#!/usr/bin/python3
"""An mms to mail converter for mmsd."""
# upstream bug dirty fix
# https://github.com/marrow/mailer/issues/87#issuecomment-689586587
import sys
if sys.version_info[0] == 3 and sys.version_info[1] > 7:
    sys.modules["cgi.parse_qsl"] = None
# upstream bug dirty fix
# https://github.com/marrow/mailer/issues/87#issuecomment-713319548
import base64
if sys.version_info[0] == 3 and sys.version_info[1] > 8:
    def encodestring(value):
        """
        Encode string in base64.

        :param value: the string to encode.
        :type value: str

        :rtype str
        :return: the base64 encoded string
        """
        return base64.b64encode(value)
    base64.encodestring = encodestring
# end bugfix

import argparse
import configparser
import re
import time
import getpass
import socket
from pathlib import Path

from messaging.mms.message import MMSMessage
from marrow.mailer import Mailer, Message

from gi.repository import GLib
import dbus
import dbus.mainloop.glib
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler


class MMS2Mail:
    """
    The class handling the conversion between MMS and mail format.

    MMS support is provided by python-messaging
    Mail support is provided by marrow.mailer
    """

    def __init__(self, delete=False, force_read=False):
        """
        Return class instance.

        :param delete: delete MMS after conversion
        :type delete: bool

        :param force_read: force converting an already read MMS (batch mode)
        :type force_read: bool
        """
        self.delete = delete
        self.force_read = force_read
        self.config = configparser.ConfigParser()
        self.config.read(f"{Path.home()}/.mms/modemmanager/mms2mail.ini")
        self.attach_mms = self.config.getboolean('mail', 'attach_mms',
                                                 fallback=False)
        self.domain = self.config.get('mail', 'domain',
                                      fallback=socket.getfqdn())
        self.user = self.config.get('mail', 'user', fallback=getpass.getuser())
        mbox_file = self.config.get('mail', 'mailbox',
                                    fallback=f"/var/mail/{self.user}")
        self.mailer = Mailer({'manager.use': 'immediate',
                              'transport.use': 'mbox',
                              'transport.file': mbox_file})
        dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
        self.bus = dbus.SessionBus()

    def get_bus(self):
        """
        Return the DBus SessionBus.

        :rtype dbus.SessionBus()
        :return: an active SessionBus
        """
        return self.bus

    def mark_mms_read(self, dbus_path):
        """
        Ask mmsd to mark the mms as read.

        :param dbus_path: the mms dbus path
        :type dbus_path: str
        """
        message = dbus.Interface(self.bus.get_object('org.ofono.mms',
                                                     dbus_path),
                                 'org.ofono.mms.Message')
        print(f"Marking MMS as read {dbus_path}", file=sys.stderr)
        message.MarkRead()

    def delete_mms(self, dbus_path):
        """
        Ask mmsd to delete the mms.

        :param dbus_path: the mms dbus path
        :type dbus_path: str
        """
        message = dbus.Interface(self.bus.get_object('org.ofono.mms',
                                                     dbus_path),
                                 'org.ofono.mms.Message')
        print(f"Deleting MMS {dbus_path}", file=sys.stderr)
        message.Delete()

    def check_mms(self, path):
        """
        Check wether the provided file would be converted.

        :param path: the mms filesystem path
        :type path: str
        :rtype bool
        """
        # Check for mmsd data file
        if not Path(f"{path}").is_file():
            print("MMS file not found : aborting", file=sys.stderr)
            return False
        # Check for mmsd status file
        status = configparser.ConfigParser()
        if not Path(f"{path}.status").is_file():
            print("MMS status file not found : aborting", file=sys.stderr)
            return False
        status.read_file(open(f"{path}.status"))
        # Allow only incoming MMS for the time beeing
        if not (status['info']['state'] == 'downloaded' or
                status['info']['state'] == 'received'):
            print("Outgoing MMS : aborting", file=sys.stderr)
            return False
        if not (self.force_read or not status.getboolean('info', 'read')):
            print("Already converted MMS : aborting", file=sys.stderr)
            return False
        return True

    def convert(self, path, dbus_path=None):
        """
        Convert a provided mms file to a mail stored in a mbox.

        :param path: the mms filesystem path
        :type path: str

        :param dbus_path: the mms dbus path
        :type dbus_path: str
        """
        # Check if the provided file present
        if not self.check_mms(path):
            print("MMS file not convertible.", file=sys.stderr)
            return
        # Generate its dbus path, for future operation (mark as read, delete)
        if not dbus_path:
            dbus_path = f"/org/ofono/mms/modemmanager/{path.split('/')[-1]}"

        mms = MMSMessage.from_file(path)

        self.mailer.start()
        message = Message()

        # Generate Mail Headers
        mms_from, mms_from_type = mms.headers.get('From',
                                                  'unknown/undef').split('/')
        message.author = f"{mms_from}@{self.domain}"
        mms_from, mms_from_type = mms.headers.get('To',
                                                  'unknown/undef').split('/')
        message.to = f"{self.user}@{self.domain}"

        if 'Subject' in mms.headers and mms.headers['Subject']:
            message.subject = mms.headers['Subject']
        else:
            message.subject = f"MMS from {mms_from}"

        if 'Date' in mms.headers and mms.headers['Date']:
            message.date = mms.headers['Date']

        # Recopy MMS HEADERS
        for header in mms.headers:
            message.headers.append((f"X-MMS-{header}",
                                    f"{mms.headers[header]}"))

        for data_part in mms.data_parts:
            datacontent = data_part.headers['Content-Type']
            if datacontent is not None:
                if 'text/plain' in datacontent[0]:
                    message.plain = f"{data_part.data} \n"
                if 'Name' in datacontent[1]:
                    filename = datacontent[1]['Name']
                    message.attach(filename, data_part.data)
        # Ensure a proper body content in the resulting mail
        if not message.plain:
            message.plain = " "
        # Add MMS binary file, for debugging purpose or reparsing in the future
        if self.attach_mms:
            message.attach(path, None, None, None, False, "mms.bin")

        # Creating an empty file stating the mms as been converted
        self.mark_mms_read(dbus_path)

        if self.delete:
            self.delete_mms(dbus_path)

        # Write the mail
        self.mailer.send(message)
        self.mailer.stop()


class FSWatcher:
    """
    Use OS filesystem notification to watch for new MMS (DEPRECATED).

    Events are send to the FSHandler class
    """

    # Path to modemmanager storage
    mms_folder = f"{Path.home()}/.mms/modemmanager"

    def __init__(self):
        """Construct an instance."""
        self.observer = Observer()
        self.patternold = re.compile('[0-9A-F]{40}$')
        self.pattern = re.compile('[0-9a-f]{36}$')

    def is_mmsd_mms_file(self, path):
        """
        Test if the provided file seems to be a mms file created by mmsd.

        :param path: the mms filesystem path
        :type path: str

        :rtype boolean
        :return: the test result
        """
        if self.pattern.search(path) or self.patternold.search(path):
            return True
        else:
            return False

    def run(self):
        """Run the watcher mainloop."""
        event_handler = FSHandler()
        self.observer.schedule(event_handler, self.mms_folder, recursive=False)
        self.observer.start()
        try:
            while True:
                time.sleep(5)
        finally:
            self.observer.stop()
            self.observer.join()


class FSHandler(FileSystemEventHandler):
    """Handle the FSWatcher event."""

    @staticmethod
    def on_any_event(event):
        """Trigger conversion on event by the FSWatcher."""
        if event.is_directory:
            return None
        elif event.event_type == 'created' or event.event_type == 'modified':
            if w.is_mmsd_mms_file(event.src_path):
                print(f"New MMS found : {event.src_path}.", file=sys.stderr)
                m.convert(event.src_path)
        elif event.event_type == 'moved':
            if w.is_mmsd_mms_file(event.dest_path):
                print(f"New MMS found : {event.dest_path}.", file=sys.stderr)
                m.convert(event.dest_path)


class DbusWatcher():
    """Use DBus Signal notification to watch for new MMS."""

    def run(self):
        """Run the watcher mainloop."""
        bus = m.get_bus()
        bus.add_signal_receiver(self.message_added,
                                bus_name="org.ofono.mms",
                                signal_name="MessageAdded",
                                member_keyword="member",
                                path_keyword="path",
                                interface_keyword="interface")
        mainloop = GLib.MainLoop()
        mainloop.run()

    def message_added(self, name, value, member, path, interface):
        """Trigger conversion on MessageAdded signal."""
        if value['Status'] == 'downloaded' or value['Status'] == 'received':
            print(f"New incoming MMS found ({name.split('/')[-1]})")
            m.convert(value['Attachments'][0][2], name)
        else:
            print(f"New outgoing MMS found ({name.split('/')[-1]})")


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    mode = parser.add_mutually_exclusive_group()
    mode.add_argument("-d", "--daemon",
                      help="Use dbus signal from mmsd by default but can also \
                            watch mmsd storage folder (useful for mmsd < 1.0)",
                      nargs="?", default="dbus",
                      choices=['dbus', 'filesystem'], dest='watcher')
    mode.add_argument("-f", "--file", nargs='+',
                      help="Parse specified mms files and quit", dest='files')
    parser.add_argument('--delete', action='store_true', dest='delete',
                        help="Ask mmsd to delete the converted MMS")
    parser.add_argument('--force-read', action='store_true',
                        dest='force_read', help="Force conversion even if MMS \
                                                is marked as read")
    args = parser.parse_args()

    m = MMS2Mail(args.delete, args.force_read)

    if args.files:
        for mms_file in args.files:
            m.convert(mms_file)
    elif args.watcher == 'dbus':
        print("Starting mms2mail in daemon mode with dbus watcher")
        w = DbusWatcher()
        w.run()
    elif args.watcher == 'filesystem':
        print("Starting mms2mail in daemon mode with filesystem watcher")
        w = FSWatcher()
        w.run()
    else:
        parser.print_help()