package aufgabe1;

import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;
import java.util.Optional;

public record BookDatabase(List<Book> books) {

    public static BookDatabase readFromFile(File file) {
        if (!file.exists() || !file.canRead() || file.isDirectory())
            throw new IllegalArgumentException("Cannot read from file");

        try {
            var source = Files.readString(Paths.get(file.getPath()), StandardCharsets.UTF_8);

            var books = source.lines().skip(1).map(Book::parseFromCommaSeparatedString).toList();

            return  new BookDatabase(books);
        } catch (ArrayIndexOutOfBoundsException | IOException e) {
            throw new IllegalStateException("Cannot read from file: " + e);
        }
    }

    public Optional<Book> getBook(String title) {
        return books.stream().filter(book -> book.title().equals(title)).findFirst();
    }

    public List<String> getTitles() {
        return books.stream().map(Book::title).toList();
    }
}