package day58;

import java.util.ArrayList;
import java.util.List;

/*While writing his next book George wanted to program a digital representation of his book
 *  shelf, he already made a book class so he will be able to save the books title, author name,
 *   id, number of pages on the same object and manipulate it easily even if he has thousands
 *   of books. Instead of using an array to hold the books he decided to put it in a class
 *   called Shelf representing a book shelf. Shelf has a List of Book objects. Using static
 *    methods of Shelf class, George can add, remove, read, get title etc of the books.
 *    */

public class Shelf {
	/**
	 * Constructor is made private to prevent any instantiation. Since all methods
	 * in this class are static that can be called without an object
	 */
	private Shelf() {
		// nothing todo here.
	}

	/**
	 * List<Book> theBooks will hold all book object in the shelf in form of a List
	 * of Book objects
	 */
	private static List<Book> theBooks = new ArrayList<>();

	/**
	 * public static getter method for theBooks list
	 *
	 * @return theBooks
	 */
	public static List<Book> getTheBooks() {

		return theBooks;
	}

	/**
	 * isShelfEmpty is used to see if shelf is empty or not. Shelf is empty when
	 * List<Book> theBooks has no Book objects added
	 *
	 * @return true if list is empty or false if not
	 */
	public static boolean isShelfEmpty() {

		boolean result = false;

		if (!theBooks.isEmpty()) {
			result = true;
		}
		return result;
	}

	/**
	 * isIDUnique accepts an id and loops though each Book object in theBooks list
	 * ,and if id was already assigned to another book, it will return false, If id
	 * was never used, it will return true
	 *
	 * @param id
	 * @return true or false
	 */
	public static boolean isIDUnique(int id) {
		boolean result = true;
		for (int i = 0; i < theBooks.size(); i++) {
			if (theBooks.get(i).getId() == id) {
				result = false;
				break;
			}
		}
		return result;

	}

	/**
	 * static addBook method is used to add a book to the Shelf. to List<Book>
	 * theBooks
	 *
	 * @param id
	 * @param author
	 * @param title
	 * @param pages
	 * @returns true if Book was successfully added or false if not Conditions:
	 *          returns false and does NOT add a book to the list if:
	 *          - id is not unique. was already used by other books. Call isIDUnique to check that
	 *          - title is empty
	 *          - pages <= 0
	 *          returns true and adds a new Book object to List<Book> theBooks if:
	 *           - all above checks passed.
	 *          Shelf.addBook(100,"j.K. rowLing","harry potter",556); => returns true
	 *          and adds the book to the list: theBooks.add(new Book(id,author,title,pages));
	 */
	public static boolean addBook(int id, String author, String title, int pages) {

		boolean result = false;
		if (isIDUnique(id) && !title.isEmpty() && pages > 0) {

			theBooks.add(new Book(id, author, title, pages));
			result = true;
		}

		return result;
	}

	/**
     * static addBook method is used to add a book to the Shelf. to List<Book> theBooks
     * @param  book object
     * @return true if Book was successfully added or false if not
       Conditions:
     *     returns false and does NOT add a book to the list if:
     *      - book.getId() is not unique. was already used by other books. Call isIDUnique to check that
     *      - book's title is empty
     *      - book's pages <= 0
     *     returns true and adds the Book object to List<Book> theBooks if:
     *      - all above checks passed.
     *
     *      Book book1, book2;
     *      book1 = new Book(44, "shel silverstein" ,"the Giving tRee",532);
     *      book2 = new Book(434, "Dan Brown" ,"the da Vinci coDe",1532);
     *
     *      Shelf.addBook(book1); => true
     *      Shelf.addBook(book1); => true
     *
     */
	public static boolean addBook(Book book) {

		boolean result = false;
		if (isIDUnique(book.getId()) && !book.getTitle().isEmpty() && book.getPages() > 0) {

			theBooks.add(book);
			result = true;
		}

		return result;
	}

	 /**
     * static getTitleByID method looks up title of the Book by id
     * @param id
     * @return title
     * Loop through each book in Shelf (the theBooks list) and if you find a book
     * matching id then return that book's title
     * Ex:
     *  Assume we have Book id=100, title=Start With Why
     *  Shelf.getTitleByID(100); => "Start With Why"
     *  Shelf.getTitleByID(100534534); => "book not found"
     */
	public static String getTitleByID(int id) {
		String title = "book not found";
		for (int i = 0; i < theBooks.size(); i++) {
			if (theBooks.get(i).getId() == id) {
				title = theBooks.get(i).getTitle();
			}
		}
		return title;
	}

    /**
     * static method findBookByPartialTitle
     * Looks for a book and if title parameter matches partially
     * return that book object.
     * @param title: partial string to match
     * @return Book object
     *
     * Assume we have Book id=100, title=Start With Why, Author: Simon Sinek
     *    Shelf.findBookByPartialTitle("start"); => returns that Book object
     *    Shelf.findBookByPartialTitle("why"); => returns that Book object
     *    Shelf.findBookByPartialTitle("Wooden Spoon); returns null
     *
     */
	public static Book findBookByPartialTitle(String title) {

		Book object = null;
		for (int i = 0; i < theBooks.size(); i++) {
			if (theBooks.get(i).getTitle().toLowerCase().contains(title.toLowerCase())) {
				object = theBooks.get(i);
			}
		}
		return object;
	}

	 /**
     * static method getAllBooksForAuthor.
     * Loops through each book in shelf(theBooks list) and returns
     * a new List<Book> objects for that author.
     * If no book is found for that author, returns an empty list
     * @param author
     * @return List<Book> that belongs to that Author
     */
	public static List<Book> getAllBooksForAuthor(String author) {
		List<Book> specified = new ArrayList<Book>();
		for (int i = 0; i < theBooks.size(); i++) {
			if (theBooks.get(i).getAuthor().toLowerCase().contains(author.toLowerCase())) {
				specified.add(theBooks.get(i));
			}
		}
		return specified;
	}

	/**
	 * static removeBook method removes the Book from the Shelf(theBooks list)
	 *
	 * @param id Look for the book in the theBooks list that matches the id and
	 *           remove it if there is not match, no action needed
	 */
	public static void removeBook(int id) {
		for (int i = 0; i < theBooks.size(); i++) {
			if (theBooks.get(i).getId() == id) {
				theBooks.remove(i);
			}
		}
	}

	/**
	 * static removeBook method removes the Book from the Shelf(theBooks list)
	 *
	 * @param author Look for the book in the theBooks list that matches the author
	 *               and remove ALL of matches if there is not match, no action
	 *               needed
	 */
	public static void removeBook(String author) {
		for (int i = 0; i < theBooks.size(); i++) {
			if (theBooks.get(i).getAuthor().equalsIgnoreCase(author)) {
				theBooks.remove(i);
			}
		}
	}

	/**
	 * Clears the BookShelf of all books
	 */
	public static void clearBookShelf() {
		theBooks.clear();
	}
}