import sys, io, os, traceback

def _disable_stdout_buffering():
  sys.stdout.flush()
  fileno=sys.stdout.fileno()
  temp_fd=os.dup(fileno)
  sys.stdout.close()
  os.dup2(temp_fd, fileno)
  os.close(temp_fd)
  sys.stdout=os.fdopen(fileno, 'w', 0)

_disable_stdout_buffering()

# print 'python module parameters:', ', '.join(sys.argv)

WSGI_APP=None

if len(sys.argv)>=4 and sys.argv[3]:
  activate_this=os.path.abspath(os.path.join(sys.argv[3], 'bin/activate_this.py'))
  if os.path.isfile(activate_this):
    execfile(activate_this, dict(__file__=activate_this))
  else:
    print 'python config error: cannot activate virtualenv', activate_this

if len(sys.argv)>=3:
  if sys.argv[1]:
    project_path=os.path.abspath(sys.argv[1])
    sys.path.append(project_path)
    print 'python project path:', project_path
  project_app=sys.argv[2]
  if project_app:
    p=project_app.rsplit('.', 1)
    if len(p)==2:
      module_name, app_name=p
      try:
        mod=__import__(module_name, globals(), locals(), [app_name])
        if mod and hasattr(mod, app_name):
          WSGI_APP=getattr(mod, app_name)
        else:
          print 'python config error: there is no', app_name, 'in module', module_name
      except:
        traceback.print_exc()
        print 'python config error: failed to import module', module_name
    else:
      print 'python config error: wsgi_application is expected in form <module>.<app>'

if not WSGI_APP:
  raise Exception('python config error: no WSGI_APP defined')

def _userver_on_request(environ):
  try:
    environ['wsgi.version']=(1, 0)
    environ['wsgi.errors']=sys.stderr
    if 'userver.req.content' in environ:
      environ['wsgi.input']=io.BytesIO(environ['userver.req.content'])
    else:
      environ['wsgi.input']=None
    return _call_wsgi_application(WSGI_APP, environ)
  except:
    ei=sys.exc_info()
    traceback.print_exception(*ei)
    return repr(ei[1])+' see log for details'

def _call_wsgi_application(app, environ):
  body_writer=io.BytesIO()
  status_headers=[None, None]
  def start_response(status, headers, exc_info=None):
    status_headers[:]=[status, headers]
    return body_writer
  app_iter=app(environ, start_response)
  try:
    for item in app_iter:
      body_writer.write(item)
  finally:
    if hasattr(app_iter, 'close'):
      app_iter.close()
  return status_headers[0], status_headers[1], body_writer.getvalue()