const { query, one, limitClause } = require('../lib/db')

/**
 * Create a scan report
 * @param {Object} report
 * @param {number} report.user_id
 * @param {string|null} report.device_id
 * @param {string|null} report.scanned_at - MySQL datetime string
 * @param {string} report.regions - JSON string (array)
 * @param {string} report.overall - JSON string (array)
 * @param {number} report.recommend_mask
 * @param {string} report.recommend_plan - JSON string (array)
 * @param {string} report.raw_pd - JSON string
 * @param {number} report.calibrated - 0/1
 * @returns {Promise<Object>} query result (has insertId)
 */
async function create(report) {
  return query(
    `INSERT INTO scan_reports
     (user_id, device_id, scanned_at, regions, overall, recommend_mask, recommend_plan, raw_pd, calibrated)
     VALUES (:user_id, :device_id, :scanned_at, :regions, :overall, :recommend_mask, :recommend_plan, :raw_pd, :calibrated)`,
    report
  )
}

/**
 * Find a scan report by id
 * @param {number} id
 * @returns {Promise<Object|null>}
 */
async function findById(id) {
  return one('SELECT * FROM scan_reports WHERE id = :id', { id })
}

/**
 * Find the latest scan report for a user, optionally filtered by device
 * @param {number} userId
 * @param {string} [deviceId]
 * @returns {Promise<Object|null>}
 */
async function findLatestByUser(userId, deviceId) {
  if (deviceId) {
    return one(
      'SELECT * FROM scan_reports WHERE user_id = :user_id AND device_id = :device_id ORDER BY created_at DESC, id DESC LIMIT 1',
      { user_id: userId, device_id: deviceId }
    )
  }
  return one(
    'SELECT * FROM scan_reports WHERE user_id = :user_id ORDER BY created_at DESC, id DESC LIMIT 1',
    { user_id: userId }
  )
}

/**
 * List scan reports for a user with pagination
 * @param {number} userId
 * @param {Object} opts
 * @param {number} opts.pageSize
 * @param {number} opts.offset
 * @returns {Promise<{records: Array, total: number}>}
 */
async function listByUser(userId, { pageSize, offset }) {
  const total = await query(
    'SELECT COUNT(*) AS total FROM scan_reports WHERE user_id = :user_id',
    { user_id: userId }
  )
  const records = await query(
    'SELECT * FROM scan_reports WHERE user_id = :user_id ORDER BY created_at DESC, id DESC' + limitClause(pageSize, offset),
    { user_id: userId }
  )
  return { records, total: total[0].total }
}

module.exports = {
  create,
  findById,
  findLatestByUser,
  listByUser
}