import java.util.*;
/**
 * 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) {
        String lastStr = array[array.length - 1];
        return lastStr;
    }

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

    /**
     * @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 (int i = 0; i < array.length; i++){
            if (array[i] == value) {
                String result = array[i];
            }
            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) {
        for (int i = 0; i < array.length/2; i++){
            String temp = array[i];
            array[i] = array[array.length - i - 1];
            array[array.length - i - 1] = temp;
        }
        return array;
    }

    /**
     * @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) {
        int i1 = 0;
        int i2 = array.length - 1;
        while (i2 > i1) {
            if (array[i1] != array[i2]) {
                return false;
            }
            ++i1;
            --i2;
        }
        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) {
        boolean bool = true;
        for (char letter = 'a'; letter <= 'z'; letter++){
            boolean bool2 = false;

            for (int i = 0; i < array.length; i++){
                if (array[i].toLowerCase().contains(Character.toString(letter))){
                    bool2 = true;
                }
            }
            if (!bool2) {
                bool = false;
            }
        }

        return bool;
    }

    /**
     * @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 word : array) {
            if (value.equals(word)){
                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) {
        ArrayList<String> strArr = new ArrayList<String> (Arrays.asList(array));
        strArr.remove(valueToRemove);
        String[] newArr = strArr.toArray(new String[strArr.size()]);
        return newArr;
    }

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

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

        String[] newArr = new String[array.length - counter];
        String str = null;

        for (int i = 0; i < array.length; i++){
            if(!array[i].equals(str)){
                newArr[duplicate] = array[i];
                str = array[i];
                duplicate++;

            }
        } 
        return newArr;
    }

    /**
     * @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) {
        int counter = getCounter(array);
        String[] result = new String[array.length - counter];
        String last = array[0];
        result[0] = array[0];
        int index = 0;

        for (int i = 1; i < array.length; i++){
            if (array[i].equals(last)){
                result[index] += array[i];
                last = array[i];
            }
            else {
                index++;
                result[index] = array[i];
                last = array[i];
            }
        }

        return result;
    }

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