package fr.wildcodeschool.unittesting;


import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.stream.Collectors;

public class StringUtils {

    private static final String ALL_VOWELS = "aeiouyAEIOUY";

    /**
     * Renvoie la chaine formée par les voyelles d'une chaine de caractères
     * @return Chaine avec uniquement des voyelles
     */
    public static String vowels(String candidate) {


        if (candidate == null) {
            throw new IllegalArgumentException();
        }

        String noAccent = org.apache.commons.lang3.StringUtils.stripAccents(candidate);


        String vowels = "";
        char[] letters = noAccent.toCharArray();
        for (int i = 0; i < candidate.length(); i++) {
            if (ALL_VOWELS.indexOf(letters[i]) >= 0) {
                vowels += letters[i];
            }
        }
        return vowels;
    }

    public static String removeDuplicates(final String input) {
        Set<Character> knownCharacters = new HashSet<>(input.length(), 1.0f);
        StringBuilder noDuplicates = new StringBuilder(input.length());

        for(char character : input.toCharArray()){
            if(knownCharacters.add(character)){
                noDuplicates.append(character);
            }
        }
        return noDuplicates.toString();
    }

    public static String uniqueVowels(String candidate){
        if (candidate == null) {
            throw new IllegalArgumentException();
        }
        String noAccent = org.apache.commons.lang3.StringUtils.stripAccents(candidate);
        return vowels(removeDuplicates(noAccent));
    }

}