feat: track designer downloads and notifications

backend/app/services/download_tracker.py

@@ -0,0 +1,46 @@
+from datetime import datetime
+
+from sqlalchemy.orm import Session
+
+from app.models.download import DownloadRecord
+from app.models.order import Order
+from app.models.user import User
+from app.models.work import Work
+from app.services.wecom_bot import send_wecom_text
+
+
+def _build_download_notice(work: Work, buyer: User, order: Order) -> str:
+    return "\n".join(
+        [
+            "【图绘下载通知】",
+            f"作品ID：{work.id}",
+            f"作品标题：{work.title}",
+            f"设计师：{work.designer or '-'}",
+            f"购买用户：{buyer.nickname or buyer.phone or buyer.id}",
+            f"金额：{order.amount}元",
+            f"下载时间：{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}",
+            f"作品链接：https://tuhui.cloud/detail/{work.id}",
+        ]
+    )
+
+
+def record_download(db: Session, order: Order, work: Work, buyer: User) -> DownloadRecord:
+    existing = db.query(DownloadRecord).filter(DownloadRecord.order_id == order.id).first()
+    if existing:
+        return existing
+
+    record = DownloadRecord(
+        user_id=buyer.id,
+        work_id=work.id,
+        order_id=order.id,
+        designer_name=work.designer or "",
+        work_title=work.title or "",
+        amount=float(order.amount or 0.0),
+    )
+    db.add(record)
+    work.downloads = int(work.downloads or 0) + 1
+    return record
+
+
+def notify_download(work: Work, buyer: User, order: Order):
+    send_wecom_text(_build_download_notice(work, buyer, order))