# persistor.py

# Persistence data container.

#

# Copyright (C) 2013-2016 Red Hat, Inc.

#

# This copyrighted material is made available to anyone wishing to use,

# modify, copy, or redistribute it subject to the terms and conditions of

# the GNU General Public License v.2, or (at your option) any later version.

# This program is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY expressed or implied, including the implied warranties 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., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the

# source code or documentation are not subject to the GNU General Public

# License and may only be used or replicated with the express permission of

# Red Hat, Inc.

#

# The current implementation is storing to files in persistdir. Do not depend on

# specific files existing, instead use the persistor API. The underlying

# implementation can change, e.g. for one general file with a serialized dict of

# data etc.

from __future__ import absolute_import

from __future__ import unicode_literals

from dnf.i18n import _

import distutils.version

import dnf.util

import errno

import fnmatch

import json

import logging

import os

import re

logger = logging.getLogger("dnf")

class JSONDB(object):

    def _check_json_db(self, json_path):

        if not os.path.isfile(json_path):

            # initialize new db

            dnf.util.ensure_dir(os.path.dirname(json_path))

            self._write_json_db(json_path, [])

    def _get_json_db(self, json_path, default=[]):

        with open(json_path, 'r') as f:

            content = f.read()

        if content == "":

            # empty file is invalid json format

            logger.warning(_("%s is empty file"), json_path)

            self._write_json_db(json_path, default)

        else:

            try:

                default = json.loads(content)

            except ValueError as e:

                logger.warning(e)

        return default

    @staticmethod

    def _write_json_db(json_path, content):

        with open(json_path, 'w') as f:

            json.dump(content, f)

class RepoPersistor(JSONDB):

    """Persistent data kept for repositories.

    Is arch/releasever specific and stores to cachedir.

    """

    def __init__(self, cachedir):

        self.cachedir = cachedir

        self.db_path = os.path.join(self.cachedir, "expired_repos.json")

        self.expired_to_add = set()

        self.reset_last_makecache = False

    @property

    def _last_makecache_path(self):

        return os.path.join(self.cachedir, "last_makecache")

    def get_expired_repos(self):

        self._check_json_db(self.db_path)

        return set(self._get_json_db(self.db_path))

    def save(self):

        self._check_json_db(self.db_path)

        self._write_json_db(self.db_path, list(self.expired_to_add))

        if self.reset_last_makecache:

            try:

                dnf.util.touch(self._last_makecache_path)

                return True

            except IOError:

                logger.info(_("Failed storing last makecache time."))

                return False

    def since_last_makecache(self):

        try:

            return int(dnf.util.file_age(self._last_makecache_path))

        except OSError:

            logger.info(_("Failed determining last makecache time."))

            return None

class TempfilePersistor(JSONDB):

    def __init__(self, cachedir):

        self.db_path = os.path.join(cachedir, "tempfiles.json")

        self.tempfiles_to_add = set()

        self._empty = False

    def get_saved_tempfiles(self):

        self._check_json_db(self.db_path)

        return self._get_json_db(self.db_path)

    def save(self):

        if not self._empty and not self.tempfiles_to_add:

            return

        self._check_json_db(self.db_path)

        if self._empty:

            self._write_json_db(self.db_path, [])

            return

        if self.tempfiles_to_add:

            data = set(self._get_json_db(self.db_path))

            data.update(self.tempfiles_to_add)

            self._write_json_db(self.db_path, list(data))

    def empty(self):

        self._empty = True