#
# The idea is to simplify a little bit the mechanics
# of setting up even the simplest COM program. You
# have to set out a fair bit of boilerplate text
# to even get started. We're trying to Pythonise
# that boilerplate.
#
import pythoncom
from win32com.shell import shell, shellcon
from win32com import taskscheduler, axdebug, adsi

COM_MODULES = [pythoncom, shell, axdebug, taskscheduler, axdebug, adsi]
#
# Interface ids all starts with IID_... so pick them out of the
# module we know have some.
#
def _find_interfaces (module):
  PREFIX = "IID_"
  interfaces = {}
  interfaces.update ((i, getattr (module, i)) for i in dir (module) if i.startswith (PREFIX))
  interfaces.update ((i[len (PREFIX):], getattr (module, i)) for i in dir (module) if i.startswith (PREFIX))
  return interfaces

_INTERFACES = {}
for module in COM_MODULES:
  _INTERFACES.update (_find_interfaces (module))
  
def _find_classes (module):
  PREFIX = "CLSID_"
  classes = {}
  for item in dir (module):
    if item.startswith (PREFIX):
      name = item[len (PREFIX):]
      for interface in _INTERFACES:
        if interface[1:] == name:
          break
        elif "Std" + interface[1:] == name:
          break
        elif "Default" + interface[1:] == name:
          break
      else:
        interface = None
      classes[name] = (getattr (module, item), interface)
  
  return classes

_CLASSES = {}
for module in COM_MODULES:
  _CLASSES.update (_find_classes (module))

#
# This is the most by-hand section of the lot. We have
# to identify what interfaces have been exposed by pywin32
# and set up a mapping with a usable name -- as close as
# possible to the MS ones -- which maps to the CLSID and
# the default interface.
#
# The default interface may be None, in which case the
# user has to pass one in when the class is instantiated.
# This may always be done in any case to override the
# default.
#
_MAP = {
  "ShellLink" : (shell.CLSID_ShellLink, shell.IID_IShellLink),
  "ActiveDesktop" : (shell.CLSID_ActiveDesktop, shell.IID_IActiveDesktop),
  "InternetShortcut" : (shell.CLSID_InternetShortcut, shell.IID_IUniformResourceLocator),
}

class _COMInterface (object):
  
  def __init__ (self, instance, *args, **kwargs):
    self.instance = instance
    
  def __getattr__ (self, attr):
    try:
      return getattr (self.instance, attr)
    except AttributeError:
      try:
        interface = _INTERFACES[attr]
      except KeyError:
        raise AttributeError, "No such interface"
      else:
        return _COMInterface (self.instance.QueryInterface (interface))

class _COMInstance (object):
  
  def __init__ (self, clsid, default_interface):
    self.clsid = clsid
    self.default_interface = default_interface
    
  def __call__ (self, default_interface=None, *args, **kwargs):
    if default_interface is None:
      default_interface = self.default_interface
    elif isinstance (default_interface, basestring):
      default_interface = _INTERFACES[default_interface]
    else:
      default_interface = self.default_interface
    
    instance = pythoncom.CoCreateInstance (
      self.clsid, 
      None, 
      pythoncom.CLSCTX_INPROC_SERVER, 
      default_interface
    )
    return _COMInterface (instance)

class _COM (object):
  
  def __getattr__ (self, attr):
    try:
      clsid, default_interface = _MAP[attr]
    except KeyError:
      raise AttributeError
    else:
      return _COMInstance (clsid, default_interface)

COM = _COM ()