<?php
require '../connect.php'; 

header('Content-Type: application/json');

try {
    // Ensure Book ID is provided
    if (!isset($_GET['id']) || empty($_GET['id'])) {
        echo json_encode(['error' => 'Book ID is required']);
        exit();
    }
    
    $bookId = $_GET['id'];

    // Fetch basic book details
    $query = "SELECT * FROM book WHERE bookid = :bookId";
    $stmt = $conn->prepare($query);
    $stmt->execute([':bookId' => $bookId]);
    
    $book = $stmt->fetch(PDO::FETCH_ASSOC);
    
    if (!$book) {
        echo json_encode(['error' => 'Book not found']);
        exit();
    }

    // Fetch additional book details
    $sql = "
        SELECT 
            b.BookID,
            b.ISBN,
            b.Title,
            b.Genre,
            b.PublishedYear,
            b.Description,
            b.CoverImage,
            b.TotalCopies,
            bd.Format,
            bd.Language,
            bd.Publisher,
            bd.Pages
        FROM Book b
        LEFT JOIN Book_Details bd ON b.BookID = bd.BookID
        WHERE b.BookID = :bookId
    ";
    $stmt = $conn->prepare($sql);
    $stmt->bindParam(':bookId', $bookId, PDO::PARAM_INT);
    $stmt->execute();

    if ($stmt->rowCount() === 0) {
        echo json_encode(['error' => 'Book details not found']);
        exit();
    }

    $bookDetails = $stmt->fetch(PDO::FETCH_ASSOC);

    // Merge book details into the original book data
    $book = array_merge($book, $bookDetails);

    // Fetch authors associated with the book
    $sqlAuthors = "
        SELECT a.AuthorID, a.FirstName, a.LastName
        FROM Book_Author ba
        JOIN Author a ON ba.AuthorID = a.AuthorID
        WHERE ba.BookID = :bookId
    ";
    $stmtAuthors = $conn->prepare($sqlAuthors);
    $stmtAuthors->bindParam(':bookId', $bookId, PDO::PARAM_INT);
    $stmtAuthors->execute();

    $authors = $stmtAuthors->fetchAll(PDO::FETCH_ASSOC); // Fetch all author details
    $book['authors'] = $authors;

    // Fetch book copies with their condition
    $sqlCopies = "
        SELECT bc.CopyID, bc.Condition
        FROM Book_Copies bc
        WHERE bc.BookID = :bookId
    ";
    $stmtCopies = $conn->prepare($sqlCopies);
    $stmtCopies->bindParam(':bookId', $bookId, PDO::PARAM_INT);
    $stmtCopies->execute();

    $copies = $stmtCopies->fetchAll(PDO::FETCH_ASSOC);
    $book['copies'] = $copies;
    
    echo json_encode($book);
} catch (PDOException $e) {
    echo json_encode(['error' => 'Database error: ' . $e->getMessage()]);
    exit();
}
?>