from celery import shared_task
from django.utils import timezone
from datetime import timedelta


@shared_task
def cleanup_old_request_logs():
    threshold = timezone.now() - timedelta(days=30)
    from .models import ApiRequestLog
    deleted_count, _ = ApiRequestLog.objects.filter(timestamp__lt=threshold).delete()
    return f'已清理 {deleted_count} 条过期请求日志'


@shared_task
def cleanup_old_error_logs():
    threshold = timezone.now() - timedelta(days=90)
    from .models import ErrorLog
    deleted_count, _ = ErrorLog.objects.filter(
        timestamp__lt=threshold,
        is_resolved=True
    ).delete()
    return f'已清理 {deleted_count} 条已处理的过期错误日志'


@shared_task
def cleanup_old_event_logs():
    threshold = timezone.now() - timedelta(days=60)
    from .models import SystemEventLog
    deleted_count, _ = SystemEventLog.objects.filter(timestamp__lt=threshold).delete()
    return f'已清理 {deleted_count} 条过期事件日志'


@shared_task
def generate_daily_stats():
    from .models import ApiRequestLog, ErrorLog
    from django.db.models import Count, Avg

    today_start = timezone.now().replace(hour=0, minute=0, second=0, microsecond=0)
    yesterday_start = today_start - timedelta(days=1)

    yesterday_stats = ApiRequestLog.objects.filter(
        timestamp__gte=yesterday_start,
        timestamp__lt=today_start
    ).aggregate(
        total_requests=Count('id'),
        error_count=Count('id', filter={'is_error': True}),
        avg_duration=Avg('duration_ms'),
    )

    error_count = ErrorLog.objects.filter(
        timestamp__gte=yesterday_start,
        timestamp__lt=today_start
    ).count()

    return {
        'date': yesterday_start.date().isoformat(),
        'total_requests': yesterday_stats['total_requests'],
        'error_requests': yesterday_stats['error_count'],
        'error_logs': error_count,
        'avg_duration_ms': round(yesterday_stats['avg_duration'] or 0, 2),
    }