import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import org.json.simple.parser.ParseException;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Random;

public class ApacheHttpClientGetPost {
    private static final String CATEGORY = "тестовая-страница";
    private static final String GET_URL = "https://public-api.wordpress.com/rest/v1.1/sites/loadtestweb.wordpress.com/posts/?category=";

    public static String getJSON() {
        String jsonString = "";
        try {

            HttpClient httpClient = HttpClientBuilder.create().build();
            HttpGet getRequest = new HttpGet(GET_URL + CATEGORY);
            getRequest.addHeader("accept", "application/json");

            HttpResponse response = httpClient.execute(getRequest);

            if (response.getStatusLine().getStatusCode() != 200) {
                throw new RuntimeException("Failed : HTTP error code : "
                        + response.getStatusLine().getStatusCode());
            }

            BufferedReader br = new BufferedReader(
                    new InputStreamReader((response.getEntity().getContent())));

            StringBuffer result = new StringBuffer();
            String line = "";
            while ((line = br.readLine()) != null) {
                result.append(line);
            }
            jsonString = result.toString();
            br.close();
            ((CloseableHttpClient) httpClient).close();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return jsonString;
    }

    public static String getRandomArticleUrl(String jsonString) {
        String randomURL = "";
        try {
            JSONObject articles = (JSONObject) JSONValue.parseWithException(jsonString);
            JSONArray jsonArray = (JSONArray) articles.get("posts");
            Random random = new Random();
            int n = random.nextInt(jsonArray.size());
            HashMap targetURL = (HashMap) jsonArray.get(n);
            randomURL = (String) targetURL.get("URL");
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return randomURL;
    }

    public static void openUrl(String url) {
        HttpClient httpClient = HttpClientBuilder.create().build();

        HttpPost postRequest = new HttpPost(url);
        postRequest.addHeader("accept", "application/json");
        try {
            HttpResponse response = httpClient.execute(postRequest);
            if (response.getStatusLine().getStatusCode() != 200) {
                throw new RuntimeException("Failed : HTTP error code : "
                        + response.getStatusLine().getStatusCode());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        String jsonResult = getJSON();
        String randomURL = getRandomArticleUrl(jsonResult);
        openUrl(randomURL);
    }
}