# -*- coding: utf-8 -*-
#
# This file is part of Radicale Server - Calendar Server
# Copyright © 2008 Nicolas Kandel
# Copyright © 2008 Pascal Halter
# Copyright © 2008-2013 Guillaume Ayoub
#
# This library 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.
#
# This library 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 Radicale.  If not, see <http://www.gnu.org/licenses/>.

"""
Rights management.

"""

import re
import io
import os.path

from . import config, log

# Manage Python2/3 different modules
# pylint: disable=F0401
try:
    from configparser import ConfigParser
except ImportError:
    from ConfigParser import ConfigParser
# pylint: enable=F0401


FILENAME = os.path.expanduser(config.get("rights", "file"))
TYPE = config.get("rights", "type").lower()
DEFINED_RIGHTS = {
    "owner_write": "[r]\nuser:.*\ncollection:.*\npermission:r\n"
                   "[w]\nuser:.*\ncollection:^%(login)s/.+$\npermission:w",
    "owner_only": "[rw]\nuser:.\ncollection: ^%(login)s/.+$\npermission:rw"}


def _read_from_sections(user, collection, permission):
    """Get regex sections."""
    regex = ConfigParser({"login": user, "path": collection})
    if TYPE in DEFINED_RIGHTS:
        log.LOGGER.debug("Rights type '%s'" % TYPE)
        regex.readfp(io.BytesIO(DEFINED_RIGHTS[TYPE]))
    elif TYPE == "from_file":
        log.LOGGER.debug("Reading rights from file %s" % FILENAME)
        if not regex.read(FILENAME):
            log.LOGGER.error("File '%s' not found for rights" % FILENAME)
            return False
    else:
        log.LOGGER.error("Unknown rights type '%s'" % TYPE)
        return False

    for section in regex.sections():
        re_user = regex.get(section, "user")
        re_collection = regex.get(section, "collection")
        log.LOGGER.debug(
            "Test if '%s:%s' matches against '%s:%s' from section '%s'" % (
                user, collection, re_user, re_collection, section))
        user_match = re.match(re_user, user)
        if user_match:
            re_collection = re_collection.format(*user_match.groups())
            if re.match(re_collection, collection):
                log.LOGGER.debug("Section '%s' matches" % section)
                if permission in regex.get(section, "permission"):
                    return True
        log.LOGGER.debug("Section '%s' does not match" % section)
    return False


def authorized(user, collection, right):
    """Check if the user is allowed to read or write the collection."""
    return TYPE == "none" or (user and _read_from_sections(
        user, collection.url.rstrip("/") or "/", right))