import ffmpeg
import os
import json
import subprocess
import unicodedata
import urllib

from django.urls import reverse
from django.db import models, transaction
from django.db.models.functions import Length
from django.conf import settings
from django.http import StreamingHttpResponse

from rest_framework import viewsets, views, mixins
from rest_framework.decorators import detail_route, list_route
from rest_framework.response import Response
from rest_framework import permissions
from musicbrainzngs import ResponseError
from django.contrib.auth.decorators import login_required
from django.utils.decorators import method_decorator

from funkwhale_api.musicbrainz import api
from funkwhale_api.common.permissions import (
    ConditionalAuthentication, HasModelPermission)
from taggit.models import Tag

from . import forms
from . import models
from . import serializers
from . import importers
from . import filters
from . import tasks
from . import utils


class SearchMixin(object):
    search_fields = []

    @list_route(methods=['get'])
    def search(self, request, *args, **kwargs):
        query = utils.get_query(request.GET['query'], self.search_fields)
        queryset = self.get_queryset().filter(query)
        serializer = self.serializer_class(queryset, many=True)
        return Response(serializer.data)

class TagViewSetMixin(object):

    def get_queryset(self):
        queryset = super().get_queryset()
        tag = self.request.query_params.get('tag')
        if tag:
            queryset = queryset.filter(tags__pk=tag)
        return queryset

class ArtistViewSet(SearchMixin, viewsets.ReadOnlyModelViewSet):
    queryset = (
        models.Artist.objects.all()
                             .prefetch_related(
                                'albums__tracks__files',
                                'albums__tracks__artist',
                                'albums__tracks__tags'))
    serializer_class = serializers.ArtistSerializerNested
    permission_classes = [ConditionalAuthentication]
    search_fields = ['name']
    filter_class = filters.ArtistFilter
    ordering_fields = ('id', 'name', 'creation_date')

class AlbumViewSet(SearchMixin, viewsets.ReadOnlyModelViewSet):
    queryset = (
        models.Album.objects.all()
                            .order_by('-creation_date')
                            .select_related()
                            .prefetch_related('tracks__tags',
                                              'tracks__files'))
    serializer_class = serializers.AlbumSerializerNested
    permission_classes = [ConditionalAuthentication]
    search_fields = ['title']
    ordering_fields = ('creation_date',)


class ImportBatchViewSet(
        mixins.CreateModelMixin,
        mixins.ListModelMixin,
        mixins.RetrieveModelMixin,
        viewsets.GenericViewSet):
    queryset = (
        models.ImportBatch.objects.all()
                          .prefetch_related('jobs__track_file')
                          .order_by('-creation_date'))
    serializer_class = serializers.ImportBatchSerializer
    permission_classes = (permissions.DjangoModelPermissions, )

    def get_queryset(self):
        return super().get_queryset().filter(submitted_by=self.request.user)

    def perform_create(self, serializer):
        serializer.save(submitted_by=self.request.user)


class ImportJobPermission(HasModelPermission):
    # not a typo, perms on import job is proxied to import batch
    model = models.ImportBatch


class ImportJobViewSet(
        mixins.CreateModelMixin,
        viewsets.GenericViewSet):
    queryset = (models.ImportJob.objects.all())
    serializer_class = serializers.ImportJobSerializer
    permission_classes = (ImportJobPermission, )

    def get_queryset(self):
        return super().get_queryset().filter(batch__submitted_by=self.request.user)

    def perform_create(self, serializer):
        source = 'file://' + serializer.validated_data['audio_file'].name
        serializer.save(source=source)
        tasks.import_job_run.delay(import_job_id=serializer.instance.pk)


class TrackViewSet(TagViewSetMixin, SearchMixin, viewsets.ReadOnlyModelViewSet):
    """
    A simple ViewSet for viewing and editing accounts.
    """
    queryset = (models.Track.objects.all().for_nested_serialization())
    serializer_class = serializers.TrackSerializerNested
    permission_classes = [ConditionalAuthentication]
    search_fields = ['title', 'artist__name']
    ordering_fields = (
        'creation_date',
        'title',
        'album__title',
        'artist__name',
    )

    def get_queryset(self):
        queryset = super().get_queryset()
        filter_favorites = self.request.GET.get('favorites', None)
        user = self.request.user
        if user.is_authenticated and filter_favorites == 'true':
            queryset = queryset.filter(track_favorites__user=user)

        return queryset

    @detail_route(methods=['get'])
    @transaction.non_atomic_requests
    def lyrics(self, request, *args, **kwargs):
        try:
            track = models.Track.objects.get(pk=kwargs['pk'])
        except models.Track.DoesNotExist:
            return Response(status=404)

        work = track.work
        if not work:
            work = track.get_work()

        if not work:
            return Response({'error': 'unavailable work '}, status=404)

        lyrics = work.fetch_lyrics()
        try:
            if not lyrics.content:
                tasks.fetch_content(lyrics_id=lyrics.pk)
                lyrics.refresh_from_db()
        except AttributeError:
            return Response({'error': 'unavailable lyrics'}, status=404)
        serializer = serializers.LyricsSerializer(lyrics)
        return Response(serializer.data)


class TrackFileViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = (models.TrackFile.objects.all().order_by('-id'))
    serializer_class = serializers.TrackFileSerializer
    permission_classes = [ConditionalAuthentication]

    @detail_route(methods=['get'])
    def serve(self, request, *args, **kwargs):
        try:
            f = models.TrackFile.objects.get(pk=kwargs['pk'])
        except models.TrackFile.DoesNotExist:
            return Response(status=404)

        response = Response()
        filename = "filename*=UTF-8''{}".format(
            urllib.parse.quote(f.filename))
        response["Content-Disposition"] = "attachment; {}".format(filename)
        response['X-Accel-Redirect'] = "{}{}".format(
            settings.PROTECT_FILES_PATH,
            f.audio_file.url)
        return response

    @list_route(methods=['get'])
    def viewable(self, request, *args, **kwargs):
        return Response({}, status=200)

    @list_route(methods=['get'])
    def transcode(self, request, *args, **kwargs):
        form = forms.TranscodeForm(request.GET)
        if not form.is_valid():
            return Response(form.errors, status=400)

        f = form.cleaned_data['track_file']
        output_kwargs = {
            'format': form.cleaned_data['to']
        }
        args = (ffmpeg
            .input(f.audio_file.path)
            .output('pipe:', **output_kwargs)
            .get_args()
        )
        # we use a generator here so the view return immediatly and send
        # file chunk to the browser, instead of blocking a few seconds
        def _transcode():
            p = subprocess.Popen(
                ['ffmpeg'] + args,
                stdout=subprocess.PIPE)
            for line in p.stdout:
                yield line

        response = StreamingHttpResponse(
            _transcode(), status=200,
            content_type=form.cleaned_data['to'])

        return response


class TagViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = Tag.objects.all().order_by('name')
    serializer_class = serializers.TagSerializer
    permission_classes = [ConditionalAuthentication]


class Search(views.APIView):
    max_results = 3

    def get(self, request, *args, **kwargs):
        query = request.GET['query']
        results = {
            'tags': serializers.TagSerializer(self.get_tags(query), many=True).data,
            'artists': serializers.ArtistSerializerNested(self.get_artists(query), many=True).data,
            'tracks': serializers.TrackSerializerNested(self.get_tracks(query), many=True).data,
            'albums': serializers.AlbumSerializerNested(self.get_albums(query), many=True).data,
        }
        return Response(results, status=200)

    def get_tracks(self, query):
        search_fields = ['mbid', 'title', 'album__title', 'artist__name']
        query_obj = utils.get_query(query, search_fields)
        return (
            models.Track.objects.all()
                        .filter(query_obj)
                        .select_related('album__artist')
                        .prefetch_related(
                            'tags',
                            'artist__albums__tracks__tags',
                            'files')
        )[:self.max_results]


    def get_albums(self, query):
        search_fields = ['mbid', 'title', 'artist__name']
        query_obj = utils.get_query(query, search_fields)
        return (
            models.Album.objects.all()
                        .filter(query_obj)
                        .select_related()
                        .prefetch_related(
                            'tracks__tags',
                            'tracks__files',
                            )
        )[:self.max_results]


    def get_artists(self, query):
        search_fields = ['mbid', 'name']
        query_obj = utils.get_query(query, search_fields)
        return (
            models.Artist.objects.all()
                         .filter(query_obj)
                         .select_related()
                         .prefetch_related(
                             'albums__tracks__tags',
                             'albums__tracks__files',
                             )

        )[:self.max_results]


    def get_tags(self, query):
        search_fields = ['slug', 'name']
        query_obj = utils.get_query(query, search_fields)

        # We want the shortest tag first
        qs = Tag.objects.all().annotate(slug_length=Length('slug')).order_by('slug_length')

        return qs.filter(query_obj)[:self.max_results]


class SubmitViewSet(viewsets.ViewSet):
    queryset = models.ImportBatch.objects.none()
    permission_classes = (permissions.DjangoModelPermissions, )

    @list_route(methods=['post'])
    @transaction.non_atomic_requests
    def single(self, request, *args, **kwargs):
        try:
            models.Track.objects.get(mbid=request.POST['mbid'])
            return Response({})
        except models.Track.DoesNotExist:
            pass
        batch = models.ImportBatch.objects.create(submitted_by=request.user)
        job = models.ImportJob.objects.create(mbid=request.POST['mbid'], batch=batch, source=request.POST['import_url'])
        tasks.import_job_run.delay(import_job_id=job.pk)
        serializer = serializers.ImportBatchSerializer(batch)
        return Response(serializer.data)

    @list_route(methods=['post'])
    @transaction.non_atomic_requests
    def album(self, request, *args, **kwargs):
        data = json.loads(request.body.decode('utf-8'))
        import_data, batch = self._import_album(data, request, batch=None)
        return Response(import_data)

    def _import_album(self, data, request, batch=None):
        # we import the whole album here to prevent race conditions that occurs
        # when using get_or_create_from_api in tasks
        album_data = api.releases.get(id=data['releaseId'], includes=models.Album.api_includes)['release']
        cleaned_data = models.Album.clean_musicbrainz_data(album_data)
        album = importers.load(models.Album, cleaned_data, album_data, import_hooks=[models.import_tracks])
        try:
            album.get_image()
        except ResponseError:
            pass
        if not batch:
            batch = models.ImportBatch.objects.create(submitted_by=request.user)
        for row in data['tracks']:
            try:
                models.TrackFile.objects.get(track__mbid=row['mbid'])
            except models.TrackFile.DoesNotExist:
                job = models.ImportJob.objects.create(mbid=row['mbid'], batch=batch, source=row['source'])
                tasks.import_job_run.delay(import_job_id=job.pk)
        serializer = serializers.ImportBatchSerializer(batch)
        return serializer.data, batch

    @list_route(methods=['post'])
    @transaction.non_atomic_requests
    def artist(self, request, *args, **kwargs):
        data = json.loads(request.body.decode('utf-8'))
        artist_data = api.artists.get(id=data['artistId'])['artist']
        cleaned_data = models.Artist.clean_musicbrainz_data(artist_data)
        artist = importers.load(models.Artist, cleaned_data, artist_data, import_hooks=[])

        import_data = []
        batch = None
        for row in data['albums']:
            row_data, batch = self._import_album(row, request, batch=batch)
            import_data.append(row_data)

        return Response(import_data[0])