let selectedDeviceId;
let isScanning = false; // Flag to prevent multiple scans at the same time
let quaggaInitialized = false; // Flag to check if Quagga has been initialized

// Get available video input devices (cameras)
async function getCameras() {
    try {
        const cameraSelect = document.getElementById('camera-select');
        const stream = await navigator.mediaDevices.getUserMedia({ video: true }); // Prompt for camera access
        const devices = await navigator.mediaDevices.enumerateDevices();
        const videoDevices = devices.filter(device => device.kind === 'videoinput');

        if (videoDevices.length > 0) {
            // Clear any existing options
            cameraSelect.innerHTML = '';
            videoDevices.forEach((device, index) => {
                const option = document.createElement('option');
                option.value = device.deviceId;
                option.text = device.label || `Camera ${index + 1}`;
                cameraSelect.appendChild(option);
            });
            // Set selectedDeviceId to the first camera by default
            selectedDeviceId = cameraSelect.value;
            startScanner(); // Start the scanner with the default camera
        } else {
            console.log("No video devices found.");
            cameraSelect.innerHTML = '<option>No cameras found</option>';
        }

        // Update selectedDeviceId when user selects a camera
        cameraSelect.addEventListener('change', function() {
            selectedDeviceId = this.value;
            // Stop Quagga and re-initialize with the new deviceId
            if (quaggaInitialized) {
                Quagga.stop();
                quaggaInitialized = false;
            }
            startScanner();
        });

    } catch (error) {
        console.error("Error accessing the camera or enumerating devices:", error);
        document.getElementById('camera-select').innerHTML = '<option>' + error + '</option>';
    }
}

function startScanner() {
    if (!selectedDeviceId) {
        alert('No camera selected or available.');
        return;
    }

    if (quaggaInitialized) {
        Quagga.start();
    } else {
        Quagga.init({
            inputStream: {
                name: "Live",
                type: "LiveStream",
                target: document.querySelector('#interactive'),
                constraints: {
                    deviceId: selectedDeviceId,
                    facingMode: "environment",
                    // Remove advanced constraints if not needed
                },
            },
            decoder: {
                readers: ["ean_reader", "ean_8_reader"]
            }
        }, function (err) {
            if (err) {
                console.log(err);
                return;
            }
            console.log("Initialization finished. Ready to start");
            Quagga.start();
            quaggaInitialized = true;

            // Set up the onDetected handler
            Quagga.onDetected(processBarcode);
        });
    }
}

async function processBarcode(data) {
    if (isScanning) return; // Prevent further scans while a scan is being processed
    isScanning = true; // Set the scanning flag

    const isbn = data.codeResult.code;
    console.log("Detected ISBN:", isbn);
    Quagga.stop(); // Stop the scanner once an ISBN is detected

    if (document.getElementById('confirm-mode').checked) {
        // Confirm book in library
        await confirmBookInLibrary(isbn);
    } else {
        // Normal flow
        await fetchBookInfo(isbn);
    }

    isScanning = false; // Reset the scanning flag once processing is done
}

async function fetchBookInfo(isbn) {
    try {
        const response = await fetch(`/book/${isbn}`);
        const bookData = await response.json();

        if (bookData.title) {
            bookData.isbn2 = isbn; // Add the ISBN to the book data
            promptUserWithBook(bookData);
        } else {
            console.log("No book data found. Restarting scanner...");
            startScanner(); // Restart the scanner if no book information is found
        }
    } catch (error) {
        console.error('Error fetching book data:', error);
        startScanner(); // Restart the scanner on error as well
    }
}

function promptUserWithBook(bookData) {
    // Prepare the information to display in the confirm dialog
    const title = bookData.title;
    const authors = bookData.authors ? bookData.authors.join(', ') : 'Unknown Author';
    const description = bookData.description || 'No description available';

    // Combine the information into a single message
    const message = `Title: ${title}\nAuthor(s): ${authors}\nDescription: ${description}\n\nDo you want to add this book to the database?`;

    // Use the built-in confirm prompt to ask the user
    const userConfirmed = confirm(message);

    if (userConfirmed) {
        console.log('User confirmed to add the book to the database.');
        storeBookInDatabase(bookData);
    } else {
        console.log('User declined to add the book to the database.');
        startScanner(); // Restart the scanner if the user declines
    }
}

async function storeBookInDatabase(bookData) {
    try {
        const response = await fetch('/store-book', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                isbn: bookData.isbn || bookData.isbn2,
                title: bookData.title,
                authors: bookData.authors,
                publishedDate: bookData.publishedDate,
                description: bookData.description,
                url: bookData.url,
                number_of_pages: bookData.number_of_pages,
                identifiers: bookData.identifiers,
                publishers: bookData.publishers,
                subjects: bookData.subjects,
                notes: bookData.notes,
                cover_small: bookData.cover_small,
                cover_medium: bookData.cover_medium,
                cover_large: bookData.cover_large
            })
        });

        const result = await response.json();

        if (result.success) {
            alert('Book added to the database successfully!');
        } else {
            alert('Failed to add the book to the database.');
        }
    } catch (error) {
        console.error('Error storing book in database:', error);
        alert('An error occurred while storing the book.');
    } finally {
        startScanner(); // Restart the scanner after storing the book or handling errors
    }
}

async function confirmBookInLibrary(isbn) {
    try {
        const response = await fetch(`/book/confirm/${isbn}`);
        const bookData = await response.json();

        if (bookData.title) {
            // Display the book information and a success message
            const title = bookData.title;
            const authors = bookData.authors ? bookData.authors.join(', ') : 'Unknown Author';
            const description = bookData.description || 'No description available';

            const message = `Title: ${title}\nAuthor(s): ${authors}\nDescription: ${description}\n\nBook found in the library!`;

            alert(message);
        } else {
            alert('Book not found in the library.');
        }
    } catch (error) {
        console.error('Error confirming book in library:', error);
        alert('An error occurred while confirming the book in the library.');
    } finally {
        startScanner(); // Restart the scanner after processing
    }
}

// Add an event listener for the search button
document.getElementById('search-title').addEventListener('click', function() {
    const title = document.getElementById('title-input').value;
    searchByTitle(title);
});

async function searchByTitle(title = '') {
    if (!title) {
        alert('Please enter a book title to search.');
        return;
    }

    try {
        const response = await fetch(`/search-title?title=${encodeURIComponent(title)}`);
        const data = await response.json();

        if (data.results && data.results.length > 0) {
            displaySearchResults(data.results);
        } else {
            alert('No books found with that title.');
        }
    } catch (error) {
        console.error('Error searching for book by title:', error);
        alert('An error occurred while searching for the book.');
    }
}

function displaySearchResults(results) {
    // Display the search results and allow the user to select one
    const bookInfoDiv = document.getElementById('book-info');
    bookInfoDiv.innerHTML = ''; // Clear previous results

    results.forEach((book, index) => {
        const bookElement = document.createElement('div');
        bookElement.innerHTML = `
            <p><strong>Title:</strong> ${book.title}</p>
            <p><strong>Author(s):</strong> ${book.authors.join(', ')}</p>
            <p><strong>Published:</strong> ${book.publishDate || 'N/A'}</p>
            <p><strong>ISBN:</strong> ${book.isbn}</p>
            <p><strong>Publisher:</strong> ${book.publishers || 'N/A'}</p>
            <button onclick="selectBook(${index})">Select this book</button>
        `;
        bookInfoDiv.appendChild(bookElement);
    });

    // Store the results so that we can reference them when the user makes a selection
    window.searchResults = results;
}

// Client-side function to request checkout
function requestCheckout(isbn) {
    fetch(`/api/checkout/${isbn}`, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        }
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            alert('Checkout request sent successfully.');
        } else {
            alert('Failed to send checkout request.');
        }
    })
    .catch(error => {
        console.error('Error:', error);
        alert('An error occurred while sending the checkout request.');
    });
}

function selectBook(index) {
    const selectedBook = window.searchResults[index];
    console.log('Selected book:', selectedBook);

    // You can now fetch more details using the unique key if needed, or directly store this in your database
    const isbn = selectedBook.isbn;

    if (isbn) {
        fetchBookInfo(isbn);
    } else {
        promptUserWithBook(selectedBook); // You might have to adapt this if there's no ISBN
    }
}

// Get cameras on page load
window.onload = function() {
    getCameras();
    searchByTitle('');
};