const axios = require('axios');
const express = require('express');
const https = require('https');
const fs = require('fs');
const path = require('path');
const sqlite3 = require('sqlite3').verbose();
const bodyParser = require('body-parser');

const app = express();
const PORT = process.env.PORT || 3000;

// SSL certificate paths
const privateKey = fs.readFileSync(path.join(__dirname, 'server.key'), 'utf8');
const certificate = fs.readFileSync(path.join(__dirname, 'server.cert'), 'utf8');

const credentials = { key: privateKey, cert: certificate };

// Middleware to parse JSON bodies
app.use(express.json()); // Use built-in body-parser for JSON

// Set up the SQLite database
// Set up the SQLite database
const db = new sqlite3.Database('./books.db', (err) => {
    if (err) {
        console.error('Could not connect to database', err);
    } else {
        console.log('Connected to database');
        db.run(`
            CREATE TABLE IF NOT EXISTS books (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                isbn TEXT,
                title TEXT,
                authors TEXT,
                publishedDate TEXT,
                description TEXT,
                url TEXT,
                number_of_pages INTEGER,
                identifiers TEXT,
                publishers TEXT,
                subjects TEXT,
                notes TEXT,
                cover_small TEXT,
                cover_medium TEXT,
                cover_large TEXT
            )
        `);
    }
});


// Serve static files from the 'public' directory
app.use(express.static(path.join(__dirname, 'public')));

// Endpoint to fetch book details by ISBN
// Endpoint to fetch book details by ISBN
app.get('/book/:isbn', async (req, res) => {
    const { isbn } = req.params;
    console.log(`Fetching book data for ISBN: ${isbn}`);

    try {
        // First try Open Library
        const openLibraryResponse = await axios.get(`https://openlibrary.org/api/books?bibkeys=ISBN:${isbn}&format=json&jscmd=data`);
        const bookData = openLibraryResponse.data[`ISBN:${isbn}`];
        //Check for timeout or rate limit:
        if(openLibraryResponse.status === 429){
            console.log('Rate limit exceeded');
            res.status(429).json({ error: 'Rate limit exceeded' });
        }

        if(openLibraryResponse.status === 408){
            console.log('Request Timeout');
            res.status(408).json({ error: 'Request Timeout' });
        }

        if (bookData) {
            console.log('Book data found in Open Library');
            res.json(formatOpenLibraryData(bookData));
        } else {
            console.log('Book not found in Open Library');
            console.log('Trying Internet Archive...');

            // Fallback to Internet Archive if no data from Open Library
            const archiveResponse = await axios.get(`https://archive.org/advancedsearch.php?q=isbn:${isbn}&output=json`);
            const archiveData = archiveResponse.data;
            console.log(archiveData);

            if (archiveData.response.numFound > 0) {
                res.json(formatArchiveData(archiveData.response.docs[0]));
            } else {
                res.status(404).json({ error: 'Book not found in Open Library or Internet Archive.' });
            }
        }
    } catch (error) {
        console.error(error);
        res.status(500).json({ error: 'Failed to fetch book data' });
    }
});



// Endpoint to search for book by title
app.get('/search-title', async (req, res) => {
    const { title } = req.query;
    console.log(`Searching for book by title: ${title}`);

    try {
        // Search Open Library by title, limit to 5 results
        const openLibraryResponse = await axios.get(`https://openlibrary.org/search.json?q=${encodeURIComponent(title)}&limit=7`);
        const searchResults = openLibraryResponse.data.docs;
        console.log(searchResults);

        if (searchResults.length > 0) {
            console.log('Books found by title');
            const bookData = searchResults.map(result => ({
                title: result.title,
                authors: result.author_name || [],
                publish_date: result.first_publish_year,
                isbn: result.isbn ? result.isbn[0] : '',
                publisher: result.publisher ? result.publisher[0] : '',
                key: result.key // Unique key to fetch more detailed data later if needed
            }));
            console.log(bookData);
            res.json({ results: bookData });
        } else {
            res.status(404).json({ error: 'No books found with that title.' });
        }
    } catch (error) {
        console.error(error);
        res.status(500).json({ error: 'Failed to search for book by title' });
    }
});


// Endpoint to store book in the database
// Endpoint to store book in the database
// Endpoint to store book in the database
app.post('/store-book', (req, res) => {
    const {
        isbn, title, authors, publishedDate, description, url,
        number_of_pages, identifiers, publishers, subjects,
        notes, cover_small, cover_medium, cover_large
    } = req.body;

    // Check if a book with the same ISBN already exists
    const checkQuery = `SELECT * FROM books WHERE isbn = ?`;
    db.get(checkQuery, [isbn], (err, row) => {
        if (err) {
            console.error('Error checking for existing book:', err);
            return res.status(500).json({ error: 'Failed to check for existing book' });
        }

        if (row) {
            // Book already exists, update the existing record
            const updateQuery = `
                UPDATE books
                SET title = ?, authors = ?, publishedDate = ?, description = ?, url = ?,
                    number_of_pages = ?, identifiers = ?, publishers = ?, subjects = ?,
                    notes = ?, cover_small = ?, cover_medium = ?, cover_large = ?
                WHERE isbn = ?
            `;

            const updateParams = [
                title, authors ? authors.join(', ') : '', publishedDate, description || '',
                url, number_of_pages, identifiers, publishers, subjects,
                notes, cover_small, cover_medium, cover_large, isbn
            ];

            db.run(updateQuery, updateParams, function (err) {
                if (err) {
                    console.error('Error updating book in database:', err);
                    return res.status(500).json({ error: 'Failed to update book in database' });
                } else {
                    res.json({ success: true, message: 'Book updated successfully' });
                }
            });
        } else {
            // Book does not exist, insert a new record
            const insertQuery = `
                INSERT INTO books (
                    isbn, title, authors, publishedDate, description, url,
                    number_of_pages, identifiers, publishers, subjects,
                    notes, cover_small, cover_medium, cover_large
                ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
            `;

            const insertParams = [
                isbn, title, authors ? authors.join(', ') : '', publishedDate, description || '',
                url, number_of_pages, identifiers, publishers, subjects,
                notes, cover_small, cover_medium, cover_large
            ];

            db.run(insertQuery, insertParams, function (err) {
                if (err) {
                    console.error('Error storing book in database:', err);
                    return res.status(500).json({ error: 'Failed to store book in database' });
                } else {
                    res.json({ success: true, message: 'Book stored successfully', bookId: this.lastID });
                }
            });
        }
    });
});


function formatOpenLibraryData(data) {
    return {
        isbn: data.identifiers.isbn_13 ? data.identifiers.isbn_13[0] : '',
        title: data.title,
        authors: data.authors ? data.authors.map(author => author.name) : [],
        publishedDate: data.publish_date,
        description: data.excerpts ? data.excerpts[0].text : 'No description available',
        url: data.url,
        number_of_pages: data.number_of_pages || null,
        identifiers: JSON.stringify(data.identifiers), // Store as JSON string
        publishers: data.publishers ? data.publishers.map(pub => pub.name).join(', ') : '',
        subjects: data.subjects ? data.subjects.map(sub => sub.name).join(', ') : '',
        notes: data.notes || '',
        cover_small: data.cover ? data.cover.small : '',
        cover_medium: data.cover ? data.cover.medium : '',
        cover_large: data.cover ? data.cover.large : ''
    };
}


function formatArchiveData(data) {
    return {
        isbn: data.isbn ? data.isbn[0] : '',
        title: data.title,
        authors: data.contributor ? [data.contributor] : [],
        publishedDate: data.date ? new Date(data.date).getFullYear() : '',
        description: data.description ? data.description.join(' ') : 'No description available',
        url: `https://archive.org/details/${data.identifier}`,
        number_of_pages: data.imagecount || null,
        identifiers: JSON.stringify({
            archive_identifier: data.identifier,
            oclc: data['external-identifier'] ? data['external-identifier'].filter(id => id.includes('urn:oclc')).map(id => id.split(':')[2]) : []
        }),
        publishers: data.publisher || '',
        subjects: data.subject ? data.subject.join(', ') : '',
        notes: '', // Archive data does not provide specific notes like Open Library
        cover_small: '', // Placeholder, as cover image URLs need to be constructed manually
        cover_medium: '', // Same as above
        cover_large: ''  // Same as above
    };
}

const httpsServer = https.createServer(credentials, app);

httpsServer.listen(PORT, () => {
    console.log(`HTTPS Server running on https://localhost:${PORT}`);
});