require 'flexnbd'
require 'file_writer'

class Environment
  attr_reader(:blocksize, :filename1, :filename2, :ip,
              :port1, :port2, :nbd1, :nbd2, :file1, :file2)

  def initialize
    @blocksize = 1024
    @filename1 = "/tmp/.flexnbd.test.#{$PROCESS_ID}.#{Time.now.to_i}.1"
    @filename2 = "/tmp/.flexnbd.test.#{$PROCESS_ID}.#{Time.now.to_i}.2"
    @ip = '127.0.0.1'
    @available_ports = [*40_000..41_000] - listening_ports
    @port1 = @available_ports.shift
    @port2 = @available_ports.shift
    @nbd1 = FlexNBD::FlexNBD.new('../../build/flexnbd', @ip, @port1)
    @nbd2 = FlexNBD::FlexNBD.new('../../build/flexnbd', @ip, @port2)

    @fake_pid = nil
  end

  def blocksize=(b)
    raise RuntimeError, "Unable to change blocksize after files have been opened" if @file1 or @file2
    @blocksize = b
  end

  def prefetch_proxy!
    @nbd1.prefetch_proxy = true
    @nbd2.prefetch_proxy = true
  end

  def proxy1(port = @port2)
    @nbd1.proxy(@ip, port)
  end

  def proxy2(port = @port1)
    @nbd2.proxy(@ip, port)
  end

  def serve1(*acl)
    @nbd1.serve(@filename1, *acl)
  end

  def serve2(*acl)
    @nbd2.serve(@filename2, *acl)
  end

  def listen1(*acl)
    @nbd1.listen(@filename1, *(acl.empty? ? @acl1 : acl))
  end

  def listen2(*acl)
    @nbd2.listen(@filename2, *acl)
  end

  def break1
    @nbd1.break
  end

  def acl1(*acl)
    @nbd1.acl(*acl)
  end

  def acl2(*acl)
    @nbd2.acl(*acl)
  end

  def status1
    @nbd1.status.first
  end

  def status2
    @nbd2.status.first
  end

  def mirror12
    @nbd1.mirror(@nbd2.ip, @nbd2.port)
  end

  def mirror12_unchecked
    @nbd1.mirror_unchecked(@nbd2.ip, @nbd2.port, nil, nil, 10)
  end

  def mirror12_unlink
    @nbd1.mirror_unlink(@nbd2.ip, @nbd2.port, 2)
  end

  def write1(data)
    @nbd1.write(0, data)
  end

  def writefile1(data)
    @file1 = FileWriter.new(@filename1, @blocksize).write(data)
  end

  def writefile2(data)
    @file2 = FileWriter.new(@filename2, @blocksize).write(data)
  end

  def truncate1(size)
    system "truncate -s #{size} #{@filename1}"
  end

  def listening_ports
    `netstat -ltn`
      .split("\n")
      .map { |x| x.split(/\s+/) }[2..-1]
      .map { |l| l[3].split(':')[-1].to_i }
  end

  def cleanup
    if @fake_pid
      begin
        Process.waitpid2(@fake_pid)
      rescue Errno::ESRCH
      end
    end

    @nbd1.can_die(0)
    @nbd1.kill
    @nbd2.kill

    [@filename1, @filename2].each do |f|
      File.unlink(f) if File.exist?(f)
    end
  end

  def run_fake(name, addr, port, sock = nil)
    fakedir = File.join(File.dirname(__FILE__), 'fakes')
    fakeglob = File.join(fakedir, name) + '*'
    fake = Dir[fakeglob].sort.find do |fn|
      File.executable?(fn)
    end

    raise "no fake executable at #{fakeglob}" unless fake
    raise 'no addr' unless addr
    raise 'no port' unless port

    @fake_pid = fork do
      exec [fake, addr, port, @nbd1.pid, sock].map(&:to_s).join(' ')
    end
    sleep(0.5)
  end

  def fake_reports_success
    _, status = Process.waitpid2(@fake_pid)
    @fake_pid = nil
    status.success?
  end
end # class Environment