// Game-account unlinks that a website account's deletion could not finish
// (ACCOUNT_DELETION.md §4.4, AD11). See utils/accountDeletion.js for who writes
// and who clears these rows.

const { query } = require('../../core')

const COLS = 'account, web_user_id, state, queued_at, attempts, last_attempt_at, last_error'

// Queue an account before the first call to the shard, so a hook core abandons
// at its time limit still leaves the account here. A re-queue (the same account
// deleted twice is impossible, but a test or a retry is not) starts it over.
const queue = ({ account, webUserId }) =>
  query(
    `INSERT INTO shard_pending_unlinks (account, web_user_id, state)
     VALUES (?, ?, 'pending')
     ON DUPLICATE KEY UPDATE web_user_id = VALUES(web_user_id), state = 'pending',
       attempts = 0, last_attempt_at = NULL, last_error = NULL`,
    [account, webUserId],
  )

const remove = (account) => query('DELETE FROM shard_pending_unlinks WHERE account = ?', [account])

// One attempt that did not finish. `state` is `pending` (try again) or `refused`
// (the shard said no for good: a protected staff account).
const recordAttempt = ({ account, state, error }) =>
  query(
    `UPDATE shard_pending_unlinks
        SET state = ?, attempts = attempts + 1, last_attempt_at = CURRENT_TIMESTAMP, last_error = ?
      WHERE account = ?`,
    [state, error ? String(error).slice(0, 255) : null, account],
  )

const listPending = () =>
  query(`SELECT ${COLS} FROM shard_pending_unlinks WHERE state = 'pending' ORDER BY queued_at ASC`)

const listAll = () => query(`SELECT ${COLS} FROM shard_pending_unlinks ORDER BY queued_at ASC`)

// The shard just reported this account logging in with `webId` (or none). When
// that is no longer the deleted user, the tag is gone and the row has nothing
// left to wait for. Returns the number of rows dropped.
async function clearIfNotAttributed(account, webId) {
  const result = await query(
    `DELETE FROM shard_pending_unlinks
      WHERE account = ? AND (? IS NULL OR web_user_id <> ?)`,
    [account, webId, webId],
  )
  return Number(result && result.affectedRows) || 0
}

module.exports = { queue, remove, recordAttempt, listPending, listAll, clearIfNotAttributed }