import datetime
import json
import logging
import os

from django.conf import settings
from django.db.models import Q
from django.utils import timezone

from requests.exceptions import RequestException
from dynamic_preferences.registries import global_preferences_registry

from funkwhale_api.common import session
from funkwhale_api.history.models import Listening
from funkwhale_api.taskapp import celery

from . import actors
from . import library as lb
from . import models
from . import signing


logger = logging.getLogger(__name__)


@celery.app.task(
    name='federation.send',
    autoretry_for=[RequestException],
    retry_backoff=30,
    max_retries=5)
@celery.require_instance(models.Actor, 'actor')
def send(activity, actor, to):
    logger.info('Preparing activity delivery to %s', to)
    auth = signing.get_auth(
        actor.private_key, actor.private_key_id)
    for url in to:
        recipient_actor = actors.get_actor(url)
        logger.debug('delivering to %s', recipient_actor.inbox_url)
        logger.debug('activity content: %s', json.dumps(activity))
        response = session.get_session().post(
            auth=auth,
            json=activity,
            url=recipient_actor.inbox_url,
            timeout=5,
            verify=settings.EXTERNAL_REQUESTS_VERIFY_SSL,
            headers={
                'Content-Type': 'application/activity+json'
            }
        )
        response.raise_for_status()
        logger.debug('Remote answered with %s', response.status_code)


@celery.app.task(
    name='federation.scan_library',
    autoretry_for=[RequestException],
    retry_backoff=30,
    max_retries=5)
@celery.require_instance(models.Library, 'library')
def scan_library(library, until=None):
    if not library.federation_enabled:
        return

    data = lb.get_library_data(library.url)
    scan_library_page.delay(
        library_id=library.id, page_url=data['first'], until=until)
    library.fetched_date = timezone.now()
    library.tracks_count = data['totalItems']
    library.save(update_fields=['fetched_date', 'tracks_count'])


@celery.app.task(
    name='federation.scan_library_page',
    autoretry_for=[RequestException],
    retry_backoff=30,
    max_retries=5)
@celery.require_instance(models.Library, 'library')
def scan_library_page(library, page_url, until=None):
    if not library.federation_enabled:
        return

    data = lb.get_library_page(library, page_url)
    lts = []
    for item_serializer in data['items']:
        item_date = item_serializer.validated_data['published']
        if until and item_date < until:
            return
        lts.append(item_serializer.save())

    next_page = data.get('next')
    if next_page and next_page != page_url:
        scan_library_page.delay(library_id=library.id, page_url=next_page)


@celery.app.task(name='federation.clean_music_cache')
def clean_music_cache():
    preferences = global_preferences_registry.manager()
    delay = preferences['federation__music_cache_duration']
    if delay < 1:
        return  # cache clearing disabled
    limit = timezone.now() - datetime.timedelta(minutes=delay)

    candidates = models.LibraryTrack.objects.filter(
        Q(audio_file__isnull=False) & (
            Q(local_track_file__accessed_date__lt=limit) |
            Q(local_track_file__accessed_date=None)
        )
    ).exclude(audio_file='').only('audio_file', 'id')
    for lt in candidates:
        lt.audio_file.delete()

    # we also delete orphaned files, if any
    storage = models.LibraryTrack._meta.get_field('audio_file').storage
    files = get_files(storage, 'federation_cache')
    existing = models.LibraryTrack.objects.filter(audio_file__in=files)
    missing = set(files) - set(existing.values_list('audio_file', flat=True))
    for m in missing:
        storage.delete(m)


def get_files(storage, *parts):
    """
    This is a recursive function that return all files available
    in a given directory using django's storage.
    """
    if not parts:
        raise ValueError('Missing path')

    dirs, files = storage.listdir(os.path.join(*parts))
    for dir in dirs:
        files += get_files(storage, *(list(parts) + [dir]))
    return [
        os.path.join(parts[-1], path)
        for path in files
    ]