# Copyright (C) 2006-2010 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman 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 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman 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
# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.

"""Configuration file loading and management."""

from __future__ import absolute_import, unicode_literals

__metaclass__ = type
__all__ = [
    'Configuration',
    ]


import os
import sys
import errno
import logging

from lazr.config import ConfigSchema, as_boolean
from pkg_resources import resource_stream
from zope.component import getUtility
from zope.interface import Interface, implements

from mailman import version
from mailman.core import errors
from mailman.interfaces.languages import ILanguageManager
from mailman.styles.manager import StyleManager
from mailman.utilities.filesystem import makedirs
from mailman.utilities.modules import call_name


SPACE = ' '



class IConfiguration(Interface):
    """Marker interface; used for adaptation in the REST API."""



class Configuration:
    """The core global configuration object."""

    implements(IConfiguration)

    def __init__(self):
        self.switchboards = {}
        self.style_manager = StyleManager()
        self.QFILE_SCHEMA_VERSION = version.QFILE_SCHEMA_VERSION
        self._config = None
        self.filename = None
        # Create various registries.
        self.chains = {}
        self.rules = {}
        self.handlers = {}
        self.pipelines = {}
        self.commands = {}

    def _clear(self):
        """Clear the cached configuration variables."""
        self.switchboards.clear()
        getUtility(ILanguageManager).clear()

    def __getattr__(self, name):
        """Delegate to the configuration object."""
        return getattr(self._config, name)

    def load(self, filename=None):
        """Load the configuration from the schema and config files."""
        schema_file = config_file = None
        try:
            schema_file = resource_stream('mailman.config', 'schema.cfg')
            schema = ConfigSchema('schema.cfg', schema_file)
            # If a configuration file was given, load it now too.  First, load
            # the absolute minimum default configuration, then if a
            # configuration filename was given by the user, push it.
            config_file = resource_stream('mailman.config', 'mailman.cfg')
            self._config = schema.loadFile(config_file, 'mailman.cfg')
            if filename is not None:
                self.filename = filename
                with open(filename) as user_config:
                    self._config.push(filename, user_config.read())
        finally:
            if schema_file:
                schema_file.close()
            if config_file:
                config_file.close()
        self._post_process()

    def push(self, config_name, config_string):
        """Push a new configuration onto the stack."""
        self._clear()
        self._config.push(config_name, config_string)
        self._post_process()

    def pop(self, config_name):
        """Pop a configuration from the stack."""
        self._clear()
        self._config.pop(config_name)
        self._post_process()

    def _post_process(self):
        """Perform post-processing after loading the configuration files."""
        # Set up directories.
        self.BIN_DIR = os.path.abspath(os.path.dirname(sys.argv[0]))
        self.VAR_DIR = var_dir = self._config.mailman.var_dir
        # Now that we've loaded all the configuration files we're going to
        # load, set up some useful directories.
        join = os.path.join
        self.LIST_DATA_DIR      = join(var_dir, 'lists')
        self.LOG_DIR            = join(var_dir, 'logs')
        self.LOCK_DIR = lockdir = join(var_dir, 'locks')
        self.DATA_DIR = datadir = join(var_dir, 'data')
        self.ETC_DIR = etcdir   = join(var_dir, 'etc')
        self.SPAM_DIR           = join(var_dir, 'spam')
        self.EXT_DIR            = join(var_dir, 'ext')
        self.QUEUE_DIR          = join(var_dir, 'qfiles')
        self.MESSAGES_DIR       = join(var_dir, 'messages')
        self.PUBLIC_ARCHIVE_FILE_DIR  = join(var_dir, 'archives', 'public')
        self.PRIVATE_ARCHIVE_FILE_DIR = join(var_dir, 'archives', 'private')
        # Other useful files
        self.PIDFILE                = join(datadir, 'master-qrunner.pid')
        self.SITE_PW_FILE           = join(datadir, 'adm.pw')
        self.LISTCREATOR_PW_FILE    = join(datadir, 'creator.pw')
        self.CONFIG_FILE            = join(etcdir, 'mailman.cfg')
        self.LOCK_FILE              = join(lockdir, 'master-qrunner')
        # Set up the switchboards.
        from mailman.queue import Switchboard
        Switchboard.initialize()
        # Set up all the languages.
        languages = self._config.getByCategory('language', [])
        language_manager = getUtility(ILanguageManager)
        for language in languages:
            if language.enabled:
                code = language.name.split('.')[1]
                language_manager.add(
                    code, language.charset, language.description)
        # The default language must always be available.
        assert self._config.mailman.default_language in language_manager, (
            'System default language code not defined: %s' %
            self._config.mailman.default_language)
        self.ensure_directories_exist()
        self.style_manager.populate()
        # Set the default system language.
        from mailman.core.i18n import _
        _.default = self.mailman.default_language

    @property
    def logger_configs(self):
        """Return all log config sections."""
        return self._config.getByCategory('logging', [])

    @property
    def paths(self):
        """Return a substitution dictionary of all path variables."""
        return dict((k, self.__dict__[k])
                    for k in self.__dict__
                    if k.endswith('_DIR'))

    def ensure_directories_exist(self):
        """Create all path directories if they do not exist."""
        for variable, directory in self.paths.items():
            makedirs(directory)

    @property
    def qrunner_configs(self):
        """Iterate over all the qrunner configuration sections."""
        for section in self._config.getByCategory('qrunner', []):
            yield section

    @property
    def archivers(self):
        """Iterate over all the enabled archivers."""
        for section in self._config.getByCategory('archiver', []):
            if not as_boolean(section.enable):
                continue
            class_path = section['class']
            yield call_name(class_path)

    @property
    def style_configs(self):
        """Iterate over all the style configuration sections."""
        for section in self._config.getByCategory('style', []):
            yield section

    @property
    def header_matches(self):
        """Iterate over all spam matching headers.

        Values are 3-tuples of (header, pattern, chain)
        """
        matches = self._config.getByCategory('spam.headers', [])
        for match in matches:
            yield (matches.header, matches.pattern, matches.chain)
