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) {
        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) {
        return Arrays.asList(array).contains(value);
    }

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

    /**
     * @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) {
        return Arrays.equals(array, reverse(array));
    }

    /**
     * @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[] alpha = {"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"};
        String s = "";   
        int count = 0;
        for (String e : array) {
             s += e.replace(" ", "");
        }
        String[] check = s.toLowerCase().split("");
        for (String letter : alpha) {
            if (contains(check, letter)) count++;
        }
        return count == alpha.length;
    }

    /**
     * @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 count = 0;
        for (String i : array) {
            count += (i == value) ? 1 : 0;    
        }
        return count;
    }

    /**
     * @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> result = new ArrayList<>();
    for (String s : array) {
        if (!s.equals(valueToRemove)) result.add(s);
    }    
    return result.toArray(new String[result.size()]);
    }

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {        
        ArrayList<String> result = new ArrayList<>();
        for (int i = 0; i < array.length - 1; i++) {
            if (!array[i].equals(array[i + 1])) result.add(array[i]); 
        }
        result.add(array[array.length - 1]);
        return result.toArray(new String[result.size()]);
    }

    /**
     * @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) {
        ArrayList<String> result = new ArrayList<>();
        StringBuilder addMe = new StringBuilder();
        for (int i = 0; i < array.length - 1; i++) {          
            if (!array[i].equals(array[i + 1])) {
                addMe.append(array[i]);
                result.add(addMe.toString());
                addMe = new StringBuilder();
            }
            else {
                addMe.append(array[i]);
            }
        }
        addMe.append(array[array.length - 1]);
        result.add(addMe.toString());
        return result.toArray(new String[result.size()]);
    }


}