import java.util.TreeSet; 
import java.util.ArrayList; 

/**
 * 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) {
        for(String element:array){
            if(element==value){
                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) {
        String flip="";
        for(int i=0;i<array.length/2;i++){
            flip=array[i];
            array[i]=array[array.length-1-i];
            array[array.length-1-i] = flip; 
        }
        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 palindrome = array.length;
        for(int i=0;i<array.length;i++){
            String start = array[i];
            String end =array[--palindrome];
            if(palindrome<i){
                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) {
        int counter=0;
        int i;
        /*for(String e:array){
        if(e==(i = 'a';i <= 'z'));{
        counter++;}}
        if(counter<26){
        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 counter=0;
        for(int i=0;i<array.length;i++){
            if(array[i]==value){
                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> remove = new ArrayList<String>();
        for(String e:array){
            if(!e.equals(valueToRemove)){
                remove.add(e);
            }
        }
        return remove.toArray(new String[remove.size()]);
    }

    /**
     * @param array array of chars
     * @return array of Strings with consecutive duplicates removes
     */ // TODO
    public static String[] removeConsecutiveDuplicates(String[] array) {
        
        // for(String e:array){
            // if(array[e] !=array[-1]){
                // remove.removeAll();
            // }
        // }
        // return remove.toArray(new String[remove.add()]);
        
        
        //Code below is skipping on index value
        // StringBuilder answerString = new StringBuilder();
        // for(int i = 1; i < array.length; i++){
         // if((array[i] != array[i-1]) && (i < array.length-1)){
            // answerString.append(array[i-1] + "`");
            // }else if (array[i] != array[i-1]){
            // answerString.append(array[i] + "`");
            // }
        // }
        
        // String answer = answerString.toString();
        // String[] answerArray = answer.split("`");
        
        // for(int i = 0; i < answerArray.length; i++){
        // System.out.println(answerArray[i]);
        // }
        
        // return answerArray;
        
        
        
        
        //loop through code
        //compare all digits 
        //if element appears more than once, count it
        //if not, keep it pushing 
        //ArrayList<String> remove = new ArrayList<String>();
        
                        
        //String getAnswer = null;
        //int counter = getCounter(array);
        String [] answer = new String[array.length];
        int index = 0;
        answer[index]=array[0];
        
        index++; 
        for(int i=1;i<array.length;i++){
        if(!answer[index-1].equals(array[i])){
            answer[index]=array[i];
            index++; 
        }
        }
        String [] blank = new String [index];  
        System.arraycopy(answer, 0, blank, 0, index);
        return blank; 
    }

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

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