package ch.qos.logback.classic.issue.lbclassic36;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.atomic.AtomicLong;

import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

public class DateFormatPerfTest {
  public static final String ISO8601_PATTERN = "yyyy-MM-dd HH:mm:ss,SSS";
  static final long NANOS_IN_ONE_SEC = 1000 * 1000 * 1000L;
  static final DateTimeFormatter jodaFormat = DateTimeFormat.forPattern(ISO8601_PATTERN);
  static long cachedTime = 0;

  static long RUN_LENGTH = 1000 * 1000;
  static int THREAD_COUNT = 10;

  public static void main(String[] args) {
    for (int i = 0; i < 5; i++) {
      doRawJoda();
      doRawSDF();
      doJoda();
      doGuardedSDF();
    }

    print("Raw Joda:     ", doRawJoda());
    print("Raw SDF:      ", doRawSDF());
    print("Cached Joda: ", doJoda());
    print("Guarded SDF:  ", doGuardedSDF());
    printElapsed("Threaded Joda: ", doThreadedJoda());
    printElapsed("Threaded SDF: ", doThreadedSDF());

  }

  static void print(String msg, double avg) {
    System.out.println(msg + " average tick " + avg + " nanoseconds");
  }

  static void printElapsed(String msg, long elapsed) {
    System.out.println(msg + " elapsed " + elapsed + " ms");
  }

  static double doRawJoda() {
    DateTimeFormatter jodaFormat = DateTimeFormat.forPattern(ISO8601_PATTERN);
    long timeInMillis = new Date().getTime();
    long start = System.nanoTime();
    for (int i = 0; i < RUN_LENGTH; ++i) {
      jodaFormat.print(timeInMillis);
    }
    return (System.nanoTime() - start) * 1.0d / RUN_LENGTH;
  }

  static double doJoda() {
    long start = System.nanoTime();
    for (int i = 0; i < RUN_LENGTH; ++i) {
        long now = System.currentTimeMillis();
        if (!isCached(now)) {
          jodaFormat.print(now);
      }
    }
    return (System.nanoTime() - start) * 1.0d / RUN_LENGTH;
  }

  static double doRawSDF() {
    SimpleDateFormat simpleFormat = new SimpleDateFormat(ISO8601_PATTERN);
    long timeInMillis = new Date().getTime();
    long start = System.nanoTime();
    for (int i = 0; i < RUN_LENGTH; ++i) {
      simpleFormat.format(timeInMillis);
    }
    return (System.nanoTime() - start) * 1.0d / RUN_LENGTH;
  }

  static double doGuardedSDF() {
    SimpleDateFormat simpleFormat = new SimpleDateFormat(ISO8601_PATTERN);
    long start = System.nanoTime();
    long cache = 0;
    for (int i = 0; i < RUN_LENGTH; ++i) {
      synchronized (simpleFormat) {
        long now = System.currentTimeMillis();
        if (cache != now) {
          cache = now;
          simpleFormat.format(now);
        }
      }
    }
    return (System.nanoTime() - start) * 1.0d / RUN_LENGTH;
  }

  static long doThreadedJoda() {
    Thread[] formatThreads = new Thread[THREAD_COUNT];
    JodaFormatter formatter = new JodaFormatter();
    cachedTime = 0;

    for (int i = 0; i < THREAD_COUNT; i++) {
      formatThreads[i] = new DateFormatThread(formatter);
    }
    long start = System.currentTimeMillis();
    for (Thread thread : formatThreads) {
      thread.start();
    }
    try {
      for (Thread thread : formatThreads) {
        thread.join();
      }
    } catch (Exception ex) {
      throw new RuntimeException("join failed", ex);
    }
    return System.currentTimeMillis() - start;
  }

  static long doThreadedSDF() {
    Thread[] formatThreads = new Thread[THREAD_COUNT];
    SDFFormatter formatter = new SDFFormatter();
    cachedTime = 0;

    for (int i = 0; i < THREAD_COUNT; i++) {
      formatThreads[i] = new DateFormatThread(formatter);
    }
    long start = System.currentTimeMillis();
    for (Thread thread : formatThreads) {
      thread.start();
    }
    try {
      for (Thread thread : formatThreads) {
        thread.join();
      }
    } catch (Exception ex) {
      throw new RuntimeException("join failed", ex);
    }
    return System.currentTimeMillis() - start;
  }

  public static boolean isCached(long now) {
    if (cachedTime != now) {
      synchronized(jodaFormat) {
        if (cachedTime != now) {
          cachedTime = now;
          return false;
        }
      }
    }
    return true;
  }

  public static interface Formatter {
    String format(long dateTime);
  }

  public static class JodaFormatter implements Formatter {

    public String format(long dateTime) {
      return jodaFormat.print(dateTime);
    }
  }

  public static class SDFFormatter implements Formatter {
     static SimpleDateFormat simpleFormat = new SimpleDateFormat(ISO8601_PATTERN);

     public synchronized String format(long dateTime) {
        return simpleFormat.format(dateTime);
     }
  }

  public static class DateFormatThread extends Thread {
    Formatter formatter;

    public DateFormatThread(Formatter f) {
      this.formatter = f;
    }

    public void run() {
      for (int i = 0; i < RUN_LENGTH; ++i) {
        long now = System.currentTimeMillis();
        if (!isCached(now)) {
          formatter.format(now);
        }
      }
    }
  }
}