import android.os.AsyncTask;

import java.io.IOException;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.Scanner;
import javax.net.ssl.HttpsURLConnection;

import org.json.JSONArray;
import org.json.JSONObject;

public abstract class RequestSender extends AsyncTask<Void, Void, Object> {
    public static final String URL = "https://wingstaxi.ru/api/";
    public static final String ENCODING = "UTF-8";

    private JSONObject request;

    protected URL getURL() throws MalformedURLException {
        return new URL(URL);
    }

    protected int getReadTimeout() { return READ_TIMEOUT; }

    /**
     * Формирует запрос с подписью, который будет отправлен на сервер
     */
    protected JSONObject onFormRequest() throws Throwable {
        return null;
    }

    /**
     * Вызывается когда ответ успешно получен с сервера
     */
    protected abstract void onResponseReceived(JSONObject request, JSONObject response) throws Throwable;

    /**
     * Вызывается при ошибке в формировании/отправке/обработке запроса
     */
    protected void onRequestFailed(JSONObject request, Throwable cause) {
        cause.printStackTrace();
    }

    @Override
    protected final Object doInBackground(Void[] args) {
        try {
            request = onFormRequest();
            return send(request);
        } catch(Throwable e) {
            try { Thread.sleep(1000); }
            catch (InterruptedException ex) { ex.printStackTrace(); }
            return e;
        }
    }

    @Override
    protected final void onPostExecute(Object result) {
        if(result instanceof JSONObject) {
            try {
                onResponseReceived(request, (JSONObject)result);
            } catch(Throwable e) {
                onRequestFailed(request, e);
            }
        } else {
            onRequestFailed(request, (Throwable)result);
        }
    }

    protected JSONObject send(JSONObject request) throws Throwable {
        HttpsURLConnection conn = null;
        try {
            conn = (HttpsURLConnection) getURL().openConnection();
            conn.setReadTimeout(getReadTimeout());
            conn.setConnectTimeout(CONNECT_TIMEOUT);
            conn.setRequestMethod(request == null ? "GET" : "POST");
            conn.setDoInput(true);
            conn.setDoOutput(request != null);
            conn.connect();

            if(Thread.interrupted()) throw new InterruptedException();

            if(request != null) {
                conn.getOutputStream().write(request.toString().getBytes(ENCODING));
                conn.getOutputStream().close();
            }

            int responseCode = conn.getResponseCode();
            if(responseCode == HttpsURLConnection.HTTP_OK) {
                StringBuilder sb = new StringBuilder();
                Scanner sc = new Scanner(conn.getInputStream(), ENCODING);
                while (sc.hasNextLine()) {
                    sb.append(sc.nextLine());
                    sb.append('\n');
                }

                if(Thread.interrupted()) throw new InterruptedException();

                conn.disconnect();

                return new JSONObject(sb.toString());
            } else {
                throw new IOException("Bad response: " + responseCode);
            }
        } catch(Throwable e) {
            if(conn != null) conn.disconnect();
            throw e;
        }
    }
}