import logging

from rest_framework import status
from rest_framework.decorators import api_view, permission_classes, parser_classes
from rest_framework.parsers import MultiPartParser, JSONParser
from rest_framework.permissions import IsAuthenticated, IsAdminUser
from rest_framework.response import Response
from django.contrib.auth import get_user_model
from django.utils import timezone
from django.db.models import Sum, Q
from django.db.models.functions import TruncDate
from datetime import timedelta

from .models import GenerationRecord, QuotaConfig
from .serializers import (
    VideoGenerateSerializer, QuotaUpdateSerializer,
    UserStatusSerializer, SystemSettingsSerializer,
    AdminCreateUserSerializer,
)
from utils.tos_client import upload_file as tos_upload
from utils.seedance_client import create_task, query_task, extract_video_url, map_status

User = get_user_model()
logger = logging.getLogger(__name__)

# File validation constants
ALLOWED_IMAGE_EXTS = {'jpeg', 'jpg', 'png', 'webp', 'bmp', 'tiff', 'gif'}
ALLOWED_VIDEO_EXTS = {'mp4', 'mov'}
MAX_IMAGE_SIZE = 30 * 1024 * 1024   # 30MB
MAX_VIDEO_SIZE = 50 * 1024 * 1024   # 50MB


# ──────────────────────────────────────────────
# Media Upload
# ──────────────────────────────────────────────

@api_view(['POST'])
@permission_classes([IsAuthenticated])
@parser_classes([MultiPartParser])
def upload_media_view(request):
    """POST /api/v1/media/upload — Upload file to TOS, return public URL."""
    file = request.FILES.get('file')
    if not file:
        return Response({'error': '未上传文件'}, status=status.HTTP_400_BAD_REQUEST)

    ext = file.name.rsplit('.', 1)[-1].lower() if '.' in file.name else ''

    if ext in ALLOWED_IMAGE_EXTS:
        media_type = 'image'
        max_size = MAX_IMAGE_SIZE
    elif ext in ALLOWED_VIDEO_EXTS:
        media_type = 'video'
        max_size = MAX_VIDEO_SIZE
    else:
        return Response(
            {'error': f'不支持的文件格式: {ext}'},
            status=status.HTTP_400_BAD_REQUEST,
        )

    if file.size > max_size:
        limit_mb = max_size // (1024 * 1024)
        return Response(
            {'error': f'{media_type} 文件不能超过 {limit_mb}MB'},
            status=status.HTTP_400_BAD_REQUEST,
        )

    try:
        url = tos_upload(file, folder=media_type)
    except Exception as e:
        logger.exception('TOS upload failed')
        return Response(
            {'error': f'文件上传失败: {str(e)}'},
            status=status.HTTP_500_INTERNAL_SERVER_ERROR,
        )

    return Response({
        'url': url,
        'type': media_type,
        'filename': file.name,
        'size': file.size,
    })


# ──────────────────────────────────────────────
# Video Generation (with Seedance API)
# ──────────────────────────────────────────────

@api_view(['POST'])
@permission_classes([IsAuthenticated])
def video_generate_view(request):
    """POST /api/v1/video/generate — Create video generation task.

    Accepts JSON:
    {
        "prompt": "...",
        "mode": "universal" | "keyframe",
        "model": "seedance_2.0" | "seedance_2.0_fast",
        "aspect_ratio": "16:9",
        "duration": 10,
        "references": [
            {"url": "https://...", "type": "image", "role": "reference_image", "label": "图片1"},
            {"url": "https://...", "type": "video", "role": "reference_video", "label": "视频1"}
        ]
    }
    """
    serializer = VideoGenerateSerializer(data=request.data)
    serializer.is_valid(raise_exception=True)

    user = request.user
    today = timezone.now().date()
    first_of_month = today.replace(day=1)
    duration = serializer.validated_data['duration']

    # ── Quota check ──
    daily_used = user.generation_records.filter(
        created_at__date=today
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    monthly_used = user.generation_records.filter(
        created_at__date__gte=first_of_month
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    if daily_used + duration > user.daily_seconds_limit:
        return Response({
            'error': 'quota_exceeded',
            'message': '您今日的生成额度已用完',
            'daily_seconds_limit': user.daily_seconds_limit,
            'daily_seconds_used': daily_used,
            'reset_at': (timezone.now() + timedelta(days=1)).replace(
                hour=0, minute=0, second=0, microsecond=0
            ).isoformat(),
        }, status=status.HTTP_429_TOO_MANY_REQUESTS)

    if monthly_used + duration > user.monthly_seconds_limit:
        return Response({
            'error': 'quota_exceeded',
            'message': '您本月的生成额度已用完',
            'monthly_seconds_limit': user.monthly_seconds_limit,
            'monthly_seconds_used': monthly_used,
        }, status=status.HTTP_429_TOO_MANY_REQUESTS)

    # ── Build Seedance content items from references ──
    references = request.data.get('references', [])
    content_items = []
    reference_snapshots = []

    for ref in references:
        url = ref.get('url', '')
        ref_type = ref.get('type', 'image')
        role = ref.get('role', '')
        label = ref.get('label', '')

        reference_snapshots.append({
            'url': url,
            'type': ref_type,
            'role': role,
            'label': label,
        })

        if ref_type == 'image':
            item = {
                'type': 'image_url',
                'image_url': {'url': url},
            }
            if role:
                item['role'] = role
            content_items.append(item)
        elif ref_type == 'video':
            item = {
                'type': 'video_url',
                'video_url': {'url': url},
            }
            if role:
                item['role'] = role
            content_items.append(item)

    # ── Create DB record first ──
    prompt = serializer.validated_data['prompt']
    mode = serializer.validated_data['mode']
    model = serializer.validated_data['model']
    aspect_ratio = serializer.validated_data['aspect_ratio']

    record = GenerationRecord.objects.create(
        user=user,
        prompt=prompt,
        mode=mode,
        model=model,
        aspect_ratio=aspect_ratio,
        duration=duration,
        seconds_consumed=duration,
        reference_urls=reference_snapshots,
    )

    # ── Call Seedance API (or skip if not enabled) ──
    from django.conf import settings as django_settings
    if django_settings.SEEDANCE_ENABLED and django_settings.ARK_API_KEY:
        try:
            ark_response = create_task(
                prompt=prompt,
                model=model,
                content_items=content_items,
                aspect_ratio=aspect_ratio,
                duration=duration,
            )
            ark_task_id = ark_response.get('id', '')
            record.ark_task_id = ark_task_id
            record.status = 'processing'
            record.save(update_fields=['ark_task_id', 'status'])
        except Exception as e:
            logger.exception('Seedance API create task failed')
            record.status = 'failed'
            record.error_message = str(e)
            record.save(update_fields=['status', 'error_message'])
    else:
        # Seedance not enabled — treat as completed immediately
        record.status = 'completed'
        record.save(update_fields=['status'])

    remaining = user.daily_seconds_limit - daily_used - duration
    return Response({
        'task_id': str(record.task_id),
        'ark_task_id': record.ark_task_id,
        'status': record.status,
        'estimated_time': 120,
        'seconds_consumed': duration,
        'remaining_seconds_today': max(remaining, 0),
    }, status=status.HTTP_202_ACCEPTED)


# ──────────────────────────────────────────────
# Video Tasks: List + Detail (for frontend polling)
# ──────────────────────────────────────────────

@api_view(['GET'])
@permission_classes([IsAuthenticated])
def video_tasks_list_view(request):
    """GET /api/v1/video/tasks — User's recent generation tasks."""
    user = request.user
    page_size = min(int(request.query_params.get('page_size', 50)), 100)

    records = user.generation_records.order_by('-created_at')[:page_size]

    results = []
    for r in records:
        results.append(_serialize_task(r))

    return Response({'results': results})


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def video_task_detail_view(request, task_id):
    """GET /api/v1/video/tasks/<task_id> — Get task status, poll Seedance if active."""
    try:
        record = GenerationRecord.objects.get(task_id=task_id, user=request.user)
    except GenerationRecord.DoesNotExist:
        return Response({'error': '任务不存在'}, status=status.HTTP_404_NOT_FOUND)

    # If task is still active, poll Seedance API for latest status
    if record.status in ('queued', 'processing') and record.ark_task_id:
        try:
            ark_resp = query_task(record.ark_task_id)
            new_status = map_status(ark_resp.get('status', ''))
            record.status = new_status

            if new_status == 'completed':
                video_url = extract_video_url(ark_resp)
                if video_url:
                    record.result_url = video_url
            elif new_status == 'failed':
                error = ark_resp.get('error', {})
                record.error_message = (
                    error.get('message', '') if isinstance(error, dict) else str(error)
                )

            record.save(update_fields=['status', 'result_url', 'error_message'])
        except Exception as e:
            logger.exception('Seedance API query failed for %s', record.ark_task_id)

    return Response(_serialize_task(record))


def _serialize_task(record):
    """Serialize a GenerationRecord for the frontend."""
    return {
        'id': record.id,
        'task_id': str(record.task_id),
        'ark_task_id': record.ark_task_id,
        'prompt': record.prompt,
        'mode': record.mode,
        'model': record.model,
        'aspect_ratio': record.aspect_ratio,
        'duration': record.duration,
        'seconds_consumed': record.seconds_consumed,
        'status': record.status,
        'result_url': record.result_url,
        'error_message': record.error_message,
        'reference_urls': record.reference_urls or [],
        'created_at': record.created_at.isoformat(),
    }


# ──────────────────────────────────────────────
# Admin: Dashboard Stats
# ──────────────────────────────────────────────

@api_view(['GET'])
@permission_classes([IsAdminUser])
def admin_stats_view(request):
    """GET /api/v1/admin/stats"""
    today = timezone.now().date()
    yesterday = today - timedelta(days=1)
    first_of_month = today.replace(day=1)
    thirty_days_ago = today - timedelta(days=29)

    total_users = User.objects.count()
    new_users_today = User.objects.filter(date_joined__date=today).count()

    seconds_today = GenerationRecord.objects.filter(
        created_at__date=today
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    seconds_yesterday = GenerationRecord.objects.filter(
        created_at__date=yesterday
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    seconds_this_month = GenerationRecord.objects.filter(
        created_at__date__gte=first_of_month
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    # Last month same period for comparison
    if first_of_month.month == 1:
        last_month_start = first_of_month.replace(year=first_of_month.year - 1, month=12)
    else:
        last_month_start = first_of_month.replace(month=first_of_month.month - 1)
    days_into_month = (today - first_of_month).days + 1
    last_month_same_day = last_month_start + timedelta(days=days_into_month - 1)
    seconds_last_month_period = GenerationRecord.objects.filter(
        created_at__date__gte=last_month_start,
        created_at__date__lte=last_month_same_day
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    today_change = round(((seconds_today - seconds_yesterday) / max(seconds_yesterday, 1)) * 100, 1) if seconds_yesterday else 0
    month_change = round(((seconds_this_month - seconds_last_month_period) / max(seconds_last_month_period, 1)) * 100, 1) if seconds_last_month_period else 0

    # Daily trend for past 30 days
    daily_trend_qs = (
        GenerationRecord.objects
        .filter(created_at__date__gte=thirty_days_ago)
        .annotate(date=TruncDate('created_at'))
        .values('date')
        .annotate(seconds=Sum('seconds_consumed'))
        .order_by('date')
    )
    trend_map = {str(item['date']): item['seconds'] or 0 for item in daily_trend_qs}
    daily_trend = []
    for i in range(30):
        d = thirty_days_ago + timedelta(days=i)
        daily_trend.append({'date': str(d), 'seconds': trend_map.get(str(d), 0)})

    # Top 10 users by seconds consumed this month
    top_users = (
        User.objects.annotate(
            seconds_consumed=Sum(
                'generation_records__seconds_consumed',
                filter=Q(generation_records__created_at__date__gte=first_of_month),
            )
        )
        .filter(seconds_consumed__gt=0)
        .order_by('-seconds_consumed')[:10]
    )

    return Response({
        'total_users': total_users,
        'new_users_today': new_users_today,
        'seconds_consumed_today': seconds_today,
        'seconds_consumed_this_month': seconds_this_month,
        'today_change_percent': today_change,
        'month_change_percent': month_change,
        'daily_trend': daily_trend,
        'top_users': [
            {'user_id': u.id, 'username': u.username, 'seconds_consumed': u.seconds_consumed or 0}
            for u in top_users
        ],
    })


# ──────────────────────────────────────────────
# Admin: User Management
# ──────────────────────────────────────────────

@api_view(['GET'])
@permission_classes([IsAdminUser])
def admin_users_list_view(request):
    """GET /api/v1/admin/users"""
    today = timezone.now().date()
    first_of_month = today.replace(day=1)

    page = int(request.query_params.get('page', 1))
    page_size = min(int(request.query_params.get('page_size', 20)), 100)
    search = request.query_params.get('search', '').strip()
    status_filter = request.query_params.get('status', '').strip()

    qs = User.objects.annotate(
        seconds_today=Sum(
            'generation_records__seconds_consumed',
            filter=Q(generation_records__created_at__date=today),
        ),
        seconds_this_month=Sum(
            'generation_records__seconds_consumed',
            filter=Q(generation_records__created_at__date__gte=first_of_month),
        ),
    )

    if search:
        qs = qs.filter(Q(username__icontains=search) | Q(email__icontains=search))
    if status_filter == 'active':
        qs = qs.filter(is_active=True)
    elif status_filter == 'disabled':
        qs = qs.filter(is_active=False)

    total = qs.count()
    offset = (page - 1) * page_size
    users = qs.order_by('-date_joined')[offset:offset + page_size]

    results = []
    for u in users:
        results.append({
            'id': u.id,
            'username': u.username,
            'email': u.email,
            'is_active': u.is_active,
            'date_joined': u.date_joined.isoformat(),
            'daily_seconds_limit': u.daily_seconds_limit,
            'monthly_seconds_limit': u.monthly_seconds_limit,
            'seconds_today': u.seconds_today or 0,
            'seconds_this_month': u.seconds_this_month or 0,
        })

    return Response({
        'total': total,
        'page': page,
        'page_size': page_size,
        'results': results,
    })


@api_view(['GET'])
@permission_classes([IsAdminUser])
def admin_user_detail_view(request, user_id):
    """GET /api/v1/admin/users/:id"""
    try:
        user = User.objects.get(id=user_id)
    except User.DoesNotExist:
        return Response({'error': '用户不存在'}, status=status.HTTP_404_NOT_FOUND)

    today = timezone.now().date()
    first_of_month = today.replace(day=1)

    seconds_today = user.generation_records.filter(
        created_at__date=today
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    seconds_this_month = user.generation_records.filter(
        created_at__date__gte=first_of_month
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    seconds_total = user.generation_records.aggregate(
        total=Sum('seconds_consumed')
    )['total'] or 0

    recent_records = user.generation_records.order_by('-created_at')[:20]

    return Response({
        'id': user.id,
        'username': user.username,
        'email': user.email,
        'is_active': user.is_active,
        'is_staff': user.is_staff,
        'date_joined': user.date_joined.isoformat(),
        'daily_seconds_limit': user.daily_seconds_limit,
        'monthly_seconds_limit': user.monthly_seconds_limit,
        'seconds_today': seconds_today,
        'seconds_this_month': seconds_this_month,
        'seconds_total': seconds_total,
        'recent_records': [
            {
                'id': r.id,
                'created_at': r.created_at.isoformat(),
                'seconds_consumed': r.seconds_consumed,
                'prompt': r.prompt,
                'mode': r.mode,
                'model': r.model,
                'status': r.status,
            }
            for r in recent_records
        ],
    })


@api_view(['PUT'])
@permission_classes([IsAdminUser])
def admin_user_quota_view(request, user_id):
    """PUT /api/v1/admin/users/:id/quota"""
    try:
        user = User.objects.get(id=user_id)
    except User.DoesNotExist:
        return Response({'error': '用户不存在'}, status=status.HTTP_404_NOT_FOUND)

    serializer = QuotaUpdateSerializer(data=request.data)
    serializer.is_valid(raise_exception=True)

    user.daily_seconds_limit = serializer.validated_data['daily_seconds_limit']
    user.monthly_seconds_limit = serializer.validated_data['monthly_seconds_limit']
    user.save(update_fields=['daily_seconds_limit', 'monthly_seconds_limit'])

    return Response({
        'user_id': user.id,
        'username': user.username,
        'daily_seconds_limit': user.daily_seconds_limit,
        'monthly_seconds_limit': user.monthly_seconds_limit,
        'updated_at': timezone.now().isoformat(),
    })


@api_view(['PATCH'])
@permission_classes([IsAdminUser])
def admin_user_status_view(request, user_id):
    """PATCH /api/v1/admin/users/:id/status"""
    try:
        user = User.objects.get(id=user_id)
    except User.DoesNotExist:
        return Response({'error': '用户不存在'}, status=status.HTTP_404_NOT_FOUND)

    serializer = UserStatusSerializer(data=request.data)
    serializer.is_valid(raise_exception=True)

    user.is_active = serializer.validated_data['is_active']
    user.save(update_fields=['is_active'])

    return Response({
        'user_id': user.id,
        'username': user.username,
        'is_active': user.is_active,
        'updated_at': timezone.now().isoformat(),
    })


@api_view(['POST'])
@permission_classes([IsAdminUser])
def admin_create_user_view(request):
    """POST /api/v1/admin/users — Admin creates a new user"""
    serializer = AdminCreateUserSerializer(data=request.data)
    serializer.is_valid(raise_exception=True)

    username = serializer.validated_data['username']
    email = serializer.validated_data['email']

    if User.objects.filter(username=username).exists():
        return Response({'error': '用户名已存在'}, status=status.HTTP_400_BAD_REQUEST)
    if User.objects.filter(email=email).exists():
        return Response({'error': '邮箱已存在'}, status=status.HTTP_400_BAD_REQUEST)

    user = User.objects.create_user(
        username=username,
        email=email,
        password=serializer.validated_data['password'],
        daily_seconds_limit=serializer.validated_data['daily_seconds_limit'],
        monthly_seconds_limit=serializer.validated_data['monthly_seconds_limit'],
        is_staff=serializer.validated_data['is_staff'],
    )

    return Response({
        'id': user.id,
        'username': user.username,
        'email': user.email,
        'is_active': user.is_active,
        'is_staff': user.is_staff,
        'daily_seconds_limit': user.daily_seconds_limit,
        'monthly_seconds_limit': user.monthly_seconds_limit,
        'created_at': timezone.now().isoformat(),
    }, status=status.HTTP_201_CREATED)


# ──────────────────────────────────────────────
# Admin: Consumption Records
# ──────────────────────────────────────────────

@api_view(['GET'])
@permission_classes([IsAdminUser])
def admin_records_view(request):
    """GET /api/v1/admin/records"""
    page = int(request.query_params.get('page', 1))
    page_size = min(int(request.query_params.get('page_size', 20)), 100)
    search = request.query_params.get('search', '').strip()
    start_date = request.query_params.get('start_date', '').strip()
    end_date = request.query_params.get('end_date', '').strip()

    qs = GenerationRecord.objects.select_related('user').order_by('-created_at')

    if search:
        qs = qs.filter(user__username__icontains=search)
    if start_date:
        qs = qs.filter(created_at__date__gte=start_date)
    if end_date:
        qs = qs.filter(created_at__date__lte=end_date)

    total = qs.count()
    offset = (page - 1) * page_size
    records = qs[offset:offset + page_size]

    results = []
    for r in records:
        results.append({
            'id': r.id,
            'created_at': r.created_at.isoformat(),
            'user_id': r.user_id,
            'username': r.user.username,
            'seconds_consumed': r.seconds_consumed,
            'prompt': r.prompt,
            'mode': r.mode,
            'model': r.model,
            'aspect_ratio': r.aspect_ratio,
            'status': r.status,
        })

    return Response({
        'total': total,
        'page': page,
        'page_size': page_size,
        'results': results,
    })


# ──────────────────────────────────────────────
# Admin: System Settings
# ──────────────────────────────────────────────

@api_view(['GET', 'PUT'])
@permission_classes([IsAdminUser])
def admin_settings_view(request):
    """GET/PUT /api/v1/admin/settings"""
    config, _ = QuotaConfig.objects.get_or_create(pk=1)

    if request.method == 'GET':
        return Response({
            'default_daily_seconds_limit': config.default_daily_seconds_limit,
            'default_monthly_seconds_limit': config.default_monthly_seconds_limit,
            'announcement': config.announcement,
            'announcement_enabled': config.announcement_enabled,
        })

    serializer = SystemSettingsSerializer(data=request.data)
    serializer.is_valid(raise_exception=True)

    config.default_daily_seconds_limit = serializer.validated_data['default_daily_seconds_limit']
    config.default_monthly_seconds_limit = serializer.validated_data['default_monthly_seconds_limit']
    config.announcement = serializer.validated_data.get('announcement', '')
    config.announcement_enabled = serializer.validated_data.get('announcement_enabled', False)
    config.save()

    return Response({
        'default_daily_seconds_limit': config.default_daily_seconds_limit,
        'default_monthly_seconds_limit': config.default_monthly_seconds_limit,
        'announcement': config.announcement,
        'announcement_enabled': config.announcement_enabled,
        'updated_at': config.updated_at.isoformat(),
    })


# ──────────────────────────────────────────────
# Profile: User's own consumption data
# ──────────────────────────────────────────────

@api_view(['GET'])
@permission_classes([IsAuthenticated])
def profile_overview_view(request):
    """GET /api/v1/profile/overview"""
    user = request.user
    today = timezone.now().date()
    first_of_month = today.replace(day=1)
    period = request.query_params.get('period', '7d')
    days = 30 if period == '30d' else 7
    start_date = today - timedelta(days=days - 1)

    daily_seconds_used = user.generation_records.filter(
        created_at__date=today
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    monthly_seconds_used = user.generation_records.filter(
        created_at__date__gte=first_of_month
    ).aggregate(total=Sum('seconds_consumed'))['total'] or 0

    total_seconds_used = user.generation_records.aggregate(
        total=Sum('seconds_consumed')
    )['total'] or 0

    # Daily trend
    trend_qs = (
        user.generation_records
        .filter(created_at__date__gte=start_date)
        .annotate(date=TruncDate('created_at'))
        .values('date')
        .annotate(seconds=Sum('seconds_consumed'))
        .order_by('date')
    )
    trend_map = {str(item['date']): item['seconds'] or 0 for item in trend_qs}
    daily_trend = []
    for i in range(days):
        d = start_date + timedelta(days=i)
        daily_trend.append({'date': str(d), 'seconds': trend_map.get(str(d), 0)})

    return Response({
        'daily_seconds_limit': user.daily_seconds_limit,
        'daily_seconds_used': daily_seconds_used,
        'monthly_seconds_limit': user.monthly_seconds_limit,
        'monthly_seconds_used': monthly_seconds_used,
        'total_seconds_used': total_seconds_used,
        'daily_trend': daily_trend,
    })


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def profile_records_view(request):
    """GET /api/v1/profile/records"""
    user = request.user
    page = int(request.query_params.get('page', 1))
    page_size = min(int(request.query_params.get('page_size', 20)), 100)

    qs = user.generation_records.order_by('-created_at')
    total = qs.count()
    offset = (page - 1) * page_size
    records = qs[offset:offset + page_size]

    results = []
    for r in records:
        results.append({
            'id': r.id,
            'created_at': r.created_at.isoformat(),
            'seconds_consumed': r.seconds_consumed,
            'prompt': r.prompt,
            'mode': r.mode,
            'model': r.model,
            'aspect_ratio': r.aspect_ratio,
            'status': r.status,
        })

    return Response({
        'total': total,
        'page': page,
        'page_size': page_size,
        'results': results,
    })