"""
Customer-facing review API views.
Writes to admin_api.Review so admin panel sees reviews immediately.
"""
import json
from django.http import JsonResponse
from django.utils.decorators import method_decorator
from django.views.decorators.csrf import csrf_exempt
from rest_framework.views import APIView
from rest_framework.permissions import AllowAny
from django.db.models import Avg, Count, Q
from admin_api.models import Review, ReviewInteraction
from events.models import Event
from mobile_api.utils import validate_token_and_get_user


_STATUS_TO_JSON = {'live': 'PUBLISHED', 'pending': 'PENDING', 'rejected': 'FLAGGED'}
_JSON_TO_STATUS = {'PUBLISHED': 'live', 'PENDING': 'pending', 'FLAGGED': 'rejected'}


def _serialize_review(r, user_interactions=None):
    """Serialize a Review to match the customer app's expected shape."""
    interactions = user_interactions or {}
    try:
        display = r.display_name or r.reviewer.get_full_name() or r.reviewer.username
    except Exception:
        display = r.display_name or ''
    try:
        uname = r.reviewer.username
    except Exception:
        uname = ''
    try:
        pic = r.reviewer.profile_picture
        if pic and pic.name and 'default.png' not in pic.name:
            profile_photo = pic.url
        else:
            profile_photo = ''
    except Exception:
        profile_photo = ''
    return {
        'id': r.id,
        'event_id': r.event_id,
        'username': uname,
        'display_name': display,
        'profile_photo': profile_photo,
        'rating': r.rating,
        'comment': r.review_text,
        'status': _STATUS_TO_JSON.get(r.status, r.status),
        'is_verified': r.is_verified,
        'helpful_count': r.helpful_count,
        'flag_count': r.flag_count,
        'has_helpful': interactions.get('HELPFUL', False),
        'has_flagged': interactions.get('FLAG', False),
        'created_at': r.submission_date.isoformat() if r.submission_date else '',
    }


def _rating_distribution(event_id):
    """Return {1:count, 2:count, ..., 5:count} for live reviews."""
    dist = {1: 0, 2: 0, 3: 0, 4: 0, 5: 0}
    qs = Review.objects.filter(event_id=event_id, status='live').values('rating').annotate(c=Count('id'))
    for row in qs:
        dist[row['rating']] = row['c']
    return dist


def _aggregates(event_id):
    """Return (average_rating, review_count) for live reviews."""
    agg = Review.objects.filter(event_id=event_id, status='live').aggregate(
        avg=Avg('rating'), cnt=Count('id')
    )
    return round(float(agg['avg'] or 0), 1), agg['cnt'] or 0


@method_decorator(csrf_exempt, name='dispatch')
class ReviewSubmitView(APIView):
    """POST /api/reviews/submit -- Submit or update a review."""
    authentication_classes = []
    permission_classes = [AllowAny]

    def post(self, request):
        user, token, data, error_response = validate_token_and_get_user(request)
        if error_response:
            return error_response

        event_id = data.get('event_id')
        rating = data.get('rating')
        comment = data.get('comment', '') or ''
        is_verified = bool(data.get('is_verified', False))

        if not event_id or not rating:
            return JsonResponse({'status': 'error', 'message': 'event_id and rating are required'}, status=400)

        try:
            rating = int(rating)
            if rating < 1 or rating > 5:
                raise ValueError
        except (ValueError, TypeError):
            return JsonResponse({'status': 'error', 'message': 'Rating must be 1-5'}, status=400)

        try:
            event = Event.objects.get(pk=event_id)
        except Event.DoesNotExist:
            return JsonResponse({'status': 'error', 'message': 'Event not found'}, status=404)

        # Upsert: one review per user per event
        review, created = Review.objects.update_or_create(
            reviewer=user,
            event=event,
            defaults={
                'rating': rating,
                'review_text': comment,
                'is_verified': is_verified,
                'status': 'live',  # auto-approve for customer submissions
                'display_name': user.get_full_name() or user.username,
            }
        )

        avg_rating, review_count = _aggregates(event_id)

        return JsonResponse({
            'status': 'success',
            'review': _serialize_review(review),
            'average_rating': avg_rating,
            'review_count': review_count,
        })


@method_decorator(csrf_exempt, name='dispatch')
class MobileReviewListView(APIView):
    """POST /api/reviews/list -- Get published reviews for an event."""
    authentication_classes = []
    permission_classes = [AllowAny]

    def post(self, request):
        try:
            body = json.loads(request.body) if request.body else {}
        except json.JSONDecodeError:
            body = {}

        event_id = body.get('event_id')
        username = body.get('username', '')
        page = int(body.get('page', 1))
        page_size = min(int(body.get('page_size', 10)), 50)

        if not event_id:
            return JsonResponse({'status': 'error', 'message': 'event_id is required'}, status=400)

        qs = Review.objects.filter(event_id=event_id, status='live').select_related('reviewer')
        qs = qs.order_by('-is_verified', '-helpful_count', '-submission_date')

        total = qs.count()
        reviews = list(qs[(page - 1) * page_size: page * page_size])

        # Bulk lookup interactions for current user
        user_interactions = {}
        if username and reviews:
            review_ids = [r.id for r in reviews]
            interactions = ReviewInteraction.objects.filter(
                username=username, review_id__in=review_ids
            )
            for inter in interactions:
                if inter.review_id not in user_interactions:
                    user_interactions[inter.review_id] = {}
                user_interactions[inter.review_id][inter.interaction_type] = True

        formatted = [
            _serialize_review(r, user_interactions.get(r.id, {}))
            for r in reviews
        ]

        avg_rating, review_count = _aggregates(event_id)
        distribution = _rating_distribution(event_id)

        # Get user's own review (any status)
        user_review = None
        if username:
            try:
                from accounts.models import User
                u = User.objects.get(username=username)
                ur = Review.objects.filter(event_id=event_id, reviewer=u).first()
                if ur:
                    user_review = _serialize_review(ur)
            except Exception:
                pass

        return JsonResponse({
            'status': 'success',
            'reviews': formatted,
            'total': total,
            'page': page,
            'page_size': page_size,
            'average_rating': avg_rating,
            'review_count': review_count,
            'distribution': distribution,
            'user_review': user_review,
        })


@method_decorator(csrf_exempt, name='dispatch')
class ReviewHelpfulView(APIView):
    """POST /api/reviews/helpful -- Mark a review as helpful."""
    authentication_classes = []
    permission_classes = [AllowAny]

    def post(self, request):
        user, token, data, error_response = validate_token_and_get_user(request)
        if error_response:
            return error_response

        review_id = data.get('review_id')
        if not review_id:
            return JsonResponse({'status': 'error', 'message': 'review_id is required'}, status=400)

        try:
            review = Review.objects.get(pk=review_id)
        except Review.DoesNotExist:
            return JsonResponse({'status': 'error', 'message': 'Review not found'}, status=404)

        if review.reviewer == user:
            return JsonResponse({'status': 'error', 'message': 'Cannot mark your own review as helpful'}, status=400)

        _, created = ReviewInteraction.objects.get_or_create(
            review=review,
            username=user.username,
            interaction_type='HELPFUL'
        )

        if created:
            new_count = ReviewInteraction.objects.filter(review=review, interaction_type='HELPFUL').count()
            review.helpful_count = new_count
            review.save(update_fields=['helpful_count'])

        return JsonResponse({
            'status': 'success',
            'helpful_count': review.helpful_count,
        })


@method_decorator(csrf_exempt, name='dispatch')
class ReviewFlagView(APIView):
    """POST /api/reviews/flag -- Flag/report a review."""
    authentication_classes = []
    permission_classes = [AllowAny]

    def post(self, request):
        user, token, data, error_response = validate_token_and_get_user(request)
        if error_response:
            return error_response

        review_id = data.get('review_id')
        if not review_id:
            return JsonResponse({'status': 'error', 'message': 'review_id is required'}, status=400)

        try:
            review = Review.objects.get(pk=review_id)
        except Review.DoesNotExist:
            return JsonResponse({'status': 'error', 'message': 'Review not found'}, status=404)

        if review.reviewer == user:
            return JsonResponse({'status': 'error', 'message': 'Cannot flag your own review'}, status=400)

        _, created = ReviewInteraction.objects.get_or_create(
            review=review,
            username=user.username,
            interaction_type='FLAG'
        )

        new_count = ReviewInteraction.objects.filter(review=review, interaction_type='FLAG').count()
        new_status = review.status
        if new_count >= 3 and review.status == 'live':
            new_status = 'rejected'
            review.status = 'rejected'
            review.reject_reason = 'inappropriate'

        review.flag_count = new_count
        review.save(update_fields=['flag_count', 'status', 'reject_reason'])

        return JsonResponse({
            'status': 'success',
            'flag_count': new_count,
            'review_status': _STATUS_TO_JSON.get(new_status, new_status),
        })