'use strict'

const co = require('co')
const cli = require('heroku-cli-util')

function * run (context, heroku) {
  const fetcher = require('../lib/fetcher')(heroku)
  const psql = require('../lib/psql')

  let db = yield fetcher.database(context.app, context.args.database)

  let query = `
WITH table_opts AS (
  SELECT
    pg_class.oid, relname, nspname, array_to_string(reloptions, '') AS relopts
  FROM
     pg_class INNER JOIN pg_namespace ns ON relnamespace = ns.oid
), vacuum_settings AS (
  SELECT
    oid, relname, nspname,
    CASE
      WHEN relopts LIKE '%autovacuum_vacuum_threshold%'
        THEN substring(relopts, '.*autovacuum_vacuum_threshold=([0-9.]+).*')::integer
        ELSE current_setting('autovacuum_vacuum_threshold')::integer
      END AS autovacuum_vacuum_threshold,
    CASE
      WHEN relopts LIKE '%autovacuum_vacuum_scale_factor%'
        THEN substring(relopts, '.*autovacuum_vacuum_scale_factor=([0-9.]+).*')::real
        ELSE current_setting('autovacuum_vacuum_scale_factor')::real
      END AS autovacuum_vacuum_scale_factor
  FROM
    table_opts
)
SELECT
  vacuum_settings.nspname AS schema,
  vacuum_settings.relname AS table,
  to_char(psut.last_vacuum, 'YYYY-MM-DD HH24:MI') AS last_vacuum,
  to_char(psut.last_autovacuum, 'YYYY-MM-DD HH24:MI') AS last_autovacuum,
  to_char(pg_class.reltuples, '9G999G999G999') AS rowcount,
  to_char(psut.n_dead_tup, '9G999G999G999') AS dead_rowcount,
  to_char(autovacuum_vacuum_threshold
       + (autovacuum_vacuum_scale_factor::numeric * pg_class.reltuples), '9G999G999G999') AS autovacuum_threshold,
  CASE
    WHEN autovacuum_vacuum_threshold + (autovacuum_vacuum_scale_factor::numeric * pg_class.reltuples) < psut.n_dead_tup
    THEN 'yes'
  END AS expect_autovacuum
FROM
  pg_stat_user_tables psut INNER JOIN pg_class ON psut.relid = pg_class.oid
    INNER JOIN vacuum_settings ON pg_class.oid = vacuum_settings.oid
ORDER BY 1
`

  let output = yield psql.exec(db, query)
  process.stdout.write(output)
}

const cmd = {
  topic: 'pg',
  description: 'show dead rows and whether an automatic vacuum is expected to be triggered',
  needsApp: true,
  needsAuth: true,
  args: [{ name: 'database', optional: true }],
  run: cli.command({ preauth: true }, co.wrap(run))
}

module.exports = [
  Object.assign({ command: 'vacuum-stats' }, cmd),
  Object.assign({ command: 'vacuum_stats', hidden: true }, cmd)
]