package com.mycompany.testproject;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.ClientRequestContext;
import javax.ws.rs.client.ClientRequestFilter;
import javax.ws.rs.client.Entity;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedHashMap;
import javax.ws.rs.core.MultivaluedMap;
import javax.xml.bind.DatatypeConverter;

class Authenticator implements ClientRequestFilter {

    private final String user;
    private final String password;

    public Authenticator(String user, String password) {
        this.user = user;
        this.password = password;
    }

    @Override
    public void filter(ClientRequestContext requestContext) throws IOException {
        MultivaluedMap<String, Object> headers = requestContext.getHeaders();
        final String basicAuthentication = getBasicAuthentication();
        headers.add("Authorization", basicAuthentication);

    }

    private String getBasicAuthentication() {
        String token = this.user + ":" + this.password;
        try {
            return "BASIC " + DatatypeConverter.printBase64Binary(token.getBytes("UTF-8"));
        } catch (UnsupportedEncodingException ex) {
            throw new IllegalStateException("Cannot encode with UTF-8", ex);
        }
    }
}

public class App {

    public static void main(String[] args) throws Exception {

        WebTarget path = ClientBuilder.newClient()
                .target("https://api.mailgun.net/v3/samples.mailgun.org/messages")
                .register(new Authenticator("api", "key-3ax6xnjp29jd6fds4gc373sgvjxteol0"));

        MultivaluedMap<String, String> formData = new MultivaluedHashMap<>();
        formData.add("from", "Formularz Kontaktowy <kontakt@reservly.com>");
        formData.add("to", "tomaszdudzik.web@gmail.com");
        formData.add("subject", "Temat wiadomości");
        formData.add("text", "Treść wiadomości");

        path.request(MediaType.APPLICATION_FORM_URLENCODED).post(Entity.form(formData));
    }

}