import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.io.OutputStream;
  
import java.net.*;

import java.util.concurrent.TimeUnit;
import java.util.*;
public class MAuthn
{

private static String SendRequest(String email_of_user, String required_data, String requester) throws Exception
{
    URL url =  new URL("https://emauth.mukham.in/add_request");
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setRequestMethod("POST");
    connection.setDoOutput(true);
    Map<String, String> args = new HashMap<>();
    args.put("email", email_of_user);
    args.put("data", required_data);
    args.put("requester", requester);
    StringJoiner sj = new StringJoiner("&");
    for(Map.Entry<String, String> entry : args.entrySet())
    {
        sj.add(URLEncoder.encode(entry.getKey(), "UTF-8") + "=" + URLEncoder.encode(entry.getValue(), "UTF-8"));
    }
    byte out[] = sj.toString().getBytes(StandardCharsets.UTF_8);
    int len = out.length;

    connection.setFixedLengthStreamingMode(len);
    connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
    connection.connect();
    OutputStream os = connection.getOutputStream();
    os.write(out);

    String token="0000";
    StringBuilder sb = new StringBuilder();
    int httpResult = connection.getResponseCode();
    if(httpResult == HttpURLConnection.HTTP_OK)
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
        String line = null;
        while ((line = br.readLine()) !=null)
        {
            sb.append(line + "\n");
        }
        token = sb.toString();
    }
    
    if (token.equals("0000"))
    {
        throw new Exception("Account does not exist");
    }
    
    String status="";
    
    do
    {
        TimeUnit.SECONDS.sleep(10);
        
        url =  new URL("https://emauth.mukham.in/get_data");
        connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setDoOutput(true);
        args = new HashMap<>();
        args.put("token", token.substring(0,36));
        sj = new StringJoiner("&");
        for(Map.Entry<String, String> entry : args.entrySet())
        {
            sj.add(URLEncoder.encode(entry.getKey(), "UTF-8") + "=" + URLEncoder.encode(entry.getValue(), "UTF-8"));
        }
        out = sj.toString().getBytes(StandardCharsets.UTF_8);
        len = out.length;

        connection.setFixedLengthStreamingMode(len);
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
        connection.connect();
        os = connection.getOutputStream();
        os.write(out);

        sb = new StringBuilder();
        httpResult = connection.getResponseCode();
        if(httpResult == HttpURLConnection.HTTP_OK)
        {
           BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
            String line = null;
            while ((line = br.readLine()) !=null)
            {
                sb.append(line + "\n");
            }
            status = sb.toString();
        }      
        //System.out.println(status);
    } while(status.startsWith("pending"));
    
    if (status.startsWith("expired"))
        return "Authorization denied";
    else 
        return status;
}
public static boolean verifyUser(String email_of_user, String requester)throws Exception
{
    String k=SendRequest(email_of_user, "0000", requester);
    //System.out.println(k);
    if (k.equalsIgnoreCase("Authorization denied"))
        return false;
    else
        return true;
}
public static String getUserData(String email_of_user, List requested_data, String requester) throws Exception
{
    String data="";
    if(requested_data.contains("Name"))
        data=data+"1";
    else
        data=data+"0";
        
    if(requested_data.contains("Date-Of-Birth"))
        data=data+"1";
    else
        data=data+"0";
        
    if(requested_data.contains("Image"))
        data=data+"1";
    else
        data=data+"0";
        
    if(requested_data.contains("IP"))
        data=data+"1";
    else
        data=data+"0";
        
    String resp=SendRequest(email_of_user, data, requester);
    return resp;
}
}