// ── The five rules core ships, all of them OFF ─────────────────────────────
//
// ENGAGEMENT.md Phase 6, decision 3. Before this phase the Team pipeline mailed
// people with no operator configuration at all: the code decided who was mailed
// and about what, and the only knobs were per-user. Phase 6 moves that decision
// onto rules — which default `enabled = 0`, and of which core seeds none.
//
// **So a straight migration would have stopped Team email on every existing
// deployment, silently.** The org lead's decision was to honour the invariant
// rather than carve an exception into it: the rules are seeded, and they are
// seeded OFF. Team email resumes when an operator opens Admin → Engagement →
// Rules and switches one on, and until then the admin screen says so in as many
// words (`EngagementRules.jsx`). The release note names it.
//
// The alternative — seeding them enabled so nothing changes for anybody — was
// considered and refused. "Nothing is seeded, nothing is on by default" is what
// makes a rules table safe to restore, import or replicate, and an exception
// carved for the one pipeline that predates the engine is an exception that has
// to be re-argued every time somebody reads the invariant.
//
// **Seeded once, not ensured on every boot**, and the difference matters: an
// operator who deletes a rule must not find it back after a restart. The guard is
// a settings key, the same mechanism a one-shot migration uses, so a deployment
// that has seen this seed never sees it again — deleted rules stay deleted, and
// an enabled rule stays enabled rather than being reset to off.

// **Phase 11 added a fifth, for `news.post`, and it needed its OWN one-shot key
// rather than an entry in the list above.** The Team key is already stamped on
// every deployment that has booted since Phase 6, and the guard reads its
// presence — so appending to `RULES` would have seeded the news rule on fresh
// installs only, and on exactly the upgrades that need it, never. Those are the
// deployments where `pushDispatch.publish('news.post', …)` used to run and no
// longer does (§7.1 Q9): they would have lost news push with no rule to switch
// on and no way to tell why. One key per seed GROUP is the rule this establishes;
// a sixth rule for a new trigger takes a sixth key, and a rule added to an
// existing group is a rule that only fresh installs will ever see.

const rulesDb = require('../model/engagement/engagementRules.db')
const settingsDb = require('../model/settings/settings.db')
const log = require('../utils/logger')('engagement')

// The one-shot guard. Its VALUE is the timestamp, purely so an operator reading
// the settings table can tell when it ran; only its presence is read.
const SEEDED_KEY = 'engagement_team_rules_seeded'

// Phase 11's, and separate for the reason above. Same shape, same semantics.
const NEWS_SEEDED_KEY = 'engagement_news_rule_seeded'

const RULES = [
  {
    trigger_id: 'team.forum.post',
    name: 'Team forum posts',
    // `members`, which resolves to the recipient set the event carries — the
    // access-checked list `teamNotify` has always computed. Not `authenticated`,
    // and the trigger's own ceiling would refuse that anyway: a private Team's
    // forum excerpt reaching the whole site is the failure G24 exists for.
    audience: 'members',
    channels: ['email'],
    // `email` is the instant body; `digest` is what the digest worker renders.
    // Two keys because they are two different messages — a template written for
    // one post renders a day of them as a single missing variable.
    template_keys: { email: 'notify.team-post', digest: 'notify.digest' },
    // No cooldown. A busy thread is exactly what the per-user `email_mode` and
    // the digest option are for, and a cooldown here would silently drop the
    // second reply of a conversation rather than batching it.
    cooldown_seconds: 0,
    max_sends_per_hour: 500,
  },
  {
    trigger_id: 'team.announcement',
    name: 'Team announcements',
    audience: 'members',
    channels: ['email'],
    // **The generic body, not `notify.team-post`, and the reason is a naming
    // inconsistency in the Phase 2 declarations rather than a design choice
    // here.** The two triggers describe the same underlying thing — a thread in a
    // Team forum — but `team.forum.post` declares its title as `threadTitle` and
    // `team.announcement` declares it as `title`. A template can only name one of
    // them, so `notify.team-post`'s `{{threadTitle}}` renders empty for an
    // announcement. `notify.event` + the structural projection gets it right
    // (`title` is in the payload, `actionUrl` falls back to `postUrl`), and
    // reconciling the two declarations is a version bump this phase did not take
    // on its own authority.
    template_keys: { email: 'notify.event', digest: 'notify.digest' },
    cooldown_seconds: 0,
    max_sends_per_hour: 500,
  },
  {
    trigger_id: 'team.member.joined',
    name: 'Team — new member',
    audience: 'members',
    channels: ['email'],
    // The generic body: `notify.event` plus the structural projection renders it
    // with no authoring (§4.6.1 property 1). A deployment that wants a better one
    // duplicates the template and points this rule at the copy.
    template_keys: { email: 'notify.event' },
    // An hour, per user per Team. This is the rule §6.4 argued should not exist
    // as a sink at all — a fifteen-minute sweep, already on the activity feed —
    // and the cooldown is what makes it survivable for the operator who wants it
    // anyway: a guild recruiting ten people in an afternoon sends one mail.
    cooldown_seconds: 3600,
    max_sends_per_hour: 200,
  },
  {
    trigger_id: 'team.leadership.changed',
    name: 'Team — leadership change',
    audience: 'members',
    channels: ['email'],
    template_keys: { email: 'notify.event' },
    cooldown_seconds: 3600,
    max_sends_per_hour: 200,
  },
]

// Phase 11's one rule, in its own list so it can carry its own one-shot key.
const NEWS_RULES = [
  {
    trigger_id: 'news.post',
    name: 'News posts',
    // `subscribers`, which is the trigger's declared default and the population
    // `pushDispatch.publish('news.post', …)` used to reach directly: users who
    // opted into this id on at least one channel. Not `authenticated`, even
    // though the trigger's ceiling permits it — a news post is worth telling
    // people who asked to be told, and mailing the whole user table on every
    // publish is how a notification feature earns a spam complaint.
    audience: 'subscribers',
    // **All three channels, unlike the Team rules' `email` alone**, and that is
    // the continuity half of §7.1 Q9's answer. Push is on this rule because push
    // is what the raw tickle did; leaving it off would mean an operator who
    // enabled the rule to restore news push got mail instead. In-app rides along
    // because the inbox is the surface a tickle deep-links into (Phase 7).
    channels: ['email', 'inapp', 'push'],
    // The generic body plus the structural projection (§4.6.1 property 1):
    // `news.post` declares its own `title` and `postUrl`, which the projection
    // leaves exactly as emitted, so an unauthored mail already names the post and
    // links it. `inapp.event` is the in-app renderer's; push carries no content
    // by construction and needs no template.
    template_keys: { email: 'notify.event', inapp: 'inapp.event', digest: 'notify.digest' },
    // An hour, per USER — `news.post` declares no `subjectKey`, so the cooldown
    // subject is the recipient. "Do not tell me about news more than once an
    // hour" is the useful rule; keying it per post would make it a no-op, since
    // every post is a new subject.
    cooldown_seconds: 3600,
    max_sends_per_hour: 1000,
  },
]

/**
 * Seed one group of rules, once, under its own guard key.
 *
 * Never throws: it is on the boot path beside `seedTemplates`, and a rule that
 * failed to seed costs an operator one visit to the "new rule" form, not a
 * deployment.
 *
 * @param {string} key   the one-shot settings guard for THIS group
 * @param {object[]} rules
 * @param {string} note  what the boot log should say when it inserts
 */
async function seedGroup(key, rules, note) {
  const summary = { inserted: 0, skipped: 0 }
  try {
    // **Claimed BEFORE the loop, atomically**, and the stamp is the claim. A
    // `get()` here with a `set()` after the inserts is not a guard when two
    // instances boot together — both read "absent", both seed — and a duplicate
    // rule is two mails per event. `claim()` is an `INSERT IGNORE` reporting its
    // own `affectedRows`, so exactly one caller proceeds. See the note below on
    // what a partial run costs: that trade is unchanged, only its ordering.
    if (!(await settingsDb.claim(key, new Date().toISOString()))) {
      return { ...summary, skipped: rules.length }
    }

    for (const rule of rules) {
      try {
        await rulesDb.insert({
          audience_segment_id: null,
          conditions: null,
          // No delay and nothing cancels these. `delay_seconds` is the grace
          // window a cancelling event needs, and nothing cancels "someone
          // posted" — the post happened.
          delay_seconds: 0,
          cancel_on: [],
          ...rule,
          enabled: 0,
          updated_by: null,
        })
        summary.inserted += 1
      } catch (err) {
        log.error('team rule seed failed', { trigger: rule.trigger_id, message: err.message })
      }
    }
    // Stamped even on a partial run — the claim above is the stamp. Re-running
    // would duplicate the rules that did insert, and a duplicate rule is two
    // mails per event, a worse outcome than the one missing rule an operator can
    // add from the screen.
    if (summary.inserted) {
      log.info('seeded engagement rules, all disabled', { rules: summary.inserted, note })
    }
  } catch (err) {
    log.error('rule seeding failed', { key, message: err.message })
  }
  return summary
}

/** The four Team rules (Phase 6). */
const seedTeamRules = () =>
  seedGroup(SEEDED_KEY, RULES, 'Team email stays off until an operator enables one')

/** The one news rule (Phase 11). */
const seedNewsRule = () =>
  seedGroup(NEWS_SEEDED_KEY, NEWS_RULES, 'News notifications stay off until an operator enables this rule')

/**
 * Both groups, which is what the boot path calls.
 *
 * Sequential rather than concurrent, and not for correctness — each group has its
 * own guard key and its own rows — but so the boot log reads in a fixed order and
 * a failure names one group rather than an interleaving of two.
 */
async function seedCoreRules() {
  const team = await seedTeamRules()
  const news = await seedNewsRule()
  return {
    inserted: team.inserted + news.inserted,
    skipped: team.skipped + news.skipped,
  }
}

module.exports = {
  seedCoreRules,
  seedTeamRules,
  seedNewsRule,
  RULES,
  NEWS_RULES,
  SEEDED_KEY,
  NEWS_SEEDED_KEY,
}