import jwt from 'jsonwebtoken';
import { OAuth2Client } from 'google-auth-library';
import env from '../../../config/env.js';
import * as db from '../../../db/googleAuth.js';
import { clearCachedUser } from '../../middleware/auth.js';

const googleClient = new OAuth2Client(env.googleClientId);

/**
 * Registers the login route (Google SSO → JWT cookie session).
 * @param {import('express').Application} app - Express app
 * @param {string} [basePath=''] - Optional URL prefix for all routes in this module
 */
export function register(app, basePath = '') {
    /**
     * @openapi
     * /auth/login:
     *   post:
     *     tags: [Auth]
     *     summary: Login with Google ID token
     *     description: Verifies a Google ID token, checks allowlist (or creates entry when `IMPLICIT_CREATE=true`), and sets an HTTP-only `token` cookie.
     *     security: []
     *     x-markdown: auth/login.md
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             type: object
     *             required: [idToken]
     *             properties:
     *               idToken:
     *                 type: string
     *                 description: Google ID token from Google Identity Services
     *             example:
     *               idToken: "<google-id-token>"
     *     responses:
     *       200:
     *         description: Login successful; `token` cookie set
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 message:
     *                   type: string
     *                   example: Login successful
     *                 user:
     *                   $ref: '#/components/schemas/User'
     *       400:
     *         description: Missing token or Google client not configured
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Invalid Google token or account
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       403:
     *         description: Email not on allowlist
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       500:
     *         description: Server error
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    app.post(`${basePath}/auth/login`, async (req, res) => {
        try {
            const { idToken } = req.body;
            if (!idToken) {
                return res.status(400).json({ error: 'idToken is required' });
            }

            if (!env.googleClientId) {
                return res.status(400).json({ error: 'GOOGLE_CLIENT_ID is not configured' });
            }

            let ticket;
            try {
                ticket = await googleClient.verifyIdToken({
                    idToken,
                    audience: env.googleClientId,
                });
            } catch {
                return res.status(401).json({ error: 'Invalid Google token' });
            }
            const payload = ticket.getPayload();
            const email = payload?.email?.toLowerCase();

            if (!email || !payload.email_verified) {
                return res.status(401).json({ error: 'Invalid Google account' });
            }

            let allowed = await db.getAllowedEmail(email);
            if (!allowed && env.implicitCreate) {
                await db.addAllowedEmail(email);
                allowed = await db.getAllowedEmail(email);
            }
            if (!allowed) {
                console.warn(`Login rejected: email not authorized (${email})`);
                return res.status(403).json({ error: 'Email is not authorized' });
            }

            await db.setProfile(allowed.id, {
                picture: payload.picture ?? null,
                sub: payload.sub ?? null,
            });
            clearCachedUser(email);

            const user = {
                id: allowed.id,
                email: allowed.email,
                selectedCompanyId: allowed.selectedCompanyId,
                ...(payload.picture && { picture: payload.picture }),
            };
            const token = jwt.sign(user, env.jwtSecret, { expiresIn: '1d' });

            res.cookie('token', token, {
                httpOnly: true,
                secure: true,
                sameSite: 'strict',
                maxAge: 24 * 60 * 60 * 1000,
            });

            res.status(200).json({ message: 'Login successful', user });
        } catch (error) {
            console.error('Login failed:', error);
            res.status(500).json({ error: 'Login failed' });
        }
    });
}