// ── SQL, and nothing else ─────────────────────────────────────────────────
//
// The `.db.js` half of the pair (see `servers.db.js` for why the split earns its
// keep). Raw parameterised SQL through `core.query`, placeholders always.

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

const LINKS = 'rust_account_links'
const PLAYERS = 'rust_players'
const STATS = 'rust_player_wipe_stats'

/**
 * The link for one Steam id, or undefined.
 *
 * Joins core's `users` for the username, because every caller that asks "who
 * owns this?" wants a name rather than an integer — and the one caller that
 * refuses a re-link has to be able to say *whose* it is.
 */
async function getBySteamId(steamId) {
  const rows = await core.query(
    `SELECT l.steam_id AS steamId, l.user_id AS userId, l.name, l.server_id AS serverId,
            l.linked_at AS linkedAt, u.username
       FROM ${LINKS} l
       JOIN users u ON u.id = l.user_id
      WHERE l.steam_id = ?`,
    [steamId],
  )
  return rows[0]
}

/** Every Steam account one website user holds, newest first. */
async function listForUser(userId) {
  return core.query(
    `SELECT steam_id AS steamId, user_id AS userId, name, server_id AS serverId,
            linked_at AS linkedAt
       FROM ${LINKS}
      WHERE user_id = ?
      ORDER BY linked_at DESC`,
    [userId],
  )
}

/**
 * Record a link.
 *
 * **A plain INSERT, never an upsert**, and that is the whole of D23 expressed in
 * SQL. `ON DUPLICATE KEY UPDATE` here would silently move a Steam id from one
 * website account to another — which, once phase 7 makes a link a privilege path
 * and phase 13 makes it an entitlement, is an account takeover performed by
 * typing a six-character code. The duplicate-key error is the refusal, and the
 * controller turns it into a sentence.
 */
async function insert({ steamId, userId, name, serverId }) {
  await core.query(
    `INSERT INTO ${LINKS} (steam_id, user_id, name, server_id)
     VALUES (?, ?, ?, ?)`,
    [steamId, userId, name || null, serverId || null],
  )
}

/**
 * Remove a link the caller owns.
 *
 * Scoped by `user_id` in the statement rather than checked before it: a delete
 * that reads, decides, then writes has a gap between the read and the write, and
 * this way the ownership test and the deletion are the same operation. Answers
 * how many rows went, so a caller can tell "removed" from "was not yours".
 */
async function removeOwned(steamId, userId) {
  const result = await core.query(
    `DELETE FROM ${LINKS} WHERE steam_id = ? AND user_id = ?`,
    [steamId, userId],
  )
  return Number(result && result.affectedRows) || 0
}

/**
 * Remove a link whoever holds it — the in-game `/unlink` path, and the staff
 * unlink on the `admin.users.detail` panel (D25).
 *
 * Unscoped by user on purpose: neither caller is the link's owner and both have
 * already established their authority another way. In game the authority is the
 * Steam account itself — whoever is connected as it is who it is; on the admin
 * panel it is the tier gate. Which is why the admin caller writes an
 * `activity.log` entry naming the operator and this does not: it cannot tell the
 * two apart, and a log line that guessed would be worse than none.
 */
async function removeBySteamId(steamId) {
  const result = await core.query(`DELETE FROM ${LINKS} WHERE steam_id = ?`, [steamId])
  return Number(result && result.affectedRows) || 0
}

/**
 * Every link one user holds, enriched with what this module knows about that
 * player — for the `admin.users.detail` panel.
 *
 * A LEFT JOIN, because a player can link an account and never play on it. An
 * operator looking at that user should see the link, not an empty panel.
 */
async function listForUserWithPlayer(userId) {
  return core.query(
    `SELECT l.steam_id AS steamId, l.name, l.server_id AS serverId, l.linked_at AS linkedAt,
            p.name AS playerName, p.first_seen AS firstSeen, p.last_seen AS lastSeen
       FROM ${LINKS} l
       LEFT JOIN ${PLAYERS} p ON p.steam_id = l.steam_id
      WHERE l.user_id = ?
      ORDER BY l.linked_at DESC`,
    [userId],
  )
}

/**
 * Per-server all-time totals for one Steam id.
 *
 * The same rows the public leaderboard sums, grouped by server instead of
 * filtered to one — so an operator sees a player across the fleet in one read.
 * All-time, deliberately: an admin looking at a user wants their history, not
 * this week's.
 */
async function statsForSteamId(steamId) {
  return core.query(
    `SELECT s.server_id AS serverId, srv.name AS serverName,
            SUM(s.kills)        AS kills,
            SUM(s.deaths)       AS deaths,
            SUM(s.npc_kills)    AS npcKills,
            SUM(s.structures)   AS structures,
            SUM(s.playtime_sec) AS playtimeSec,
            MAX(s.last_seen)    AS lastSeen,
            COUNT(DISTINCT s.wipe_id) AS wipes
       FROM ${STATS} s
       LEFT JOIN rust_servers srv ON srv.id = s.server_id
      WHERE s.steam_id = ?
      GROUP BY s.server_id, srv.name
      ORDER BY SUM(s.playtime_sec) DESC`,
    [steamId],
  )
}

module.exports = {
  getBySteamId,
  listForUser,
  listForUserWithPlayer,
  insert,
  removeOwned,
  removeBySteamId,
  statsForSteamId,
}