// ── `/guild` — the first chat command through the module contract ──────────
//
// Registered with `api.registerSlashCommands` (MODULE_API 1.6.0, TEAMS.md §7.1).
// The definition and this handler live here; the bot pulls the definition over
// the app's internal API and runs nothing of ours. Nothing in this file knows
// what Discord is — it is handed an `actor` and returns an envelope, and the
// same handler would serve a second platform unchanged.
//
// **Why `/guild` and not `/team`.** Teams are core's primitive and "guild" is
// this module's word for one; core does not own the word, so it does not publish
// the noun in a channel either. That is the same correction that deleted core's
// Team pages in phase 3, applied to the chat surface.
//
// **The audience rungs are enforced here, exactly as they are on the website.**
// A shard whose `guilds` feature is gated to staff does not become public
// because the question arrived over Discord — this handler resolves the caller's
// rung through the same `shardVisibility` config the routes use. It is the one
// piece of this file that is a security boundary rather than presentation.
const core = require('../core')
const db = require('../model/teamProvider/teamProvider.db')
const provider = require('../model/teamProvider/teamProvider.model')
const visibility = require('../utils/shardVisibility')

const log = core.logger('guild-command')

// How many guilds the no-argument form lists. A Discord embed takes 25 fields;
// ten is a summary a person reads rather than a table they scroll past.
const LIST_LIMIT = 10

/**
 * Where the caller sits on this module's ladder.
 *
 * The same resolution `projectRoster` does, and it is duplicated in shape rather
 * than shared because the inputs differ: that one is handed a viewer core
 * described, this one an actor. Both end at `viewerLevel`, and both answer
 * `anonymous` DIRECTLY for a caller with no site account — handing `viewerLevel`
 * a synthetic empty request makes it fall through to `auth.getUserFromRequest`,
 * which expects real cookies and throws (the phase 3 bug).
 */
async function levelFor(actor) {
  if (!actor || !actor.userId) return 'anonymous'
  return visibility.viewerLevel({ user: { id: actor.userId, role: actor.role } })
}

// The nudge §9 answer 5 asks for, and only when it is TRUE.
//
// **Linking reaches exactly two rungs and no further.** Signing in gets a caller
// to `logged_in` and linking a game account to `player`; `staff` and `admin` are
// roles an operator grants and no amount of linking will earn. So a shard that
// gates guilds to staff refuses an unlinked caller WITHOUT the invitation —
// telling them to link would be telling them to do something that changes
// nothing, which is worse than saying no.
//
// The live walk found this: gated to `staff`, the refusal still read "this shard
// shows guild information to linked players".
const LINKING_REACHES = new Set(['logged_in', 'player'])

function linkPrompt(actor, audience) {
  if (actor.isLinked) return null
  if (!LINKING_REACHES.has(audience)) return null
  return 'Link your account on the site to see more — this shard shows guild information to linked players.'
}

const pageUrl = (externalId) =>
  `${core.baseUrl}${provider.pageUrlTemplate.replace('{externalId}', externalId)}`

// Match on abbreviation first, then an exact name, then a unique prefix. Players
// type the abbreviation — it is what appears over a character's head — and a
// wrong-guild answer is worse than "say which one".
function findByName(rows, wanted) {
  const needle = wanted.trim().toLowerCase()
  const byAbbr = rows.filter((r) => (r.abbr || '').toLowerCase() === needle)
  if (byAbbr.length === 1) return { guild: byAbbr[0] }
  const exact = rows.filter((r) => r.name.toLowerCase() === needle)
  if (exact.length === 1) return { guild: exact[0] }
  const partial = rows.filter((r) => r.name.toLowerCase().includes(needle))
  if (partial.length === 1) return { guild: partial[0] }
  if (partial.length > 1) return { ambiguous: partial.slice(0, LIST_LIMIT) }
  return {}
}

/** The counts for one guild, from the roster rather than the board's assertions. */
async function summarise(guild) {
  const members = await db.listGuildMembers(guild.id)
  const leaders = members
    .filter((m) => Number(m.rank) >= db.LEADER_RANK)
    .map((m) => m.name)
  // The board's founder-leader is folded in as a floor, the same way
  // getTeamLeaders does it: it arrives on a different frame, and a shard whose
  // roster predates the rank amendment has no other leadership signal.
  if (guild.leader_name && !leaders.includes(guild.leader_name)) leaders.push(guild.leader_name)

  return {
    // `members`/`online` are the BOARD's counts, which is what the shard asserts;
    // the roster is what it enumerated, and the two legitimately disagree for the
    // moment between a membership change and the sweep that reports it. The
    // assertion is the more current of the two, so it is what is shown.
    members: guild.members,
    online: guild.online,
    linked: members.filter((m) => provider.resolveUserId(m) !== null).length,
    leaders,
  }
}

async function detail(guild, actor, audience) {
  const counts = await summarise(guild)
  const fields = [
    { name: 'Members', value: String(counts.members ?? '—'), inline: true },
    { name: 'Online', value: String(counts.online ?? 0), inline: true },
    { name: 'Linked accounts', value: String(counts.linked), inline: true },
  ]
  if (counts.leaders.length) {
    fields.push({ name: 'Leaders', value: counts.leaders.join(', ') })
  }
  return {
    title: guild.abbr ? `${guild.name} [${guild.abbr}]` : guild.name,
    text: guild.alliance ? `Alliance: ${guild.alliance}` : undefined,
    fields,
    url: pageUrl(guild.id),
    notice: linkPrompt(actor, audience),
  }
}

/**
 * `/guild [name]` — one guild's summary, or the shard's largest guilds.
 *
 * Never throws for an ordinary miss: "no such guild" and "the shard is offline"
 * are answers, and letting either become an exception would turn a routine
 * question into "that command failed" with nothing an operator could act on.
 */
async function handler({ options, actor }) {
  const config = await visibility.getConfig()
  const feature = config.guilds

  // An admin turned guilds off. The switch means "this shard does not publish
  // guild data" — over any surface, to anyone, staff included.
  if (!feature || !feature.enabled) {
    return { text: 'This shard does not publish guild information.', ephemeral: true }
  }

  const level = await levelFor(actor)
  if (!visibility.meets(level, feature.audience)) {
    return {
      text: 'Guild information on this shard is not shown to your account.',
      ephemeral: true,
      notice: linkPrompt(actor, feature.audience),
    }
  }

  // The provider's own staleness guard, asked before any board read: an
  // unreachable sidecar means the board is a snapshot of unknown age, and
  // reporting it as current here would contradict what every other surface says.
  const ready = await provider.boardIsCurrent()
  if (!ready.ok) {
    log.info('guild command answered offline', { reason: ready.reason })
    return { text: 'The shard is not connected right now, so guild information may be out of date.', ephemeral: true }
  }

  const rows = await db.listGuilds()
  if (!rows.length) return { text: 'No guilds are on the board yet.', ephemeral: true }

  const wanted = options && typeof options.name === 'string' ? options.name : null
  if (!wanted) {
    const top = [...rows].sort((a, b) => (b.members || 0) - (a.members || 0)).slice(0, LIST_LIMIT)
    return {
      // Not "Guilds on <host>": `ctx.site` carries a base URL and no brand name,
      // so naming the deployment here can only mean printing its hostname into
      // an embed title, which is noise on a shard's own Discord server.
      title: 'Guilds on this shard',
      fields: top.map((g) => ({
        name: g.abbr ? `${g.name} [${g.abbr}]` : g.name,
        value: `${g.members || 0} members · ${g.online || 0} online`,
        inline: true,
      })),
      notice: linkPrompt(actor, feature.audience),
    }
  }

  const { guild, ambiguous } = findByName(rows, wanted)
  if (ambiguous) {
    return {
      text: `Several guilds match “${wanted}”: ${ambiguous.map((g) => g.name).join(', ')}`,
      ephemeral: true,
    }
  }
  if (!guild) return { text: `No guild matches “${wanted}”.`, ephemeral: true }
  return detail(guild, actor, feature.audience)
}

module.exports = {
  name: 'guild',
  description: 'Show a guild on this shard — members, who is online, and its leaders',
  options: [
    { name: 'name', type: 'string', description: 'Guild name or abbreviation', required: false },
  ],
  // Everyone, deliberately. The gate that matters is the shard's own audience
  // rung, resolved inside the handler — `access: 'linked'` would hide the command
  // from exactly the unlinked members §9 answer 5 wants to invite to link.
  access: 'everyone',
  handler,
}