interface Book {
  title: string;
  author: string;
}

export const sortBooksByTitle = (books: Book[]) => {
  // Create a shallow copy of the array to avoid modifying the original array
  return books.slice().sort((a, b) => {
    // Secondary comparison on authors if titles are the same
    const authorA = a.author.toLowerCase();
    const authorB = b.author.toLowerCase();
    if (authorA < authorB) return -1;
    if (authorA > authorB) return 1;

    // Convert titles to lowercase to achieve case-insensitive comparison
    const titleA = a.title.toLowerCase();
    const titleB = b.title.toLowerCase();

    // Primary comparison on titles
    if (titleA < titleB) return -1;
    if (titleA > titleB) return 1;

    return 0; // If authors are also the same, keep original order
  });
};

// Example usage with books array
const books: Book[] = [
  { title: "The Great Gatsby", author: "F. Scott Fitzgerald" },
  { title: "Moby Dick", author: "Herman Melville" },
  { title: "1984", author: "George Orwell" },
  { title: "a Farewell to Arms", author: "Ernest Hemingway" },
];

const sortedBooks = sortBooksByTitle(books);
console.log(sortedBooks);