const pg = require('pg')
const config = require('../config')
const path = require('path')
const fs = require('fs')

const versions = require('./dbVersion.json').versions
const schemaPath = path.resolve(__dirname, '../schema')

if (!Array.isArray(versions) || versions.length === 0) {
  throw new Error('Schema version empty')
}

const client = new pg.Client({
  host: config.database.host,
  port: config.database.port,
  user: config.database.user,
  password: config.database.pass,
  database: config.database.db_name
})

// auto start function
;
!(async function () {
  let flag = false
  await client.connect()

  await client.query(`select now()`)
  console.log('Database Connected')

  let version = -1
  let checkTable = await client.query(`select exists(select 1 from "information_schema"."tables" where "table_schema" = $1 and "table_name" = $2) as exists`, ['public', 'version_ctrl'])
  if (checkTable.rows.length > 0 && checkTable.rows[0].exists === true) {
    let checkVersion = await client.query(`select max(version) as version from "public"."version_ctrl"`)
    if (checkVersion.rows.length > 0 && 'version' in checkVersion.rows[0] && isFinite(checkVersion.rows[0].version)) {
      version = checkVersion.rows[0].version
    }
  }

  let runVer = versions.filter(t => t.version > version).sort((a, b) => a.version - b.version)

  if (runVer.length === 0) return

  await client.query('begin')
  try {
    // write table query
    for (let i in runVer) {
      let qstr = fs.readFileSync(path.resolve(schemaPath, runVer[i].file)).toString()
      await client.query(qstr)
      let query = `insert into "public"."version_ctrl" ("version", "ctime", "querystr") values ($1, now(), $2)`
      let param = [runVer[i].version, qstr]
      await client.query(query, param)
    }

    await client.query('commit')
  } catch (err) {
    flag = true
    console.log(err)
    await client.query('rollback')
  }

  await client.end()
  if (flag) throw new Error('Not Finish')
})().then(() => {
  console.log('Finish')
  process.exit(0)
}).catch(err => {
  console.error(err)
  process.exit(1)
})