package lab.util;

import static org.junit.Assert.*;

import java.util.Date;
import java.util.NoSuchElementException;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.Timeout;

public class QueueTest {

  @Rule
  public Timeout globalTimeout = new Timeout(500);

  @Test
  public void testEnqueuePeek() {
    Queue<Date> q = new Queue<Date>();
    try {
      q.dequeue();
    } catch (NoSuchElementException x) {
      // we should end up here
      Date exp0 = new Date();
      Date exp1 = new Date(exp0.getTime() + 10000);
      Date exp2 = new Date(exp1.getTime() + 10000);
      q.enqueue(exp0);
      q.enqueue(exp1);
      q.enqueue(exp2);
      Date got0 = q.peek();
      assertSame("peek did not return a reference to the front object", exp0,
          got0);

      return;
    } catch (Exception x) {
      fail("peek threw the wrong type of exception");
    }
    fail("peek on an empty queue should have thrown an exception");
  }

  @Test
  public void testEnqueueDequeue() {
    Queue<Date> q = new Queue<Date>();
    try {
      q.dequeue();
    } catch (NoSuchElementException x) {
      // we should end up here
      Date exp0 = new Date();
      Date exp1 = new Date(exp0.getTime() + 10000);
      Date exp2 = new Date(exp1.getTime() + 10000);
      q.enqueue(exp0);
      q.enqueue(exp1);
      q.enqueue(exp2);
      System.out.println(q);
      Date got0 = q.dequeue();
      assertSame("dequeue did not return a reference to the enqueued object",
          exp0, got0);
      Date got1 = q.dequeue();
      assertSame("dequeue did not return a reference to the enqueued object",
          exp1, got1);
      Date got2 = q.dequeue();
      assertSame("dequeue did not return a reference to the enqueued object",
          exp2, got2);
      return;
    } catch (Exception x) {
      fail("dequeue threw the wrong type of exception");
    }
    fail("dequeue on an empty queue should have thrown an exception");
  }

  @Test
  public void testSize() {
    Queue<String> q = new Queue<String>();
    assertEquals("default queue size should be zero", 0, q.size());
    for (int i = 1; i < 10000; i++) {
      q.enqueue("" + i);
      assertEquals("queue size should be " + i, i, q.size());
    }
  }

  @Test
  public void testIsEmpty() {
    Queue<String> q = new Queue<String>();
    assertTrue("default queue should be empty", q.isEmpty());
    q.enqueue("not empty");
    assertFalse("queue with one element should not be empty", q.isEmpty());
    q.dequeue();
    assertTrue("empty queue should be empty", q.isEmpty());
  }

}