import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
 * Created by leon on 1/29/18.
 */
public class StringArrayUtils {
    /**
     * @param array array of String objects
     * @return first element of specified array
     */ // TODO
    public static String getFirstElement(String[] array) {
        return array[0];
    }

    /**
     * @param array array of String objects
     * @return second element in specified array
     */
    public static String getSecondElement(String[] array) {
        return array[1];
    }

    /**
     * @param array array of String objects
     * @return last element in specified array
     */ // TODO
    public static String getLastElement(String[] array) {
        return array[array.length - 1];
    }

    /**
     * @param array array of String objects
     * @return second to last element in specified array
     */ // TODO
    public static String getSecondToLastElement(String[] array) {
        return array[array.length - 2];
    }

    /**
     * @param array array of String objects
     * @param value value to check array for
     * @return true if the array contains the specified `value`
     */ // TODO
    public static boolean contains(String[] array, String value) {
        for (String ithString : array) {
            if (ithString.equals(value)) {
                return true;
            }
        }
        return false;
    }

    /**
     * @param array of String objects
     * @return an array with identical contents in reverse order
     */ // TODO
    public static String[] reverse(String[] array) {
        String[] reverse = new String[array.length];
        for (int i = 0; i < array.length; i++) {
            reverse[i] = array[array.length - 1 - i];
        }
        return reverse;
    }

    /**
     * @param array array of String objects
     * @return true if the order of the array is the same backwards and forwards
     */ // TODO
    public static boolean isPalindromic(String[] array) {
        String[] reverse = reverse(array);
        for (int i = 0; i < array.length; i++) {
            if (!array[i].equals(reverse[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * @param array array of String objects
     * @return true if each letter in the alphabet has been used in the array
     */ // TODO
    public static boolean isPangramic(String[] array) {
        //stringbuilder holding all letters of alpha
        StringBuilder alphabet = new StringBuilder("abcdefghijklmnopqrstuvwxyz");
        //iterate over each word of the array and then each char of word
        for (String word : array) {
            for (int i = 0; i < word.length(); i++) {
                int index = alphabet.indexOf("" + word.toLowerCase().charAt(i));
                if (index >= 0) {
                    alphabet.deleteCharAt(index);
                }
                if (alphabet.length() == 0) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * @param array array of String objects
     * @param value value to check array for
     * @return number of occurrences the specified `value` has occurred
     */ // TODO
    public static int getNumberOfOccurrences(String[] array, String value) {
        int occurrences = 0;
        for (String word : array) {
            if (value.equals(word)) {
                occurrences++;
            }
        }
        return occurrences;
    }

    /**
     * @param array         array of String objects
     * @param valueToRemove value to remove from array
     * @return array with identical contents excluding values of `value`
     */ // TODO
    public static String[] removeValue(String[] array, String valueToRemove) {
        List<String> arrRemoved = new ArrayList<String>();
        for (String word : array) {
            if (!word.equals(valueToRemove)) {
                arrRemoved.add(word);
            }
        }
        String[] removedArray = new String[arrRemoved.size()];
        removedArray = arrRemoved.toArray(removedArray);
        return removedArray;
             
    }

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        List<String> removedValues = new ArrayList<String>();
        for (String word : array) {
            //empty or last added value doesnt equal iterated word of array
            if (removedValues.isEmpty() || 
            !removedValues.get(removedValues.size() - 1).equals(word)) {
                removedValues.add(word);
            }
        }
        String[] nonDuplicate = new String[removedValues.size()];
        nonDuplicate = removedValues.toArray(nonDuplicate);
        return nonDuplicate;
    }

    /**
     * @param array array of chars
     * @return array of Strings with each consecutive duplicate occurrence concatenated as a single string in an array of Strings
     */ // TODO
    public static String[] packConsecutiveDuplicates(String[] array) {
        for (String singleChar : array) {
            
        }
        return null;
    }

}