COS498-HW3/backend/modules/RoutingManager.js

// Helper functions for server-side rendering
function loadBooks(db) {
    return new Promise((resolve, reject) => {
        const query = 'SELECT id, folder_name, display_name, author FROM books ORDER BY display_name';
        db.all(query, [], (err, rows) => {
            if (err) {
                console.error('Error loading books from database:', err.message);
                resolve([]);
            } else {
                const books = rows.map(row => ({
                    id: row.id,
                    name: row.folder_name,
                    displayName: row.display_name || row.folder_name.replace(/-/g, ' '),
                    author: row.author
                }));
                resolve(books);
            }
        });
    });
}

function loadChapters(db, bookName) {
    return new Promise((resolve, reject) => {
        const query = `
            SELECT c.id, c.chapter_number, c.display_name, c.filename, b.folder_name
            FROM chapters c
            JOIN books b ON c.book_id = b.id
            WHERE b.folder_name = ?
            ORDER BY c.chapter_number
        `;
        db.all(query, [bookName], (err, rows) => {
            if (err) {
                console.error('Error loading chapters from database:', err.message);
                resolve([]);
            } else {
                const chapters = rows.map(row => ({
                    id: row.id,
                    chapterNumber: row.chapter_number,
                    filename: row.filename,
                    displayName: row.display_name,
                    url: `/pdf/${row.folder_name}/${encodeURIComponent(row.filename)}`
                }));
                resolve(chapters);
            }
        });
    });
}

// Page Route handlers
async function homePage(db, req, res) {
    try {
        const books = await loadBooks(db);
        res.render('index', { 
            title: 'Book Viewer',
            books: books,
            selectedBook: null,
            selectedChapter: null,
            chapters: []
        });
    } catch (error) {
        console.error('Error loading books for home page:', error);
        res.render('index', {
            title: 'Book Viewer',
            books: [],
            selectedBook: null,
            selectedChapter: null,
            chapters: [],
            error: 'Failed to load books'
        });
    }
}

async function bookPage(db, req, res) {
    const bookName = req.params.bookName;
    
    try {
        const [books, chapters] = await Promise.all([
            loadBooks(db),
            loadChapters(db, bookName)
        ]);
        const selectedBook = books.find(book => book.name === bookName);
        
        if (!selectedBook) {
            return res.redirect('/');
        }
        
        res.render('index', {
            title: 'Book Viewer',
            books: books,
            selectedBook: selectedBook,
            selectedChapter: null,
            chapters: chapters
        });
    } catch (error) {
        console.error('Error loading book page:', error);
        res.redirect('/');
    }
}

async function chapterPage(db, req, res) {
    const bookName = req.params.bookName;
    const chapterFile = decodeURIComponent(req.params.chapterFile);
    
    try {
        const [books, chapters] = await Promise.all([
            loadBooks(db),
            loadChapters(db, bookName)
        ]);
        const selectedBook = books.find(book => book.name === bookName);
        const selectedChapter = chapters.find(chapter => chapter.filename === chapterFile);
        
        if (!selectedBook || !selectedChapter) {
            return res.redirect('/');
        }
        
        res.render('index', {
            title: 'Book Viewer',
            books: books,
            selectedBook: selectedBook,
            selectedChapter: selectedChapter,
            chapters: chapters
        });
    } catch (error) {
        console.error('Error loading chapter page:', error);
        res.redirect('/');
    }
}

// Setup routes function
function setupRoutes(app, db) {
    // Page Routes
    app.get('/', async (req, res) => {
        await homePage(db, req, res);
    });

    app.get('/book/:bookName', async (req, res) => {
        await bookPage(db, req, res);
    });

    app.get('/book/:bookName/chapter/:chapterFile', async (req, res) => {
        await chapterPage(db, req, res);
    });
}

module.exports = {
    setupRoutes,
    loadBooks,
    loadChapters,
    homePage,
    bookPage,
    chapterPage
};