File size: 3,214 Bytes
8eaa451 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | """
MediGenius — services/database_service.py
DatabaseService: all CRUD operations for chat history.
"""
from typing import Dict, List, Optional
from sqlalchemy import delete, desc, func, select
from sqlalchemy.orm import Session
from app.core.logging_config import logger
from app.db.session import SessionLocal, engine
from app.models.message import Base, Message
class DatabaseService:
"""All database CRUD operations for chat history."""
def __init__(self, session_local=None, engine_instance=None):
self.SessionLocal = session_local or SessionLocal
self.engine = engine_instance or engine
logger.info("DatabaseService initialized")
def init_db(self) -> None:
"""Create all tables if they don't exist."""
logger.info("Initializing database tables...")
Base.metadata.create_all(bind=self.engine)
def get_session(self) -> Session:
return self.SessionLocal()
def save_message(
self,
session_id: str,
role: str,
content: str,
source: Optional[str] = None,
) -> None:
logger.debug("Saving %s message for session %s...", role, session_id[:8])
with self.get_session() as session:
session.add(
Message(
session_id=session_id, role=role, content=content, source=source
)
)
session.commit()
def get_chat_history(self, session_id: str) -> List[Dict]:
with self.get_session() as session:
stmt = (
select(Message)
.where(Message.session_id == session_id)
.order_by(Message.timestamp)
)
return [msg.to_dict() for msg in session.execute(stmt).scalars().all()]
def get_all_sessions(self) -> List[Dict]:
with self.get_session() as session:
latest_sub = (
select(
Message.session_id,
func.max(Message.timestamp).label("max_ts"),
)
.where(Message.role == "user")
.group_by(Message.session_id)
.subquery()
)
stmt = (
select(Message.session_id, Message.content, Message.timestamp)
.join(
latest_sub,
(Message.session_id == latest_sub.c.session_id)
& (Message.timestamp == latest_sub.c.max_ts),
)
.order_by(desc(Message.timestamp))
)
return [
{
"session_id": row[0],
"preview": row[1][:50] + "..." if len(row[1]) > 50 else row[1],
"last_active": row[2].isoformat() if row[2] else None,
}
for row in session.execute(stmt).all()
]
def delete_session(self, session_id: str) -> None:
logger.info("Deleting session %s...", session_id[:8])
with self.get_session() as session:
session.execute(delete(Message).where(Message.session_id == session_id))
session.commit()
# Module-level singleton
db_service = DatabaseService()
|