// ── SQL, and nothing else ─────────────────────────────────────────────────
//
// Core's own backend is layered `router → controller → model → db`, with models
// in pairs: a `.db.js` holding the SQL and a `.model.js` holding the logic that
// calls it. The split earns its keep here for the same reason it does in core —
// 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.
//
// Raw parameterised SQL through `core.query`, no ORM. Placeholders always.

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

const SERVERS = 'rust_servers'
const STATE = 'rust_server_state'

/**
 * Every configured server, in the operator's own order.
 *
 * **The encrypted token comes back on this read and is never returned to a
 * client.** Decryption happens in the model, one layer up; this file's job is to
 * fetch a column, not to decide who may see it.
 */
async function listServers({ enabledOnly = false } = {}) {
  return core.query(
    `SELECT id, name, sidecar_base_url AS sidecarBaseUrl, sidecar_token_enc AS sidecarTokenEnc,
            protocol, enabled, sort_order AS sortOrder, created_at AS createdAt, updated_at AS updatedAt
       FROM ${SERVERS}
      ${enabledOnly ? 'WHERE enabled = 1' : ''}
      ORDER BY sort_order ASC, id ASC`,
  )
}

async function getServer(id) {
  const rows = await core.query(
    `SELECT id, name, sidecar_base_url AS sidecarBaseUrl, sidecar_token_enc AS sidecarTokenEnc,
            protocol, enabled, sort_order AS sortOrder, created_at AS createdAt, updated_at AS updatedAt
       FROM ${SERVERS}
      WHERE id = ?`,
    [id],
  )
  return rows[0] || null
}

/**
 * Create or replace a server row.
 *
 * **`sidecar_token_enc` is only written when a value is supplied.** An admin form
 * that shows a blank token field — which is the only thing it can show, since the
 * token is write-only — posts an empty string on every save that did not intend
 * to change it. Writing that through would erase the credential every time an
 * operator renamed a server, and the failure would present as the bridge going
 * down for no reason an hour after an unrelated edit.
 */
async function upsertServer({ id, name, sidecarBaseUrl, sidecarTokenEnc, protocol, enabled, sortOrder }) {
  const setToken = sidecarTokenEnc !== null && sidecarTokenEnc !== undefined

  await core.query(
    `INSERT INTO ${SERVERS}
       (id, name, sidecar_base_url, sidecar_token_enc, protocol, enabled, sort_order, updated_at)
     VALUES (?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
     ON DUPLICATE KEY UPDATE
       name = VALUES(name),
       sidecar_base_url = VALUES(sidecar_base_url),
       ${setToken ? 'sidecar_token_enc = VALUES(sidecar_token_enc),' : ''}
       protocol = VALUES(protocol),
       enabled = VALUES(enabled),
       sort_order = VALUES(sort_order),
       updated_at = CURRENT_TIMESTAMP`,
    [id, name, sidecarBaseUrl, setToken ? sidecarTokenEnc : null, protocol, enabled ? 1 : 0, sortOrder],
  )
}

async function deleteServer(id) {
  await core.query(`DELETE FROM ${SERVERS} WHERE id = ?`, [id])
}

/** The last thing each server said about itself, keyed by server id. */
async function listState() {
  return core.query(
    `SELECT server_id AS serverId, reachable, online, players, max_players AS maxPlayers,
            hostname, level, seed, world_size AS worldSize, boot_id AS bootId,
            save_created_at AS saveCreatedAt, wipe_id AS wipeId, protocol,
            last_seen_at AS lastSeenAt, updated_at AS updatedAt
       FROM ${STATE}`,
  )
}

/** One server's observed state, or `null`. The single-row twin of `listState`. */
async function getState(serverId) {
  const rows = await core.query(
    `SELECT server_id AS serverId, reachable, online, players, max_players AS maxPlayers,
            hostname, level, seed, world_size AS worldSize, boot_id AS bootId,
            save_created_at AS saveCreatedAt, wipe_id AS wipeId, protocol,
            last_seen_at AS lastSeenAt, updated_at AS updatedAt
       FROM ${STATE}
      WHERE server_id = ?`,
    [serverId],
  )
  return rows[0] || null
}

/**
 * Mark a server unreachable **without forgetting what it last said**.
 *
 * `putState` replaces the row whole, which is right when a sidecar answered: the
 * frame it answered with is the complete truth about that server. It is wrong
 * when nothing answered. A refresh that cannot reach a sidecar knows exactly one
 * new fact — that it could not reach it — and writing the whole row from that
 * one fact sets `hostname`, `level`, `seed`, `world_size` and `wipe_id` to NULL.
 *
 * The site's whole premise is that it renders the last thing each server said
 * while every server is off. A row blanked the first time a game host reboots
 * cannot do that: the page loses the map, the size, the seed and the wipe, and
 * what it shows is not "offline, here is what we know" but "offline, and we have
 * never heard of it". It is invisible in every test that stubs a reachable
 * sidecar, and it shows up as a page that was complete an hour ago.
 *
 * So: three columns move, and the description stays where it is.
 */
async function markUnreachable(serverId, reachable = false) {
  await core.query(
    `INSERT INTO ${STATE} (server_id, reachable, online, players, updated_at)
     VALUES (?, ?, 0, 0, CURRENT_TIMESTAMP)
     ON DUPLICATE KEY UPDATE
       reachable = VALUES(reachable),
       online = 0,
       players = 0,
       updated_at = CURRENT_TIMESTAMP`,
    [serverId, reachable ? 1 : 0],
  )
}

/**
 * Replace one server's observed state.
 *
 * **`updated_at` is set explicitly, and it has to be.** MariaDB's
 * `ON UPDATE CURRENT_TIMESTAMP` fires only when an UPDATE actually CHANGES a
 * value, so an update writing the same numbers back — exactly what a quiet
 * server looks like — leaves the timestamp where it was. The row would then
 * cross the freshness window and the page would report the server offline while
 * it was up and reporting normally. That is invisible to every test and shows up
 * as a page that was right when you looked at it and wrong an hour later.
 */
async function putState(state) {
  await core.query(
    `INSERT INTO ${STATE}
       (server_id, reachable, online, players, max_players, hostname, level, seed,
        world_size, boot_id, save_created_at, wipe_id, protocol, raw, last_seen_at, updated_at)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
     ON DUPLICATE KEY UPDATE
       reachable = VALUES(reachable), online = VALUES(online), players = VALUES(players),
       max_players = VALUES(max_players), hostname = VALUES(hostname), level = VALUES(level),
       seed = VALUES(seed), world_size = VALUES(world_size), boot_id = VALUES(boot_id),
       save_created_at = VALUES(save_created_at), wipe_id = VALUES(wipe_id),
       protocol = VALUES(protocol),
       raw = VALUES(raw),
       -- Only a frame moves this; an unreachable write leaves it alone, which is
       -- what lets a page say how long a server has been down rather than how
       -- recently we failed to reach it.
       last_seen_at = CURRENT_TIMESTAMP,
       updated_at = CURRENT_TIMESTAMP`,
    [
      state.serverId,
      state.reachable ? 1 : 0,
      state.online ? 1 : 0,
      state.players || 0,
      state.maxPlayers || 0,
      state.hostname || null,
      state.level || null,
      state.seed === undefined ? null : state.seed,
      state.worldSize === undefined ? null : state.worldSize,
      state.bootId || null,
      state.saveCreatedAt || null,
      state.wipeId || null,
      state.protocol === undefined ? null : state.protocol,
      state.raw ? JSON.stringify(state.raw) : null,
    ],
  )
}

module.exports = {
  SERVERS,
  STATE,
  listServers,
  getServer,
  upsertServer,
  deleteServer,
  listState,
  getState,
  markUnreachable,
  putState,
}