initial_commit

backend/app/core/config.py

@@ -0,0 +1,9 @@
+from dotenv import load_dotenv
+import os
+
+load_dotenv()
+
+DATABASE_URL: str = os.getenv("DATABASE_URL", "sqlite:///./playchat.db")
+DEFAULT_MODEL: str = os.getenv("DEFAULT_MODEL", "gpt-4o")
+MEMORY_SUMMARIZE_THRESHOLD: int = int(os.getenv("MEMORY_SUMMARIZE_THRESHOLD", "20"))
+CORS_ORIGINS: list[str] = os.getenv("CORS_ORIGINS", "http://localhost:5173").split(",")

backend/app/core/llm.py

@@ -0,0 +1,29 @@
+from typing import AsyncIterator
+import litellm
+from app.core.config import DEFAULT_MODEL
+
+litellm.drop_params = True
+
+
+async def stream_chat(
+    messages: list[dict],
+    model: str | None = None,
+) -> AsyncIterator[str]:
+    response = await litellm.acompletion(
+        model=model or DEFAULT_MODEL,
+        messages=messages,
+        stream=True,
+    )
+    async for chunk in response:
+        delta = chunk.choices[0].delta.content
+        if delta:
+            yield delta
+
+
+async def complete(messages: list[dict], model: str | None = None) -> str:
+    response = await litellm.acompletion(
+        model=model or DEFAULT_MODEL,
+        messages=messages,
+        stream=False,
+    )
+    return response.choices[0].message.content or ""

backend/app/core/memory.py

@@ -0,0 +1,44 @@
+from sqlalchemy.orm import Session as DBSession
+from app.db.models import Memory, Message, Session
+from app.core.config import MEMORY_SUMMARIZE_THRESHOLD
+from app.core import llm
+
+
+def get_context_messages(db: DBSession, session_id: str) -> list[dict]:
+    """短期メモリ（最近のメッセージ）と長期メモリ（要約）を結合してコンテキストを返す。"""
+    memories = db.query(Memory).filter(Memory.session_id == session_id).order_by(Memory.created_at).all()
+    messages = db.query(Message).filter(Message.session_id == session_id).order_by(Message.created_at).all()
+
+    context: list[dict] = []
+
+    if memories:
+        combined_summary = "\n\n".join(m.summary for m in memories)
+        context.append({
+            "role": "system",
+            "content": f"以下はこの会話の過去の要約です:\n\n{combined_summary}",
+        })
+
+    context.extend({"role": m.role, "content": m.content} for m in messages)
+    return context
+
+
+async def maybe_summarize(db: DBSession, session: Session) -> None:
+    """メッセージ数が閾値を超えたら古いメッセージを要約してMemoryに保存し、元メッセージを削除する。"""
+    messages = db.query(Message).filter(Message.session_id == session.id).order_by(Message.created_at).all()
+    if len(messages) < MEMORY_SUMMARIZE_THRESHOLD:
+        return
+
+    # 古いメッセージ（閾値の半分）を要約対象にする
+    half = MEMORY_SUMMARIZE_THRESHOLD // 2
+    to_summarize = messages[:half]
+
+    summary_prompt = [
+        {"role": "system", "content": "以下の会話を簡潔に要約してください。重要な事実・決定・文脈を保持してください。"},
+        *[{"role": m.role, "content": m.content} for m in to_summarize],
+    ]
+    summary_text = await llm.complete(summary_prompt)
+
+    db.add(Memory(session_id=session.id, summary=summary_text))
+    for msg in to_summarize:
+        db.delete(msg)
+    db.commit()