/*                        __    __  __  __    __  ___
    *                       \  \  /  /    \  \  /  /  __/
    *                        \  \/  /  /\  \  \/  /  /
    *                         \____/__/  \__\____/__/.ɪᴏ
    * ᶜᵒᵖʸʳᶦᵍʰᵗ ᵇʸ ᵛᵃᵛʳ ⁻ ˡᶦᶜᵉⁿˢᵉᵈ ᵘⁿᵈᵉʳ ᵗʰᵉ ᵃᵖᵃᶜʰᵉ ˡᶦᶜᵉⁿˢᵉ ᵛᵉʳˢᶦᵒⁿ ᵗʷᵒ ᵈᵒᵗ ᶻᵉʳᵒ
    */
   package io.vavr.concurrent;
   
   import io.vavr.CheckedFunction0;
  import io.vavr.control.Try;
  
  import java.util.Random;
  import java.util.function.Supplier;
  
  import static org.assertj.core.api.Assertions.fail;
  
  final class Concurrent {
  
      private static final Random RND = new Random();
  
      // Max wait time for results = WAIT_MILLIS * WAIT_COUNT (however, most probably it will take only WAIT_MILLIS * 1)
      private static final long WAIT_MILLIS = 50;
      private static final int WAIT_COUNT = 100;
  
      // Max sleep time to delay computation
      private static final int SLEEP_MAX_MILLIS = 150;
  
      private Concurrent() {
      }
  
      /**
       * Frequently checking if something happened by testing a condition.
       * If after {@link #WAIT_COUNT} * {@link #WAIT_MILLIS} ms nothing happened, an {@code AssertionError} is thrown.
       *
       * @param condition A condition.
       */
      static void waitUntil(Supplier<Boolean> condition) {
          int count = 0;
          while (!condition.get()) {
              if (++count > WAIT_COUNT) {
                  fail("Condition not met.");
              } else {
                  Try.run(() -> Thread.sleep(WAIT_MILLIS));
              }
          }
      }
  
      /**
       * Block current thread a random time between 0 and {@link #SLEEP_MAX_MILLIS} ms.
       */
      static void zZz() {
          Try.run(() -> Thread.sleep(RND.nextInt(SLEEP_MAX_MILLIS)));
      }
  
      static <T> CheckedFunction0<T> zZz(T value) {
          return () -> {
              zZz();
              return value;
          };
      }
  
      static <T, X extends Throwable> CheckedFunction0<T> zZz(X exception) {
          return () -> {
              zZz();
              throw exception;
          };
      }
  
      static Void waitForever() {
          while (true) {
              Try.run(() -> Thread.sleep(WAIT_MILLIS));
          }
      }
  }