const fs = require('fs').promises;
const path = require('path');

const filePath = path.join(__dirname, '../user.json');

async function getUserData() {
    try {
        const fileContent = await fs.readFile(filePath, 'utf8');
        return JSON.parse(fileContent);
    } catch (err) {
        console.error(`Failed to read from ${filePath}: ${err}`);
        throw err;
    }
}

async function checkUserExistsAD(req, res, next) {
    let userData = await getUserData();

    if (!req.user || (!req.user.name && !req.user.id)) {
        return res.status(500).send('Internal Server Error');
    }

    try {
        let users = userData;

        let existingUser;
        if (req.user.name) {
            existingUser = users.find(u => u.name === req.user.name);
        } else if (req.user.id) {
            existingUser = users.find(u => u.id === req.user.id);
        }
        
        if (!existingUser) {
            const id = Math.floor(Math.random() * 1e19);        
            const newUser = {
                id: id.toString(),
                name: req.user.name || req.user.id,
                role: "user"
            };
            users.push(newUser);

            try {
                await fs.promises.writeFile(filePath, JSON.stringify(users, null, 2), 'utf8');
            } catch (error) {
                console.error(`Failed to write to ${filePath}: ${error}`);
                return next(error);
            }

            req.user = newUser;
            req.session.userId = newUser.id;
        } else {
            req.user = existingUser;
            req.session.userId = existingUser.id;
            res.render('AuthLogin', { isAuthenticated: true, setupData: {}, currentUrl: req.originalUrl, errorMessage: '' });
        }

        return next();
    } catch (error) {
        return next(error);
    }
}

module.exports = { checkUserExistsAD };