#
# pluginmanagerbase.py
#
# Copyright (C) 2007 Andrew Resch <andrewresch@gmail.com>
#
# Deluge is free software.
#
# You may redistribute it and/or modify it under the terms of the
# GNU General Public License, as published by the Free Software
# Foundation; either version 3 of the License, or (at your option)
# any later version.
#
# deluge 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 deluge.    If not, write to:
# 	The Free Software Foundation, Inc.,
# 	51 Franklin Street, Fifth Floor
# 	Boston, MA  02110-1301, USA.
#
#    In addition, as a special exception, the copyright holders give
#    permission to link the code of portions of this program with the OpenSSL
#    library.
#    You must obey the GNU General Public License in all respects for all of
#    the code used other than OpenSSL. If you modify file(s) with this
#    exception, you may extend this exception to your version of the file(s),
#    but you are not obligated to do so. If you do not wish to do so, delete
#    this exception statement from your version. If you delete this exception
#    statement from all source files in the program, then also delete it here.
#
#


"""PluginManagerBase"""

import os.path
import logging
import pkg_resources

import deluge.common
import deluge.configmanager

import deluge.component as component

log = logging.getLogger(__name__)

METADATA_KEYS = [
    "Name",
    "License",
    "Author",
    "Home-page",
    "Summary",
    "Platform",
    "Version",
    "Author-email",
    "Description",
]

DEPRECATION_WARNING = """
The plugin %s is not using the "deluge.plugins" namespace.
In order to avoid package name clashes between regular python packages and
deluge plugins, the way deluge plugins should be created has changed.
If you're seeing this message and you're not the developer of the plugin which
triggered this warning, please report to it's author.
If you're the developer, please take a look at the plugins hosted on deluge's
git repository to have an idea of what needs to be changed.
"""

class PluginManagerBase:
    """PluginManagerBase is a base class for PluginManagers to inherit"""

    def __init__(self, config_file, entry_name):
        log.debug("Plugin manager init..")

        self.config = deluge.configmanager.ConfigManager(config_file)

        # Create the plugins folder if it doesn't exist
        if not os.path.exists(os.path.join(deluge.configmanager.get_config_dir(), "plugins")):
            os.mkdir(os.path.join(deluge.configmanager.get_config_dir(), "plugins"))

        # This is the entry we want to load..
        self.entry_name = entry_name

        # Loaded plugins
        self.plugins = {}

        # Scan the plugin folders for plugins
        self.scan_for_plugins()

    def enable_plugins(self):
        # Load plugins that are enabled in the config.
        for name in self.config["enabled_plugins"]:
            self.enable_plugin(name)

    def disable_plugins(self):
        # Disable all plugins that are enabled
        for key in self.plugins.keys():
            self.disable_plugin(key)

    def __getitem__(self, key):
        return self.plugins[key]

    def get_available_plugins(self):
        """Returns a list of the available plugins name"""
        return self.available_plugins

    def get_enabled_plugins(self):
        """Returns a list of enabled plugins"""
        return self.plugins.keys()

    def scan_for_plugins(self):
        """Scans for available plugins"""
        base_plugin_dir = deluge.common.resource_filename("deluge", "plugins")
        pkg_resources.working_set.add_entry(base_plugin_dir)
        user_plugin_dir = os.path.join(deluge.configmanager.get_config_dir(), "plugins")

        plugins_dirs = [base_plugin_dir]
        for dirname in os.listdir(base_plugin_dir):
            plugin_dir = os.path.join(base_plugin_dir, dirname)
            pkg_resources.working_set.add_entry(plugin_dir)
            plugins_dirs.append(plugin_dir)
        pkg_resources.working_set.add_entry(user_plugin_dir)
        plugins_dirs.append(user_plugin_dir)

        self.pkg_env = pkg_resources.Environment(plugins_dirs)

        self.available_plugins = []
        for name in self.pkg_env:
            log.debug("Found plugin: %s %s at %s",
                self.pkg_env[name][0].project_name,
                self.pkg_env[name][0].version,
                self.pkg_env[name][0].location)
            self.available_plugins.append(self.pkg_env[name][0].project_name)

    def enable_plugin(self, plugin_name):
        """Enables a plugin"""
        if plugin_name not in self.available_plugins:
            log.warning("Cannot enable non-existant plugin %s", plugin_name)
            return

        if plugin_name in self.plugins:
            log.warning("Cannot enable already enabled plugin %s", plugin_name)
            return

        plugin_name = plugin_name.replace(" ", "-")
        egg = self.pkg_env[plugin_name][0]
        egg.activate()
        for name in egg.get_entry_map(self.entry_name):
            entry_point = egg.get_entry_info(self.entry_name, name)
            try:
                cls = entry_point.load()
                instance = cls(plugin_name.replace("-", "_"))
            except Exception, e:
                log.error("Unable to instantiate plugin %r from %r!",
                          name, egg.location)
                log.exception(e)
                continue
            instance.enable()
            if not instance.__module__.startswith("deluge.plugins."):
                import warnings
                warnings.warn_explicit(
                    DEPRECATION_WARNING % name,
                    DeprecationWarning,
                    instance.__module__, 0
                )
            if self._component_state == "Started":
                component.start([instance.plugin._component_name])
            plugin_name = plugin_name.replace("-", " ")
            self.plugins[plugin_name] = instance
            if plugin_name not in self.config["enabled_plugins"]:
                log.debug("Adding %s to enabled_plugins list in config",
                    plugin_name)
                self.config["enabled_plugins"].append(plugin_name)
            log.info("Plugin %s enabled..", plugin_name)

    def disable_plugin(self, name):
        """Disables a plugin"""
        try:
            self.plugins[name].disable()
            component.deregister(self.plugins[name].plugin)
            del self.plugins[name]
            self.config["enabled_plugins"].remove(name)
        except KeyError:
            log.warning("Plugin %s is not enabled..", name)

        log.info("Plugin %s disabled..", name)

    def get_plugin_info(self, name):
        """Returns a dictionary of plugin info from the metadata"""
        info = {}.fromkeys(METADATA_KEYS)
        last_header = ""
        cont_lines = []
        for line in self.pkg_env[name][0].get_metadata("PKG-INFO").splitlines():
            if not line:
                continue
            if line[0] in ' \t' and (len(line.split(":", 1)) == 1 or line.split(":", 1)[0] not in info.keys()):
                # This is a continuation
                cont_lines.append(line.strip())
            else:
                if cont_lines:
                    info[last_header] = "\n".join(cont_lines).strip()
                    cont_lines = []
                if line.split(":", 1)[0] in info.keys():
                    last_header = line.split(":", 1)[0]
                    info[last_header] = line.split(":", 1)[1].strip()

        return info