import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;

import java.util.Random;
import java.util.ArrayList;


// TODO: Replace examples and use TDD by writing your own tests

class SolutionTest {
	@Test
	@Tag("BasicTest")
	void BasicTest() {
    
    String[] reverseLetterHellowWorld = { "eello  world", "Hlllo  world", "Hello  world", "Heloo  world", "Hellw  world", "Hello  oorld", "Hello  wrrld", "Hello  wolld", "Hello  wordd", "Hello  worlH" };
    assertArrayEquals(reverseLetterHellowWorld, Kata.replaceLetter("Hello  world", 1));
    
		String[] reverseLeterHello = { "lello", "hollo", "hehlo", "heleo", "helll" };
    assertArrayEquals(reverseLeterHello, Kata.replaceLetter("hello", 3));
    
		String[] reverseLeterBye = { "eye", "bbe", "byy" };
    assertArrayEquals(reverseLeterBye, Kata.replaceLetter("bye", 2));
    

		String[] reverseLeterThanks = { "Thanks", "Thanks", "Thanks", "Thanks", "Thanks", "Thanks" };
    assertArrayEquals(reverseLeterThanks, Kata.replaceLetter("Thanks", 0));

	}

	@Test
	@Tag("SpecialCase")
	void SpecialCase() {
		String[] reverseLeterVoid = {};
		assertArrayEquals(reverseLeterVoid, Kata.replaceLetter("", 2));
		assertArrayEquals(reverseLeterVoid, Kata.replaceLetter(" ", 2));
		assertArrayEquals(reverseLeterVoid, Kata.replaceLetter(" ", 0));

	}
  

  @Tag("RandomTest")
	@RepeatedTest(10)
	@DisplayName("RandomWord")
	void RandomTest() {
		String word = generate(new Random().nextInt(15) + 1);
		int letterRandom = new Random().nextInt(word.length());
		assertArrayEquals(replaceLetter(word, letterRandom), Kata.replaceLetter(word, letterRandom));

	}
  
	public static String generate(int length) {

		String strChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890     ^*¨_:;=?¿";
		StringBuilder sb = new StringBuilder();
    
		for (int i = 0; i < length; i++) {
			int nRandom = new Random().nextInt(strChars.length());
			sb.append(strChars.charAt(nRandom));
		}
		return sb.toString();
	}

		public static String[] replaceLetter(String str, int n) {

		ArrayList<String> arr = new ArrayList<>();
		StringBuilder strFinal = new StringBuilder(str);

		for (int i = 0; i < str.length(); i++) {
			int nextIndex = (i + n) % str.length();
			if (str.charAt(i) != ' ') {

				if (str.charAt(nextIndex) != ' ') {

					strFinal.replace(i, i + 1, String.valueOf(str.charAt(nextIndex)));
					arr.add(strFinal.toString());
					strFinal.replace(0, str.length(), str);

				} else {
					while (str.charAt(nextIndex) == ' ') {
						nextIndex++;
					}
					strFinal.replace(i, i + 1, String.valueOf(str.charAt(nextIndex)));
					arr.add(strFinal.toString());
					strFinal.replace(0, str.length(), str);

				}
			}

		}

		return arr.toArray(new String[arr.size()]);

	}
}

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;

import java.util.Random;
import java.util.ArrayList;


// TODO: Replace examples and use TDD by writing your own tests

class SolutionTest {
	@Test
	@Tag("BasicTest")
	void BasicTest() {
		String [] reverseLeterHello = {"lello", "hollo", "hehlo", "heleo", "helll"};
		String [] reverseLeterBye = {"eye", "bbe", "byy"};
		String [] reverseLeterCodewars = {"oello codewars", "hdllo codewars", "heelo codewars", "helwo codewars", "hella codewars", "hello sodewars", "hello chdewars", "hello coeewars", "hello codlwars", "hello codelars", "hello codewors", "hello codewarc"};
		
		
		assertArrayEquals(reverseLeterHello, Kata.replaceLetter("hello", 3));
		assertArrayEquals(reverseLeterBye, Kata.replaceLetter("bye", 2));
		assertArrayEquals(reverseLeterCodewars, Kata.replaceLetter("hello codewars", 7));


	}
  
  	@Test
	  @Tag("UnitTest")
	  void parseExceptionFecha() {
	        assertThrows(NullPointerException.class, () -> {
	        	int nRandom =  new Random().nextInt(15)+1;
	        	Kata.replaceLetter(null, nRandom);
	        });
	}
  @Tag("RandomTest")
	@RepeatedTest(10)
	@DisplayName("RandomWord")
	void RandomTest() {
		String word = generate(new Random().nextInt(15) + 1);
		int letterRandom = new Random().nextInt(word.length());
		assertArrayEquals(replaceLetter(word, letterRandom), Kata.replaceLetter(word, letterRandom));

	}
  
	public static String generate(int length) {

		String strChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!?%$&/([]     ";


		StringBuilder sb = new StringBuilder();

		for (int i = 0; i < length; i++) {
			int nRandom = new Random().nextInt(strChars.length());

			sb.append(strChars.charAt(nRandom));

		}

		return sb.toString();

	}

	public static String[] replaceLetter(String str, int n) {

		ArrayList<String> arr = new ArrayList<>();
		StringBuilder strFinal = new StringBuilder(str);

		for (int i = 0; i < str.length(); i++) {
			int nextIndex = (i + n) % str.length();

			if (str.charAt(i) != ' ' && str.charAt(nextIndex) != ' ') {

				nextIndex = (i + n) % str.length();
				strFinal.replace(i, i + 1, String.valueOf(str.charAt(nextIndex)));
				arr.add(strFinal.toString());
				strFinal.replace(0, str.length(), str);
			}

		}


		String[] array = arr.toArray(new String[arr.size()]);

		return array;

	}
	
	
}

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;
import java.util.Random;


// TODO: Replace examples and use TDD by writing your own tests

class SolutionTest {
	@Test
	@Tag("BasicTest")
	void BasicTest() {
		String [] reverseLeterHello = {"lello", "hollo", "hehlo", "heleo", "helll"};
		String [] reverseLeterBye = {"eye", "bbe", "byy"};
		String [] reverseLeterCodewars = {"oello codewars", "hdllo codewars", "heelo codewars", "helwo codewars", "hella codewars", "hello sodewars", "hello chdewars", "hello coeewars", "hello codlwars", "hello codelars", "hello codewors", "hello codewarc"};
		
		
		assertArrayEquals(reverseLeterHello, Kata.replaceLetter("hello", 3));
		assertArrayEquals(reverseLeterBye, Kata.replaceLetter("bye", 2));
		assertArrayEquals(reverseLeterCodewars, Kata.replaceLetter("hello codewars", 7));


	}
  
  	@Test
	  @Tag("UnitTest")
	  void parseExceptionFecha() {
	        assertThrows(NullPointerException.class, () -> {
	        	int nRandom =  new Random().nextInt(15)+1;
	        	Kata.replaceLetter(null, nRandom);
	        });
	}
	
	
}

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;


// TODO: Replace examples and use TDD by writing your own tests

class SolutionTest {
	@Test
	@Tag("BasicTest")
	void BasicTest() {
		String [] reverseLeterHola = {"oola", "hlla", "hoaa", "holh"};
		String [] reverseLeterAdios = {"ddios", "aiios", "adoos", "adiss", "adioa"};
		assertArrayEquals(reverseLeterHola, Kata.replaceLetter("hola"));
		assertArrayEquals(reverseLeterAdios, Kata.replaceLetter("adios"));


	}
	
}