1.6

backend/app/services/capsule_service.py

@@ -0,0 +1,105 @@
+"""时光胶囊服务（懒解锁）"""
+
+import uuid
+from datetime import datetime
+
+from sqlalchemy import select, or_
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.time_capsule import TimeCapsule
+from app.models.friend import Friend
+
+
+class CapsuleService:
+    def __init__(self, db: AsyncSession):
+        self.db = db
+
+    async def create_capsule(self, sender_id: str, recipient_id: str, title: str,
+                             content: str, unlock_at: datetime,
+                             mood: str | None = None) -> dict:
+        """创建时光胶囊"""
+        # 校验解锁时间是未来
+        if unlock_at <= datetime.utcnow():
+            raise ValueError("解锁时间必须是未来时间")
+
+        # 校验收件人：自己 或 好友
+        if recipient_id != sender_id:
+            friend_result = await self.db.execute(
+                select(Friend).where(
+                    Friend.user_id == sender_id,
+                    Friend.friend_user_id == recipient_id,
+                )
+            )
+            if not friend_result.scalars().first():
+                raise ValueError("只能给好友或自己寄胶囊")
+
+        capsule = TimeCapsule(
+            id=str(uuid.uuid4()),
+            sender_id=sender_id,
+            recipient_id=recipient_id,
+            title=title,
+            content=content,
+            unlock_at=unlock_at,
+            mood=mood,
+        )
+        self.db.add(capsule)
+        await self.db.flush()
+        return self._capsule_to_dict(capsule, sender_id)
+
+    async def get_capsules(self, user_id: str) -> list[dict]:
+        """获取我发的 + 我收的胶囊"""
+        result = await self.db.execute(
+            select(TimeCapsule).where(
+                or_(
+                    TimeCapsule.sender_id == user_id,
+                    TimeCapsule.recipient_id == user_id,
+                )
+            ).order_by(TimeCapsule.unlock_at.desc())
+        )
+        return [self._capsule_to_dict(c, user_id) for c in result.scalars().all()]
+
+    async def get_capsule(self, user_id: str, capsule_id: str) -> dict:
+        """获取单个胶囊"""
+        result = await self.db.execute(
+            select(TimeCapsule).where(TimeCapsule.id == capsule_id)
+        )
+        capsule = result.scalars().first()
+        if not capsule:
+            raise ValueError("胶囊不存在")
+        if capsule.sender_id != user_id and capsule.recipient_id != user_id:
+            raise ValueError("无权查看此胶囊")
+
+        # 若已解锁且收件人首次查看，标记 opened
+        now = datetime.utcnow()
+        if now >= capsule.unlock_at and capsule.recipient_id == user_id and not capsule.is_opened:
+            capsule.is_opened = True
+            await self.db.flush()
+        return self._capsule_to_dict(capsule, user_id)
+
+    def _capsule_to_dict(self, capsule: TimeCapsule, viewer_id: str) -> dict:
+        """转字典，应用懒解锁：未到期则隐藏内容"""
+        now = datetime.utcnow()
+        locked = now < capsule.unlock_at
+        seconds_left = int((capsule.unlock_at - now).total_seconds()) if locked else 0
+
+        # 内容可见性：发送人可看自己的（即使锁定）；收件人锁定时不可看
+        can_see_content = (
+            capsule.sender_id == viewer_id  # 发送人始终能看自己发的
+            or not locked  # 已解锁
+        )
+
+        return {
+            "id": capsule.id,
+            "sender_id": capsule.sender_id,
+            "recipient_id": capsule.recipient_id,
+            "is_mine_sent": capsule.sender_id == viewer_id,
+            "is_mine_received": capsule.recipient_id == viewer_id,
+            "title": capsule.title,
+            "content": capsule.content if can_see_content else None,
+            "unlock_at": capsule.unlock_at.isoformat(),
+            "mood": capsule.mood,
+            "locked": locked,
+            "seconds_left": seconds_left,
+            "is_opened": capsule.is_opened,
+            "created_at": capsule.created_at.isoformat(),
+        }