const express = require('express');
const { fetchClosedTickets, fetchWorkload, fetchUnassigned } = require('./tickets');
const { LIMITS, PANELS, SettingsError } = require('./settings');

// Sign-in: Zoho's web OAuth flow. Every user approves with their own Zoho account.
function createAuthRoutes({ zoho, sessions }) {
    const router = express.Router();

    router.get('/login', (req, res) => {
        res.redirect(zoho.authorizeUrl(sessions.startState(res)));
    });

    router.get('/callback', async (req, res) => {
        if (!sessions.checkState(req, res, req.query.state)) {
            return res.redirect('/?signin=expired');
        }
        if (req.query.error || !req.query.code) {
            console.warn('Sign-in refused by Zoho:', req.query.error || 'no code');
            return res.redirect('/?signin=denied');
        }

        try {
            const tokens = await zoho.exchangeCode(String(req.query.code));
            const user = await zoho.getUser(tokens.accessToken);
            if (!sessions.isAllowed(user)) {
                console.warn(`Sign-in refused, not an allowed domain: ${user.email || 'no email'} from ${req.ip}`);
                // they never get a session, so drop the token Zoho just issued
                await zoho.revokeToken(tokens.refreshToken).catch(err => {
                    console.warn('Could not revoke Zoho token:', err.message);
                });
                return res.redirect('/?signin=notallowed');
            }
            sessions.start(res, tokens, user);
            console.log(`Signed in: ${user.email || user.name || 'unknown user'} from ${req.ip}`);
            res.redirect('/');
        } catch (err) {
            console.error('Sign-in failed:', err.response?.data || err.message);
            res.redirect('/?signin=failed');
        }
    });

    router.post('/logout', async (req, res) => {
        const session = sessions.read(req);
        sessions.clear(res);
        if (session) {
            console.log(`Signed out: ${session.user?.email || session.user?.name || 'unknown user'}`);
            await zoho.revokeToken(session.refreshToken).catch(err => {
                console.warn('Could not revoke Zoho token:', err.message);
            });
        }
        res.json({ ok: true });
    });

    return router;
}

// Data: each call runs against SDP with the caller's own token and their saved settings.
// Nothing is cached per user, so the browser decides how often to ask (see checkMinutes and
// the user's workloadMinutes).
function createApiRoutes({ sessions, weatherService, settings, timing, userSettings, nameCache, places }) {
    const router = express.Router();

    router.use((req, res, next) => {
        res.set('Cache-Control', 'no-store');
        next();
    });
    router.use(sessions.requireSession);

    // turns an SDP 401 thrown by tickets.js into a sign-out
    const signedOutOnSdp401 = handler => async (req, res) => {
        try {
            await handler(req, res);
        } catch (err) {
            if (err.response?.status !== 401) throw err;
            sessions.clear(res);
            res.status(401).json({ error: 'ServiceDesk Plus rejected your sign-in' });
        }
    };

    // everything the settings panel needs, sent with the session and after each save
    const settingsReply = user => ({
        settings: userSettings.forUser(user),
        settingsSaved: userSettings.hasSaved(user),
        canSaveSettings: userSettings.canSave(user)
    });

    router.get('/session', (req, res) => {
        res.json({
            user: req.session.user,
            sessionEndsAt: req.session.startedAt + timing.sessionDays * 24 * 60 * 60 * 1000,
            ...settingsReply(req.session.user),
            settingsLimits: { ...LIMITS, panels: PANELS },
            places: weatherService.enabled ? places : [],
            checkMinutes: timing.checkMinutes,
            windowMinutes: timing.windowMinutes
        });
    });

    // only JSON bodies; a cross-site form can't send one without a CORS preflight we never answer
    const readJson = express.json({ limit: '32kb' });
    const jsonBody = (req, res, next) => readJson(req, res, err => {
        if (err) return res.status(400).json({ error: 'Settings were not valid JSON' });
        next();
    });

    router.put('/settings', jsonBody, async (req, res) => {
        if (!req.is('application/json')) return res.status(415).json({ error: 'Send settings as JSON' });
        const input = { ...req.body };
        for (const field of ['sites', 'groups', 'technicians']) {
            if (Array.isArray(input[field])) input[field] = nameCache.canonical(field, input[field]);
        }
        try {
            await userSettings.save(req.session.user, input);
        } catch (err) {
            if (err instanceof SettingsError) return res.status(400).json({ error: err.message });
            console.error('Could not save settings:', err.message);
            return res.status(500).json({ error: 'The server could not save your settings' });
        }
        res.json(settingsReply(req.session.user));
    });

    router.delete('/settings', async (req, res) => {
        try {
            await userSettings.reset(req.session.user);
        } catch (err) {
            console.error('Could not reset settings:', err.message);
            return res.status(500).json({ error: 'The server could not reset your settings' });
        }
        res.json(settingsReply(req.session.user));
    });

    // suggestions for the settings panel; typing any name still works
    router.get('/names', signedOutOnSdp401(async (req, res) => {
        let names;
        try {
            names = await nameCache.list(req.session.accessToken);
        } catch (err) {
            if (err.response?.status === 401) throw err;
            console.warn(`Name suggestions refused for ${req.session.user?.email}:`, err.response?.status || err.message);
            return res.status(403).json({ error: 'ServiceDesk Plus did not allow this request' });
        }
        res.json(names);
    }));

    router.get('/closed', signedOutOnSdp401(async (req, res) => {
        const prefs = userSettings.forUser(req.session.user);
        // the page asks for the full feed on first load, then a short overlapping window each check
        const minutes = Math.min(Math.max(Number(req.query.minutes) || timing.windowMinutes, 1), prefs.feedHours * 60);
        const state = { lastCheck: null, lastError: null };
        const tickets = new Map();

        await fetchClosedTickets({
            accessToken: req.session.accessToken,
            state,
            tickets,
            technicians: prefs.technicians,
            statusSet: settings.statusSet,
            scope: { sites: prefs.sites, groups: prefs.groups },
            windowMinutes: minutes
        });

        res.json({
            checkedAt: state.lastCheck,
            error: state.lastError,
            tickets: [...tickets.values()].sort((a, b) => b.closedAt - a.closedAt)
        });
    }));

    router.get('/workload', signedOutOnSdp401(async (req, res) => {
        const prefs = userSettings.forUser(req.session.user);
        const scope = { sites: prefs.sites, groups: prefs.groups };
        const workload = { updatedAt: null, error: null, truncated: false, statuses: [], technicians: [] };
        const unassigned = { updatedAt: null, error: null, truncated: false, count: 0, discarded: 0, tickets: [] };

        await fetchWorkload({
            accessToken: req.session.accessToken,
            workload,
            technicians: prefs.technicians,
            closedStatuses: settings.closedStatuses,
            scope
        });
        await fetchUnassigned({
            accessToken: req.session.accessToken,
            unassigned,
            excludedStatuses: settings.unassignedExcludedStatuses,
            scope
        });

        res.json({ workload, unassigned });
    }));

    router.get('/weather', async (req, res) => {
        res.json(await weatherService.getWeather(userSettings.forUser(req.session.user).weatherZip));
    });

    return router;
}

module.exports = {
    createAuthRoutes,
    createApiRoutes
};