from sqlalchemy import create_engine
from sqlalchemy.orm import declarative_base, sessionmaker
import os

DATABASE_URL = os.getenv("DATABASE_URL", "postgresql://postgres:postgres@postgres:5432/vector_mchs")
engine = create_engine(DATABASE_URL, echo=False)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    Base.metadata.create_all(bind=engine)


class _CompatDB:
    def __init__(self):
        self._cases = []

    def create_case(self, **data):
        raise NotImplementedError('compat db is for import only')

    def list_cases(self):
        return []

    def get_case(self, case_id):
        return None

    def update_case(self, case_id, **patch):
        return None

    def delete_case(self, case_id):
        return False

    def stats(self):
        return {
            'total_cases': 0,
            'found_alive_count': 0,
            'found_deceased_count': 0,
            'unknown_outcome_count': 0,
            'median_found_distance_km': None,
            'recent_activity_count': 0,
        }

    def heatmap(self):
        return []


db = _CompatDB()