import java.util.Arrays;

/**
 * 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) {
        boolean output = false;
        for (String element : array) {
            if (element.equals(value)) {
                output = true;
            }
        }
        return output;
    }

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

    /**
     * @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) {
        boolean output = false;
        String[] reversedArray = reverse(array);
        if (Arrays.equals(array, reversedArray)) {
            output = true;
        }
        return output;
    }

    /**
     * @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) {
        boolean outcome = true;
        String[] arrayGiven = new String[1];
        arrayGiven[0]="";
        for (int i=0; i < array.length; i++) {
            arrayGiven[0] = arrayGiven[0].concat(array[i]);
        }
        arrayGiven = arrayGiven[0].toLowerCase().split("");
        for (char alph = 'a'; alph <= 'z'; alph++) {
            if (contains(arrayGiven, String.valueOf(alph))==false) {
                outcome = false;
            }
        }
        return outcome;
    }

    /**
     * @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 counter = 0;
        for (String element : array) {
            if (element.equals(value)) {
                counter++;
            }
        }
        return counter;
    }

    /**
     * @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) {
        int numberOfElementsToDelete = getNumberOfOccurrences(array, valueToRemove);
        String[] arrayWithRemovedValue = new String[array.length-numberOfElementsToDelete];
        int j=0; //index of arrayWithRemovedValue       
        for (int i=0; i < array.length; i++) {
            if (array[i].compareTo(valueToRemove) != 0) {
                arrayWithRemovedValue[j] = array[i];
                j++;
            }
        }
        return arrayWithRemovedValue;
    }

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        int numberOfElementsToDelete = 0;
        int j=0; //index of arrayWithRemovedVConsecutiveDuplicates
        String[] arrayWithRemovedConsecutiveDuplicates = new String[array.length];
        for (int i=0; i < array.length-1; i++) {
            if (array[i].compareTo(array[i+1]) != 0) {
                arrayWithRemovedConsecutiveDuplicates[j] = array[i];
                j++;
            } else {
                numberOfElementsToDelete++;
            }
        }
        arrayWithRemovedConsecutiveDuplicates = Arrays.copyOf(arrayWithRemovedConsecutiveDuplicates, array.length-numberOfElementsToDelete);
        arrayWithRemovedConsecutiveDuplicates[arrayWithRemovedConsecutiveDuplicates.length-1] = array[array.length-1];
        return arrayWithRemovedConsecutiveDuplicates;
    }

    /**
     * @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) {
        String[] arrayWithPackedConsecutiveDuplicates = new String[array.length];
        int j=0; //index of arrayWithPackedVConsecutiveDuplicates
        int numberOfElementsToDelete = 0;
        arrayWithPackedConsecutiveDuplicates[0] = array[0];
        for (int i=0; i < array.length-1; i++) {
            if (array[i].compareTo(array[i+1]) == 0) {
                arrayWithPackedConsecutiveDuplicates[j] = arrayWithPackedConsecutiveDuplicates[j] + array[i+1];
                numberOfElementsToDelete++;
            } else {
                arrayWithPackedConsecutiveDuplicates[j+1] = array[i+1];
                j++;
            }
        }
        arrayWithPackedConsecutiveDuplicates = Arrays.copyOf(arrayWithPackedConsecutiveDuplicates, array.length-numberOfElementsToDelete);
        return arrayWithPackedConsecutiveDuplicates;
    }

}