#!/usr/bin/env python
# encoding: utf-8

"""Magic command interface for interactive parallel work."""

#-----------------------------------------------------------------------------
#  Copyright (C) 2008-2009  The IPython Development Team
#
#  Distributed under the terms of the BSD License.  The full license is in
#  the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

from IPython.core.component import Component
from IPython.utils.traitlets import Bool, Any
from IPython.utils.autoattr import auto_attr


#-------------------------------------------------------------------------------
# Definitions of magic functions for use with IPython
#-------------------------------------------------------------------------------

NO_ACTIVE_MULTIENGINE_CLIENT = """
Error:  No Controller is activated
Use activate() on a MultiEngineClient object to activate it for magics.
"""


class ParalleMagicComponent(Component):

    active_multiengine_client = Any()
    verbose = Bool(False, config=True)

    def __init__(self, parent, name=None, config=None):
        super(ParalleMagicComponent, self).__init__(parent, name=name, config=config)
        self._define_magics()

    # Access other components like this rather than by a regular attribute.
    # This won't lookup the InteractiveShell object until it is used and
    # then it is cached.  This is both efficient and couples this class 
    # more loosely to InteractiveShell.
    @auto_attr
    def shell(self):
        return Component.get_instances(
            root=self.root,
            klass='IPython.core.iplib.InteractiveShell')[0]

    def _define_magics(self):
        self.shell.define_magic('result', self.magic_result)
        self.shell.define_magic('px', self.magic_px)
        self.shell.define_magic('autopx', self.magix_autopx)

    def magic_result(self, ipself, parameter_s=''):
        """Print the result of command i on all engines of the active controller.
    
        To activate a controller in IPython, first create it and then call
        the activate() method.
    
        Then you can do the following:
    
        >>> result                                # Print the latest result
        Printing result... 
        [127.0.0.1:0] In [1]: b = 10
        [127.0.0.1:1] In [1]: b = 10
    
        >>> result 0                              # Print result 0
        In [14]: result 0
        Printing result... 
        [127.0.0.1:0] In [0]: a = 5
        [127.0.0.1:1] In [0]: a = 5
        """
        if self.active_multiengine_client is None:
            print NO_ACTIVE_MULTIENGINE_CLIENT
            return

        try:
            index = int(parameter_s)
        except:
            index = None
        result = self.active_multiengine_client.get_result(index)
        return result

    # def magic_px(self,parameter_s=''):
    #     """Executes the given python command on the active IPython Controller.
    # 
    #     To activate a Controller in IPython, first create it and then call
    #     the activate() method.
    # 
    #     Then you can do the following:
    #  
    #     >>> %px a = 5       # Runs a = 5 on all nodes
    #     """
    # 
    #     try:
    #         activeController = __IPYTHON__.activeController
    #     except AttributeError:
    #         print NO_ACTIVE_CONTROLLER
    #     else:
    #         print "Parallel execution on engines: %s" % activeController.targets
    #         result = activeController.execute(parameter_s)
    #         return result
    # 
    # def pxrunsource(self, source, filename="<input>", symbol="single"):
    # 
    #     try:
    #         code = self.compile(source, filename, symbol)
    #     except (OverflowError, SyntaxError, ValueError):
    #         # Case 1
    #         self.showsyntaxerror(filename)
    #         return None
    # 
    #     if code is None:
    #         # Case 2
    #         return True
    # 
    #     # Case 3
    #     # Because autopx is enabled, we now call executeAll or disable autopx if
    #     # %autopx or autopx has been called
    #     if 'get_ipython().magic("%autopx' in source or 'get_ipython().magic("autopx' in source:
    #         _disable_autopx(self)
    #         return False
    #     else:
    #         try:
    #             result = self.activeController.execute(source)
    #         except:
    #             self.showtraceback()
    #         else:
    #             print result.__repr__()
    #         return False
    #     
    # def magic_autopx(self, parameter_s=''):
    #     """Toggles auto parallel mode for the active IPython Controller.
    # 
    #     To activate a Controller in IPython, first create it and then call
    #     the activate() method.
    # 
    #     Then you can do the following:
    #  
    #     >>> %autopx                    # Now all commands are executed in parallel
    #     Auto Parallel Enabled
    #     Type %autopx to disable
    #     ...
    #     >>> %autopx                    # Now all commands are locally executed
    #     Auto Parallel Disabled
    #     """
    #   
    #     if hasattr(self, 'autopx'):
    #         if self.autopx == True:
    #             _disable_autopx(self)
    #         else:
    #             _enable_autopx(self)
    #     else:
    #         _enable_autopx(self)
    # 
    # def _enable_autopx(self):
    #     """Enable %autopx mode by saving the original runsource and installing 
    #     pxrunsource.
    #     """
    #     try:
    #         activeController = __IPYTHON__.activeController
    #     except AttributeError:
    #         print "No active RemoteController found, use RemoteController.activate()."
    #     else:
    #         self._original_runsource = self.runsource
    #         self.runsource = new.instancemethod(pxrunsource, self, self.__class__)
    #         self.autopx = True
    #         print "Auto Parallel Enabled\nType %autopx to disable"
    # 
    # def _disable_autopx(self):
    #     """Disable %autopx by restoring the original runsource."""
    #     if hasattr(self, 'autopx'):
    #         if self.autopx == True:
    #             self.runsource = self._original_runsource
    #             self.autopx = False
    #             print "Auto Parallel Disabled"


_loaded = False

def load_ipython_extension(ip):
    """Load the extension in IPython as a hook."""
    global _loaded
    if not _loaded:
        prd = ParalleMagicComponent(ip, name='parallel_magic')
        _loaded = True