// ── SQL for the permission mirror, and nothing else ───────────────────────
//
// The tables this file reads are described at length in `db/schema.sql`; what
// matters here is which of them is authoritative for what, because four of the
// eight look similar and answer completely different questions:
//
//   AUTHORED   `rust_perm_groups`, `..._group_permissions`, `..._group_members`,
//              `rust_perm_grants` — what an operator (and later an event) says
//              should be true. Keyed by WEBSITE USER (D28).
//   PUSHED     `rust_perm_pushed` — what this site has confirmed into one game's
//              store. Keyed by STEAM ID, because it records what is in the game
//              and the game has never heard of a website account.
//   FOUND      `rust_perm_drift` — what a sync found that the site did not
//              author. Replaced whole by each report: it is the current
//              difference, not a history of differences.
//   INSTRUCTED `rust_perm_revocations` — remove this, even though we never put
//              it there. The only way to act on drift, since a foreign grant
//              often names a Steam id no website account holds.
//
// Raw parameterised SQL through `core.query`, no ORM, like every other `.db.js`
// here. Bulk writes are batched into one statement with a generated placeholder
// list rather than looped, because a fleet-wide sync writes hundreds of rows and
// a round trip each is how a boot tick becomes a second long.

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

const GROUPS = 'rust_perm_groups'
const GROUP_PERMISSIONS = 'rust_perm_group_permissions'
const GROUP_MEMBERS = 'rust_perm_group_members'
const GRANTS = 'rust_perm_grants'
const PUSHED = 'rust_perm_pushed'
const DRIFT = 'rust_perm_drift'
const REVOCATIONS = 'rust_perm_revocations'
const SYNC = 'rust_perm_sync'
const CATALOGUE = 'rust_perm_catalogue'
const LINKS = 'rust_account_links'
const SERVERS = 'rust_servers'

/** `(?,?,?),(?,?,?)` for `rows.length` rows of `width` columns. */
function placeholders(rows, width) {
  return rows.map(() => `(${new Array(width).fill('?').join(',')})`).join(',')
}

// ---- the authored set ----

async function listGroups() {
  return core.query(
    `SELECT name, title, \`rank\`, scope, created_at AS createdAt, updated_at AS updatedAt
       FROM ${GROUPS}
      ORDER BY \`rank\` DESC, name ASC`,
  )
}

async function getGroup(name) {
  const rows = await core.query(
    `SELECT name, title, \`rank\`, scope FROM ${GROUPS} WHERE name = ?`,
    [name],
  )

  return rows[0] || null
}

/**
 * Create or update one group.
 *
 * `ON DUPLICATE KEY UPDATE` rather than a check-then-write: two admins on the
 * same screen is not a race worth losing a title over, and the row's identity is
 * its name either way.
 */
async function upsertGroup({ name, title, rank, scope }) {
  await core.query(
    `INSERT INTO ${GROUPS} (name, title, \`rank\`, scope)
          VALUES (?, ?, ?, ?)
     ON DUPLICATE KEY UPDATE title = VALUES(title), \`rank\` = VALUES(\`rank\`),
                             scope = VALUES(scope), updated_at = CURRENT_TIMESTAMP`,
    [name, title, rank, scope],
  )
}

async function deleteGroup(name) {
  const result = await core.query(`DELETE FROM ${GROUPS} WHERE name = ?`, [name])
  return Number(result.affectedRows || 0) > 0
}

async function listGroupPermissions() {
  return core.query(
    `SELECT group_name AS groupName, permission FROM ${GROUP_PERMISSIONS} ORDER BY permission ASC`,
  )
}

/** Replace a group's permission list whole. The form edits a list, so the write is a list. */
async function setGroupPermissions(name, permissions) {
  await core.query(`DELETE FROM ${GROUP_PERMISSIONS} WHERE group_name = ?`, [name])

  if (!permissions.length) return

  await core.query(
    `INSERT INTO ${GROUP_PERMISSIONS} (group_name, permission)
          VALUES ${placeholders(permissions, 2)}`,
    permissions.flatMap((permission) => [name, permission]),
  )
}

/**
 * Every membership, with the member's Steam accounts joined on.
 *
 * One query rather than a membership read plus a link read per member: the admin
 * screen renders both together and the push needs both together, and a fleet's
 * worth of members is one round trip either way.
 */
async function listGroupMembers() {
  return core.query(
    `SELECT m.group_name AS groupName, m.user_id AS userId, m.added_at AS addedAt,
            u.username, l.steam_id AS steamId, p.name AS playerName
       FROM ${GROUP_MEMBERS} m
       JOIN users u ON u.id = m.user_id
       LEFT JOIN ${LINKS} l ON l.user_id = m.user_id
       LEFT JOIN rust_players p ON p.steam_id = l.steam_id
      ORDER BY m.group_name ASC, u.username ASC`,
  )
}

async function addGroupMember(groupName, userId, addedBy) {
  await core.query(
    `INSERT IGNORE INTO ${GROUP_MEMBERS} (group_name, user_id, added_by) VALUES (?, ?, ?)`,
    [groupName, userId, addedBy],
  )
}

async function removeGroupMember(groupName, userId) {
  const result = await core.query(
    `DELETE FROM ${GROUP_MEMBERS} WHERE group_name = ? AND user_id = ?`,
    [groupName, userId],
  )

  return Number(result.affectedRows || 0) > 0
}

/**
 * Every direct grant, with the holder's accounts joined on.
 *
 * `username` is on the row because a grant with no linked Steam account still
 * has to be listable and nameable — that state is the one the admin screen most
 * needs to show, since it looks exactly like a working grant from every other
 * angle and reaches nobody.
 */
async function listGrants({ userId = null } = {}) {
  return core.query(
    `SELECT g.id, g.user_id AS userId, g.permission, g.scope, g.source, g.note,
            g.granted_at AS grantedAt, u.username,
            l.steam_id AS steamId, p.name AS playerName
       FROM ${GRANTS} g
       JOIN users u ON u.id = g.user_id
       LEFT JOIN ${LINKS} l ON l.user_id = g.user_id
       LEFT JOIN rust_players p ON p.steam_id = l.steam_id
      ${userId === null ? '' : 'WHERE g.user_id = ?'}
      ORDER BY u.username ASC, g.permission ASC`,
    userId === null ? [] : [userId],
  )
}

async function getGrant(id) {
  const rows = await core.query(
    `SELECT id, user_id AS userId, permission, scope, source FROM ${GRANTS} WHERE id = ?`,
    [id],
  )

  return rows[0] || null
}

/**
 * Add a grant, or leave the one that is already there alone.
 *
 * `INSERT IGNORE` against the unique key, and the return says which happened —
 * the controller needs to tell "granted" from "they already had it" to write an
 * honest activity row.
 */
async function insertGrant({ userId, permission, scope, source, note, grantedBy }) {
  const result = await core.query(
    `INSERT IGNORE INTO ${GRANTS} (user_id, permission, scope, source, note, granted_by)
          VALUES (?, ?, ?, ?, ?, ?)`,
    [userId, permission, scope, source, note, grantedBy],
  )

  return { inserted: Number(result.affectedRows || 0) > 0, id: result.insertId }
}

async function deleteGrant(id) {
  const result = await core.query(`DELETE FROM ${GRANTS} WHERE id = ?`, [id])
  return Number(result.affectedRows || 0) > 0
}

/**
 * One website account by name, for the authoring form.
 *
 * A form that made an operator type a numeric user id would be a form nobody
 * could use, and the alternative — calling core's own admin user search from the
 * client — would bind this module to the shape of a response the contract does
 * not cover. Reading the `users` table is already what every join in this file
 * does.
 *
 * Case-insensitive because the column's collation is: core stores usernames in a
 * `_ci` collation and an exact-case lookup would refuse a name the site itself
 * considers the same one.
 */
async function findUserByUsername(username) {
  const rows = await core.query(`SELECT id, username FROM users WHERE username = ? LIMIT 1`, [username])
  return rows[0] || null
}

/** Which website user holds which Steam account. The join that turns an authored row into a push. */
async function listLinks() {
  return core.query(`SELECT user_id AS userId, steam_id AS steamId FROM ${LINKS}`)
}

// ---- what is actually out there ----

async function listPushed(serverId) {
  return core.query(
    `SELECT kind, subject, object FROM ${PUSHED} WHERE server_id = ?`,
    [serverId],
  )
}

async function addPushed(serverId, rows) {
  if (!rows.length) return

  await core.query(
    `INSERT IGNORE INTO ${PUSHED} (server_id, kind, subject, object)
          VALUES ${placeholders(rows, 4)}`,
    rows.flatMap((row) => [serverId, row.kind, row.subject, row.object]),
  )
}

async function removePushed(serverId, rows) {
  for (const row of rows) {
    // eslint-disable-next-line no-await-in-loop
    await core.query(
      `DELETE FROM ${PUSHED} WHERE server_id = ? AND kind = ? AND subject = ? AND object = ?`,
      [serverId, row.kind, row.subject, row.object],
    )
  }
}

/**
 * Replace one server's drift list with what the latest report found.
 *
 * Whole, rather than merged, and `first_seen` survives through the
 * `ON DUPLICATE KEY UPDATE` — so "this has been here since Tuesday" is still
 * answerable while "somebody has since undone it" removes the row.
 */
async function replaceDrift(serverId, rows) {
  if (!rows.length) {
    await core.query(`DELETE FROM ${DRIFT} WHERE server_id = ?`, [serverId])
    return
  }

  await core.query(
    `INSERT INTO ${DRIFT} (server_id, kind, subject, object)
          VALUES ${placeholders(rows, 4)}
     ON DUPLICATE KEY UPDATE last_seen = CURRENT_TIMESTAMP`,
    rows.flatMap((row) => [serverId, row.kind, row.subject, row.object]),
  )

  // Anything this report did NOT name is gone from the game, so it goes from
  // here. Named explicitly rather than swept by timestamp: two syncs a second
  // apart would make a timestamp window either delete live rows or keep dead
  // ones, depending on the clock.
  await core.query(
    `DELETE FROM ${DRIFT}
      WHERE server_id = ?
        AND (kind, subject, object) NOT IN (${placeholders(rows, 3)})`,
    [serverId, ...rows.flatMap((row) => [row.kind, row.subject, row.object])],
  )
}

async function listDrift() {
  return core.query(
    `SELECT d.id, d.server_id AS serverId, d.kind, d.subject, d.object,
            d.first_seen AS firstSeen, d.last_seen AS lastSeen,
            l.user_id AS userId, u.username, p.name AS playerName
       FROM ${DRIFT} d
       LEFT JOIN ${LINKS} l ON l.steam_id = d.subject
       LEFT JOIN users u ON u.id = l.user_id
       LEFT JOIN rust_players p ON p.steam_id = d.subject
      ORDER BY d.server_id ASC, d.kind ASC, d.subject ASC`,
  )
}

async function getDrift(id) {
  const rows = await core.query(
    `SELECT id, server_id AS serverId, kind, subject, object FROM ${DRIFT} WHERE id = ?`,
    [id],
  )

  return rows[0] || null
}

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

async function queueRevocation({ serverId, kind, subject, object, requestedBy }) {
  await core.query(
    `INSERT IGNORE INTO ${REVOCATIONS} (server_id, kind, subject, object, requested_by)
          VALUES (?, ?, ?, ?, ?)`,
    [serverId, kind, subject, object, requestedBy],
  )
}

async function listRevocations(serverId) {
  return core.query(
    `SELECT id, kind, subject, object FROM ${REVOCATIONS} WHERE server_id = ?`,
    [serverId],
  )
}

async function deleteRevocations(ids) {
  if (!ids.length) return

  await core.query(
    `DELETE FROM ${REVOCATIONS} WHERE id IN (${ids.map(() => '?').join(',')})`,
    ids,
  )
}

// ---- the state of the mirror ----

/**
 * One sync row per configured server, created on demand.
 *
 * A server added today has no row and must not therefore be skipped for ever, so
 * the read inserts what is missing rather than the writer remembering to.
 */
async function ensureSyncRows() {
  await core.query(
    `INSERT IGNORE INTO ${SYNC} (server_id) SELECT id FROM ${SERVERS}`,
  )
}

async function listSync() {
  return core.query(
    `SELECT s.server_id AS serverId, s.state, s.dirty, s.desired_hash AS desiredHash,
            s.synced_hash AS syncedHash, s.boot_id AS bootId, s.wipe_id AS wipeId,
            s.last_attempt_at AS lastAttemptAt, s.last_ok_at AS lastOkAt,
            s.report, s.error
       FROM ${SYNC} s
      ORDER BY s.server_id ASC`,
  )
}

/**
 * Mark servers as needing a sync.
 *
 * `scope` is a server id or `*`; a fleet-wide change dirties every row, which is
 * right: the set each server should hold has changed even if only one of them
 * will notice a difference.
 */
async function markDirty(scope) {
  if (!scope || scope === '*') {
    await core.query(`UPDATE ${SYNC} SET dirty = 1, updated_at = CURRENT_TIMESTAMP`)
    return
  }

  await core.query(
    `UPDATE ${SYNC} SET dirty = 1, updated_at = CURRENT_TIMESTAMP WHERE server_id = ?`,
    [scope],
  )
}

/**
 * Record the outcome of one attempt.
 *
 * **`dirty` is cleared unconditionally, and that is safe because it is an
 * optimisation rather than the truth.** Something may well have changed the
 * authored set while this sync was in flight, and clearing the flag would then
 * lose that change — except that the loop's real condition is
 * `desired_hash != synced_hash`, recomputed from the tables on every tick. The
 * flag only saves a hash comparison; the hash is what cannot be wrong.
 *
 * `last_ok_at` moves only on success, and it is passed rather than composed into
 * the SQL so the statement is the same string every time.
 */
async function putSyncResult(serverId, { state, syncedHash, desiredHash, bootId, wipeId, report, error }) {
  const okAt = state === 'ok' ? new Date() : null

  await core.query(
    `INSERT INTO ${SYNC} (server_id, state, dirty, desired_hash, synced_hash, boot_id, wipe_id,
                          last_attempt_at, last_ok_at, report, error, updated_at)
          VALUES (?, ?, 0, ?, ?, ?, ?, NOW(), ?, ?, ?, NOW())
     ON DUPLICATE KEY UPDATE state = VALUES(state), dirty = 0,
                             desired_hash = VALUES(desired_hash),
                             synced_hash = VALUES(synced_hash),
                             boot_id = VALUES(boot_id), wipe_id = VALUES(wipe_id),
                             last_attempt_at = NOW(),
                             last_ok_at = COALESCE(VALUES(last_ok_at), last_ok_at),
                             report = VALUES(report), error = VALUES(error),
                             updated_at = NOW()`,
    [serverId, state, desiredHash, syncedHash, bootId, wipeId, okAt, report, error],
  )
}

// ---- the option source ----

async function putCatalogue(serverId, permissions) {
  await core.query(`DELETE FROM ${CATALOGUE} WHERE server_id = ?`, [serverId])

  if (!permissions.length) return

  await core.query(
    `INSERT IGNORE INTO ${CATALOGUE} (server_id, permission)
          VALUES ${placeholders(permissions, 2)}`,
    permissions.flatMap((permission) => [serverId, permission]),
  )
}

async function listCatalogue() {
  return core.query(
    `SELECT server_id AS serverId, permission FROM ${CATALOGUE} ORDER BY permission ASC`,
  )
}

module.exports = {
  GROUPS,
  GRANTS,
  PUSHED,
  DRIFT,
  listGroups,
  getGroup,
  upsertGroup,
  deleteGroup,
  listGroupPermissions,
  setGroupPermissions,
  listGroupMembers,
  addGroupMember,
  removeGroupMember,
  listGrants,
  getGrant,
  insertGrant,
  deleteGrant,
  findUserByUsername,
  listLinks,
  listPushed,
  addPushed,
  removePushed,
  replaceDrift,
  listDrift,
  getDrift,
  deleteDrift,
  queueRevocation,
  listRevocations,
  deleteRevocations,
  ensureSyncRows,
  listSync,
  markDirty,
  putSyncResult,
  putCatalogue,
  listCatalogue,
}