# Source code for terminatorlib.plugin

    #!/usr/bin/python
    # Terminator by Chris Jones <cmsj@tenshu.net>
    # GPL v2 only
    """plugin.py - Base plugin system
       Inspired by Armin Ronacher's post at
       http://lucumr.pocoo.org/2006/7/3/python-plugin-system
       Used with permission (the code in that post is to be
       considered BSD licenced, per the authors wishes)

    >>> registry = PluginRegistry()
    >>> registry.instances
    {}
    >>> registry.load_plugins(True)
    >>> plugins = registry.get_plugins_by_capability('test')
    >>> len(plugins)
    1
    >>> plugins[0] #doctest: +ELLIPSIS
    <testplugin.TestPlugin object at 0x...>
    >>> registry.get_plugins_by_capability('this_should_not_ever_exist')
    []
    >>> plugins[0].do_test()
    'TestPluginWin'

    """

    import sys
    import os
    import borg
    from config import Config
    from util import dbg, err, get_config_dir
    from terminator import Terminator

    class Plugin(object):
        """Definition of our base plugin class"""
        capabilities = None

        def __init__(self):
            """Class initialiser."""
            pass

        def unload(self):
            """Prepare to be unloaded"""
            pass

    class PluginRegistry(borg.Borg):
        """Definition of a class to store plugin instances"""
        available_plugins = None
        instances = None
        path = None
        done = None

        def __init__(self):
            """Class initialiser"""
            borg.Borg.__init__(self, self.__class__.__name__)
            self.prepare_attributes()

        def prepare_attributes(self):
            """Prepare our attributes"""
            if not self.instances:
                self.instances = {}
            if not self.path:
                self.path = []
                (head, _tail) = os.path.split(borg.__file__)
                self.path.append(os.path.join(head, 'plugins'))
                self.path.append(os.path.join(get_config_dir(), 'plugins'))
                dbg('PluginRegistry::prepare_attributes: Plugin path: %s' %
                    self.path)
            if not self.done:
                self.done = False
            if not self.available_plugins:
                self.available_plugins = {}

        def load_plugins(self, testing=False):
            """Load all plugins present in the plugins/ directory in our module"""
            if self.done:
                dbg('PluginRegistry::load_plugins: Already loaded')
                return

            config = Config()

            for plugindir in self.path:
                sys.path.insert(0, plugindir)
                try:
                    files = os.listdir(plugindir)
                except OSError:
                    sys.path.remove(plugindir)
                    continue
                for plugin in files:
                    pluginpath = os.path.join(plugindir, plugin)
                    if os.path.isfile(pluginpath) and plugin[-3:] == '.py':
                        dbg('PluginRegistry::load_plugins: Importing plugin %s' %
                            plugin)
                        try:
                            module = __import__(plugin[:-3], None, None, [''])
                            for item in getattr(module, 'AVAILABLE'):
                                if item not in self.available_plugins.keys():
                                    func = getattr(module, item)
                                    self.available_plugins[item] = func

                                if not testing and item not in config['enabled_plugins']:
                                    dbg('plugin %s not enabled, skipping' % item)
                                    continue
                                if item not in self.instances:
                                    self.instances[item] = func()
                        except Exception, ex:
                            err('PluginRegistry::load_plugins: Importing plugin %s \
    failed: %s' % (plugin, ex))

            self.done = True

        def get_plugins_by_capability(self, capability):
            """Return a list of plugins with a particular capability"""
            result = []
            dbg('PluginRegistry::get_plugins_by_capability: searching %d plugins \
    for %s' % (len(self.instances), capability))
            for plugin in self.instances:
                if capability in self.instances[plugin].capabilities:
                    result.append(self.instances[plugin])
            return result

        def get_all_plugins(self):
            """Return all plugins"""
            return(self.instances)

        def get_available_plugins(self):
            """Return a list of all available plugins whether they are enabled or
            disabled"""
            return(self.available_plugins.keys())

        def is_enabled(self, plugin):
            """Return a boolean value indicating whether a plugin is enabled or
            not"""
            return(self.instances.has_key(plugin))

        def enable(self, plugin):
            """Enable a plugin"""
            if plugin in self.instances:
                err("Cannot enable plugin %s, already enabled" % plugin)
            dbg("Enabling %s" % plugin)
            self.instances[plugin] = self.available_plugins[plugin]()

        def disable(self, plugin):
            """Disable a plugin"""
            dbg("Disabling %s" % plugin)
            self.instances[plugin].unload()
            del(self.instances[plugin])

    # This is where we should define a base class for each type of plugin we
    # support

    # URLHandler - This adds a regex match to the Terminal widget and provides a
    #               callback to turn that into a URL.
    class URLHandler(Plugin):
        """Base class for URL handlers"""
        capabilities = ['url_handler']
        handler_name = None
        match = None
        nameopen = None
        namecopy = None

        def __init__(self):
            """Class initialiser"""
            Plugin.__init__(self)
            terminator = Terminator()
            for terminal in terminator.terminals:
                terminal.match_add(self.handler_name, self.match)

        def callback(self, url):
            """Callback to transform the enclosed URL"""
            raise NotImplementedError

        def unload(self):
            """Handle being removed"""
            if not self.match:
                err('unload called without self.handler_name being set')
                return
            terminator = Terminator()
            for terminal in terminator.terminals:
                terminal.match_remove(self.handler_name)

    # MenuItem - This is able to execute code during the construction of the
    #             context menu of a Terminal.