env.indexOf('"', colon) + 1;
		return env.substring(a, env.indexOf('"', a));
	}

	private SparkImClient() {}
}