// ── SQL for the clan tables ───────────────────────────────────────────────
//
// The same `.db.js` / `.model.js` split as `model/worldStatus/`, for the same
// reason: the file with the queries in it has no branching to test, and the file
// with the branching in it has no database to stand up.
//
// Everything here reads this module's OWN tables. **Nothing in a module ever
// reads or writes `teams`, `team_members`, `team_forum_*` or any other core
// table** — core owns the Team, this module owns the clan, and the whole of the
// traffic between them is the provider next door answering three questions
// (MODULE_API.md §2.6's prefix rule, and §2.7).

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

const CLANS = 'examplegame_clans'
const MEMBERS = 'examplegame_clan_members'

/** Every clan the game has told us about. */
async function listClans() {
  return core.query(
    `SELECT external_id AS externalId, name, abbr, member_count AS memberCount
       FROM ${CLANS}
      ORDER BY name`,
  )
}

/** One clan, or `undefined`. */
async function findClan(externalId) {
  const rows = await core.query(
    `SELECT external_id AS externalId, name, abbr, member_count AS memberCount
       FROM ${CLANS}
      WHERE external_id = ?`,
    [externalId],
  )
  return rows[0]
}

/**
 * One clan's roster.
 *
 * Ordered so that a page rendering it directly does not have to sort: leaders
 * first, then by name. Ordering in SQL rather than in the model is a judgement
 * call and this is the case for it — the database is doing it on an index, and
 * the alternative is every caller remembering to.
 */
async function listMembers(clanId) {
  return core.query(
    `SELECT member_key AS memberKey, display_name AS displayName, rank_label AS rankLabel,
            is_leader AS isLeader, is_online AS isOnline, user_id AS userId
       FROM ${MEMBERS}
      WHERE clan_id = ?
      ORDER BY is_leader DESC, display_name`,
    [clanId],
  )
}

/**
 * Replace what we know about one clan, in one transaction-shaped pair of writes.
 *
 * Called by whatever ingests from your sidecar; here, by `boot.js`. Delete-then-
 * insert rather than an upsert, because a roster is a SET and the members who
 * left are as much a part of the update as the ones who joined — an upsert leaves
 * departed characters on the roster forever, and core would keep syncing them
 * into a Team as present members.
 */
async function replaceClan({ externalId, name, abbr, memberCount, members }) {
  await core.query(
    `INSERT INTO ${CLANS} (external_id, name, abbr, member_count, updated_at)
          VALUES (?, ?, ?, ?, CURRENT_TIMESTAMP)
     ON DUPLICATE KEY UPDATE name = VALUES(name), abbr = VALUES(abbr),
                             member_count = VALUES(member_count), updated_at = CURRENT_TIMESTAMP`,
    [externalId, name, abbr || null, memberCount],
  )
  await core.query(`DELETE FROM ${MEMBERS} WHERE clan_id = ?`, [externalId])
  for (const m of members) {
    await core.query(
      `INSERT INTO ${MEMBERS} (clan_id, member_key, display_name, rank_label, is_leader, is_online, user_id)
            VALUES (?, ?, ?, ?, ?, ?, ?)`,
      [externalId, m.memberKey, m.displayName || null, m.rankLabel || null,
        m.leader ? 1 : 0, m.online ? 1 : 0, m.userId || null],
    )
  }
}

/**
 * The site accounts behind one clan's roster — the whole of an audience resolver.
 *
 * `user_id` is NULL for most characters, and the filter is the point: an audience
 * resolves to PEOPLE WITH ACCOUNTS, and a character nobody has linked is not one.
 * Returning its NULL would hand core a hole in an array it is about to mail.
 *
 * DISTINCT because one person may hold several characters in the same clan, and
 * the resolver's contract is a set of users rather than a list of characters.
 * Without it a three-character player is told three times.
 */
async function listMemberUserIds(clanId) {
  const rows = await core.query(
    `SELECT DISTINCT user_id AS userId
       FROM ${MEMBERS}
      WHERE clan_id = ? AND user_id IS NOT NULL`,
    [clanId],
  )
  return rows.map((r) => r.userId)
}

module.exports = { listClans, findClan, listMembers, listMemberUserIds, replaceClan, CLANS, MEMBERS }