#! /usr/bin/env python3
"""
Provide SoundFile which is used to link between database and file system.


File name
=========
It tries to parse the file name to get the date of the diffusion of an
episode and associate the file with it; We use the following format:
    yyyymmdd[_n][_][name]

Where:
    'yyyy' the year of the episode's diffusion;
    'mm' the month of the episode's diffusion;
    'dd' the day of the episode's diffusion;
    'n' the number of the episode (if multiple episodes);
    'name' the title of the sound;

Sound Quality
=============
To check quality of files, call the command sound_quality_check using the
parameters given by the setting AIRCOX_SOUND_QUALITY. This script requires
Sox (and soxi).
"""
from datetime import date
import logging
import os
import re

import mutagen

from django.conf import settings as conf
from django.utils import timezone as tz
from django.utils.translation import gettext as _

from aircox import utils
from aircox.models import Program, Sound, Track
from .commands.import_playlist import PlaylistImport

logger = logging.getLogger('aircox.commands')


class SoundFile:
    """
    Handle synchronisation between sounds on files and database.
    """
    path = None
    info = None
    path_info = None
    sound = None

    def __init__(self, path):
        self.path = path

    @property
    def sound_path(self):
        """ Relative path name """
        return self.path.replace(conf.MEDIA_ROOT + '/', '')

    @property
    def episode(self):
        return self.sound and self.sound.episode

    def sync(self, sound=None, program=None, deleted=False, **kwargs):
        """
        Update related sound model and save it.
        """
        if deleted:
            return self._on_delete(self.path)

        # FIXME: sound.program as not null
        if not program:
            program = Program.get_from_path(self.path)
            logger.debug('program from path "%s" -> %s', self.path, program)
        kwargs['program_id'] = program.pk

        if sound:
            created = False
        else:
            sound, created = Sound.objects.get_or_create(
                file=self.sound_path, defaults=kwargs)

        self.sound = sound
        self.path_info = self.read_path(self.path)

        sound.program = program
        if created or sound.check_on_file():
            sound.name = self.path_info.get('name')
            self.info = self.read_file_info()
            if self.info is not None:
                sound.duration = utils.seconds_to_time(self.info.info.length)

        # check for episode
        if sound.episode is None and 'year' in self.path_info:
            sound.episode = self.find_episode(sound, self.path_info)
        sound.save()

        # check for playlist
        self.find_playlist(sound)
        return sound

    def _on_delete(self, path):
        # TODO: remove from db on delete
        sound = Sound.objects.path(self.path).first()
        if sound:
            sound.type = sound.TYPE_REMOVED
            sound.check_on_file()
            sound.save()
        return sound

    def read_path(self, path):
        """
        Parse path name returning dictionary of extracted info. It can contain:
        - `year`, `month`, `day`: diffusion date
        - `hour`, `minute`: diffusion time
        - `n`: sound arbitrary number (used for sound ordering)
        - `name`: cleaned name extracted or file name (without extension)
        """
        basename = os.path.basename(path)
        basename = os.path.splitext(basename)[0]
        reg_match = self._path_re.search(basename)
        if reg_match:
            info = reg_match.groupdict()
            for k in ('year', 'month', 'day', 'hour', 'minute', 'n'):
                if info.get(k) is not None:
                    info[k] = int(info[k])

            name = info.get('name')
            info['name'] = name and self._into_name(name) or basename
        else:
            info = {'name': basename}
        return info

    _path_re = re.compile(
        '^(?P<year>[0-9]{4})(?P<month>[0-9]{2})(?P<day>[0-9]{2})'
        '(_(?P<hour>[0-9]{2})h(?P<minute>[0-9]{2}))?'
        '(_(?P<n>[0-9]+))?'
        '_?[ -]*(?P<name>.*)$'
    )

    def _into_name(self, name):
        name = name.replace('_', ' ')
        return ' '.join(r.capitalize() for r in name.split(' '))

    def read_file_info(self):
        """ Read file information and metadata. """
        return mutagen.File(self.path) if os.path.exists(self.path) else None

    def find_episode(self, sound, path_info):
        """
        For a given program, check if there is an initial diffusion
        to associate to, using the date info we have. Update self.sound
        and save it consequently.

        We only allow initial diffusion since there should be no
        rerun.
        """
        program, pi = sound.program, path_info
        if 'year' not in pi or not sound or sound.episode:
            return None

        year, month, day = pi.get('year'), pi.get('month'), pi.get('day')
        if pi.get('hour') is not None:
            at = tz.datetime(year, month, day, pi.get('hour', 0),
                             pi.get('minute', 0))
            at = tz.get_current_timezone().localize(at)
        else:
            at = date(year, month, day)

        diffusion = program.diffusion_set.at(at).first()
        if not diffusion:
            return None

        logger.debug('%s <--> %s', sound.file.name, str(diffusion.episode))
        return diffusion.episode

    def find_playlist(self, sound=None, use_meta=True):
        """
        Find a playlist file corresponding to the sound path, such as:
            my_sound.ogg => my_sound.csv

        Use sound's file metadata if no corresponding playlist has been
        found and `use_meta` is True.
        """
        if sound is None:
            sound = self.sound
        if sound.track_set.count() > 1:
            return

        # import playlist
        path_noext, ext = os.path.splitext(self.sound.file.path)
        path = path_noext + '.csv'
        if os.path.exists(path):
            PlaylistImport(path, sound=sound).run()
        # use metadata
        elif use_meta:
            if self.info is None:
                self.read_file_info()
            if self.info and self.info.tags:
                tags = self.info.tags
                title, artist, album, year = tuple(
                    t and ', '.join(t) for t in (
                        tags.get(k) for k in ('title', 'artist', 'album',
                                              'year'))
                )
                title = title or (self.path_info and
                                  self.path_info.get('name')) or \
                    os.path.basename(path_noext)
                info = '{} ({})'.format(album, year) if album and year else \
                    album or year or ''
                track = Track(sound=sound,
                              position=int(tags.get('tracknumber', 0)),
                              title=title,
                              artist=artist or _('unknown'),
                              info=info)
                track.save()