#    Back In Time
#    Copyright (C) 2008-2009 Oprea Dan, Bart de Koning, Richard Bailey
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License along
#    with this program; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


import os.path
import tools
import types

tools.register_backintime_path( 'common' )
tools.register_backintime_path( 'plugins' )


class Plugin:
	
	def __init__( self ):
		return

	def init( self, snapshots ):
		return True

	def is_gui( self ):
		return False

	def on_process_begins( self ):
		return

	def on_process_ends( self ):
		return

	def on_error( self, code, message ):
		return

	def on_new_snapshot( self, snapshot_id, snapshot_path ):
		return


class PluginManager:
	def __init__( self ):
		self.plugins = []
		self.has_gui_plugins_ = False
		self.plugins_loaded = False

	def load_plugins( self, snapshots, force = False ):
		if self.plugins_loaded and not force:
			return

		self.plugins_loaded = True
		self.plugins = []
		self.has_gui_plugins_ = False
		
		plugins_path = tools.get_backintime_path( 'plugins' )

		for file in os.listdir( plugins_path ):
			if file.endswith( '.py' ) and not file.startswith( '__' ):
				path = os.path.join( plugins_path, file )

				module = __import__( file[ : -3 ] )
				module_dict = module.__dict__
				
 				for key, value in module_dict.items():
					if key.startswith( '__' ):
						continue

					if type(value) is types.ClassType:
						if issubclass( value, Plugin ):
							plugin = value()
							if plugin.init( snapshots ):
								if plugin.is_gui():
									self.has_gui_plugins_ = True
									self.plugins.insert( 0, plugin )
								else:
									self.plugins.append( plugin )

	def has_gui_plugins( self ):
		return self.has_gui_plugins_

	def on_process_begins( self ):
		for plugin in self.plugins:
			plugin.on_process_begins()

	def on_process_ends( self ):
		for plugin in reversed( self.plugins ):
			plugin.on_process_ends()

	def on_error( self, code, message = '' ):
		for plugin in self.plugins:
			plugin.on_error( code, message )

	def on_new_snapshot( self, snapshot_id, snapshot_path ):
		for plugin in self.plugins:
			plugin.on_new_snapshot( snapshot_id, snapshot_path )