// Self-service push-notification management for the logged-in user (any role).
// Mounted under /auth/me behind requireAuth, so req.user is the fresh DB row.
// Devices (endpoints) and stream subscriptions live here; the fan-out that
// actually delivers is utils/pushDispatch. See docs/android/PLAN.md §11.

const pushDevices = require('../../../model/pushDevices/pushDevices.model')
const notificationSubs = require('../../../model/notificationSubs/notificationSubs.model')
const channelPrefs = require('../../../model/notificationChannelPrefs/notificationChannelPrefs.model')
const registries = require('../../../modules/registries')
const teamPrefs = require('../../../model/teams/teamNotify.model')
const { isAllowedEndpoint } = require('../../../utils/pushDispatch')
const inbox = require('../../../model/userNotifications/userNotifications.db')

const log = require('../../../utils/logger')('notifications')

// POST /auth/me/devices — register (or refresh) a push endpoint for this user.
async function registerDevice(req, res) {
  const { transport = 'unifiedpush', endpoint, platform } = req.body
  // SSRF guard: the endpoint is a URL the server will later POST to. Reject
  // anything that isn't an allowed HTTPS relay origin before storing it.
  if (!isAllowedEndpoint(endpoint)) {
    return res.status(400).json({ message: 'Endpoint is not an allowed push URL' })
  }
  try {
    const device = await pushDevices.register({ userId: req.user.id, transport, endpoint, platform })
    return res.status(201).json(device)
  } catch (err) {
    log.error('registerDevice', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// GET /auth/me/devices — this user's registered devices.
async function listDevices(req, res) {
  try {
    return res.json(await pushDevices.listForUser(req.user.id))
  } catch (err) {
    log.error('listDevices', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// DELETE /auth/me/devices/:id — unregister a device (must belong to the caller).
async function removeDevice(req, res) {
  try {
    const ok = await pushDevices.remove(Number(req.params.id), req.user.id)
    if (!ok) return res.status(404).json({ message: 'Not found' })
    return res.json({ ok: true })
  } catch (err) {
    log.error('removeDevice', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// GET /auth/me/notifications/streams — the subscribable catalog: core's streams
// plus every installed module's, in registration order. Fixed for the lifetime of
// a process (registration is boot-time), not a static constant.
function getStreams(req, res) {
  return res.json({ streams: registries.allStreams() })
}

// GET /auth/me/notifications/subscriptions — the caller's opted-in stream ids.
async function getSubscriptions(req, res) {
  try {
    return res.json({ streams: await notificationSubs.getForUser(req.user.id) })
  } catch (err) {
    log.error('getSubscriptions', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// PUT /auth/me/notifications/subscriptions — replace the caller's stream set.
// Unknown ids are dropped; the stored (cleaned) set is echoed back.
async function putSubscriptions(req, res) {
  try {
    const streams = await notificationSubs.setForUser(req.user.id, req.body.streams)
    return res.json({ streams })
  } catch (err) {
    log.error('putSubscriptions', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// GET /auth/me/notifications/channels — the per-channel preferences surface
// (ENGAGEMENT.md Phase 3): the channel registry's declarative half, plus one item
// per subscribable id with its EFFECTIVE mode on each channel that applies.
//
// The superset of `/notifications/streams` + `/notifications/subscriptions`,
// which stay exactly as they are for the shipped app.
async function getChannelPrefs(req, res) {
  try {
    return res.json(await channelPrefs.getForUser(req.user.id, req.user))
  } catch (err) {
    log.error('getChannelPrefs', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// PUT /auth/me/notifications/channels — apply a SPARSE set of preferences.
//
// Only the (id, channel) pairs in the body are written; every other pair is left
// alone, so a screen that manages one channel need not know about the others. Off
// is a mode, not an omission — which is also why this endpoint has no
// empty-array case to get wrong, unlike its two neighbours. Entries naming an
// unknown id, an inapplicable channel or a mode that channel does not accept are
// dropped by the model; the full stored state is echoed back so the caller can
// see what actually took.
async function putChannelPrefs(req, res) {
  try {
    return res.json(await channelPrefs.applyForUser(req.user.id, req.body.prefs, req.user))
  } catch (err) {
    log.error('putChannelPrefs', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// GET /auth/me/notifications/teams — this user's per-Team preferences, one row
// per Team they could be notified about whether or not they have ever set one.
//
// Not gated on `teams_forums_enabled`: two of the four streams (member joined,
// leadership changed) have nothing to do with the forum, so a deployment with
// forums switched off still has preferences worth showing.
async function getTeamPrefs(req, res) {
  try {
    return res.json({ teams: await teamPrefs.listPrefs(req.user.id) })
  } catch (err) {
    log.error('getTeamPrefs', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// PUT /auth/me/notifications/teams — replace the caller's whole preference set.
//
// PUT-the-whole-set, matching the subscriptions endpoint beside it, and the
// `teams` array is REQUIRED even when empty — the Android gotcha in
// docs/android/PLAN.md §11: a DTO field with a default is dropped by kotlinx when
// it equals that default, so clearing the last entry would arrive as a body with
// no array at all and 400. Entries naming a Team the caller is not in are dropped
// by the model rather than refused here (an ordinary race, not a client bug).
async function putTeamPrefs(req, res) {
  try {
    const { prefs } = await teamPrefs.replacePrefs(req.user.id, req.body.teams)
    return res.json({ teams: prefs })
  } catch (err) {
    log.error('putTeamPrefs', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// ── The inbox (ENGAGEMENT.md §4.5 G17, Phase 7) ────────────────────────────
//
// The in-app channel's read side. Everything above this line is a PREFERENCE —
// which streams, which channels, which Teams — and everything below it is
// CONTENT addressed to the caller. They share a path prefix because a person
// calls both "notifications", and the shapes keep them apart: the preference
// endpoints are whole-set GET/PUT pairs on named sub-paths, the inbox is a
// paged GET on the bare path with POSTs that name a row.
//
// **`req.user.id` is the only user id any of these can name.** There is no route
// parameter for a user and no query string that selects one, so the ownership
// check is not something a caller can be forgetful about — it is the shape of
// the API. The model then repeats it in the WHERE clause of every statement, so
// "read someone else's notification" is a 404 twice over.

// GET /auth/me/notifications — one page of the caller's inbox, newest first.
async function getInbox(req, res) {
  try {
    const page = await inbox.list(req.user.id, {
      limit: req.query.limit,
      before: req.query.before,
      unreadOnly: req.query.unread === 'true' || req.query.unread === '1',
    })
    // The unread count rides along on every page, so the bell and the list never
    // disagree: a client that renders both from one response cannot show "3
    // unread" above a list in which the third was just marked read.
    return res.json({ ...page, unread: await inbox.unreadCount(req.user.id) })
  } catch (err) {
    log.error('getInbox', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// GET /auth/me/notifications/unread-count — the badge, on its own.
//
// Its own route rather than a field of the list, because it is polled: a client
// asking "is there anything new" every minute should not make the server
// assemble thirty rows and their bodies to answer with one integer.
async function getUnreadCount(req, res) {
  try {
    return res.json({ unread: await inbox.unreadCount(req.user.id) })
  } catch (err) {
    log.error('getUnreadCount', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// POST /auth/me/notifications/:id/read — mark one item read. Idempotent.
//
// 404 both when the row does not exist and when it belongs to somebody else,
// which is the same answer on purpose: distinguishing them would turn this route
// into a way to ask whether a given id is anybody's.
async function markRead(req, res) {
  try {
    const found = await inbox.markRead(req.user.id, req.params.id)
    if (!found) return res.status(404).json({ message: 'Not Found' })
    return res.json({ ok: true, unread: await inbox.unreadCount(req.user.id) })
  } catch (err) {
    log.error('markRead', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

// POST /auth/me/notifications/read-all — mark the whole inbox read.
async function markAllRead(req, res) {
  try {
    const changed = await inbox.markAllRead(req.user.id)
    return res.json({ ok: true, changed, unread: 0 })
  } catch (err) {
    log.error('markAllRead', err)
    return res.status(500).json({ message: 'Internal Server Error' })
  }
}

module.exports = {
  registerDevice,
  listDevices,
  removeDevice,
  getStreams,
  getSubscriptions,
  putSubscriptions,
  getChannelPrefs,
  putChannelPrefs,
  getTeamPrefs,
  putTeamPrefs,
  getInbox,
  getUnreadCount,
  markRead,
  markAllRead,
}