// OAuth endpoints.
//   GET /CollabCentral/:app/authUrl  — returns the Webex authorize URL
//                                       the browser should redirect to.
//   GET /CollabCentral/:app/oauth    — Webex redirects the user back to
//                                       this URL with a `code` query
//                                       param; we exchange it for tokens
//                                       and set the `id`+`displayName`
//                                       session cookies.
//
// registerAuthRoutes(app, { buildAuthUrl, getOAuthRedirectUri, webex,
//                           env, logger })

// Options for the session cookies set after a successful OAuth round-trip.
//
// httpOnly is deliberately false: js/app.js reads `id` (to decide whether
// to redirect to OAuth) and `displayName` (to render the user chip in the
// header) via document.cookie. Enabling httpOnly here hides the cookies
// from JS, which causes an infinite auth loop where every page load thinks
// the user is not signed in and kicks off a fresh OAuth exchange — burning
// Webex tokens until the CTS token limit is reached.
//
// sameSite is 'lax' rather than 'strict' so the cookie survives the OAuth
// redirect chain webexapis.com -> /oauth -> /sendMessage.html on all
// browsers.
const SESSION_COOKIE_OPTIONS = {
    httpOnly: false,
    secure: true,
    sameSite: 'lax',
    maxAge: 24 * 60 * 60 * 1000
};

export function registerAuthRoutes(app, deps) {
    var buildAuthUrl = deps.buildAuthUrl;
    var getOAuthRedirectUri = deps.getOAuthRedirectUri;
    var webex = deps.webex;
    var env = deps.env || {};
    var logger = deps.logger || function () {};

    app.get('/CollabCentral/:app/authUrl', function (req, res) {
        var url = buildAuthUrl(req.params.app);
        if (!url) {
            return res.status(500).send('OAuth is not configured. Check WEBEX_INTEGRATION_CLIENT_ID and OAUTH_CALLBACK_URL_TEMPLATE.');
        }
        res.send(url);
    });

    app.get('/CollabCentral/:app/oauth', async function (req, res) {
        var appName = req.params.app;
        var authCode = req.query.code;

        if (!env.WEBEX_INTEGRATION_CLIENT_ID || !env.WEBEX_INTEGRATION_CLIENT_SECRET || !env.OAUTH_CALLBACK_URL_TEMPLATE) {
            logger('oauth', 'Missing Webex integration env vars; cannot complete OAuth.');
            return res.status(500).send('OAuth is not configured on the server.');
        }
        if (!authCode) {
            return res.status(400).send('Missing OAuth `code` query parameter.');
        }

        var url = new URL('https://webexapis.com/v1/access_token');
        var params = new URLSearchParams();
        params.append('grant_type', 'authorization_code');
        params.append('client_id', env.WEBEX_INTEGRATION_CLIENT_ID);
        params.append('client_secret', env.WEBEX_INTEGRATION_CLIENT_SECRET);
        params.append('code', authCode);
        params.append('redirect_uri', getOAuthRedirectUri(appName));

        var response;
        try {
            response = await webex.fetchWithRateLimit(url, { method: 'POST', body: params });
        } catch (error) {
            logger('oauth', 'Token exchange fetch failed: ' + (error && error.message || error));
            return res.status(502).send('Failed to reach Webex to complete OAuth.');
        }

        if (!response.ok) {
            var errText = await response.text().catch(() => '');
            logger('oauth', 'Token exchange returned ' + response.status + ' ' + response.statusText + ' ' + errText);
            return res.status(401).send(response.statusText || 'OAuth token exchange failed.');
        }

        var jsonData = await response.json();
        var whoami;
        try {
            whoami = await webex.whoAmI(jsonData.access_token);
        } catch (err) {
            logger('oauth', 'whoAmI failed: ' + (err && err.message || err));
            return res.status(502).send('Failed to read your Webex profile after OAuth.');
        }
        logger('oauth', whoami.displayName + ' successfully authed for ' + appName + '.');

        // Only the two cookies that the server (req.cookies.id,
        // .displayName) and the client (getCookie('id'),
        // getCookie('displayName')) actually read. Access/refresh tokens
        // deliberately stay out of the browser: they never need to leave
        // the server, and putting them in cookies would expose them to
        // any XSS that might slip in later.
        res
            .cookie('id', whoami.id, SESSION_COOKIE_OPTIONS)
            .cookie('displayName', whoami.displayName, SESSION_COOKIE_OPTIONS)
            .redirect(301, '/CollabCentral/' + appName + '/sendMessage.html');
    });
}