package org.evryword.datastructures;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.stream.IntStream;

public class MyList {
    public static void main(String[] args) {
        // INFO THIS IS ABOUT LISTS
        /*
            List
                Array
                LinkedList
                Set
                TreeSet
                Map
                TreeMap
            ArrayList
            Set
            HashMap
            Iteration and filtering using stream
         */
        System.out.println("==== Start here ====");

        /*
            1. Convert this array = {Mary, Maryam, Mitchell, Mimi, Margaret, Emily, Monster} into a Java List.
            • Filter above list to print only words with 5 characters and below
            • Convert all the words to UpperCase and print out the content
            • Filter and Collect only the words that start with ‘Ma’.
            2. Given this array {1,2,3,4,5....20}
            • Using streams, print out only the even numbers
            • Sum up all the odd numbers in the filtered stream of odd numbers
            • Collect the even numbers in a list named evenNumbers.
            • Map the even numbers to be a square of the number itself
         */

        String[] myNameArray = {"Mary", "Maryam", "Mitchell", "Mimi", "Margaret", "Emily", "Monster"};

        // INFO Using the Stream API
        filterUsingStream(myNameArray, 5);

        System.out.println();
        System.out.println("===============================");
        System.out.println();

        // INFO Using a for loop
        convertArrayToArrayList(myNameArray, 5);

        System.out.println();
        System.out.println("===============================");
        System.out.println();

        int[] myIntegers = IntStream.rangeClosed(1, 20).toArray();

        Arrays.stream(myIntegers)
                .filter((integer) -> (integer % 2) == 0)
                .forEach((nos) -> System.out.println("the even number: " + nos));

        int sumOfOddNumbers = Arrays.stream(myIntegers)
                .filter((integer) -> (integer % 2) != 0).sum();

        System.out.println("The sum of odd numbers " + sumOfOddNumbers);

        List<Integer> evenNumbers = Arrays.stream(Arrays.stream(myIntegers)
                .filter((integer) -> (integer % 2) == 0).toArray()).boxed().toList();

        HashMap<Integer, Integer> mapOfIntegerToSquare = new HashMap<>();

        evenNumbers.forEach((item) -> {
            mapOfIntegerToSquare.put(item, item * item);
        });

        System.out.println("My list of even Numbers => " + evenNumbers);
        System.out.println("My map of integer to square of integers => " + mapOfIntegerToSquare);
    }

    public static void filterUsingStream(String[] myNameArray, int stringLength) {
        List<String> myListOfNamesWith5Characters = Arrays.stream(myNameArray)
                .filter((string) -> string.length() <= stringLength)
                .toList();

        myListOfNamesWith5Characters
                .stream()
                .map(String::toUpperCase)
                .forEach((string) -> {
                    System.out.println("word in uppercase: " + string);
                });

        System.out.println("My List of Names with 5 characters and below " + myListOfNamesWith5Characters);
        System.out.println("Words starting with \"Ma\"" + Arrays.stream(myNameArray)
                .filter((string) -> string.startsWith("Ma"))
                .toList());
    }


    public static void convertArrayToArrayList(String[] array, int stringLength) {
        List<String> myNameList = new ArrayList<>();

        for (int i = 0; i < array.length; i++) {
            String currentItem = array[i];

            if (currentItem.length() <= stringLength) {
                myNameList.add(array[i]);
            }
        }

        System.out.println("=== list of words with five characters and below => " + myNameList);

        for (String list : myNameList) {
            System.out.println("word in uppercase: " + list.toUpperCase());
        }

        List<String> myWordsStartingWithMa = new ArrayList<>();

        for (String it : array) {
            if (it.startsWith("Ma")) myWordsStartingWithMa.add(it);
        }

        System.out.println("Words starting with \"Ma\" " + myWordsStartingWithMa);
    }
}