let selectedDeviceId;
let isScanning = false; // Flag to prevent multiple scans at the same time

async function testCameraAccess() {
    try {
        const stream = await navigator.mediaDevices.getUserMedia({ video: true });
        console.log('Camera access granted', stream);
    } catch (error) {
        console.error('Error accessing camera:', error);
    }
}

// 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');

        // Update selectedDeviceId when user selects a camera
        cameraSelect.addEventListener('change', function() {
            selectedDeviceId = this.value;
            startScanner();
        });

        if (videoDevices.length > 0) {
            videoDevices.forEach((device, index) => {
                const option = document.createElement('option');
                option.value = device.deviceId;
                option.text = device.label || `Camera ${index + 1}`;
                cameraSelect.appendChild(option);
            });
        } else {
            console.log("No video devices found.");
            cameraSelect.innerHTML = '<option>No cameras found</option>';
        }
    } 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;
    }
    // TODO: Limit the field of view to a smaller area for faster detection
    Quagga.init({
        inputStream: {
            name: "Live",
            type: "LiveStream",
            target: document.querySelector('#interactive'),
            constraints: {
                deviceId: selectedDeviceId,
                facingMode: "environment", // Default to rear camera,
                advanced: [{torch: true}]
            },
        },
        decoder: {
            readers: ["ean_reader", "ean_8_reader"]
        }
    }, function (err) {
        if (err) {
            console.log(err);
            return;
        }
        console.log("Initialization finished. Ready to start");
        Quagga.start();

        // TODO: Add a button to enable/disable torch
        Quagga.CameraAccess.enableTorch();

        // TODO: Add a button to enable/disable the "locate" functionality
    });

    Quagga.onDetected(async function (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

        // TODO: Validate the ISBN before fetching book details
        // Use a library like barcode-validator to validate the ISBN

        // Fetch book details
        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();

        // TODO: If bookData value of "source" is "local", then the book data is already in the database
        // TODO: Display the book info and ask if they would like to checkout the book

        // TODO: Store scanned ISBN in a different field to check against the one we get from the API
        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
    }
}

// TODO: Function to prompt user for physical location of the book
// Should pull from the database and allow the user to select or add a location

// Add an event listener for the search button
document.getElementById('search-title').addEventListener('click', searchByTitle);

async function searchByTitle() {
    const title = document.getElementById('title-input').value;
    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.publish_date || 'N/A'}</p>
            <p><strong>ISBN:</strong> ${book.isbn}</p>
            <p><strong>Publisher:</strong> ${book.publisher || 'N/A'}</p>
            <button onclick="selectBook(${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;
}

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
    }
}


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
    }
}


// Start the scanner when the start button is clicked
//document.getElementById('start-scanner').addEventListener('click', startScanner);

// Get cameras on page load
window.onload = getCameras;