import os
from sqlalchemy import create_engine, event, text
from sqlalchemy.orm import sessionmaker
from dotenv import load_dotenv
from models import Base

load_dotenv()
DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///./stocking.db")

_is_postgres = DATABASE_URL.startswith("postgresql")

connect_args = {"sslmode": "require"} if _is_postgres else {"check_same_thread": False}
engine = create_engine(DATABASE_URL, connect_args=connect_args)

# SQLite 전용: WAL 모드 (PostgreSQL에는 적용 안 함)
if not _is_postgres:
    @event.listens_for(engine, "connect")
    def set_wal_mode(dbapi_connection, connection_record):
        """WAL 모드: 스케줄러 write + API read 동시 처리 가능."""
        cursor = dbapi_connection.cursor()
        cursor.execute("PRAGMA journal_mode=WAL")
        cursor.close()

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def init_db():
    # watchlist 테이블 스키마 마이그레이션: SQLite에만 적용 (PostgreSQL은 PRAGMA 없음)
    if not _is_postgres:
        with engine.connect() as conn:
            cols = [row[1] for row in conn.execute(text("PRAGMA table_info(watchlist)")).fetchall()]
            if cols and "user_id" not in cols:
                conn.execute(text("DROP TABLE watchlist"))
                conn.commit()
    Base.metadata.create_all(bind=engine)
    # annual_data 인덱스 마이그레이션: create_all은 기존 테이블에 인덱스를 추가하지 않으므로 직접 생성
    with engine.connect() as conn:
        conn.execute(text(
            "CREATE INDEX IF NOT EXISTS ix_annual_data_ticker_year_is_estimate "
            "ON annual_data (ticker, year, is_estimate)"
        ))
        conn.execute(text(
            "CREATE INDEX IF NOT EXISTS ix_annual_data_ticker_is_estimate "
            "ON annual_data (ticker, is_estimate)"
        ))
        conn.commit()


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