import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Type;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URL;
import java.security.SignatureException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;
import java.util.zip.GZIPInputStream;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class SignatureTest {

	public static void main(String[] args) {
		HttpURLConnection connection = null;
		String APIUrl = "https://ptx.transportdata.tw/MOTC/v2/Rail/TRA/Station?$top=1&$format=JSON";
		// 申請的APPID
		// （FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF 為 Guest
		// 帳號，以IP作為API呼叫限制，請替換為註冊的APPID & APPKey）
		String APPID = "FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF";
		// 申請的APPKey
		String APPKey = "FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF";

		// 取得當下的UTC時間，Java8有提供時間格式DateTimeFormatter.RFC_1123_DATE_TIME
		// 但是格式與C#有一點不同，所以只能自行定義
		String xdate = getServerTime();
		String SignDate = "x-date: " + xdate;
		String respond = "";

		String Signature = "";
		try {
			// 取得加密簽章
			Signature = HMAC_SHA1.Signature(SignDate, APPKey);
		} catch (SignatureException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}

		System.out.println("Signature :" + Signature);
		String sAuth = "hmac username=\"" + APPID + "\", algorithm=\"hmac-sha1\", headers=\"x-date\", signature=\""
				+ Signature + "\"";
		System.out.println(sAuth);
		try {
			URL url = new URL(APIUrl);
			if ("https".equalsIgnoreCase(url.getProtocol())) {
				SslUtils.ignoreSsl();
			}
			connection = (HttpURLConnection) url.openConnection();
			connection.setRequestMethod("GET");
			connection.setRequestProperty("Authorization", sAuth);
			connection.setRequestProperty("x-date", xdate);
			connection.setRequestProperty("Accept-Encoding", "gzip");
			connection.setDoInput(true);
			connection.setDoOutput(true);

			respond = connection.getResponseCode() + " " + connection.getResponseMessage();
			System.out.println("回傳狀態:" + respond);
			BufferedReader in;

			// 判斷來源是否為gzip
			if ("gzip".equals(connection.getContentEncoding())) {
				InputStreamReader reader = new InputStreamReader(new GZIPInputStream(connection.getInputStream()));
				in = new BufferedReader(reader);
			} else {
				InputStreamReader reader = new InputStreamReader(connection.getInputStream());
				in = new BufferedReader(reader);
			}

			// 返回的數據已經過解壓
			StringBuffer buffer = new StringBuffer();
			// 讀取回傳資料
			String line, response = "";
			while ((line = in.readLine()) != null) {
				response += (line + "\n");
			}

			Type RailStationListType = new TypeToken<ArrayList<RailStation>>() {
			}.getType();
			Gson gsonReceiver = new Gson();
			List<RailStation> obj = gsonReceiver.fromJson(response, RailStationListType);
			for (RailStation railStation : obj)
				System.out.println(railStation);

		} catch (ProtocolException e) {
			e.printStackTrace();
		}

		catch (Exception e) {
			e.printStackTrace();
		}

	}

	// 取得當下UTC時間
	public static String getServerTime() {
		Calendar calendar = Calendar.getInstance();
		SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.US);
		dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
		return dateFormat.format(calendar.getTime());
	}

}