// Per-user data endpoints:
//   GET  /CollabCentral/:app/user/groups/list    — this user's favorites
//   GET  /CollabCentral/:app/user/groups/find    — org-wide groups
//                                                  (cached)
//   POST /CollabCentral/:app/user/groups/add     — save a favorite
//   POST /CollabCentral/:app/user/groups/remove  — drop a favorite
//
// All four require the caller to be authorized on :app. Favorites live
// in the mutable `authorized` doc (config/authorized.json) so they
// survive restarts and are picklable in the compose page's Favorite
// Groups selector.
//
// registerUserRoutes(app, { isAuthorized, authorized, helpers,
//                           getGroupsFromCache, saveConfig, logger })

export function registerUserRoutes(app, deps) {
    var isAuthorized = deps.isAuthorized;
    var authorized = deps.authorized;
    var helpers = deps.helpers;
    var getGroupsFromCache = deps.getGroupsFromCache;
    var saveConfig = deps.saveConfig;
    var logger = deps.logger || function () {};

    app.get('/CollabCentral/:app/user/:scope/:action', function (req, res) {
        if (!isAuthorized(req.params.app, req.cookies.id)) {
            return res.status(401).send('Unauthorized.');
        }
        if (req.params.scope !== 'groups') {
            return res.status(404).send('Not found.');
        }
        if (req.params.action === 'list') {
            logger('apiEndpoint(' + req.params.app + ')', 'GET /user/groups/list');
            var listEntry = helpers.getAuthorizedEntry(authorized, req.params.app, req.cookies.id);
            return res.status(200).send((listEntry && listEntry.groups) || []);
        }
        if (req.params.action === 'find') {
            logger('apiEndpoint(' + req.params.app + ')', 'GET /user/groups/find');
            return getGroupsFromCache()
                .then(function (groups) { res.status(200).send(groups); })
                .catch(function (err) {
                    logger('apiEndpoint(' + req.params.app + ')',
                        'groups/find failed: ' + (err && err.message || err));
                    res.status(502).send('Failed to load groups from Webex.');
                });
        }
        return res.status(404).send('Not found.');
    });

    // Add / remove a favorite group for the calling user. Validation:
    //   - the caller is authorized for :app
    //   - :id looks like a Webex SCIM group id we know about (present in
    //     the cached org-wide list) — stops bad actors from stuffing
    //     arbitrary strings into the store.
    // Because index.js is single-process and node is single-threaded,
    // concurrent requests here can't corrupt authorized.json — every
    // read/mutate/write executes atomically within one handler.
    app.post('/CollabCentral/:app/user/groups/add', async function (req, res) {
        if (!isAuthorized(req.params.app, req.cookies.id)) return res.status(401).send('Unauthorized.');
        var appName = req.params.app;
        var personId = req.cookies.id;
        var groupId = req.body && req.body.id;
        if (!groupId) return res.status(400).send('Missing group id.');

        var group;
        try {
            var allGroups = await getGroupsFromCache();
            group = allGroups.find(function (g) { return g.id === groupId; });
        } catch (err) {
            logger('apiEndpoint(' + appName + ')',
                'groups/add cache lookup failed: ' + (err && err.message || err));
            return res.status(502).send('Group list unavailable.');
        }
        if (!group) return res.status(404).send('Unknown group id.');

        var entry = helpers.getAuthorizedEntry(authorized, appName, personId);
        // isAuthorized guarantees the entry exists but be defensive; a
        // race between an admin removal and this request could otherwise
        // crash.
        if (!entry) return res.status(401).send('Unauthorized.');
        var favorites = Array.isArray(entry.groups) ? entry.groups : [];
        if (favorites.find(function (g) { return g.id === groupId; })) {
            return res.status(200).send(favorites);
        }
        favorites.push({ name: group.displayName, id: group.id });
        entry.groups = favorites;
        try {
            saveConfig(authorized, './config/authorized.json');
        } catch (err) {
            logger('apiEndpoint(' + appName + ')',
                'groups/add save failed: ' + (err && err.message || err));
            return res.status(500).send('Failed to save favorite.');
        }
        logger('apiEndpoint(' + appName + ')',
            'groups/add ' + personId.slice(-8) + ' + "' + group.displayName + '"');
        res.status(200).send(favorites);
    });

    app.post('/CollabCentral/:app/user/groups/remove', function (req, res) {
        if (!isAuthorized(req.params.app, req.cookies.id)) return res.status(401).send('Unauthorized.');
        var appName = req.params.app;
        var personId = req.cookies.id;
        var groupId = req.body && req.body.id;
        if (!groupId) return res.status(400).send('Missing group id.');

        var entry = helpers.getAuthorizedEntry(authorized, appName, personId);
        if (!entry) return res.status(401).send('Unauthorized.');
        var favorites = Array.isArray(entry.groups) ? entry.groups : [];
        var before = favorites.length;
        var removed = favorites.find(function (g) { return g.id === groupId; });
        favorites = favorites.filter(function (g) { return g.id !== groupId; });
        if (favorites.length === before) return res.status(200).send(favorites);

        entry.groups = favorites;
        try {
            saveConfig(authorized, './config/authorized.json');
        } catch (err) {
            logger('apiEndpoint(' + appName + ')',
                'groups/remove save failed: ' + (err && err.message || err));
            return res.status(500).send('Failed to remove favorite.');
        }
        logger('apiEndpoint(' + appName + ')',
            'groups/remove ' + personId.slice(-8) + ' - "' + (removed && removed.name || groupId) + '"');
        res.status(200).send(favorites);
    });
}