import logging
from datetime import datetime, time, timedelta

from celery import shared_task
from django.conf import settings
from django.db import transaction
from django.utils import timezone

from printing.models import PlateOrder, PlateOrderTiiaUploadFailure


logger = logging.getLogger(__name__)


def _get_day_range(day) -> tuple[datetime, datetime]:
    """
    Build [start, end) datetimes for a local date.
    """
    tz = timezone.get_current_timezone()
    start = datetime.combine(day, time.min)
    end = start + timedelta(days=1)
    if timezone.is_naive(start):
        start = timezone.make_aware(start, tz)
    if timezone.is_naive(end):
        end = timezone.make_aware(end, tz)
    return start, end


@transaction.atomic
def _record_failure(*, run_date, plate_order_id: int, error: str, details):
    """
    Upsert failure record for (run_date, plate_order_id).
    """
    now = timezone.now()
    obj, created = PlateOrderTiiaUploadFailure.objects.select_for_update().get_or_create(
        run_date=run_date,
        plate_order_id=plate_order_id,
        defaults={
            'error': error or '',
            'details': details or [],
            'attempts': 1,
            'last_attempt_at': now,
        },
    )
    if not created:
        obj.error = error or obj.error or ''
        obj.details = details or obj.details or []
        obj.attempts = (obj.attempts or 0) + 1
        obj.last_attempt_at = now
        obj.save(update_fields=['error', 'details', 'attempts', 'last_attempt_at', 'updated_at'])
    return obj


@shared_task(bind=True)
def upload_yesterday_plate_order_images_to_tencent_tiia(self):
    """
    每天凌晨 03:00 运行：
    - 扫描“昨天创建”的 PlateOrder
    - 将 plate_image(JSONField) 中的所有图片 URL 上传到腾讯云图库
    - 遇错：记录失败的 plate_order_id（落库），继续处理下一个

    注意：腾讯云调用限速 10 QPS（每秒 10 次）。
    """
    from api_v1.utils.tencentcloud_tiia import (
        SimpleRateLimiter,
        upload_plate_order_images_to_tencent_tiia,
    )

    today = timezone.localdate()
    run_date = today - timedelta(days=1)
    start, end = _get_day_range(run_date)

    qps = int(getattr(settings, 'TENCENTCLOUD_TIIA_QPS', 10) or 10)
    limiter = SimpleRateLimiter(qps=float(qps))

    qs = (
        PlateOrder.objects.filter(created_at__gte=start, created_at__lt=end)
        .only('id', 'plate_image')
        .order_by('id')
    )

    total_orders = 0
    failed_ids: list[int] = []
    processed_images = 0

    for po in qs.iterator(chunk_size=200):
        total_orders += 1
        try:
            results = upload_plate_order_images_to_tencent_tiia(
                plate_order_id=po.id,
                rate_limiter=limiter,
            )
        except Exception as e:
            failed_ids.append(po.id)
            _record_failure(run_date=run_date, plate_order_id=po.id, error=str(e), details=[{'error': str(e)}])
            logger.exception('[TIIA] PlateOrder %s 上传异常（任务继续）', po.id)
            continue

        processed_images += len(results)
        bad = [r for r in results if not r.get('ok')]
        if bad:
            failed_ids.append(po.id)
            summary = '; '.join([(b.get('error') or '') for b in bad][:5])
            _record_failure(run_date=run_date, plate_order_id=po.id, error=summary, details=bad)
            logger.warning('[TIIA] PlateOrder %s 部分图片上传失败: %s', po.id, summary)

    payload = {
        'task_id': getattr(getattr(self, 'request', None), 'id', None),
        'run_date': str(run_date),
        'created_range': {'start': start.isoformat(), 'end': end.isoformat()},
        'total_orders': total_orders,
        'processed_images': processed_images,
        'failed_count': len(failed_ids),
        'failed_ids': failed_ids,
    }
    logger.info('[TIIA] 昨日 PlateOrder 图片上传任务完成: %s', payload)
    return payload