package fr.umlv.colls;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Random;
import java.util.RandomAccess;

import org.junit.Assert;
import org.junit.Test;
 
public class ListsTest {
  @Test(expected=IllegalArgumentException.class)
  public void range1() {
    Lists.range(4, 3);
  }
  
  @Test
  public void rangeSize() {
    Assert.assertEquals(3, Lists.range(0, 2).size());
    Assert.assertEquals(5, Lists.range(-2, 2).size());
  }
  
  @Test
  public void rangeIterator() {
    Random random = new Random();
    for(int i=0; i<1000; i++) {
      int start = random.nextInt();
      List<Integer> range = Lists.range(start, start + 99);
      Assert.assertEquals(100, range.size());
      
      int j = start;
      for(int value: range) {
        Assert.assertEquals(j++, value);
      }
    }
  }
  
  @Test
  public void rangeIterator2() {
    Random random = new Random();
    for(int i=0; i<1000; i++) {
      int start = random.nextInt();
      List<Integer> range = Lists.range(start, start + 73);
      Iterator<Integer> it = range.listIterator();
      for(int j = start; j <= start + 73; j++) {
        Assert.assertEquals(j, (int)it.next());
      }
      Assert.assertFalse(it.hasNext());
    }
  }
  
  @Test(expected=NoSuchElementException.class)
  public void rangeIteratorNSEE() {
    Iterator<Integer> it = Lists.range(0, 0).iterator();
    it.next();
    it.next();
  }
  
  @Test
  public void rangeRandomList() {
    Assert.assertTrue(Lists.range(0, 7) instanceof RandomAccess);
  }
  
  @Test
  public void times() {
    List<Integer> range = Lists.range(-7, 7);
    ArrayList<Integer> inverse = new ArrayList<>(range);
    Collections.reverse(inverse);
    Assert.assertEquals(inverse, Lists.times(-1, range));
  }
  
  @Test
  public void times2() {
    Random random = new Random();
    ArrayList<Integer> list = new ArrayList<>();
    ArrayList<Integer> list2 = new ArrayList<>();
    for(int i=1; i<=10000; i++) {
      int value = random.nextInt();
      list.add(value);
      list2.add(value * 3);
    }
    
    Assert.assertEquals(list2, Lists.times(3, list));
  }
  
  @Test(timeout=1000)
  public void slooowTimes() {
    LinkedList<Integer> list = new LinkedList<>();
    for(int i=1; i<=100000; i++) {
      list.add(i);
    }
    long sum = 0;
    for(int value: Lists.times(2, list)) {
      sum += value / 2;
    }
    Assert.assertEquals(100000L * (100001) / 2, sum);
  }
  
  @Test(timeout=1000)
  public void slooowTimes2() {
    ArrayList<Integer> list = new ArrayList<>();
    for(int i=1; i<=100000; i++) {
      list.add(i);
    }
    long sum = 0;
    List<Integer> list2 = Lists.times(3, list);
    for(int i = 0; i< list2.size(); i++) {
      sum += list2.get(i) / 3;
    }
    Assert.assertEquals(100000L * (100001) / 2, sum);
  }
}