// ── Core's own scope-preference provider: Teams ────────────────────────────
//
// ENGAGEMENT.md Phase 6, decision 4. `team_notification_prefs` stays exactly
// where it is and keeps exactly the meaning it has had since Teams shipped; this
// is the adapter that lets the generic engine read it without knowing what a Team
// is. Registered here rather than at the bottom of `scopedPrefs.js` for the same
// reason `coreChannels` and `transports/smtp` are: requiring a registry must not
// have the side effect of populating it.
//
// **The two columns say different things and the mapping is not symmetric.**
//
// - `muted` is the Team's master switch and it silences EVERY channel. That is
//   what the toggle has always meant on the account screen ("mute this Team"),
//   and narrowing it to email would be a behaviour change nobody asked for. Note
//   this is belt-and-braces on the live path — `teamNotify.recipientIds` already
//   excludes muted users before the event is emitted — and it is here anyway so
//   the meaning survives an emitter that stops filtering.
// - `email_mode` says nothing about any other channel, so on push or in-app this
//   provider returns no opinion and the stream-level preference decides.
//
// **Absence of a row means 'off' for email, and that is the whole reason this
// provider answers for every user rather than only for the rows it finds.** The
// column defaults to `'off'` and both recipient queries COALESCE to it: no row
// has always meant "this person has not asked for Team email". Deferring to the
// stream-level preference instead would mean a user who once switched on
// `team.forum.post` email in the channels screen starts receiving mail from every
// Team on the deployment — a widening, produced by a migration, of a preference
// they expressed about something else.

const { registerScopePreference } = require('./scopedPrefs')
const teamNotify = require('../model/teams/teamNotify.model')

// team_notification_prefs.email_mode → the three modes the engine speaks. The
// vocabularies differ by one word and only one word: 'immediate' predates
// `notification_channel_prefs`, whose ENUM says 'instant'.
const EMAIL_MODE = { off: 'off', immediate: 'instant', digest: 'digest' }

async function modesFor(userIds, channel, scopeId) {
  const teamId = Number(scopeId)
  if (!Number.isInteger(teamId) || teamId < 1) return new Map()

  const rows = await teamNotify.prefsForTeam(userIds, teamId)
  const byUser = new Map(rows.map((r) => [Number(r.user_id), r]))
  const modes = new Map()

  for (const userId of userIds) {
    const row = byUser.get(Number(userId))
    if (row && Number(row.muted)) {
      modes.set(Number(userId), 'off')
      continue
    }
    if (channel !== 'email') continue // no opinion; the stream preference decides
    modes.set(Number(userId), EMAIL_MODE[(row && row.email_mode) || 'off'] || 'off')
  }
  return modes
}

registerScopePreference({
  prefix: 'team',
  label: 'Team',
  modesFor,
})

module.exports = { modesFor, EMAIL_MODE }