package mapmaker;

import java.io.DataOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.json.*;

public class DataFetcher {
 private final String[] HIGHWAYS = {"motorway", "trunk", "primary", "secondary", "tertiary", "unclassified", "residential", "motorway_link", "trunk_link", "primary_link", "secondary_link", "tertiary_link", "living_street"};

 private String query;
 public DataFetcher(float[] bounds) {
 this.query = this.constructQuery(bounds);
 }

 public JsonObject getData() {
 HttpURLConnection conn = null;
 try {
 URL url = new URL("http://overpass-api.de/api/interpreter");
 conn = (HttpURLConnection)url.openConnection();
 conn.setDoOutput(true);
 conn.setRequestMethod("POST");
 conn.setRequestProperty("Accept-Charset", "utf-8;q=0.7,*;q=0.7");
 
 DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
 wr.writeBytes(this.query);
 wr.close();

 InputStream is = conn.getInputStream();
 JsonReader rdr = Json.createReader(is);
 
 return rdr.readObject();
 } catch (Exception e) {
 System.out.println(e);
 return null;
 }
 }

 public String constructQuery(float[] boundsArray) {
 String q = "[out:json];(";
 String bounds = "(";
 for (int i = 0; i < 4; i++) {
 bounds += boundsArray[i];
 if (i < 3) {
 bounds += ",";
 } else {
 bounds += ")";
 }
 }
 

 for (String s : HIGHWAYS) {
 q += "way[\"highway\"=\"" + s + "\"]" + bounds + ";";
 }

 q += "); (._;>;); out;";

 return q;
 }
}