import json
import urllib.parse
import xml.etree.ElementTree as ET

import feedparser
import requests
from django.conf import settings
from django.db.models import Count, Q
from django.http import JsonResponse
from django.utils import timezone
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.http import require_http_methods

from .models import EpisodeProgress, PodcastEpisode, PodcastFeed, PodcastQueue


# ---------------------------------------------------------------------------
# Duration helper
# ---------------------------------------------------------------------------

def _parse_duration(raw):
    """Return duration in seconds from itunes:duration string or int."""
    if not raw:
        return 0
    if isinstance(raw, int):
        return raw
    raw = str(raw).strip()
    parts = raw.split(':')
    try:
        if len(parts) == 3:
            return int(parts[0]) * 3600 + int(parts[1]) * 60 + int(parts[2])
        if len(parts) == 2:
            return int(parts[0]) * 60 + int(parts[1])
        return int(raw)
    except (ValueError, TypeError):
        return 0


# ---------------------------------------------------------------------------
# Shared feed refresh helper
# ---------------------------------------------------------------------------

def _refresh_feed(feed_obj):
    """Parse rss_url and upsert episodes. Returns count of new episodes."""
    parsed = feedparser.parse(feed_obj.rss_url)
    channel = parsed.feed

    feed_obj.title = channel.get('title', feed_obj.title or feed_obj.rss_url)[:300]
    feed_obj.description = channel.get('subtitle', channel.get('description', ''))[:2000]
    feed_obj.author = channel.get('author', channel.get('itunes_author', ''))[:300]
    feed_obj.link = channel.get('link', '')[:1000]

    # Artwork
    image = channel.get('image', {})
    feed_obj.artwork_url = (
        channel.get('itunes_image', {}).get('href', '')
        or image.get('href', '')
        or image.get('url', '')
    )[:1000]

    feed_obj.last_refreshed_at = timezone.now()
    feed_obj.save()

    max_ep = getattr(settings, 'PODCAST_MAX_EPISODES_PER_FEED', 200)
    new_count = 0

    for entry in parsed.entries[:max_ep]:
        # Find audio enclosure
        audio_url = ''
        for enc in entry.get('enclosures', []):
            mime = enc.get('type', '')
            if mime.startswith('audio/') or enc.get('url', '').endswith(('.mp3', '.m4a', '.ogg', '.opus', '.aac')):
                audio_url = enc.get('url', '')
                break
        if not audio_url:
            continue

        guid = entry.get('id') or entry.get('guid') or audio_url
        guid = str(guid)[:1000]
        title = entry.get('title', 'Untitled')[:500]
        description = entry.get('summary', entry.get('description', ''))

        duration_raw = entry.get('itunes_duration', 0)
        duration_seconds = _parse_duration(duration_raw)

        pub_date = None
        if entry.get('published_parsed'):
            import datetime as dt
            t = entry.published_parsed
            pub_date = dt.datetime(*t[:6], tzinfo=dt.timezone.utc)

        ep_number = None
        try:
            ep_number = int(entry.get('itunes_episode', ''))
        except (ValueError, TypeError):
            pass

        season_number = None
        try:
            season_number = int(entry.get('itunes_season', ''))
        except (ValueError, TypeError):
            pass

        artwork_url = entry.get('itunes_image', {}).get('href', '')[:1000]

        _, created = PodcastEpisode.objects.get_or_create(
            feed=feed_obj,
            guid=guid,
            defaults={
                'title': title,
                'description': description,
                'audio_url': audio_url[:1000],
                'duration_seconds': duration_seconds,
                'pub_date': pub_date,
                'episode_number': ep_number,
                'season_number': season_number,
                'artwork_url': artwork_url,
            },
        )
        if created:
            new_count += 1

    return new_count


# ---------------------------------------------------------------------------
# Search
# ---------------------------------------------------------------------------

def podcast_search(request):
    q = request.GET.get('q', '').strip()
    if not q:
        return JsonResponse({'results': []})

    try:
        url = f'https://itunes.apple.com/search?term={urllib.parse.quote(q)}&media=podcast&limit=20'
        resp = requests.get(url, timeout=6)
        resp.raise_for_status()
        raw = resp.json().get('results', [])
    except Exception as e:
        return JsonResponse({'error': str(e)}, status=502)

    results = []
    for r in raw:
        results.append({
            'id': r.get('collectionId'),
            'title': r.get('collectionName', ''),
            'author': r.get('artistName', ''),
            'artwork_url': r.get('artworkUrl100', ''),
            'rss_url': r.get('feedUrl', ''),
            'genre': r.get('primaryGenreName', ''),
        })

    return JsonResponse({'results': results})


# ---------------------------------------------------------------------------
# Feed list
# ---------------------------------------------------------------------------

@csrf_exempt
def feed_list(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    feeds = list(
        request.user.podcast_feeds
        .values('id', 'title', 'artwork_url', 'rss_url', 'last_refreshed_at', 'author')
    )

    for f in feeds:
        if f['last_refreshed_at']:
            f['last_refreshed_at'] = f['last_refreshed_at'].isoformat()

    return JsonResponse({'feeds': feeds})


# ---------------------------------------------------------------------------
# Add feed
# ---------------------------------------------------------------------------

@csrf_exempt
@require_http_methods(['POST'])
def add_feed(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    rss_url = body.get('rss_url', '').strip()
    if not rss_url:
        return JsonResponse({'error': 'rss_url required'}, status=400)

    feed, created = PodcastFeed.objects.get_or_create(
        user=request.user,
        rss_url=rss_url,
        defaults={'title': body.get('title', rss_url)[:300]},
    )

    new_episodes = 0
    if created:
        try:
            new_episodes = _refresh_feed(feed)
        except Exception as e:
            feed.delete()
            return JsonResponse({'error': f'Failed to parse feed: {e}'}, status=400)

    return JsonResponse({
        'ok': True,
        'created': created,
        'feed_id': feed.id,
        'title': feed.title,
        'artwork_url': feed.artwork_url,
        'new_episodes': new_episodes,
    })


# ---------------------------------------------------------------------------
# Remove feed
# ---------------------------------------------------------------------------

@csrf_exempt
@require_http_methods(['POST'])
def remove_feed(request, pk):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        feed = PodcastFeed.objects.get(pk=pk, user=request.user)
        feed.delete()
        return JsonResponse({'ok': True})
    except PodcastFeed.DoesNotExist:
        return JsonResponse({'error': 'not found'}, status=404)


# ---------------------------------------------------------------------------
# Feed episodes
# ---------------------------------------------------------------------------

@csrf_exempt
def feed_episodes(request, pk):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        feed = PodcastFeed.objects.get(pk=pk, user=request.user)
    except PodcastFeed.DoesNotExist:
        return JsonResponse({'error': 'not found'}, status=404)

    episodes = list(
        feed.episodes.values(
            'id', 'title', 'description', 'audio_url', 'duration_seconds',
            'pub_date', 'artwork_url', 'episode_number', 'season_number',
        )
    )

    # Batch-fetch progress
    progress_map = {
        ep['episode_id']: ep
        for ep in EpisodeProgress.objects.filter(
            user=request.user,
            episode__feed=feed,
        ).values('episode_id', 'position_seconds', 'played')
    }

    # Batch-fetch queue membership
    queued_ids = set(
        PodcastQueue.objects.filter(
            user=request.user,
            episode__feed=feed,
        ).values_list('episode_id', flat=True)
    )

    for ep in episodes:
        if ep['pub_date']:
            ep['pub_date'] = ep['pub_date'].isoformat()
        prog = progress_map.get(ep['id'], {})
        ep['position_seconds'] = prog.get('position_seconds', 0)
        ep['played'] = prog.get('played', False)
        ep['in_queue'] = ep['id'] in queued_ids

    return JsonResponse({
        'feed': {
            'id': feed.id,
            'title': feed.title,
            'artwork_url': feed.artwork_url,
            'author': feed.author,
        },
        'episodes': episodes,
    })


# ---------------------------------------------------------------------------
# Import OPML
# ---------------------------------------------------------------------------

@csrf_exempt
@require_http_methods(['POST'])
def import_opml(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    f = request.FILES.get('file')
    if not f:
        return JsonResponse({'error': 'no file uploaded'}, status=400)

    try:
        content = f.read().decode('utf-8', errors='replace')
        root = ET.fromstring(content)
    except Exception as e:
        return JsonResponse({'error': f'invalid OPML: {e}'}, status=400)

    added = 0
    skipped = 0
    for outline in root.iter('outline'):
        rss_url = outline.get('xmlUrl', '').strip()
        if not rss_url:
            continue
        title = outline.get('title', outline.get('text', rss_url))[:300]
        _, created = PodcastFeed.objects.get_or_create(
            user=request.user,
            rss_url=rss_url,
            defaults={'title': title},
        )
        if created:
            added += 1
        else:
            skipped += 1

    return JsonResponse({'ok': True, 'added': added, 'skipped': skipped})


# ---------------------------------------------------------------------------
# Refresh feed now
# ---------------------------------------------------------------------------

@csrf_exempt
@require_http_methods(['POST'])
def refresh_feed_now(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    feed_id = body.get('feed_id')
    if not feed_id:
        return JsonResponse({'error': 'feed_id required'}, status=400)

    try:
        feed = PodcastFeed.objects.get(pk=feed_id, user=request.user)
    except PodcastFeed.DoesNotExist:
        return JsonResponse({'error': 'not found'}, status=404)

    try:
        new_episodes = _refresh_feed(feed)
    except Exception as e:
        return JsonResponse({'error': str(e)}, status=502)

    return JsonResponse({'ok': True, 'new_episodes': new_episodes})


# ---------------------------------------------------------------------------
# Queue
# ---------------------------------------------------------------------------

@csrf_exempt
def queue_get(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    items = list(
        PodcastQueue.objects
        .filter(user=request.user)
        .select_related('episode__feed')
        .values(
            'id', 'position',
            'episode__id', 'episode__title', 'episode__audio_url',
            'episode__duration_seconds', 'episode__artwork_url',
            'episode__feed__id', 'episode__feed__title',
        )
    )

    return JsonResponse({'queue': items})


@csrf_exempt
@require_http_methods(['POST'])
def queue_add(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    episode_id = body.get('episode_id')
    try:
        episode = PodcastEpisode.objects.get(pk=episode_id, feed__user=request.user)
    except PodcastEpisode.DoesNotExist:
        return JsonResponse({'error': 'not found'}, status=404)

    max_pos = PodcastQueue.objects.filter(user=request.user).count()
    _, created = PodcastQueue.objects.get_or_create(
        user=request.user,
        episode=episode,
        defaults={'position': max_pos},
    )
    return JsonResponse({'ok': True, 'created': created})


@csrf_exempt
@require_http_methods(['POST'])
def queue_remove(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    episode_id = body.get('episode_id')
    PodcastQueue.objects.filter(user=request.user, episode_id=episode_id).delete()
    return JsonResponse({'ok': True})


@csrf_exempt
@require_http_methods(['POST'])
def queue_reorder(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    order = body.get('order', [])  # list of episode ids
    for pos, ep_id in enumerate(order):
        PodcastQueue.objects.filter(user=request.user, episode_id=ep_id).update(position=pos)

    return JsonResponse({'ok': True})


# ---------------------------------------------------------------------------
# Progress
# ---------------------------------------------------------------------------

@csrf_exempt
@require_http_methods(['POST'])
def save_progress(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    episode_id = body.get('episode_id')
    position = int(body.get('position_seconds', 0))

    try:
        episode = PodcastEpisode.objects.get(pk=episode_id, feed__user=request.user)
    except PodcastEpisode.DoesNotExist:
        return JsonResponse({'error': 'not found'}, status=404)

    progress, _ = EpisodeProgress.objects.get_or_create(
        user=request.user,
        episode=episode,
    )
    progress.position_seconds = position

    # Auto-mark played at 90%
    if episode.duration_seconds and episode.duration_seconds > 0:
        if position >= episode.duration_seconds * 0.9:
            progress.played = True

    progress.save()
    return JsonResponse({'ok': True, 'played': progress.played})


@csrf_exempt
@require_http_methods(['POST'])
def mark_played(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    try:
        body = json.loads(request.body)
    except (json.JSONDecodeError, ValueError):
        return JsonResponse({'error': 'invalid JSON'}, status=400)

    episode_id = body.get('episode_id')
    played = bool(body.get('played', True))

    try:
        episode = PodcastEpisode.objects.get(pk=episode_id, feed__user=request.user)
    except PodcastEpisode.DoesNotExist:
        return JsonResponse({'error': 'not found'}, status=404)

    progress, _ = EpisodeProgress.objects.get_or_create(
        user=request.user,
        episode=episode,
    )
    progress.played = played
    progress.save(update_fields=['played', 'updated_at'])
    return JsonResponse({'ok': True, 'played': played})


# ---------------------------------------------------------------------------
# Inbox
# ---------------------------------------------------------------------------

@csrf_exempt
def inbox(request):
    if not request.user.is_authenticated:
        return JsonResponse({'error': 'authentication required'}, status=401)

    played_ids = set(
        EpisodeProgress.objects.filter(
            user=request.user,
            played=True,
        ).values_list('episode_id', flat=True)
    )

    episodes = list(
        PodcastEpisode.objects.filter(feed__user=request.user)
        .exclude(id__in=played_ids)
        .select_related('feed')
        .order_by('-pub_date')
        .values(
            'id', 'title', 'audio_url', 'duration_seconds',
            'pub_date', 'artwork_url',
            'feed__id', 'feed__title', 'feed__artwork_url',
        )[:100]
    )

    for ep in episodes:
        if ep['pub_date']:
            ep['pub_date'] = ep['pub_date'].isoformat()

    return JsonResponse({'episodes': episodes})