#!/usr/bin/env python3
"""
Module Docstring
"""

__author__ = "Nikola Kotur"
__version__ = "0.1"
__license__ = "Apache License 2.0"

import os
import sys
import argparse
import threading
import tempfile
import subprocess
from pprint import pprint as pp

import pyudev
from logzero import logger


class USBDetector():
    ''' Monitor udev for detection of usb '''
 
    def __init__(self, handler, source_dir, dest_dir, ftp_args):
        self.usb_plugged_in = handler
        self.source_dir = source_dir
        self.dest_dir = dest_dir
        self.ftp_args = ftp_args
        thread = threading.Thread(target=self._work)
        thread.daemon = True
        thread.start()
        thread.join()

    def _work(self):
        self.context = pyudev.Context()
        self.monitor = pyudev.Monitor.from_netlink(self.context)
        self.monitor.filter_by(subsystem='block')
        logger.info("Starting to monitor for usb")
        self.monitor.start()
        for device in iter(self.monitor.poll, None):
            logger.debug("Got USB event: %s", device.action)
            if device.action == 'add' and device.device_type == 'partition':
                self.usb_plugged_in(device, self.source_dir, self.dest_dir, self.ftp_args)


def execute(shell_command):
    shell_command = shell_command.split(' ')
    try:
        res = subprocess.check_output(shell_command, stderr=subprocess.PIPE)
        return res.decode('utf-8')
    except subprocess.CalledProcessError as e:
        print('exit code: {}'.format(e.returncode))
        print('stdout: {}'.format(e.output.decode(sys.getfilesystemencoding())))
        print('stderr: {}'.format(e.stderr.decode(sys.getfilesystemencoding())))
        return None


def parse_video_files(usb_dir, base_dir, extension):
    files = {}
    for file in os.listdir(os.path.join(usb_dir, base_dir)):
        if file.endswith(extension):
            full_path = (os.path.join(usb_dir, base_dir, file))
            file_parts = file.split('_')
            part_date = file_parts[0]
            if part_date not in files:
                files[part_date] = []
            files[part_date].append(full_path)
    return files


def join_video_files(dest, sources):
    with tempfile.TemporaryDirectory() as tmpdirname:
        list_file = os.path.join(tmpdirname, 'list')
        with open(list_file, 'w') as lfh:
            for source_line in sources:
                lfh.write("file '%s'\n" % source_line)

        ffmpeg_line = 'ffmpeg -safe 0 -f concat -i %s -c copy %s' % (list_file, dest)
        output = execute(ffmpeg_line)
    if output != None:
        logger.info('Removing source files')
        for s_file in sources:
            os.remove(s_file)
        return True
    return False


def plugged_in(dev, source_dir, dest_dir, ftp):
    logger.info('Detected %s (%s)', dev.device_node, dev.device_type)
    with tempfile.TemporaryDirectory() as tmpdirname:
        logger.info('Mounting %s on %s', dev.device_node, tmpdirname)
        output = execute('mount %s %s' % (dev.device_node, tmpdirname))

        # Join files
        joined_files = []
        for file_group, files in parse_video_files(tmpdirname, source_dir, 'MP4').items():
            logger.info('Joining video group %s', file_group)
            outfile_name = '%s.mp4' % file_group
            outfile_path = os.path.join(dest_dir, outfile_name)
            if join_video_files(outfile_path, files):
                joined_files.append(outfile_path)

        logger.info('Umounting %s from %s', dev.device_node, tmpdirname)
        output = execute('umount %s' % (dev.device_node))

        # Beam files to FTP
        for up_file in joined_files:
            logger.info('Uploading %s to %s', up_file, ftp['host'])
            output = execute('ncftpput -u %s -p %s %s %s %s' % (ftp['user'], ftp['password'], ftp['host'], ftp['path'], up_file))
            if output != None:
                logger.info('Removing %s', up_file)
                os.remove(up_file)

    logger.info('Done')


def main(args):
    """ Main entry point of the app """
    ftp_args = {
        'host': args.ftp_host,
        'path': args.ftp_path,
        'user': args.ftp_user,
        'password': args.ftp_password,
    }
    usb_detect = USBDetector(plugged_in, args.source, args.destination, ftp_args)


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    # Directory options
    parser.add_argument("-s", "--source", help="source directory with dashcam videos", action="store", dest="source", default="DCIM/Movie")
    parser.add_argument("-d", "--destination", help="destination directory for joined dashcam videos", action="store", dest="destination", default="/var/dashcam")
    # FTP options
    parser.add_argument("--ftp-host", help="ftp host (server)", action="store", default="192.168.88.242")
    parser.add_argument("--ftp-path", help="ftp path", action="store", default="/dashcam")
    parser.add_argument("--ftp-user", help="ftp user", action="store", default="dashcam")
    parser.add_argument("--ftp-password", help="ftp user", action="store", default="")

    # Optional verbosity counter (eg. -v, -vv, -vvv, etc.)
    parser.add_argument(
        "-v",
        "--verbose",
        action="count",
        default=0,
        help="Verbosity (-v, -vv, etc)")

    # Specify output of "--version"
    parser.add_argument(
        "--version",
        action="version",
        version="%(prog)s (version {version})".format(version=__version__))

    args = parser.parse_args()
    main(args)