import static org.junit.Assert.*;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;

import org.junit.Test;

public class Test2ATester 
{
	@Test
	public void testSize() 
	{
		List<String> list = new ArrayList<String>();
		assertEquals(0, Test2A.size(list));
		list.add("");
		assertEquals(1, Test2A.size(list));
		list.add("");
		assertEquals(2, Test2A.size(list));
	}

	@Test
	public void testFirst() 
	{
		List<String> list = new ArrayList<String>();
		list.add("first");
		assertEquals("first", Test2A.first(list));
	}

	@Test(expected=IllegalArgumentException.class)
	public void testFirstNull() 
	{
		Test2A.first(null);
	}

	@Test(expected=IllegalArgumentException.class)
	public void testFirstEmpty() 
	{
		List<String> list = new ArrayList<String>();
		Test2A.first(list);
	}

	private static List<String> getRandom()
	{
		Random random = new Random(System.currentTimeMillis());

		final int MAX_SIZE = 100;
		final int MAX_LENGTH = 25;
		final int LETTER = 26;

		List<String> list = new ArrayList<String>();
		int size = 1 + random.nextInt(MAX_SIZE);
		for (int s = 0; s < size; s++)
		{
			int length = 1 + random.nextInt(MAX_LENGTH);
			StringBuffer word = new StringBuffer();
			for (int l = 0; l < length; l++)
			{
				char letter = (char) ('a' + random.nextInt(LETTER));
				word.append(letter);
			}
			list.add(word.toString());
		}
		return list;
	}

	@Test
	public void testLengthOfLongestString() 
	{
		final int TEST = 10;

		for (int t = 0; t < TEST; t++)
		{
			List<String> list = Test2ATester.getRandom();

			int length = 0;
			for (String element : list)
			{
				length = Math.max(length, element.length());
			}

			assertEquals(length, Test2A.lengthOfLongestString(list));
		}
	}
	
	@Test
	public void testMax() 
	{
		final int TEST = 10;

		for (int t = 0; t < TEST; t++)
		{
			List<String> list = Test2ATester.getRandom();

			int maxCount = 0;
			String maxWord = null;
			
			for (String word : list)
			{
				Map<Character, Integer> characterCount = new HashMap<Character, Integer>();
				for (int i = 0; i < word.length(); i++)
				{
					char letter = word.charAt(i);
					int count;
					if (!characterCount.containsKey(letter))
					{
						count = 0;
					}
					else
					{
						count = characterCount.get(letter);
					}
					characterCount.put(letter, count + 1);
				}
				
				int count = 0;
				for (Character c : characterCount.keySet())
				{
					if (characterCount.get(c) > count)
					{
						count = characterCount.get(c);
					}
				}
				
				if (count > maxCount ||
						(count == maxCount && (maxWord == null || word.compareTo(maxWord) < 0)))
				{
					maxCount = count;
					maxWord = word;
				}
			}
			
			assertEquals(maxWord, Test2A.max(list));
		}
	}
}