const { query } = require('../../utils/db')
const { parseJson } = require('./engagementRules.db')

const hydrate = (row) => row && { ...row, expression: parseJson(row.expression, null) }

const list = async () =>
  (await query('SELECT * FROM engagement_audience_segments ORDER BY name, id')).map(hydrate)

const getById = async (id) => {
  const [row] = await query('SELECT * FROM engagement_audience_segments WHERE id = ?', [id])
  return hydrate(row)
}

/**
 * `ceiling` is written by the caller from `segments.deriveCeiling`, never taken
 * from an operator. It is a stored column rather than a runtime computation so
 * an audit can read what a rule was ALLOWED to reach without re-resolving it,
 * and so a module that later widens its own audience's ceiling cannot
 * retroactively widen a segment that was saved under the old one.
 */
const insert = async (segment) => {
  const result = await query(
    'INSERT INTO engagement_audience_segments (name, expression, ceiling, updated_by) VALUES (?, ?, ?, ?)',
    [segment.name, JSON.stringify(segment.expression), segment.ceiling, segment.updated_by ?? null],
  )
  return result.insertId
}

const update = (id, segment) =>
  query(
    'UPDATE engagement_audience_segments SET name = ?, expression = ?, ceiling = ?, updated_by = ? WHERE id = ?',
    [segment.name, JSON.stringify(segment.expression), segment.ceiling, segment.updated_by ?? null, id],
  )

const remove = (id) => query('DELETE FROM engagement_audience_segments WHERE id = ?', [id])

module.exports = { list, getById, insert, update, remove }