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) {
        boolean a = true;
        
        for(int i = 0; i <= array.length; i++){
            if(array[i].equals(value)){
                a = true;
                break;
            }
            else{
                a = false;
            }
        }
        
        return a;
    }

    /**
     * @param array of String objects
     * @return an array with identical contents in reverse order
     */ // TODO
    public static String[] reverse(String[] array) {
        String[] result = new String[array.length];
        
        for (int i = 0; i< array.length; i++){
            result[i] = 
            array[array.length-i-1];
        }
        
        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) {
        int length = array.length;
        
        for (int index = 0; index < array.length; index++) {
        String start = array[index];
        
        String end = array[--length];
        
        if (length < index) {
            return true;
        }
        
        if (start != end) {
            return false;
        }
       }
        
        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) {
        String arrayToString = array.toString();
        String str = arrayToString.toLowerCase();
        
        boolean answer = true;
        
        for(char c = 'a';c <= 'z'; ++c) {
            if(!str.contains(String.valueOf(c))) {
                answer = false;
                break;
            }
        }

        return answer;
    }

    /**
     * @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(int i = 0; i <= array.length-1; i++){
            if(array[i].equals(value)){
                counter = counter + 1;
            }
        }
        
        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 count = 0;
        
        for(int i = 0; i < array.length; i++){
            if(array[i].equals(valueToRemove)){
                count = count + 1;
            }
        }
        
        String[] newArray = new String[array.length - count];
        
        int j = 0;
        for(int i = 0; i < array.length; i++){
            if(!array[i].equals(valueToRemove)){
                newArray[j++] = array[i];
            }
        }
        
        return newArray;
    }

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

    /**
     * @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 sb = new StringBuilder();
        
        int dupCounter = 0;
        
        for(int i = 0; i < array.length-1; i++){
            if(array[i].equals(array[i+1])){
                dupCounter = dupCounter + 1;
            }
        }
        
        String[] newArray = new String[array.length - dupCounter];
        
        int j = 0;
        for(int i = 0; i < array.length-1; i++){
            if(array[i].equals(array[i+1])){
                StringBuilder sb = new StringBuilder(array[i]);
                sb.append(array[i+1]);
                
                newArray[j++] = (array[i]);
            }
        }

        return newArray;
    }
}