// ── The Team provider ─────────────────────────────────────────────────────
//
// A **Team** is a core platform entity: core owns the tables, the reconciler that
// keeps them in step, the access rules, the forum and the activity feed. What
// core does not own is the word. This game calls them clans, the next will call
// them companies, and a core that picked one would be publishing a noun it
// invented. So core asks, and this file is the whole of the answer.
//
// Registered from `index.js` with `api.registerTeamProvider(...)` (MODULE_API 1.6.0).
//
// ── Why this registration is unlike every other one ───────────────────────
//
// It is the first place **core calls the module and waits**. `registerRoutes`
// hands core a router to mount, `registerNav` hands it a row to draw,
// `registerPostHook` asks to be told when something happens. This hands over
// something core will pick up and call — from its reconciler, and (for
// `projectRoster`) on a request path with someone waiting on the other end.
//
// That inversion is what every rule below follows from:
//
//   • **Core's budget is 10 seconds** and it is core's, not yours. Past it the
//     call is a refusal, whatever your function eventually returns.
//   • **Every method returns an ENVELOPE, never a bare array.** A rejected
//     promise, a synchronous throw, a timeout, a non-object, a missing `ok`, a
//     malformed row — core reads every one of them as `{ ok: false }`. There is
//     no shape a failure can take that core reads as "zero teams", which is the
//     entire argument for the envelope: a bare array has exactly one such shape,
//     `[]`, and it is the one a module returns while its sidecar is connecting.
//   • **Refusing is normal.** `{ ok: false }` is an ordinary answer and not an
//     error you failed to handle. Core keeps the projection it already has,
//     records your reason and shows it to an operator. Nothing empties.
//   • **`projectRoster` is the exception, and it fails CLOSED** — see it below.
//
// ── The one that is easy to get wrong ─────────────────────────────────────
//
// Answering `{ ok: true, teams: [] }` because the game is unreachable. It reads
// as "this deployment has no clans", which is an authoritative statement, and core
// acts on authoritative statements: it archives Teams that have stopped existing
// and departs members who have left. A cold start would empty every roster on the
// site, and the module would have done it by being helpful.
//
// So the guard is the first line of three of the four methods, and it is
// deliberately conservative: an unreachable game refuses, even though the tables
// below still hold a perfectly readable snapshot. Core cannot tell a snapshot
// five minutes old from one five days old, and it makes destructive decisions
// from a complete answer.

const core = require('../../core')

const db = require('./clanProvider.db')
const settings = require('./clanSettings')
const worldStatus = require('../worldStatus/worldStatus.model')

const log = core.logger('clans')

/** A refusal, in the shape core reads. */
const refuse = (reason) => ({ ok: false, reason })

/**
 * Is what these tables hold current enough to answer with?
 *
 * The template has no sidecar, so it asks the freshness the rest of it already
 * tracks: if nothing has reported in longer than the world-status window, the
 * clan tables are a snapshot of unknown age. In a real module this is "is my
 * sidecar socket connected", asked of the socket rather than of a status column —
 * a process that has just started has not transitioned yet, so a persisted
 * `connected` can be left over from the last run.
 */
async function gameIsReachable() {
  const status = await worldStatus.getPublicStatus()
  if (status.stale) return { ok: false, reason: 'the game has not reported recently; clan data may be stale' }
  if (!status.online) return { ok: false, reason: 'the game is offline' }
  return { ok: true }
}

/**
 * `getTeams()` — every clan this deployment has.
 *
 * `externalId` is the game's own stable id, and choosing it is the one genuinely
 * load-bearing decision in this file. **It must survive a rename**: core reads a
 * known id with a new name as a rename and keeps the Team, its forum and its
 * history; it reads an unknown id as a new Team and archives the old one. Handing
 * over the clan's NAME as its id turns every rename into "the clan was deleted
 * and a different one appeared", taking the forum with it.
 *
 * `meta` is an opaque object core stores and displays and never branches on. It
 * is how a concept core has no word for — an alliance, a faction, a season —
 * reaches a Team page without core acquiring an opinion about it.
 */
async function getTeams() {
  const ready = await gameIsReachable()
  if (!ready.ok) return refuse(ready.reason)

  try {
    const rows = await db.listClans()
    return {
      ok: true,
      // `complete: true` says "this is every clan there is", which is what
      // licenses core to archive the ones missing from it. A module that can only
      // answer about some of them — a paged source, a partial cache — must leave
      // it off, and core then adds and updates without ever archiving.
      complete: true,
      teams: rows.map((row) => ({
        externalId: String(row.externalId),
        name: row.name,
        abbr: row.abbr || null,
        meta: null,
      })),
    }
  } catch (err) {
    // The catch is not decoration. An unhandled rejection here would reach core's
    // reconciler as a rejected promise, which it reads as a refusal anyway — but
    // then nothing has logged your side of it, and the operator sees a Team sync
    // that stopped with core blamed for it.
    log.warn('getTeams failed', { message: err.message })
    return refuse(`clan list unreadable: ${err.message}`)
  }
}

/**
 * `getTeamMembers(externalId)` — one clan's roster.
 *
 * **An empty roster is refused unless the game says the clan is empty.** The
 * clan row and its members arrive on separate frames in any real ingest, so there
 * is a window — a clan created seconds ago, a website that connected between the
 * two — where core would otherwise be told authoritatively that a 40-member clan
 * has nobody in it, and would depart all forty. `member_count` is what
 * distinguishes "empty" from "not here yet", and it is the only thing that can:
 * this is why the schema keeps a count the rows cannot supply.
 */
async function getTeamMembers(externalId) {
  const ready = await gameIsReachable()
  if (!ready.ok) return refuse(ready.reason)

  try {
    const clan = await db.findClan(externalId)
    if (!clan) return refuse(`clan ${externalId} is unknown`)

    const rows = await db.listMembers(externalId)
    if (!rows.length && clan.memberCount > 0) {
      return refuse(`roster for clan ${externalId} has not arrived yet (the game says ${clan.memberCount})`)
    }

    return {
      ok: true,
      complete: true,
      members: rows.map((row) => ({
        memberKey: row.memberKey,
        displayName: row.displayName || null,
        rankLabel: row.rankLabel || null,
        leader: Boolean(row.isLeader),
        online: Boolean(row.isOnline),
        // Resolved by THIS module, from this module's own link table. Core does
        // not resolve it and could not: the game↔site mapping is yours, and a
        // core that read it would be core reading a module's table by name.
        userId: row.userId || null,
      })),
    }
  } catch (err) {
    log.warn('getTeamMembers failed', { externalId, message: err.message })
    return refuse(`roster unreadable: ${err.message}`)
  }
}

/**
 * `getTeamLeaders(externalId)` — every member who leads, by member key.
 *
 * **Plural, and answer it plurally.** Core treats multiple leaders as the normal
 * case; a provider that can only name one is a provider whose deployment has one,
 * not a shape core assumes. Leadership is what core grants forum moderation and
 * Team-management rights from, so a leader missing here is a leader locked out of
 * their own clan's forum.
 *
 * Keys, not rows: core already has the roster and only needs to know which of
 * those keys lead. A key that is not in the roster is ignored rather than
 * inventing a member.
 */
async function getTeamLeaders(externalId) {
  const ready = await gameIsReachable()
  if (!ready.ok) return refuse(ready.reason)

  try {
    const clan = await db.findClan(externalId)
    if (!clan) return refuse(`clan ${externalId} is unknown`)

    const rows = await db.listMembers(externalId)
    return { ok: true, leaders: rows.filter((r) => r.isLeader).map((r) => r.memberKey) }
  } catch (err) {
    log.warn('getTeamLeaders failed', { externalId, message: err.message })
    return refuse(`leadership unreadable: ${err.message}`)
  }
}

/**
 * May this viewer see this clan's roster? The audience model itself.
 *
 * **One rule, two callers**, and keeping it that way is the point of the split.
 * `projectRoster` below answers the question for CORE's roster; the module's own
 * `/public/clans/:externalId` route answers it for its own page. A second copy of
 * the rule is a copy that drifts, and the drift is silent in the direction that
 * matters — the page publishing what core is withholding.
 *
 * `viewer` is `{ userId, role }` or `null` for an anonymous caller. Core never
 * hands over the `users` row, which would make every column of that table part of
 * the contract.
 *
 * Throws rather than guessing when it cannot decide; both callers treat a throw
 * as "withhold".
 */
async function rosterVisibleTo(externalId, viewer) {
  const audience = await settings.getRosterAudience()
  if (audience === 'public') return true

  // **Anonymous is an ANSWER, not a failed lookup.** Core hands over `null` for a
  // viewer with no session, and treating that as "I could not work out who this
  // is" would refuse — serving an empty roster to every visitor on a deployment
  // whose clans are public.
  if (!viewer) return false

  if (audience === 'staff') return viewer.role === 'admin' || viewer.role === 'moderator'

  // `'members'`: someone whose account is behind a character in this clan.
  // Resolved from this module's own roster, the only place that mapping exists.
  const roster = await db.listMembers(externalId)
  return roster.some((r) => r.userId && r.userId === viewer.userId)
}

/**
 * `projectRoster(externalId, members, viewer)` — who may see this roster.
 *
 * Optional, and the only method core calls on a REQUEST path. Core holds the
 * roster and its public shape; the question that is yours is *who is allowed to
 * look*, because the audience model is yours and core does not have one.
 *
 * **This one fails CLOSED, and the asymmetry is the point.** For the other three,
 * an unanswered call must change nothing — core keeps what it has. For this one,
 * "keep what you have" means serving the roster unprojected to whoever asked,
 * which is a leak. So core distinguishes two refusals, and you get the right one
 * without doing anything:
 *
 *   • **no provider, or no `projectRoster`** — there is no audience model to
 *     consult and nothing is being withheld, so core serves the roster whole at
 *     its own public shape. That is what makes this member genuinely optional:
 *     omit it and a deployment with no rungs of its own still renders.
 *   • **a `projectRoster` that refused, threw, timed out or answered malformed**
 *     — core serves an EMPTY roster and says so (`projected: false`,
 *     `projectionUnavailable: true`). You said you had an opinion and then did
 *     not give it.
 *
 * **Note what it does not gate on: whether the game is reachable.** Visibility is
 * a question about this deployment's configuration, not about the game — and
 * refusing here because a socket is down would blank a public roster every time
 * the game restarted.
 *
 * **Withhold rows; do not strip fields.** Core's public roster shape already
 * omits the member key and the site account id, so there is nothing here to
 * redact. Return every key or none — and "every key or none" is the honest
 * translation of an audience model that is a property of the FEATURE rather than
 * of a member.
 */
async function projectRoster(externalId, members, viewer) {
  try {
    const visible = await rosterVisibleTo(externalId, viewer)
    return { ok: true, members: visible ? members.map((m) => m.member_key) : [] }
  } catch (err) {
    // Refusing is what withholds the roster. The tempting alternative — return
    // every key, because the lookup failed and the rows are right there —
    // publishes a roster an operator may have gated to staff.
    log.warn('projectRoster could not resolve visibility; withholding the roster', {
      externalId, message: err.message,
    })
    return refuse(`visibility could not be resolved: ${err.message}`)
  }
}

// Where core should point a link at a clan.
//
// **Data, not a method**, and the fifth member of the provider. Core cannot work
// this out for itself and is not supposed to: Teams have no core surface, so the
// module that owns the vocabulary owns the page, and the one thing core needs
// back is where that page lives. A notification email about a forum reply that
// cannot take you to the thread is most of the way to useless.
//
// Core substitutes `{externalId}` and `{slug}` and does nothing else with it. A
// **relative path only** — a template naming its own host is refused at
// registration, protocol-relative `//host/x` with it, because there is no reason
// for a module to redirect the site's outbound mail.
//
// It must match the route `client/src/entry.jsx` registers, and nothing checks
// that for you across the two halves. Omit the member and the deployment loses
// clickable links in Team notification email; omit the ROUTE and it gets links to
// a page that does not exist, which is worse.
const pageUrlTemplate = '/examplegame/clans/{externalId}'

// ── The audience resolver ─────────────────────────────────────────────────
//
// Registered in `index.js` as `examplegame.clan.members` and called by core when
// a rule pointed at that audience fires. It lives beside the provider because it
// answers a question about the same rows, and it is NOT part of the provider —
// core calls it through the audience registry, not through the five members
// above.
//
// **Three rules, and every one of them protects somebody's mailbox rather than
// this module's correctness.**
//
//  1. Return user ids and nothing else. You are not handed a template, a channel
//     or an address, and you may not enumerate them; core maps ids to addresses
//     on its own side, after preferences, suppression and the verification gate.
//  2. Never widen on failure. A resolver that cannot answer returns the EMPTY set
//     — never "everyone", never the last good answer. Core treats a throw the
//     same way, but doing it here is what lets the log say which clan.
//  3. It is a SET of people, not a list of characters. The `DISTINCT` is in the
//     query for that reason (see `clanProvider.db.js`).
async function listClanMemberUserIds({ clanId }) {
  try {
    return await db.listMemberUserIds(clanId)
  } catch (err) {
    log.warn('could not resolve clan members; resolving to nobody', {
      clanId, message: err.message,
    })
    return []
  }
}

module.exports = {
  getTeams,
  getTeamMembers,
  getTeamLeaders,
  projectRoster,
  rosterVisibleTo,
  pageUrlTemplate,
  gameIsReachable,
  listClanMemberUserIds,
}