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/**
 * Copyright (C) 2013-2016 Vasilis Vryniotis 
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.datumbox.framework.common.utilities;

import org.apache.commons.lang3.builder.ToStringBuilder;

import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * This class contains a number of convenience methods which have an API similar
 * to PHP functions and their are implemented in Java.
 * 
 * @author Vasilis Vryniotis 
 */
public class PHPMethods {
    
    private static final Pattern LTRIM = Pattern.compile("^\\s+");
    private static final Pattern RTRIM = Pattern.compile("\\s+$");
    
    /**
     * Trims spaces on the left.
     * 
     * @param s
     * @return 
     */
    public static String ltrim(String s) {
        return LTRIM.matcher(s).replaceAll("");
    }
    
    /**
     * Trims spaces on the right.
     * 
     * @param s
     * @return 
     */
    public static String rtrim(String s) {
        return RTRIM.matcher(s).replaceAll("");
    }    
    
    /**
     * Count the number of substring occurrences.
     * 
     * @param string
     * @param substring
     * @return 
     */
    public static int substr_count(final String string, final String substring) {
        if(substring.length()==1) {
            return substr_count(string, substring.charAt(0));
        }
        
        int count = 0;
        int idx = 0;

        while ((idx = string.indexOf(substring, idx)) != -1) {
           ++idx;
           ++count;
        }

        return count;
    }
    
    /**
     * Count the number of times a character appears in the string.
     * 
     * @param string
     * @param character
     * @return 
     */
    public static int substr_count(final String string, final char character) {
        int count = 0;
        int n = string.length();
        for(int i=0;i
     * @param 
     * @param map
     * @return 
     */
    public static  Map array_flip(Map map) {
        Map flipped = new HashMap<>();
        for(Map.Entry entry : map.entrySet()) {
            flipped.put(entry.getValue(), entry.getKey());
        }
        return flipped;
    }
    
    /**
     * Shuffles the values of any array in place.
     * 
     * @param 
     * @param array 
     */
    public static  void shuffle(T[] array) {
        //Implementing Fisher-Yates shuffle
        T tmp;
        Random rnd = RandomGenerator.getThreadLocalRandom();
        for (int i = array.length - 1; i > 0; --i) {
            int index = rnd.nextInt(i + 1);
            
            tmp = array[index];
            array[index] = array[i];
            array[i] = tmp;
        }
    }
    
    /**
     * Returns the contexts of an Objects in a human readable format.
     * 
     * @param 
     * @param object
     * @return 
     */
    public static  String var_export(T object) {
        return ToStringBuilder.reflectionToString(object);
    }
    
    /**
     * Sorts an array in ascending order and returns an array with indexes of 
     * the original order.
     * 
     * @param 
     * @param array
     * @return 
     */
    public static > Integer[] asort(T[] array) {
        return _asort(array, false);
    }
    
    /**
     * Sorts an array in descending order and returns an array with indexes of 
     * the original order.
     * 
     * @param 
     * @param array
     * @return 
     */
    public static > Integer[] arsort(T[] array) {
        return _asort(array, true);
    }
    
    private static > Integer[] _asort(T[] array, boolean reverse) {
        //create an array with the indexes
        Integer[] indexes = new Integer[array.length];
        for (int i = 0; i < array.length; ++i) {
            indexes[i] = i;
        }
        
        //sort the indexes first
        Comparator c = (Integer index1, Integer index2) -> array[index1].compareTo(array[index2]);
        c = reverse?Collections.reverseOrder(c):c;
        Arrays.sort(indexes, c);
        
        //rearrenage the array based on the order of indexes
        arrangeByIndex(array, indexes);
        
        return indexes;
    }
    
    /**
     * Rearranges the array based on the order of the provided indexes.
     * 
     * @param 
     * @param array
     * @param indexes 
     */
    public static  void arrangeByIndex(T[] array, Integer[] indexes) {
        if(array.length != indexes.length) {
            throw new IllegalArgumentException("The length of the two arrays must match.");
        }
        
        //sort the array based on the indexes
        for(int i=0;i