from sqlalchemy import event
from sqlmodel import Session, SQLModel, create_engine

from .config import get_config

_engine = None


def get_engine():
    global _engine
    if _engine is None:
        config = get_config()
        _engine = create_engine(
            config.database_url,
            connect_args={"check_same_thread": False},
        )

        # Set PRAGMAs on every new connection (foreign_keys must be per-connection)
        @event.listens_for(_engine, "connect")
        def _set_pragmas(dbapi_conn, _record):
            cursor = dbapi_conn.cursor()
            cursor.execute("PRAGMA journal_mode=WAL")
            cursor.execute("PRAGMA foreign_keys=ON")
            cursor.close()

    return _engine


def get_session():
    with Session(get_engine()) as session:
        yield session


def create_db_and_tables() -> None:
    from . import models  # noqa: ensure model classes are registered

    SQLModel.metadata.create_all(get_engine())
    engine = get_engine()
    with engine.connect() as conn:
        conn.exec_driver_sql(
            "CREATE INDEX IF NOT EXISTS idx_sync_map_replica ON sync_map(replica_id)"
        )
        conn.exec_driver_sql(
            "CREATE INDEX IF NOT EXISTS idx_sync_map_status ON sync_map(replica_id, status)"
        )
        conn.exec_driver_sql(
            "CREATE VIRTUAL TABLE IF NOT EXISTS logs_fts "
            "USING fts5(message, content=logs, content_rowid=id)"
        )
        conn.exec_driver_sql(
            "CREATE TRIGGER IF NOT EXISTS logs_ai AFTER INSERT ON logs BEGIN "
            "INSERT INTO logs_fts(rowid, message) VALUES (new.id, new.message); END"
        )
        conn.exec_driver_sql(
            "CREATE TRIGGER IF NOT EXISTS logs_ad AFTER DELETE ON logs BEGIN "
            "INSERT INTO logs_fts(logs_fts, rowid, message) "
            "VALUES('delete', old.id, old.message); END"
        )
        conn.commit()