"""
The video module contains the :class:`Video` class, which represents video
objects (AVI, MOV, etc.).

.. moduleauthor:: Jaisen Mathai <jaisen@jmathai.com>
"""

# load modules
from distutils.spawn import find_executable
import tempfile
from datetime import datetime

import os
import re
import shutil
import subprocess
import time

from elodie import constants
from elodie import plist_parser
from elodie.dependencies import get_exiftool
from media import Media


class Video(Media):

    """A video object.

    :param str source: The fully qualified path to the video file.
    """

    __name__ = 'Video'

    #: Valid extensions for video files.
    extensions = ('avi', 'm4v', 'mov', 'mp4', 'mpg', 'mpeg', '3gp')

    def __init__(self, source=None):
        super(Video, self).__init__(source)

    def get_avmetareadwrite(self):
        """Get path to executable avmetareadwrite binary.

        We wrap this since we call it in a few places and we do a fallback.

        :returns: None or string
        """
        avmetareadwrite = find_executable('avmetareadwrite')
        if(avmetareadwrite is None):
            avmetareadwrite = '/usr/bin/avmetareadwrite'
            if(not os.path.isfile(avmetareadwrite) or not os.access(avmetareadwrite, os.X_OK)):  # noqa
                return None

        return avmetareadwrite

    def get_coordinate(self, type='latitude'):
        """Get latitude or longitude of photo from EXIF.

        :returns: time object or None for non-video files or 0 timestamp
        """
        exif_data = self.get_exif()
        if(exif_data is None):
            return None

        coords = re.findall('(GPS %s +: .+)' % type.capitalize(), exif_data)
        if(coords is None or len(coords) == 0):
            return None

        coord_string = coords[0]
        coordinate = re.findall('([0-9.]+)', coord_string)
        direction = re.search('[NSEW]$', coord_string)
        if(coordinate is None or direction is None):
            return None

        direction = direction.group(0)

        decimal_degrees = float(coordinate[0]) + float(coordinate[1])/60 + float(coordinate[2])/3600  # noqa
        if(direction == 'S' or direction == 'W'):
            decimal_degrees = decimal_degrees * -1

        return decimal_degrees

    def get_date_taken(self):
        """Get the date which the video was taken.

        The date value returned is defined by the min() of mtime and ctime.

        :returns: time object or None for non-video files or 0 timestamp
        """
        if(not self.is_valid()):
            return None

        source = self.source
        # We need to parse a string from EXIF into a timestamp.
        # We use date.strptime -> .timetuple -> time.mktime to do the
        #   conversion in the local timezone
        # If the time is not found in EXIF we update EXIF
        seconds_since_epoch = min(os.path.getmtime(source), os.path.getctime(source))  # noqa
        exif_data = self.get_exif()
        for key in ['Creation Date', 'Media Create Date']:
            date = re.search('%s +: +([0-9: ]+)' % key, exif_data)
            if(date is not None):
                date_string = date.group(1)
                try:
                    exif_seconds_since_epoch = time.mktime(
                        datetime.strptime(
                            date_string,
                            '%Y:%m:%d %H:%M:%S'
                        ).timetuple()
                    )
                    if(exif_seconds_since_epoch < seconds_since_epoch):
                        seconds_since_epoch = exif_seconds_since_epoch
                        break
                except:
                    pass

        if(seconds_since_epoch == 0):
            return None

        return time.gmtime(seconds_since_epoch)

    def get_duration(self):
        """Get the duration of a video in seconds.

        This uses ffmpeg/ffprobe.

        :returns: str or None for a non-video file
        """
        if(not self.is_valid()):
            return None

        source = self.source
        result = subprocess.Popen(
            ['ffprobe', source],
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT
        )
        for key in result.stdout.readlines():
            if 'Duration' in key:
                return re.search(
                    '(\d{2}:\d{2}.\d{2})',
                    key
                ).group(1).replace('.', ':')
        return None

    def get_exif(self):
        """Get exif data from video file.

        Not all video files have exif and this currently relies on the CLI
        exiftool program.

        :returns: str or None if exiftool is not found
        """
        exiftool = get_exiftool()
        if(exiftool is None):
            return None

        source = self.source
        process_output = subprocess.Popen(
            '%s "%s"' % (exiftool, source),
            stdout=subprocess.PIPE,
            shell=True,
            universal_newlines=True
        )
        return process_output.stdout.read()

    def is_valid(self):
        """Check the file extension against valid file extensions.

        The list of valid file extensions come from self.extensions.

        :returns: bool
        """
        source = self.source
        return os.path.splitext(source)[1][1:].lower() in self.extensions

    def set_date_taken(self, date_taken_as_datetime):
        """
        Set the date/time a photo was taken

        :param datetime date_taken_as_datetime: datetime object of when the
            video was recorded.
        :returns: bool
        """
        if(time is None):
            return False

        source = self.source

        result = self.__update_using_plist(time=date_taken_as_datetime)
        if(result is True):
            os.utime(
                source,
                (
                    int(time.time()),
                    time.mktime(date_taken_as_datetime.timetuple())
                )
            )

        return result

    def set_location(self, latitude, longitude):
        """
        Set latitude and longitude for a video.

        :param float latitude: Latitude of the file
        :param float longitude: Longitude of the file
        :returns: bool
        """
        if(latitude is None or longitude is None):
            return False

        result = self.__update_using_plist(latitude=latitude, longitude=longitude)  # noqa
        return result

    def set_title(self, title):
        """Set title for a video.

        :param str title: Title for the file
        :returns: bool
        """
        if(title is None):
            return False

        result = self.__update_using_plist(title=title)
        return result

    def __update_using_plist(self, **kwargs):
        """Updates video metadata using avmetareadwrite.

        This method does a lot more than it should. The general steps are...

        1. Check if avmetareadwrite is installed
        2. Export a plist file to a temporary location from the source file
        3. Regex replace values in the plist file
        4. Update the source file using the updated plist and save it to a
           temporary location
        5. Validate that the metadata in the updated temorary movie is valid
        6. Copystat permission and time bits from the source file to the
           temporary movie
        7. Move the temporary file to overwrite the source file

        :param float latitude: Latitude of the file
        :param float longitude: Longitude of the file
        :returns: bool
        """
        if(
            'latitude' not in kwargs and
            'longitude' not in kwargs and
            'time' not in kwargs and
            'title' not in kwargs
        ):
            if(constants.debug is True):
                print 'No lat/lon passed into __create_plist'
            return False

        avmetareadwrite = self.get_avmetareadwrite()
        if(avmetareadwrite is None):
            if(constants.debug is True):
                print 'Could not find avmetareadwrite'
            return False

        source = self.source

        # First we need to write the plist for an existing file
        #   to a temporary location
        with tempfile.NamedTemporaryFile() as plist_temp:
            # We need to write the plist file in a child process
            #   but also block for it to be complete.
            # http://stackoverflow.com/a/5631819/1318758
            avmetareadwrite_generate_plist_command = '%s -p "%s" "%s"' % (
                avmetareadwrite,
                plist_temp.name,
                source
            )
            write_process = subprocess.Popen(
                [avmetareadwrite_generate_plist_command],
                stdout=subprocess.PIPE,
                shell=True
            )
            write_process.communicate()
            if(write_process.returncode != 0):
                if(constants.debug is True):
                    print 'Failed to generate plist file'
                return False

            plist = plist_parser.Plist(plist_temp.name)
            # Depending on the kwargs that were passed in we regex
            #   the plist_text before we write it back.
            plist_should_be_written = False
            if('latitude' in kwargs and 'longitude' in kwargs):
                latitude = str(abs(kwargs['latitude'])).lstrip('0')
                longitude = kwargs['longitude']

                # Add a literal '+' to the lat/lon if it is positive.
                # Do this first because we convert longitude to a string below.
                lat_sign = '+' if latitude > 0 else '-'
                # We need to zeropad the longitude.
                # No clue why - ask Apple.
                # We set the sign to + or - and then we take the absolute value
                #   and fill it.
                lon_sign = '+' if longitude > 0 else '-'
                longitude_str = '{:9.5f}'.format(abs(longitude)).replace(' ', '0')  # noqa
                lat_lon_str = '%s%s%s%s' % (
                    lat_sign,
                    latitude,
                    lon_sign,
                    longitude_str
                )

                plist.update_key('common/location', lat_lon_str)
                plist_should_be_written = True

            if('time' in kwargs):
                # The time formats can be YYYY-mm-dd or YYYY-mm-dd hh:ii:ss
                time_parts = str(kwargs['time']).split(' ')
                ymd, hms = [None, None]
                if(len(time_parts) >= 1):
                    ymd = [int(x) for x in time_parts[0].split('-')]

                    if(len(time_parts) == 2):
                        hms = [int(x) for x in time_parts[1].split(':')]

                    if(hms is not None):
                        d = datetime(ymd[0], ymd[1], ymd[2], hms[0], hms[1], hms[2])  # noqa
                    else:
                        d = datetime(ymd[0], ymd[1], ymd[2], 12, 00, 00)

                    offset = time.strftime("%z", time.gmtime(time.time()))
                    time_string = d.strftime('%Y-%m-%dT%H:%M:%S{}'.format(offset))  # noqa
                    plist.update_key('common/creationDate', time_string)
                    plist_should_be_written = True

            if('title' in kwargs):
                if(len(kwargs['title']) > 0):
                    plist.update_key('common/title', kwargs['title'])
                    plist_should_be_written = True

            if(plist_should_be_written is True):
                plist_final = plist_temp.name
                plist.write_file(plist_final)
            else:
                if(constants.debug is True):
                    print 'Nothing to update, plist unchanged'
                return False

            # We create a temporary file to save the modified file to.
            # If the modification is successful we will update the
            #   existing file.
            # We can't call self.get_metadata else we will run into
            #   infinite loops
            # metadata = self.get_metadata()
            temp_movie = None
            with tempfile.NamedTemporaryFile() as temp_file:
                temp_movie = '%s.%s' % (temp_file.name, self.get_extension())

            # We need to block until the child process completes.
            # http://stackoverflow.com/a/5631819/1318758
            avmetareadwrite_command = '%s -a %s "%s" "%s"' % (
                avmetareadwrite,
                plist_final,
                source,
                temp_movie
            )
            update_process = subprocess.Popen(
                [avmetareadwrite_command],
                stdout=subprocess.PIPE,
                shell=True
            )
            update_process.communicate()
            if(update_process.returncode != 0):
                if(constants.debug is True):
                    print '%s did not complete successfully' % avmetareadwrite_command  # noqa
                return False

            # Before we do anything destructive we confirm that the
            #   file is in tact.
            check_media = Media.get_class_by_file(temp_movie, [self.__class__])
            check_metadata = check_media.get_metadata()
            if(
                (
                    'latitude' in kwargs and
                    'longitude' in kwargs and
                    check_metadata['latitude'] is None and
                    check_metadata['longitude'] is None
                ) or (
                    'time' in kwargs and
                    check_metadata['date_taken'] is None
                )
            ):
                if(constants.debug is True):
                    print 'Something went wrong updating video metadata'
                return False

            # Copy file information from original source to temporary file
            #   before copying back over
            shutil.copystat(source, temp_movie)
            stat = os.stat(source)
            shutil.move(temp_movie, source)
            os.utime(source, (stat.st_atime, stat.st_mtime))

            return True


class Transcode(object):

    """Constructor takes a video object as its parameter.

    :param Video video: Video object.
    """

    def __init__(self, video=None):
        self.video = video