import java.util.Arrays;
import java.io.*;
import java.util.*;
import java.lang.StringBuilder;

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

    /**
     * @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 j=array.length-1, i=0; j>=0; j--, i++){    
            reverse[i] = array[j];
        }
        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) {
        boolean isPalindromic = false;
        String[] reverse = reverse(array);
        if (Arrays.equals(array,reverse)){
            isPalindromic = true;
        }
        return isPalindromic;
    }

    /**
     * @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 arrayString = Arrays.toString(array).toLowerCase();

        if(arrayString.length() < 26){
            return false;
        }

        for (char c = 'a'; c <='z'; c++){
            if(arrayString.indexOf(c) < 0){
                return false;
            }
        }

        return true;
    }

    /**
     * @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 numberOfOccurrences = 0;

        for (String element : array){
            if(element.equals(value)){
                numberOfOccurrences += 1;
            }
        }

        return numberOfOccurrences;
    }

    /**
     * @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 numberOfOccurrences = getNumberOfOccurrences(array, valueToRemove);
        String[] newArray = new String[array.length - numberOfOccurrences];

        int i = 0;
        for(String element : array){
            if(!element.equals(valueToRemove)){
                newArray[i] = element;
                i++;
            }
        }
        return newArray;
    }

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

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        ArrayList<String> newList = new ArrayList<String>();
        //add first element of array to new array
        newList.add(array[0]);
        //compare each element in your array starting with the second
        for (int i=1; i<=array.length-1; i++){
            //if an element does not equal an element before it, add to new array
            if(!(array[i].equals(array[i-1]))){
                newList.add(array[i]);
            }
        }
        return newList.toArray(new String[0]);
    }

    /**
     * @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) {
        //create a new string using string builder
        StringBuilder arrayAsString = new StringBuilder();
        //add first element in array to new array string
        arrayAsString.append(array[0]);
        //look at each element in the array
        for(int i=1; i<=array.length-1; i++){
            //if the element in the array equals the previous element, add it to
            //   the string
            if(array[i].equals(array[i-1])){
                arrayAsString.append(array[i]);
            } else {
                //if the element in the array does not equal the previous element,
                //   add it to the string after a space
                arrayAsString.append(" ");
                arrayAsString.append(array[i]);
            }
        }
        //convert the new string to a space split string array
        String[] packConsecDupArray = arrayAsString.toString().split(" ");
        return packConsecDupArray;
    }
}