class PgBouncerRunner
  attr_reader :pg_port, :pg_user, :pg_password, :pg_host, :pg_db
  attr_reader :pgb_port, :pgb_user, :pgb_password
  attr_reader :tmp_folder, :runner_thread, :runner_pid

  def initialize(pg_port: 5432, pg_user: ENV['USER'], pg_password: '', pg_host: '127.0.0.1', pg_db: ENV['USER'], verbose: true)
    @pg_port = pg_port
    @pg_user = pg_user
    @pg_password = pg_password
    @pg_host = pg_host
    @pg_db = pg_db
    @verbose = verbose

    @pgb_port = Network.find_available_port
  end

  def run
    create_config unless @tmp_folder

    verbose_arg = @verbose ? '-v' : ''
    pgb_user_arg = CLI_OPTS[:pgbouncer_user] ? "-u #{CLI_OPTS[:pgbouncer_user]}" : ""
    pgb_command = "#{pgbouncer_path} #{verbose_arg} #{pgb_user_arg} ./config.ini"

    if @verbose
      puts "Running pgbouncer with config at: #{@tmp_folder}"
      puts "EXEC #{pgb_command}"
    end

    Dir.chdir(@tmp_folder) do
      Open3.popen3(pgb_command) {|stdin, stdout, stderr, wait_thr|
        @runner_pid = wait_thr.pid # pid of the started process.
        #p "process_started: #{pid}"
        Thread.new do
          begin
            while line = stdout.gets
              puts "STDOUT: #{line}" if @verbose
            end
          rescue Exception => error
            puts error.message
            puts error.backtrace
          end
        end
        Thread.new do
          begin
            while line = stderr.gets
              puts "STDERR: #{line}" if @verbose
            end
          rescue Exception => error
            puts error.message
            puts error.backtrace
          end
        end
        exit_status = wait_thr.value # Process::Status object returned.
        puts "pgbouncer stoped: #{exit_status}" if @verbose
      }
    end
  end

  def pgbouncer_path
    if RUBY_PLATFORM =~ /darwin/
      BASE_DIR + '/pgbouncer'
    else

      path = `which pgbouncer 2>/dev/null`
      if path == ''
        puts "Can not find pgbouncer in your system"
        puts "Please install it"
        exit(1)
      else
        return path.strip
      end

    end
  end

  def stop_async
    if @runner_pid && System.process_alive?(@runner_pid, verbose: @verbose)
      System.stop_process(@runner_pid)
    end
  end

  def run_async
    @runner_thread = Thread.new do
      begin
        run
      rescue Exception => error
        puts error.message
        puts error.backtrace
      end
    end

    self
  end

  def wait_for_pid
    while !@runner_pid
      sleep 0.04
    end

    @runner_pid
  end

  def create_config
    @tmp_folder = Dir.mktmpdir
    pgb_config = render_template('config.ini.erb', {})
    File.open(@tmp_folder + '/config.ini', 'w') {|f| f.write(pgb_config) }

    @pgb_user = "share"
    @pgb_password = SecureRandom.hex(10)
    File.open(@tmp_folder + '/users.txt', 'w') {|f|
      f.write(%{"#{@pgb_user}" "#{@pgb_password}"})
    }
  end

  def make_db_url(remote_port)
    "postgres://#{pgb_user}:#{pgb_password}@dblink.tk:#{remote_port}/#{pg_db}"
  end

  private
  def render_template(file, params)
    erb = ERB.new(File.read(BASE_DIR + '/' + file))
    erb.filename = file
    erb.result(binding)
  end
end