stov/lib_stov/configuration.py

#   This file is part of stov, written by Helmut Pozimski 2012-2017.
#
#   stov 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, version 2 of the License.
#
#   stov 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 stov.  If not, see <http://www.gnu.org/licenses/>.


# -*- coding: utf8 -*-

"""This file takes care of reading, storing and updating the configuration of
stov, the configuration file is expected to be in json format and reside in
~/.stov/stov.json.
"""

import json
import logging
import os

from lib_stov import stov_exceptions

LOGGER = logging.getLogger("stov")


class Conf(object):
    """This class is used to create the object which is responsible for all
    configuration operations.
    """
    _instance = None

    def __init__(self):
        """Constructor

        Constructs the conf object with some reasonable default values which
        should work on most systems, existence of a local mail server is
        assumed.

        """
        self.values = {
            "database": "stov.sqlite",
            "downloaddir": str(os.environ['HOME']) + "/stov",
            "maxvideos": "25",
            "mailhost": "localhost",
            "mailto": "root",
            "mailfrom": "stov@localhost",
            "smtpport": "25",
            "auth_needed": "no",
            "user_name": "",
            "password": "",
            "youtube-dl": "",
            "notify": "yes",
            "config_version": "10",
            "db_version": "6",
            "video_codec": "mp4",
            "video_height": "1080",
            "audio_quality": "bestaudio",
            "maxfails": 50,
            "check_title": "no"
        }

        self._explanations = {
            "database": _("the name of your database file"),
            "downloaddir": _("the directory where downloaded videos are "
                             "saved"),
            "maxvideos": _("the maximum number of videos to retrieve for each "
                           "subscription"),
            "mailhost": _("the host name of your mail server"),
            "mailto": _("the address used for notifications"),
            "mailfrom": _("the sender address of notification e-mails"),
            "smtpport": _("the port to use on your mail server"),
            "auth_needed": _("if your mail server requires authentication"),
            "user_name": _("the user name used to authenticate to your mail "
                           "server"),
            "password": _("the password used to authenticate to your mail "
                          "server"),
            "youtube-dl": _("the path to your youtube-dl installation"),
            "notify": _("if you want to be notified via e-mail about new "
                        "videos"),
            "video_codec": _("which video codec you prefer (h264, webm or "
                             "flv)"),
            "video_height": _("sets the height of the video to download (e.g."
                              " 1080 for 1920x180)"),
            "audio_quality": _("sets the requested audio quality "
                               "(e.g. bestaudio)"),
            "check_title": _("if you want to compare the title of a video "
                             "with the subscription search string")
        }
        self.dbpath = str(os.environ['HOME']) + "/.stov/" + \
                      self.values["database"]
        self.outputlevel = "default"

    def __new__(cls, *args, **kwargs):
        if not Conf._instance:
            Conf._instance = super(Conf, cls).__new__(cls)
        return Conf._instance

    @staticmethod
    def get_instance():
        """
        Returns the singleton instance of the object

        :return: Conf object
        :rtype: lib_stov.configuration.Conf
        """
        return Conf._instance

    def write_config(self):
        """Writes the configuration from the dictionary into the configuration
        file for stov. The configuration is written into the home directory of
        the user by default.

        """
        LOGGER.debug(_("Writing configuration file."))
        try:
            configfile = open(str(os.environ['HOME']) +
                              "/.stov/stov.json", "w")
        except IOError:
            raise stov_exceptions.ConfigFileWriteErrorException()
        else:
            json.dump(self.values, configfile, indent=0)
            configfile.close()

    def initialize(self):
        """Creates the necessary directory for the stov configuration and
        calls the internal methods to create the database and the
        configuration file.

        """
        LOGGER.debug(_("Creating stov configuration directory"))
        try:
            os.mkdir(str(os.environ['HOME']) + "/.stov", 0o750)
        except os.error:
            raise stov_exceptions.DirectoryCreationFailedException()
        else:
            self.write_config()

    def read_old_config(self):
        """Reads the existing plain text configuration file and places the
        values in the dictionary. Existing values (such as default values)
        are overwritten.

        """
        LOGGER.debug(_("Opening old configuration file to convert it to "
                       "json"))
        try:
            configfile = open(str(os.environ['HOME']) +
                              "/.stov/stov.config", "r")
        except IOError:
            raise stov_exceptions.ConfigFileReadErrorException()
        for lines in configfile:
            tmpline = lines.strip()
            tmplist = tmpline.split("=")
            self.values[tmplist[0].lower()] = tmplist[1]
        configfile.close()
        self.dbpath = str(os.environ['HOME']) + "/.stov/" + \
                      self.values["database"]

    def read_config(self):
        """Reads the existing json configuration files and loads the values in
        the dictionary.
        """
        LOGGER.debug(_("Opening configuration file"))
        try:
            configfile = open(str(os.environ['HOME']) + "/.stov/stov.json",
                              "r")
        except IOError:
            raise stov_exceptions.ConfigFileReadErrorException()
        else:
            self.values.update(json.load(configfile))
            configfile.close()

    def check_config(self):
        """Checks if the configuration is up-to-date with the running
        stov version.

        """
        try:
            current_version = int(self.values["config_version"])
        except ValueError:
            raise stov_exceptions.InvalidConfigurationVersionException()
        self.values["config_version"] = "0"
        self.read_config()
        if self.values["config_version"] == "0" \
                or int(self.values["config_version"]) < current_version:
            self.values["config_version"] = str(current_version)
            return False
        self.values["config_version"] = current_version
        return True

    def update_config(self):
        """Update the configuration to the latest version"""
        version_buffer = self.values["config_version"]
        self.read_config()
        self.values["config_version"] = version_buffer
        self.write_config()

    def check_db(self):
        """Checks the database if it is up-to-date"""
        currentdbversion = int(self.values["db_version"])
        self.values["db_version"] = "0"
        self.read_config()
        if self.values["db_version"] == "0" or \
                int(self.values["db_version"]) < \
                int(currentdbversion):
            self.values["db_version"] = str(currentdbversion)
            return False
        self.values["db_version"] = str(currentdbversion)
        return True

    def assist(self):
        """ Ask the user to set all required configuration parameters """

        print(_("This assistant will help you to perform the initial "
                "configuration of stov. \nThe default value will be "
                "displayed in brackets.\n"
                "Please specify now :\n"))
        for value in self._explanations:
            print(self._explanations[value] + " [" + self.values[value] +
                  "]:" +
                  " ")
            user_input = input()

            if user_input != "":
                self.values[value] = user_input
        self.dbpath = str(os.environ['HOME']) + "/.stov/" + \
                      self.values["database"]

    def migrate_config(self):
        """Migrates the configuration from the old plain text config to
        the new and shiny json configuration file.
        """
        try:
            self.read_old_config()
            self.write_config()
        except stov_exceptions.ConfigFileReadErrorException:
            raise stov_exceptions.ConfigurationMigrationFailed()
        except stov_exceptions.ConfigFileWriteErrorException:
            raise stov_exceptions.ConfigurationMigrationFailed
        else:
            os.remove(str(os.environ['HOME']) + "/.stov/stov.config")

    def configure_logging(self, verbose=False, quiet=False):
        """
        Sets up logging for stov and returns a logger object

        :param verbose: whether to use verbose mode
        :type verbose: bool
        :param quiet: whether to use quiet mode
        :type quiet: bool
        :return: logger object
        :rtype: logging.Logger
        """
        logger = logging.getLogger("stov")
        # verbose takes precedence
        if verbose:
            logger.setLevel(logging.DEBUG)
            self.outputlevel = "verbose"
        elif quiet:
            logger.setLevel(logging.ERROR)
            self.outputlevel = "quiet"
        else:
            logger.setLevel(logging.INFO)
        console_handler = logging.StreamHandler()
        logger.addHandler(console_handler)
        return logger

    def get_value(self, identifier):
        return self.values[identifier];