// ── module-rust's Team provider ────────────────────────────────────────────
//
// The questions core asks this module about Teams (MODULE_API.md
// `api.registerTeamProvider`, TEAMS.md §2.3). A first-party Rust clan is a Team
// (R5); this file is the whole of the translation, and `model/clans` is where
// the clans themselves are kept.
//
// ── The envelope is the contract ──────────────────────────────────────────
//
// Every method answers `{ ok, ... }` and `{ ok: false, reason }` is an ordinary
// answer. Core reads it as "keep what you have" — staleness, never emptiness —
// and there is no shape a failure can take that core reads as "zero Teams". An
// empty array is the one thing this file must never say while it does not know.
//
// ── Many servers, one answer (D53) ─────────────────────────────────────────
//
// `module-uo` has one shard and one socket, so "is the board current" has one
// answer. This module has a fleet, and the answer is per server. `getTeams` is
// therefore:
//
//   • `complete: true`  only when EVERY configured server's board is fresh,
//                       supported and untruncated — then core may archive a
//                       Team that is missing;
//   • `complete: false` when at least one is current and some are not — core
//                       adds and updates, and removes nothing. One server being
//                       off for a patch must never archive its clans;
//   • a refusal         when none is current.
//
// A clan is only ever as current as its own server's board, so the roster
// methods ask about that server alone.

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

const db = require('./clans.db')
const clans = require('./clans.model')
const servers = require('../servers/servers.model')

const log = core.logger('teams')

const refuse = (reason) => ({ ok: false, reason })

/** Is this board record current? The rule `model/clans` states, applied to one row. */
function isFresh(board, now = Date.now()) {
  return clans.shapeBoard(board, now).fresh
}

/**
 * `getTeams()` — every clan on every server's board.
 *
 * `meta` carries the server and the clan's colour and score, opaquely: core
 * stores and shows it and never branches on it.
 */
async function getTeams(now = Date.now()) {
  try {
    const configured = await servers.listForPolling()
    if (!configured.length) return refuse('no Rust servers are configured')

    const boards = await db.listBoards()
    const byServer = new Map(boards.map((b) => [b.serverId, b]))

    const fresh = []
    const behind = []
    for (const server of configured) {
      const board = byServer.get(server.id)
      if (isFresh(board, now)) fresh.push(server.id)
      else behind.push(server.id)
    }

    if (!fresh.length) {
      return refuse(`no server has sent a current clan board (${behind.join(', ')})`)
    }

    // Complete only when nothing is behind, and nothing is at the ceiling. A
    // server that is configured but switched off in this module is "behind" by
    // construction — its board is never read — which is the conservative answer:
    // switching a server off is not a statement that its clans are gone.
    const truncated = fresh.filter((id) => byServer.get(id).truncated)
    const complete = behind.length === 0 && truncated.length === 0

    const rows = await db.listActiveClans()
    const known = new Set(configured.map((s) => s.id))

    return {
      ok: true,
      complete,
      teams: rows
        .filter((row) => known.has(row.serverId))
        .map((row) => ({
          externalId: row.externalId,
          name: row.name,
          abbr: null,
          meta: {
            server: row.serverName || row.serverId,
            serverId: row.serverId,
            color: row.color || null,
            score: Number(row.score) || 0,
          },
        })),
    }
  } catch (err) {
    log.warn('getTeams failed', { error: err.message })
    return refuse(`clans unreadable: ${err.message}`)
  }
}

/** A clan and whether its server's board vouches for it right now, or a refusal. */
async function currentClan(externalId, now) {
  const clan = await db.findClan(externalId)
  if (!clan) return { refusal: refuse(`clan ${externalId} is not on any board`) }
  if (clan.goneAt) return { refusal: refuse(`clan ${externalId} has left its server's board`) }

  const board = await db.getBoard(clan.serverId)
  if (!isFresh(board, now)) {
    return { refusal: refuse(`server ${clan.serverId} has not sent a current clan board`) }
  }
  return { clan }
}

/**
 * `getTeamMembers(externalId)` — one clan's roster.
 *
 * **A clan with no roster rows is refused, not reported empty**, unless the board
 * said it has none. A clan always has at least its leader, so an empty roster
 * beside a non-zero count is a read that happened between two writes, and
 * reporting it would tell core every member left.
 */
async function getTeamMembers(externalId, now = Date.now()) {
  try {
    const { clan, refusal } = await currentClan(externalId, now)
    if (refusal) return refusal

    const rows = await db.listMembers(externalId)
    if (!rows.length && Number(clan.memberCount) > 0) {
      return refuse(`roster for clan ${externalId} is not stored yet (board says ${clan.memberCount} members)`)
    }

    return {
      ok: true,
      complete: true,
      members: rows.map((row) => ({
        memberKey: row.steamId,
        displayName: row.name || null,
        rankLabel: row.role || null,
        // Rank 1 is leader and several may hold it. A NULL rank — a role id the
        // board could not match — is not a leader: "not known" must never read
        // as "leads this clan".
        leader: Number(row.rank) === 1,
        online: Boolean(Number(row.online)),
        userId: Number.isInteger(Number(row.userId)) && Number(row.userId) > 0 ? Number(row.userId) : null,
      })),
    }
  } catch (err) {
    log.warn('getTeamMembers failed', { externalId, error: err.message })
    return refuse(`roster unreadable: ${err.message}`)
  }
}

/** `getTeamLeaders(externalId)` — everyone at rank 1, which may be several. */
async function getTeamLeaders(externalId, now = Date.now()) {
  try {
    const { refusal } = await currentClan(externalId, now)
    if (refusal) return refusal

    const rows = await db.listMembers(externalId)
    return { ok: true, leaders: rows.filter((row) => Number(row.rank) === 1).map((row) => row.steamId) }
  } catch (err) {
    log.warn('getTeamLeaders failed', { externalId, error: err.message })
    return refuse(`leadership unreadable: ${err.message}`)
  }
}

/**
 * Which roster rows a viewer may see (D48, MODULE_API 1.6.0).
 *
 * The one provider method core calls on a REQUEST path, and the one that fails
 * CLOSED: core serves an empty roster when this refuses, because for a
 * visibility question "keep what you have" would mean publishing the roster to
 * whoever asked. So every path that cannot reach a confident answer refuses.
 *
 * All or nothing, and that is the model rather than a shortcut: the audience is
 * a property of the ROSTER, not of a member. There is no setting in which some
 * of a clan's members are visible and others are not.
 */
async function projectRoster(externalId, members, viewer) {
  try {
    const allowed = await clans.canSeeRoster(viewer, externalId)
    if (!allowed) return { ok: true, members: [] }
    return { ok: true, members: (members || []).map((m) => m.member_key).filter(Boolean) }
  } catch (err) {
    log.warn('projectRoster could not resolve the audience; withholding the roster', {
      externalId, error: err.message,
    })
    return refuse(`the roster audience could not be resolved: ${err.message}`)
  }
}

// Where core should point a link at a clan (MODULE_API 1.6.0, TEAMS.md §6.4).
// Core substitutes `{externalId}` and nothing else, which is why the page is not
// nested under its server (D56): the server is inside the id already.
const pageUrlTemplate = '/rust/clans/{externalId}'

module.exports = { getTeams, getTeamMembers, getTeamLeaders, projectRoster, pageUrlTemplate, isFresh }