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
from app.core import knowledge
from app.core.tagging import tag_memory


def get_context_messages(db: DBSession, session_id: str) -> list[dict]:
    """蓄積知識・長期メモリ（要約）・短期メモリ（最近のメッセージ）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] = []

    knowledge_context = knowledge.get_knowledge_context(db)
    if knowledge_context:
        context.append({"role": "system", "content": knowledge_context})

    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, model=session.model, session_id=session.id)

    memory = Memory(session_id=session.id, summary=summary_text)
    db.add(memory)
    for msg in to_summarize:
        db.delete(msg)
    db.commit()
    db.refresh(memory)

    await tag_memory(db, memory)