// ── The Team read model ────────────────────────────────────────────────────
//
// What the three API tiers are allowed to see (TEAMS.md §2.11), assembled from
// the projection, the resolver and the sync state.
//
// **Two rules shape every function here.**
//
// 1. *Hidden means absent from every public surface* (§2.8.3) — the index, the
//    lookup, the roster. Not archived, not deleted, and completely functional for
//    its own members. A hidden Team that 404s publicly but answers for a member
//    is the intended behaviour, not an inconsistency.
//
// 2. *Staleness is surfaced, never silent* (§2.4). Every public payload carries
//    `{ stale, lastSyncAt }`, so a page can say "roster last confirmed 14 minutes
//    ago" rather than presenting a stale roster as current. A projection nobody
//    can tell is stale is worse than one that is obviously old.
//
// The per-audience FIELD projection of a roster row is the module's, not core's
// (§10.5, §3.3) — the visibility framework and its config are module-owned. This
// phase serves a conservative core projection: a public roster carries in-game
// display names and never a site account id or a game member key. The module's
// rung-aware projection lands with the Team pages in phase 3.

const teamsDb = require('./teams.db')
const teamProvider = require('./teamProvider')
const access = require('./teamAccess.model')
const teamSync = require('./teamSync.model')

// Past this multiple of the poll interval a projection is reported stale. Two
// intervals rather than one, so an ordinary late poll does not make every page
// cry wolf — the threshold has to mean "something is wrong", not "a run is due".
const STALE_INTERVALS = 2

/** The public shape of a Team. Deliberately small. */
function publicTeam(row) {
  return {
    slug: row.slug,
    // What is DISPLAYED may have been overridden by staff; what the row IS never
    // changes (§2.2, §2.8.3). Public callers only ever see the former.
    name: row.display_name_override || row.name,
    abbr: row.abbr,
    memberCount: row.member_count,
    linkedCount: row.linked_count,
    onlineCount: row.online_count,
    meta: row.meta ?? null,
    status: row.status,
    createdAt: row.created_at,
    rosterSyncedAt: row.roster_synced_at,
    ...(row.status === 'archived' ? { archivedAt: row.archived_at, archivedReason: row.archived_reason } : {}),
  }
}

/**
 * The public shape of a roster row.
 *
 * `member_key` and `user_id` are both withheld: the first is a game-internal
 * identifier and the second names a site account. `linked` answers the only
 * question a public page has — whether this character has an account behind it —
 * without publishing which one.
 */
function publicMember(row) {
  return {
    displayName: row.display_name,
    rankLabel: row.rank_label,
    isLeader: Boolean(row.is_leader),
    online: Boolean(row.online),
    linked: row.user_id != null,
  }
}

/** The admin shape: everything, including what a decision overrode. */
function adminTeam(row) {
  return {
    id: row.id,
    moduleId: row.module_id,
    externalId: row.external_id,
    slug: row.slug,
    name: row.name,
    displayName: row.display_name_override || row.name,
    displayNameOverride: row.display_name_override,
    abbr: row.abbr,
    status: row.status,
    hidden: Boolean(row.hidden),
    hiddenReason: row.hidden_reason,
    hiddenTerm: row.hidden_term,
    nameReviewedAt: row.name_reviewed_at,
    memberCount: row.member_count,
    linkedCount: row.linked_count,
    onlineCount: row.online_count,
    rosterSyncedAt: row.roster_synced_at,
    membersEmptySince: row.members_empty_since,
    succeededBy: row.succeeded_by,
    createdAt: row.created_at,
    archivedAt: row.archived_at,
    archivedReason: row.archived_reason,
    meta: row.meta ?? null,
  }
}

function adminMember(row) {
  return {
    memberKey: row.member_key,
    displayName: row.display_name,
    userId: row.user_id,
    rankLabel: row.rank_label,
    isLeader: Boolean(row.is_leader),
    isLeaderSynced: Boolean(row.is_leader_synced),
    leaderOverride: row.leader_override || null,
    online: Boolean(row.online),
    status: row.status,
    firstSeenAt: row.first_seen_at,
    lastSeenAt: row.last_seen_at,
    departedAt: row.departed_at,
  }
}

/**
 * Freshness, as every public payload reports it.
 *
 * With no provider registered there is nothing to be stale ABOUT, so this reports
 * `stale: false` and a null timestamp rather than "very stale" — a deployment
 * with no game module is not a broken one.
 */
async function syncStatus() {
  const moduleId = teamProvider.providerModuleId()
  if (!moduleId) return { stale: false, lastSyncAt: null, configured: false }

  const [state, intervalS] = await Promise.all([
    teamsDb.syncState(moduleId),
    teamSync.intervalSeconds(),
  ])
  const lastSyncAt = state ? state.last_success_at : null
  const ageS = lastSyncAt ? (Date.now() - new Date(lastSyncAt).getTime()) / 1000 : Infinity
  return {
    configured: true,
    lastSyncAt,
    // Never synced at all is stale: a page must not present an empty projection
    // as a confirmed empty shard.
    stale: ageS > intervalS * STALE_INTERVALS,
    consecutiveFailures: state ? state.consecutive_failures : 0,
  }
}

// ── Public ─────────────────────────────────────────────────────────────────

async function listPublic({ limit = 50, offset = 0 } = {}) {
  // Every active Team, not just the registered provider's. The rows are core's
  // and they outlive the module that filled them: keying the index on a provider
  // made an uninstalled module's Teams vanish from /teams while
  // /teams/:slug/members still served them in full, because the lookup goes by
  // slug. `configured: false` is how a client learns the projection is no longer
  // being maintained -- an empty list would have said something untrue instead.
  const [rows, sync] = await Promise.all([teamsDb.allActive(), syncStatus()])
  const visible = rows.filter((r) => !r.hidden)
  return {
    teams: visible.slice(offset, offset + limit).map(publicTeam),
    total: visible.length,
    ...sync,
    // What the `teams` nav feature flag resolves from (§3.5). True if a provider
    // is registered OR any Team exists — the second half matters because Team
    // rows outlive the module that filled them, and hiding the nav entry the
    // moment a module is uninstalled would make every existing Team page
    // unreachable from the site while still answering by URL.
    //
    // False only when there is nothing and no prospect of anything, which is
    // exactly the bare-core case the flag exists for: a link to a permanently
    // empty page is worse than no link.
    enabled: Boolean(sync.configured) || visible.length > 0,
  }
}

/**
 * One Team by slug, for a public caller.
 *
 * An ARCHIVED Team resolves rather than 404ing (§2.2): a bookmark or a Discord
 * link from before a rename must land somewhere that explains itself. A HIDDEN
 * one does not resolve at all — that is the difference between retired and
 * suppressed.
 */
async function getPublic(slug) {
  const row = await teamsDb.findBySlug(slug)
  if (!row || row.hidden) return null
  const sync = await syncStatus()
  const successor = row.succeeded_by ? await teamsDb.findById(row.succeeded_by) : null
  return {
    ...publicTeam(row),
    // The three props the `team.overview` extension slot is declared with
    // (§3.4). A module's slot component runs in the browser and has to know
    // WHICH Team it is looking at, in its own vocabulary — `slug` is core's name
    // for it and resolves nothing on the module's side.
    //
    // On this route only, deliberately: the index has no slot and would
    // otherwise publish a module-internal identifier per row for nothing. None
    // of the three names a person — they are a core row id, a game-side group
    // id and a module name, and the identifiers §3.2 withholds (member keys,
    // site account ids) are not among them.
    id: row.id,
    externalId: row.external_id,
    moduleId: row.module_id,
    ...sync,
    successor: successor && !successor.hidden
      ? { slug: successor.slug, name: successor.display_name_override || successor.name }
      : null,
  }
}

/**
 * A Team's roster, projected for the caller's audience rung (§3.3).
 *
 * The ROW filter is the module's: it owns the visibility framework and its
 * configuration (§10.5), and core does not know what a rung is. The FIELD shape
 * stays core's — every row that survives goes through `publicMember`, which
 * withholds the member key and the user id whatever the module answers. So a
 * module can narrow what is published and cannot widen it, and core's "neither is
 * published" guarantee does not rest on every module's good behaviour.
 *
 * **A module that HAS a rung system and cannot answer withholds the roster.** That
 * is the one Team call where a refusal is not staleness: leaving a visibility
 * answer "alone" would publish the very rows the rungs exist to withhold. A
 * deployment with no module, or one whose module does not project at all, is a
 * different case entirely — nothing is being withheld there, so the roster is
 * served whole at core's public shape (`projects: false`).
 */
/**
 * One Team named the way the MODULE names it (§3.4 as amended).
 *
 * The lookup a module's page needs. A module holds its own identity for a Team —
 * a ServUO guild serial — and never core's row id or slug, deliberately: core's
 * identifiers are core-internal (§10.3), and handing them out is how a module
 * ends up storing them and then depending on them.
 *
 * Scoped to the naming module's OWN Teams. `module_id` comes from the path and is
 * matched, not trusted: it cannot be used to read another module's Team, which
 * matters because `external_id` is only unique within a module.
 */
async function getPublicByExternalId(moduleId, externalId) {
  const row = await teamsDb.findActive(moduleId, externalId)
  if (!row || row.hidden) return null
  return { ...publicTeam(row), id: row.id, externalId: row.external_id, moduleId: row.module_id, ...(await syncStatus()) }
}

async function rosterPublic(slug, viewer = null) {
  const row = await teamsDb.findBySlug(slug)
  if (!row || row.hidden) return null
  const [members, sync] = await Promise.all([
    access.rosterWithOverrides(row.id),
    syncStatus(),
  ])

  // The module gets the rows as it supplied them — this is its own data coming
  // home — plus who is asking, which is all a rung decision needs.
  const answer = await teamProvider.projectRoster(row.external_id, members, viewer)
  let visible
  if (answer.ok) visible = members.filter((m) => answer.members.includes(m.member_key))
  else if (answer.projects) visible = [] // fail closed: it has rungs and we could not ask
  else visible = members                 // nothing to fail closed ABOUT

  return {
    members: visible.map(publicMember),
    ...sync,
    rosterSyncedAt: row.roster_synced_at,
    // Stated rather than implied. An empty roster has three quite different
    // causes — a Team with no members, a rung that shows none, and a module that
    // could not be asked — and a page that cannot tell them apart will report the
    // last one as the first.
    projected: answer.ok,
    ...(answer.ok || !answer.projects ? {} : { projectionUnavailable: true }),
  }
}

// ── Player ─────────────────────────────────────────────────────────────────

/**
 * The caller's Teams — membership and grants — each with the REASON it is listed.
 *
 * The two are read from their own tables and merged here rather than by a query
 * that unions them, so the reason survives into the payload. `both` is a real
 * state and the UI needs it: a member who also holds a historical grant should
 * see membership as the current reason without the grant vanishing.
 *
 * A hidden Team IS listed here. Suppression is a public-surface rule; a member is
 * not a member of the public.
 */
async function listForUser(userId) {
  const memberships = await teamsDb.activeTeamsForUser(userId)
  const byId = new Map()

  for (const row of memberships) {
    byId.set(row.id, { ...publicTeam(row), reason: 'membership', isLeader: Boolean(row.is_leader) })
  }

  // Grants are per Team, so the visible set is walked rather than queried the
  // other way round; the population is small (a user's Teams), and it keeps path
  // 3's read on path 3's table.
  const all = await teamsDb.allActive()
  for (const row of all) {
    // eslint-disable-next-line no-await-in-loop
    const resolved = await access.forumAccess(row.id, userId)
    if (!resolved.viaGrant) continue
    const existing = byId.get(row.id)
    if (existing) existing.reason = 'both'
    else byId.set(row.id, { ...publicTeam(row), reason: 'grant', isLeader: false })
  }

  return { teams: [...byId.values()], ...(await syncStatus()) }
}

/** The caller's own resolved access on one Team. */
async function accessForUser(slug, userId) {
  const row = await teamsDb.findBySlug(slug)
  if (!row) return null
  const resolved = await access.forumAccess(row.id, userId)
  return { slug: row.slug, ...resolved }
}

// ── Admin ──────────────────────────────────────────────────────────────────

async function listAdmin({ includeArchived = false } = {}) {
  const moduleId = teamProvider.providerModuleId()
  const rows = await teamsDb.allActive()
  const sync = await syncStatus()
  const state = moduleId ? await teamsDb.syncState(moduleId) : null
  return {
    teams: rows.map(adminTeam),
    ...sync,
    // Shown verbatim on Admin → Teams, including the last error: an operator
    // debugging a stale projection needs what the provider actually said.
    syncState: state
      ? {
        moduleId: state.module_id,
        lastAttemptAt: state.last_attempt_at,
        lastSuccessAt: state.last_success_at,
        consecutiveFailures: state.consecutive_failures,
        lastError: state.last_error,
        pendingEmptySince: state.pending_empty_since,
      }
      : null,
    includeArchived,
  }
}

async function getAdmin(id) {
  const row = await teamsDb.findById(id)
  if (!row) return null
  const [members, grants, pending] = await Promise.all([
    access.rosterWithOverrides(row.id, { includeDeparted: true }),
    access.grantLedger(row.id),
    // eslint-disable-next-line global-require
    require('./teamModeration.model').pendingForTeam(row.id),
  ])
  return {
    ...adminTeam(row),
    members: members.map(adminMember),
    grants,
    pendingRequests: pending,
  }
}

module.exports = {
  listPublic,
  getPublic,
  getPublicByExternalId,
  rosterPublic,
  listForUser,
  accessForUser,
  listAdmin,
  getAdmin,
  syncStatus,
  publicTeam,
  publicMember,
  adminTeam,
  adminMember,
  STALE_INTERVALS,
}