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) {
        for(String answer : array){
            if(answer.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[] output = new String[array.length];
        int counter = 0;
        for (int i = array.length -1; i >= 0; i--) {
            output[counter] = array[i];
            counter++;
        }
        return output;
    }

    /**
     * @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 palindromic = false;
        for (int i = 0; i <= array.length/2; i++) {
            if (array[i] == array[array.length -1 -i]) {
                palindromic = true;
            }
        }

        return palindromic;
    }

    /**
     * @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) {
        String[] alphabet = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k",
                "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
                "w", "x", "y", "z" };

        boolean pan = true;

        for (String letter : alphabet) {
            boolean letterFound = false;
            for (String letter2 : array) {
                if (letter2.toLowerCase().contains(letter)) {
                    letterFound = true;
                }
            }
            if (!letterFound) {
                pan = false;
            }
        }

        return pan;
    }

    /**
     * @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 occurence : array){
            if(occurence.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 occurrences = getNumberOfOccurrences(array, valueToRemove);
        String[] valueRemoved;
        if(occurrences == 0){
            valueRemoved = array;
        } else {
            valueRemoved = new String[array.length - occurrences];
            int removedArr = 0;
            for (int i = 0; i < array.length; i++) {
                if (!array[i].equals(valueToRemove)) {
                    valueRemoved[removedArr] = array[i];
                    removedArr++;
                }
            }
        }
        return valueRemoved;

    }

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        String lastNumber = null;
        int index = 0;
        int counter = 0; 

        for (int i = 0; i < array.length - 1; i++) {
            if (array[i].equals(array[i + 1])) {
                counter++;
            }
        }

        String [] arr1 = new String [array.length - counter];

        for (int i = 0; i < array.length; i++) {

            if (!array[i].equals(lastNumber)){
                arr1[index] = array[i];
                lastNumber = array[i];
                index++;
            }
        }

        return arr1;
    }

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

}