1.7

backend/app/services/sync_service.py

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+"""默契种子服务"""
+
+import hashlib
+import re
+import uuid
+from datetime import datetime
+
+from sqlalchemy import select, or_, func
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.sync_seed import SyncQuestion, SyncSeed
+from app.models.friend import Friend
+from app.models.user import User
+from app.websocket.events import EventType
+from app.websocket.manager import manager
+
+
+# 预置题目池
+DEFAULT_QUESTIONS = [
+    "用一个词形容你理想中的周末",
+    "深夜最想吃的一道食物",
+    "如果有一整天完全自由，你会做什么",
+    "最近让你开心的瞬间是什么",
+    "你最向往的旅行目的地",
+    "用一种颜色形容你现在的状态",
+    "你的快乐源泉是什么",
+    "如果会一种超能力，你想要什么",
+]
+
+
+def _tokenize(text: str) -> set[str]:
+    """中文分词：按 2-gram + 标点切分；英文按单词"""
+    if not text:
+        return set()
+    tokens = set()
+    # 英文单词
+    for w in re.findall(r'[a-zA-Z]+', text.lower()):
+        if len(w) >= 2:
+            tokens.add(w)
+    # 中文 2-gram
+    cn = re.sub(r'[^一-鿿]', '', text)
+    for i in range(len(cn) - 1):
+        tokens.add(cn[i:i + 2])
+    # 单字
+    for ch in cn:
+        tokens.add(ch)
+    return tokens
+
+
+def _jaccard(a: set[str], b: set[str]) -> float:
+    if not a or not b:
+        return 0.0
+    inter = len(a & b)
+    union = len(a | b)
+    return inter / union if union else 0.0
+
+
+def _score_answers(a: str, b: str) -> int:
+    """0-100 默契分：Jaccard 为主 + 句长相似 + emoji/标点加分"""
+    if not a or not b:
+        return 0
+    ta, tb = _tokenize(a), _tokenize(b)
+    j = _jaccard(ta, tb)
+    # 句长相似度
+    len_diff = abs(len(a) - len(b)) / max(len(a), len(b), 1)
+    len_sim = 1 - len_diff
+    # emoji / 相同标点
+    emoji_a = set(re.findall(r'[\U0001F300-\U0001FAFF]', a))
+    emoji_b = set(re.findall(r'[\U0001F300-\U0001FAFF]', b))
+    emoji_bonus = 0.1 if emoji_a and emoji_a & emoji_b else 0
+    raw = j * 0.7 + len_sim * 0.2 + emoji_bonus
+    # 放大曲线：让中等重合也能有可见分数
+    score = round(min(100, raw * 130 + (10 if j > 0 else 0)))
+    return max(0, min(100, score))
+
+
+class SyncService:
+    def __init__(self, db: AsyncSession):
+        self.db = db
+
+    async def _ensure_questions(self):
+        """确保题目池存在"""
+        result = await self.db.execute(select(func.count(SyncQuestion.id)))
+        if (result.scalar() or 0) == 0:
+            for q in DEFAULT_QUESTIONS:
+                self.db.add(SyncQuestion(id=str(uuid.uuid4()), content=q))
+            await self.db.flush()
+
+    async def get_today_question(self) -> dict:
+        """获取今日题目（按日期确定性选取）"""
+        await self._ensure_questions()
+        result = await self.db.execute(select(SyncQuestion))
+        questions = result.scalars().all()
+        if not questions:
+            raise ValueError("没有题目")
+        today = datetime.utcnow().strftime("%Y%m%d")
+        idx = int(hashlib.md5(today.encode()).hexdigest(), 16) % len(questions)
+        q = questions[idx]
+        return {"id": q.id, "content": q.content}
+
+    async def _get_or_create_seed(self, question_id: str, user_a: str, user_b: str) -> SyncSeed:
+        a, b = (user_a, user_b) if user_a < user_b else (user_b, user_a)
+        result = await self.db.execute(
+            select(SyncSeed).where(
+                SyncSeed.question_id == question_id,
+                SyncSeed.user_a == a,
+                SyncSeed.user_b == b,
+            )
+        )
+        seed = result.scalars().first()
+        if not seed:
+            seed = SyncSeed(
+                id=str(uuid.uuid4()),
+                question_id=question_id,
+                user_a=a,
+                user_b=b,
+            )
+            self.db.add(seed)
+            await self.db.flush()
+        return seed
+
+    async def submit_answer(self, user_id: str, question_id: str, friend_id: str,
+                            answer: str) -> dict:
+        """提交自己的答案"""
+        # 校验是好友
+        fr = await self.db.execute(
+            select(Friend).where(Friend.user_id == user_id, Friend.friend_user_id == friend_id)
+        )
+        if not fr.scalars().first():
+            raise ValueError("只能和好友默契")
+
+        seed = await self._get_or_create_seed(question_id, user_id, friend_id)
+        # 写入自己的答案（a 或 b）
+        if seed.user_a == user_id:
+            seed.answer_a = answer
+        else:
+            seed.answer_b = answer
+
+        result: dict = {
+            "id": seed.id,
+            "question_id": question_id,
+            "my_answer": answer,
+            "status": seed.status,
+        }
+
+        # 双方都答了 → 揭晓
+        if seed.answer_a and seed.answer_b and seed.status == "draft":
+            score = _score_answers(seed.answer_a, seed.answer_b)
+            seed.score = score
+            leaf = hashlib.md5(
+                f"sync:{question_id}:{seed.user_a}:{seed.user_b}".encode()
+            ).hexdigest()[:16]
+            seed.leaf_seed = leaf
+            seed.status = "revealed"
+            seed.revealed_at = datetime.utcnow()
+            result["score"] = score
+            result["leaf_seed"] = leaf
+            result["partner_answer"] = seed.answer_b if seed.user_a == user_id else seed.answer_a
+            # 推送给搭档
+            await manager.send_to_user(friend_id, "sync.revealed", {
+                "seed_id": seed.id,
+                "question_id": question_id,
+                "score": score,
+                "leaf_seed": leaf,
+            })
+
+        await self.db.flush()
+        return result
+
+    async def get_seed(self, user_id: str, seed_id: str) -> dict:
+        result = await self.db.execute(select(SyncSeed).where(SyncSeed.id == seed_id))
+        seed = result.scalars().first()
+        if not seed:
+            raise ValueError("种子不存在")
+        if user_id not in (seed.user_a, seed.user_b):
+            raise ValueError("无权查看")
+
+        my_answer = seed.answer_a if seed.user_a == user_id else seed.answer_b
+        partner_answer = None
+        if seed.status == "revealed":
+            partner_answer = seed.answer_b if seed.user_a == user_id else seed.answer_a
+
+        return {
+            "id": seed.id,
+            "question_id": seed.question_id,
+            "my_answer": my_answer,
+            "partner_answer": partner_answer,
+            "score": seed.score,
+            "leaf_seed": seed.leaf_seed,
+            "status": seed.status,
+        }