type mysqlTester struct {
  dbConn *sql.DB

  dbName  string
  host    string
  user    string
  pass    string
  sslmode string
  port    int

  optionFile string

  testDBName string
}

func init() {
  dbMain = &mysqlTester{}
}

func (m *mysqlTester) setup() error {
  var err error

  m.dbName = viper.GetString("mysql.dbname")
  m.host = viper.GetString("mysql.host")
  m.user = viper.GetString("mysql.user")
  m.pass = viper.GetString("mysql.pass")
  m.port = viper.GetInt("mysql.port")
  m.sslmode = viper.GetString("mysql.sslmode")
  // Create a randomized db name.
  m.testDBName = getDBNameHash(m.dbName)

  if err = m.makeOptionFile(); err != nil {
    return errors.Wrap(err, "couldn't make option file")
  }

  if err = m.dropTestDB(); err != nil {
    return err
  }
  if err = m.createTestDB(); err != nil {
    return err
  }

  dumpCmd := exec.Command("mysqldump", m.defaultsFile(), m.dbName)
  createCmd := exec.Command("mysql", m.defaultsFile(), "--database", m.testDBName)

  r, w := io.Pipe()
  dumpCmd.Stdout = w
  createCmd.Stdin = io.TeeReader(r, os.Stdout)

  if err = dumpCmd.Start(); err != nil {
    return errors.Wrap(err, "failed to start mysqldump command")
  }
  if err = createCmd.Start(); err != nil {
    return errors.Wrap(err, "failed to start mysql command")
  }

  if err = dumpCmd.Wait(); err != nil {
    fmt.Println(err)
    return errors.Wrap(err, "failed to wait for mysqldump command")
  }

  w.Close() // After dumpCmd is done, close the write end of the pipe

  if err = createCmd.Wait(); err != nil {
    fmt.Println(err)
    return errors.Wrap(err, "failed to wait for mysql command")
  }

  return nil
}

func (m *mysqlTester) defaultsFile() string {
  return fmt.Sprintf("--defaults-file=%s", m.optionFile)
}

func (m *mysqlTester) makeOptionFile() error {
  tmp, err := ioutil.TempFile("", "optionfile")
  if err != nil {
    return errors.Wrap(err, "failed to create option file")
  }

  fmt.Fprintln(tmp, "[client]")
  fmt.Fprintf(tmp, "host=%s\n", m.host)
  fmt.Fprintf(tmp, "port=%d\n", m.port)
  fmt.Fprintf(tmp, "user=%s\n", m.user)
  fmt.Fprintf(tmp, "password=%s\n", m.pass)
  // BUG: SSL Mode for whatever reason is backwards in the mysql driver
  // taking options like true or false, but here taking options like
  // required/disabled. Until this gets sorted, ignore this.
  //fmt.Fprintf("ssl-mode=%s\n", m.password)

  fmt.Fprintln(tmp, "[mysqldump]")
  fmt.Fprintf(tmp, "host=%s\n", m.host)
  fmt.Fprintf(tmp, "port=%d\n", m.port)
  fmt.Fprintf(tmp, "user=%s\n", m.user)
  fmt.Fprintf(tmp, "password=%s\n", m.pass)

  m.optionFile = tmp.Name()

  return tmp.Close()
}

func (m *mysqlTester) createTestDB() error {
  sql := fmt.Sprintf("create database %s;", m.testDBName)
  return m.runCmd(sql, "mysql")
}

func (m *mysqlTester) dropTestDB() error {
  sql := fmt.Sprintf("drop database if exists %s;", m.testDBName)
  return m.runCmd(sql, "mysql")
}

func (m *mysqlTester) teardown() error {
  if err := m.dropTestDB(); err != nil {
    return err
  }

  if m.dbConn != nil {
    m.dbConn.Close()
  }

  return os.Remove(m.optionFile)
}

func (m *mysqlTester) runCmd(stdin, command string, args ...string) error {
  args = append([]string{m.defaultsFile()}, args...)

  cmd := exec.Command(command, args...)
  cmd.Stdin = strings.NewReader(stdin)

  stdout := &bytes.Buffer{}
  stderr := &bytes.Buffer{}
  cmd.Stdout = stdout
  cmd.Stderr = stderr
  if err := cmd.Run(); err != nil {
    fmt.Println("failed running:", command, args)
    fmt.Println(stdout.String())
    fmt.Println(stderr.String())
    return err
  }

  return nil
}

func (m *mysqlTester) conn() (*sql.DB, error) {
  if m.dbConn != nil {
    return m.dbConn, nil
  }

  var err error
  m.dbConn, err = sql.Open("mysql", drivers.MySQLBuildQueryString(m.user, m.pass, m.testDBName, m.host, m.port, m.sslmode))
  if err != nil {
    return nil, err
  }

  return m.dbConn, nil
}