import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
 * 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 ithString : array) {
            if (ithString.equals(value)) {
                contains = true;
                break;
            }
        }
        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 i = 0; i < array.length; i++) {
            reverse[i] = array[array.length - 1 - i];
        }
        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) {
        String[] reverse = reverse(array);
        boolean isPalindrome = true;
        for (int i = 0; i < array.length; i++) {
            if (!array[i].equals(reverse[i])) {
                isPalindrome = false;
                break;
            }
        }
        return isPalindrome;
    }

    /**
     * @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 isPangramic = true;
        String alpha = "abcdefghijklmnopqrstuvwxyz";
        String[] alphaArr = newArray(alpha);
        StringBuilder allChars = new StringBuilder();
        for(String word1 : array) {
            allChars.append(word1);
        }
        String[] allCharsArr = newArray(allChars.toString().toLowerCase());
        
        for (String letter1 : alphaArr) {
            if (!contains(allCharsArr, letter1)) {
                isPangramic = false;
                break;
            }
        }
        return isPangramic;
    }
    
    public static String[] newArray(String word) {
        String[] newArr = new String[word.length()];
        for (int i = 0; i < word.length(); i++) {
            newArr[i] = "" + word.charAt(i);
        }
        return newArr;
    }

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

    /**
     * @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 numOcc = getNumberOfOccurrences(array, valueToRemove);
        String[] removedArr = new String[array.length - numOcc];
        int i = 0;
        for (String word1 : array) {
            if (!word1.equals(valueToRemove)) {
                removedArr[i] = word1;
                i++;
            }
        }
        return removedArr;
    }
    
    public static int countDuplicated(String[] array) {
        int count = 0;
        for (int i = 1; i < array.length; i++) {
            if (array[i].equals(array[i - 1])) {
                count++;
            }
        }
        return count;
    }
    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        int totalDups = countDuplicated(array);
        String[] removedArr = new String[array.length - totalDups];
        
        int index = 1;
        removedArr[0] = array[0];
        for (int i = 1; i < array.length; i++) {
            if (!array[i].equals(array[i - 1])) {
                removedArr[index] = array[i];
                index++;
            }
        }
        return removedArr;
    }

    /**
     * @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) {
        StringBuilder dupB = new StringBuilder(array[0]);
        String[] packedDupArr= new String[array.length - countDuplicated(array)];
        
        int index = 0;
        for (int i = 1; i < array.length; i++) {
            if (array[i].equals(array[i - 1])) {
                dupB.append(array[i]);
            } else {
                packedDupArr[index] = dupB.toString();
                dupB.setLength(0);
                dupB.append(array[i]);
                index++;
            }
        }
        packedDupArr[index] = dupB.toString();
        return packedDupArr;
    }

}