package btools.routingapp;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Date;

import android.os.Environment;


/**
 * static logger interface to be used in the android app
 */
public class AppLogger {
  private static FileWriter debugLogWriter = null;
  private static boolean initDone = false;

  private static void init() {
    try {
      // open logfile if existing
      File sd = Environment.getExternalStorageDirectory();
      if (sd == null) return;
      File debugLog = new File(sd, "Android/media/btools.routingapp/brouter/brouterapp.txt");
      if (debugLog.exists()) {
        debugLogWriter = new FileWriter(debugLog, true);
      }
    } catch (IOException ioe) {
    }
  }

  /**
   * log an info trace to the app log file, if any
   */
  public static boolean isLogging() {
    if (!initDone) {
      initDone = true;
      init();
      log("logging started at " + new Date());
    }
    return debugLogWriter != null;
  }

  /**
   * log an info trace to the app log file, if any
   */
  public static void log(String msg) {
    if (isLogging()) {
      try {
        debugLogWriter.write(msg);
        debugLogWriter.write('\n');
        debugLogWriter.flush();
      } catch (IOException e) {
        throw new RuntimeException("cannot write brouterapp.txt: " + e);
      }
    }
  }

  /**
   * Format an exception using
   */
  public static String formatThrowable(Throwable t) {
    StringWriter sw = new StringWriter();
    PrintWriter pw = new PrintWriter(sw);
    t.printStackTrace(pw);
    return sw.toString();
  }

}