from django.db.models import Max
from django.http import JsonResponse
from django.utils import timezone
from django.views.decorators.http import require_http_methods

from books.models import EBook, EBookProgress, EBookHighlights, EBookBookmarks
from podcasts.models import PodcastFeed, EpisodeProgress, PodcastQueue
from radio.models import SavedStation


@require_http_methods(['GET'])
def sync_snapshot(request):
    """Aggregate read-only snapshot of a user's data for local/native clients
    (see accounts/middleware.py for the Bearer-token auth that makes this
    reachable without a browser session).

    Deliberately excludes book file bytes and podcast audio — those stay
    large/expensive and are fetched lazily via the existing per-resource
    endpoints (e.g. GET /books/<id>/data/), which this same token also
    unlocks. Writes (progress, highlights, bookmarks, ...) go through those
    existing endpoints too, to reuse their merge semantics rather than
    duplicating it here."""
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    user = request.user

    books = list(EBook.objects.filter(user=user).values('id', 'meta_ct', 'meta_iv', 'uploaded_at', 'is_read'))
    for b in books:
        b['uploaded_at'] = b['uploaded_at'].isoformat()

    book_progress = list(
        EBookProgress.objects.filter(user=user).values('book_id', 'scroll_fraction', 'position_anchor', 'updated_at')
    )
    for p in book_progress:
        p['updated_at'] = p['updated_at'].isoformat()

    book_highlights = list(EBookHighlights.objects.filter(user=user).values('book_id', 'ct', 'iv', 'updated_at'))
    for h in book_highlights:
        h['updated_at'] = h['updated_at'].isoformat()

    book_bookmarks = list(EBookBookmarks.objects.filter(user=user).values('book_id', 'ct', 'iv', 'updated_at'))
    for bm in book_bookmarks:
        bm['updated_at'] = bm['updated_at'].isoformat()

    podcast_feeds = list(
        PodcastFeed.objects.filter(user=user)
        .annotate(latest_episode_at=Max('episodes__pub_date'))
        .values('id', 'title', 'artwork_url', 'rss_url', 'last_refreshed_at', 'author', 'added_at', 'auto_queue', 'latest_episode_at')
    )
    for f in podcast_feeds:
        for key in ('last_refreshed_at', 'added_at', 'latest_episode_at'):
            if f[key]:
                f[key] = f[key].isoformat()

    episode_progress = list(
        EpisodeProgress.objects.filter(user=user)
        .values('episode_id', 'position_seconds', 'played', 'dismissed', 'updated_at')
    )
    for ep in episode_progress:
        ep['updated_at'] = ep['updated_at'].isoformat()

    podcast_queue = list(
        PodcastQueue.objects.filter(user=user).order_by('position').values('episode_id', 'position')
    )

    saved_stations = list(
        SavedStation.objects.filter(user=user)
        .values('id', 'name', 'url', 'bitrate', 'country', 'tags', 'favicon_url', 'is_favorite', 'notes')
    )

    return JsonResponse({
        'server_time': timezone.now().isoformat(),
        'books': books,
        'book_progress': book_progress,
        'book_highlights': book_highlights,
        'book_bookmarks': book_bookmarks,
        'podcast_feeds': podcast_feeds,
        'episode_progress': episode_progress,
        'podcast_queue': podcast_queue,
        'saved_stations': saved_stations,
    })