#       This file is part of stov, written by Helmut Pozimski 2012-2021.
#
#       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 module contains the functions that make up the core of the
application.
"""

import logging
import smtplib
import socket
import sys
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

from lib_stov import stov_exceptions
from lib_stov import subscription
from lib_stov.configuration import Conf
from lib_stov.database import Db

LOGGER = logging.getLogger("stov")


def add_subscription(channel="", search="", playlist="", site="youtube"):
    """
    Takes care of adding a new subscription to the database.

    :param site: site the subscription is about to be created for
    :type site: str
    :param channel: optional channel name
    :type channel: str
    :param search: optional search string
    :type search: str
    :param playlist: optional playlist ID
    :type playlist: str
    """
    database = Db.get_instance()
    LOGGER.debug(_("Creating new subscription with the following "
                   "parameters:\nChannel: %s\nSearch: %s\nPlaylist: %s"),
                 channel, search, playlist)
    try:
        if channel and not search:
            new_subscription = subscription.Sub(subscription_type="user",
                                                name=channel, site=site)
        elif channel and search:
            new_subscription = subscription.Sub(subscription_type="user",
                                                name=channel, site=site,
                                                search=search)
        elif not channel and search:
            new_subscription = subscription.Sub(subscription_type="search",
                                                name=_("Search_"), site=site,
                                                search=search)
        elif playlist:
            if search:
                LOGGER.error(_("Playlists do not support searching, the "
                               "search option will be ignored!"))
            new_subscription = subscription.Sub(subscription_type="playlist",
                                                name=playlist, site=site)
        else:
            LOGGER.error(_("None or invalid subscription type given, please "
                           "check the type option and try again."))
            sys.exit(1)
    except stov_exceptions.TypeNotSupported as error:
        LOGGER.error(error)
        sys.exit(1)
    try:
        subscription_data = new_subscription.add_sub()
        site_id = database.get_site_id(subscription_data[6])
        new_sub_data = (subscription_data[0], subscription_data[1],
                        subscription_data[2], subscription_data[3],
                        subscription_data[4], subscription_data[5],
                        site_id)
        subscription_id = database.insert_subscription(new_sub_data)
        new_subscription.set_id(subscription_id)
    except stov_exceptions.DBWriteAccessFailedException as error:
        LOGGER.error(error)
        sys.exit(1)
    except stov_exceptions.ChannelNotFound as error:
        LOGGER.error(error)
        sys.exit(1)
    else:
        LOGGER.debug(_("Subscription sucessfully inserted into database."))
    try:
        new_subscription.update_data()
    except stov_exceptions.YoutubeAPITimeoutException as error:
        LOGGER.error(error)
    except stov_exceptions.NoDataFromYoutubeAPIException as error:
        LOGGER.error(error)
    for video in new_subscription.parsed_response.videos:
        if not database.video_in_database(video.video_id):
            if new_subscription.check_string_match(video):
                try:
                    database.insert_video(video, new_subscription.get_id())
                except stov_exceptions.DBWriteAccessFailedException as error:
                    LOGGER.error(error)
                    sys.exit(1)
                else:
                    LOGGER.debug(_("Video %s successfully inserted into "
                                   "database."), video.title)
    LOGGER.info(_("New subscription ") + new_subscription.get_title() +
                _(" successfully added"))


def list_subscriptions():
    """
    Prints a list of subscriptions from the database.

    """
    database = Db.get_instance()
    conf = Conf.get_instance()
    subscriptions_list = database.get_subscriptions(conf)
    sub_state = None
    if subscriptions_list:
        LOGGER.info(_("ID Title Site"))
        for sub in subscriptions_list:
            if not sub.disabled:
                sub_state = _("enabled")
            elif sub.disabled:
                sub_state = _("disabled")
            LOGGER.info(str(sub.get_id()) + " " + sub.get_title() +
                        " " + sub.site + " " + "(%s)" % sub_state)
    else:
        LOGGER.info(_("No subscriptions added yet, add one!"))


def delete_subscription(sub_id):
    """
    Deletes a specified subscription from the database

    :param sub_id: ID of the subscription to be deleted
    :type sub_id: int
    """
    database = Db.get_instance()
    try:
        database.delete_subscription(sub_id)
    except stov_exceptions.SubscriptionNotFoundException as error:
        LOGGER.error(error)
        sys.exit(1)
    except stov_exceptions.DBWriteAccessFailedException as error:
        LOGGER.error(error)
        sys.exit(1)
    else:
        LOGGER.info(_("Subscription deleted successfully!"))


def update_subscriptions(subscriptions=None):
    """
    Updates data about videos in a subscription.

    :param subscriptions: list of subscriptions to update
    :type subscriptions: list
    """
    database = Db.get_instance()
    subscriptions_list = get_subscriptions(subscriptions)
    for element in subscriptions_list:
        LOGGER.debug(_("Updating subscription %s"), element.get_title())
        videos = database.get_videos(element.get_id())
        element.gather_videos(videos)
        try:
            element.update_data()
        except stov_exceptions.YoutubeAPITimeoutException as error:
            LOGGER.error(error)
        except stov_exceptions.NoDataFromYoutubeAPIException as error:
            LOGGER.error(error)
        for video in element.parsed_response.videos:
            if not database.video_in_database(video.video_id):
                if element.check_string_match(video):
                    try:
                        database.insert_video(video, element.get_id())
                    except stov_exceptions.DBWriteAccessFailedException as \
                            error:
                        LOGGER.error(error)
                        sys.exit(1)
                    else:
                        LOGGER.debug(_("Video %s successfully inserted into "
                                       "database."), video.title)


def download_videos(subscriptions=None):
    """
    Downloads videos that haven't been previously downloaded.

    :param subscriptions: list of subscriptions to consider for downloading
    :type subscriptions: list
    :return: tuple containing (in that order) downloaded videos, failed \
    videos and a list of the videos downloaded
    :rtype: tuple
    """
    database = Db.get_instance()
    conf = Conf.get_instance()
    video_titles = []
    subscriptions_list = get_subscriptions(subscriptions)
    videos_downloaded = 0
    videos_failed = 0
    for sub in subscriptions_list:
        videos = database.get_videos(sub.get_id())
        sub.gather_videos(videos)
        try:
            sub.download_videos()
        except stov_exceptions.SubscriptionDisabledException as error:
            LOGGER.debug(error)
        for entry in sub.downloaded_videos:
            database.update_video_download_status(entry.get_id(), 1)
            video_titles.append(entry.title)
        videos_downloaded = len(video_titles)
        videos_failed = videos_failed + sub.failed_videos_count
        for video in sub.failed_videos:
            try:
                database.update_video_fail_count(video.failcnt, video.get_id())
                if video.failcnt >= int(conf.values["maxfails"]):
                    database.disable_failed_video(video.get_id())
            except stov_exceptions.DBWriteAccessFailedException as error:
                LOGGER.error(error)
                sys.exit(1)
    return videos_downloaded, videos_failed, video_titles


def compose_email(downloaded_videos, video_titles):
    """
    Composes an e-mail that can be send out to the user.

    :param downloaded_videos: number of downloaded videos
    :type downloaded_videos: int
    :param video_titles: titles of the downloaded videos
    :type video_titles: list
    :return: e-mail contents
    :rtype: MIMEMultipart
    """
    conf = Conf.get_instance()
    mail_text = ""
    msg = MIMEMultipart()
    if downloaded_videos == 1:
        msg["Subject"] = _("Downloaded %i new video") % downloaded_videos
        mail_text = _("The following episode has been downloaded by stov: "
                      "\n\n")
    else:
        msg["Subject"] = _("Downloaded %i new videos") % downloaded_videos
        mail_text = _("The following episodes have been downloaded by "
                      "stov: \n\n")
    msg["From"] = "stov <%s>" % conf.values["mailfrom"]
    msg["To"] = "<%s>" % conf.values["mailto"]
    for line in video_titles:
        mail_text += line + "\n"
    msg_text = MIMEText(mail_text.encode("utf8"), _charset="utf8")
    msg.attach(msg_text)
    return msg


def send_email(msg):
    """
    Sends an e-mail to the user.

    :param msg: message to be sent
    :type msg: MIMEMultipart
    """
    conf = Conf.get_instance()
    server_connection = smtplib.SMTP(conf.values["mailhost"],
                                     conf.values["smtpport"])
    try:
        server_connection.connect()
    except (smtplib.SMTPConnectError, smtplib.SMTPServerDisconnected,
            socket.error):
        LOGGER.error(_("Could not connect to the smtp server, please check"
                       " your settings!"))
    else:
        try:
            server_connection.starttls()
        except smtplib.SMTPException:
            LOGGER.debug(_("TLS not available, proceeding unencrypted."))
        if conf.values["auth_needed"] == "yes":
            try:
                server_connection.login(conf.values["user_name"],
                                        conf.values["password"])
            except smtplib.SMTPAuthenticationError:
                LOGGER.error(_("Authentication failed, please check user "
                               "name and password!"))
            except smtplib.SMTPException:
                LOGGER.error(_("Could not authenticate, server probably "
                               "does not support authentication!"))
        try:
            server_connection.sendmail(conf.values["mailfrom"],
                                       conf.values["mailto"],
                                       msg.as_string())
        except smtplib.SMTPRecipientsRefused:
            LOGGER.error(_("The server refused the recipient address, "
                           "please check your settings."))
        except smtplib.SMTPSenderRefused:
            LOGGER.error(_("The server refused the sender address, "
                           "please check your settings."))
        server_connection.quit()


def list_videos(sub_id):
    """
    Lists all videos in a specified subscription

    :param sub_id: ID of the subscription
    :type sub_id: int
    """
    database = Db.get_instance()
    try:
        data = database.get_subscription(sub_id)
    except stov_exceptions.DBWriteAccessFailedException as error:
        LOGGER.error(error)
        sys.exit(1)
    else:
        if data:
            sub = subscription.Sub(subscription_type=data[0][2],
                                   name=data[0][3], site=data[0][7],
                                   search=data[0][4],
                                   subscription_id=data[0][0],
                                   title=data[0][1], directory=data[0][5],
                                   disabled=data[0][6])
            videos = database.get_videos(sub.get_id())
            sub.gather_videos(videos)
            videos_list = sub.print_videos()
            for video in videos_list:
                LOGGER.info(video)
        else:
            LOGGER.error(_("Invalid subscription, please check the list and "
                           "try again."))


def catchup(sub_id):
    """
    Marks all videos in a subscription as downloaded

    :param sub_id: ID of the subscription
    :type sub_id: int
    """
    database = Db.get_instance()
    try:
        sub_data = database.get_subscription_title(sub_id)
    except stov_exceptions.DBWriteAccessFailedException as error:
        LOGGER.error(error)
        sys.exit(1)
    else:
        if sub_data:
            try:
                database.mark_video_downloaded(sub_id)
            except stov_exceptions.DBWriteAccessFailedException as error:
                LOGGER.error(error)
        else:
            LOGGER.error(_("The subscription could not be updated, "
                           "please check if the ID given is correct."))


def clean_database():
    """
    Initiates a database cleanup, deleting all videos that are no longer
    in the scope of the query and vacuuming the database to free up space.

    """
    database = Db.get_instance()
    conf = Conf.get_instance()
    subscription_list = database.get_subscriptions()
    for element in subscription_list:
        videos = database.get_videos(element.get_id(), conf)
        element.check_and_delete(videos)
        for delete_video in element.to_delete:
            LOGGER.debug(_("Deleting video %s from "
                           "database"), delete_video.title)
            try:
                database.delete_video(delete_video.get_id())
            except stov_exceptions.DBWriteAccessFailedException as error:
                LOGGER.error(error)
                sys.exit(1)
    try:
        database.vacuum()
    except stov_exceptions.DBWriteAccessFailedException as error:
        LOGGER.error(error)
        sys.exit(1)


def change_subscription_state(sub_id, enable=False):
    """
    Enables or disables a subscription.

    :param sub_id: ID of the subscription
    :type sub_id: int
    :param enable: whether to enable or disable the subscription
    :type enable: bool
    """
    database = Db.get_instance()
    subscription_state = database.get_subscription(sub_id)
    try:
        if enable:
            if int(subscription_state[0][6]) == 0:
                LOGGER.error(_("The subscription ID %s is already enabled."),
                             sub_id)
            elif int(subscription_state[0][6]) == 1:
                try:
                    database.change_subscription_state(sub_id, 0)
                except stov_exceptions.DBWriteAccessFailedException as error:
                    LOGGER.error(error)
                    sys.exit(1)
                else:
                    LOGGER.info(_("Enabled subscription ID %s."), sub_id)
        else:
            if int(subscription_state[0][6]) == 1:
                LOGGER.error(_("Subscription ID %s is already disabled."),
                             sub_id)
            elif int(subscription_state[0][6]) == 0:
                try:
                    database.change_subscription_state(sub_id, 1)
                except stov_exceptions.DBWriteAccessFailedException as error:
                    LOGGER.error(error)
                    sys.exit(1)
                else:
                    LOGGER.info(_("Disabled subscription ID %s."),
                                sub_id)
    except IndexError:
        LOGGER.error(_("Could not find the subscription with ID %s, "
                       "please check and try again."), sub_id)


def print_license():
    """
    Prints the license of the application.
    """
    LOGGER.info("""
        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/>.""")


def download_notify(subscriptions=None):
    """
    starts an update of not yet downloaded videos and notifies the user

    :param subscriptions: list of subscriptions to consider for downloading
    :type subscriptions: list
    """
    conf = Conf.get_instance()
    videos_downloaded, videos_failed, video_titles = \
        download_videos(subscriptions)
    if videos_downloaded > 0 and conf.values["notify"] == "yes":
        msg = compose_email(videos_downloaded, video_titles)
        send_email(msg)
    elif videos_downloaded == 0 and videos_failed == 0:
        if conf.values["notify"] == "no":
            LOGGER.info(_("There are no videos to be downloaded."))
    elif conf.values["notify"] == "no":
        if videos_failed == 0:
            LOGGER.info(_("The following videos have been downloaded:\n"))
            for i in video_titles:
                LOGGER.info(i)
    else:
        if conf.values["notify"] != "yes":
            LOGGER.error(_("Could not determine how you want to be informed "
                           "about new videos, please check the notify "
                           "parameter in your configuration."))


def initialize_sites():
    """
    Adds sites to the database if they are not in there yet.

    """
    database = Db.get_instance()
    supported_sites = ["youtube", "zdf_mediathek", "twitch"]
    sites = database.get_sites()
    for site in supported_sites:
        site_found = False
        for result in sites:
            if site in result:
                site_found = True
        if not site_found:
            database.add_site(site)
    for site in sites:
        if site[1] not in supported_sites:
            database.remove_site(site[1])


def list_sites():
    """
    Lists the currently supported sites.

    """
    database = Db.get_instance()
    sites = database.get_sites()
    LOGGER.info(_("Sites currently supported by stov:"))
    for entry in sites:
        LOGGER.info(entry[1])


def get_subscriptions(subscriptions=None):
    """
    Retrieves all or only specific subscriptions from the database and
    returns them as a list of subscription objects.

    :param subscriptions: list of subscriptions to retrieve
    :type subscriptions: list
    :return: list of subscription objects
    :rtype: list
    """
    database = Db.get_instance()
    if subscriptions:
        subscriptions_list = []
        for element in subscriptions:
            data = database.get_subscription(element)
            if data:
                sub = subscription.Sub(subscription_type=data[0][2],
                                       name=data[0][3], site=data[0][7],
                                       search=data[0][4],
                                       subscription_id=data[0][0],
                                       title=data[0][1], directory=data[0][5],
                                       disabled=data[0][6])
                subscriptions_list.append(sub)
            else:
                LOGGER.error(
                    _("Invalid subscription, please check the list and "
                      "try again."))
    else:
        subscriptions_list = database.get_subscriptions()
    return subscriptions_list