# Copyright (C) 2006 Adam Olsen
#
# 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 1, 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., 675 Mass Ave, Cambridge, MA 02139, USA.

import os, re, traceback, sys, plugins

try:
    # setuptools is optional
    import pkg_resources
except ImportError:
    pkg_resources = None

class Manager(object):
    """
        Plugin manager. 
        Manages loading plugins, and sending events to them
    """
    def __init__(self, app):
        """
            Initializes the manager
        """
        self.plugins = []
        self.app = app
        self.loaded = []

    def load_plugins(self, dir, enabled):
        """
            Loads all plugins in a specified directory
        """
        if not os.path.isdir(dir): return
        for file in os.listdir(dir):
            if file.endswith('.py'):
                self.initialize_plugin(dir, file, enabled)

        # load egg files
        if pkg_resources:
            pkg_env = pkg_resources.Environment([dir])
            print "Checking in %s for egg plugins" % dir
            print pkg_env
            for name in pkg_env:
                print name
                egg = pkg_env[name][0]
                for n in egg.get_entry_map('exaile.plugins'):
                    p = None
                    try:
                        egg.activate()
                        entry_point = egg.get_entry_info('exaile.plugins', n)
                        plugin = entry_point.load()
                    
                        if plugin.PLUGIN_NAME in self.loaded: continue
                        self.loaded.append(plugin.PLUGIN_NAME)
                        print "Plugins '%s' version '%s' loaded successfully" % \
                            (plugin.PLUGIN_NAME, plugin.PLUGIN_VERSION)
                    
                        plugin.FILE_NAME = entry_point.module_name
                        plugin.APP = self.app
                        file = entry_point.module_name
                        p = plugin()

                        if file in enabled or plugin.PLUGIN_ENABLED:
                            p.initialize()
                            plugin.PLUGIN_ENABLED = True
                        self.plugins.append(p)
                    except plugins.PluginInitException, e:
                        if p: self.plugins.append(p)
                    except Exception, e:
                        print "Failed to load plugin"
                        traceback.print_exc()

    def initialize_plugin(self, dir, file, enabled=None, upgrading=False):
        if not dir in sys.path: sys.path.append(dir)
        try:
            plugin = __import__(re.sub('\.pyc?$', '', file))
            if not hasattr(plugin, "PLUGIN_NAME"):
                return

            if plugin.PLUGIN_NAME in self.loaded and upgrading: return
            if not upgrading:
                # check to see if this plugin is already installed and remove
                # it if that's the case
                for p in self.plugins:
                    if p.PLUGIN_NAME == plugin.PLUGIN_NAME:
                        p.destroy()
                        self.plugins.remove(p)

                if plugin.PLUGIN_NAME in self.loaded:
                    self.loaded.remove(plugin.PLUGIN_NAME)

            self.loaded.append(plugin.PLUGIN_NAME)
            
            print "Plugins '%s' version '%s' loaded successfully" % \
                (plugin.PLUGIN_NAME, plugin.PLUGIN_VERSION)

            plugin.FILE_NAME = file
            plugin.APP = self.app
            if (enabled is None or file in enabled) or plugin.PLUGIN_ENABLED:
                if plugin.initialize():
                    plugin.PLUGIN_ENABLED = True
            self.plugins.append(plugin)
        except plugins.PluginInitException, e:
            self.plugins.append(plugin)
        except Exception, e:
            print "Failed to load plugin"
            traceback.print_exc()

    def fire_event(self, event):
        """
            Fires an event to all plugins
        """
        check = True
        for plugin in self.plugins:
            if not plugin.PLUGIN_ENABLED: continue
            for method, args in event.calls.iteritems():
                if not hasattr(plugin, method): continue
                func = getattr(plugin, method)
                if func and callable(func):
                    if not func(*args):
                        check = False
        return check