"""Connection and table-maintenance helpers for the economics import."""

import sqlite3
from pathlib import Path


def connect(db_path: Path) -> sqlite3.Connection:
    """Open systems.db with foreign-key enforcement on."""
    conn = sqlite3.connect(str(db_path))
    conn.execute("PRAGMA foreign_keys=ON")
    return conn


def clear_economics_tables(conn: sqlite3.Connection) -> None:
    """Clear economics tables in FK-safe order (children before parents).

    corp_presence is cleared here; the corporations table is append-only
    (never cleared).  Runs inside the caller's transaction, so a failure
    later in the import rolls these DELETEs back too.
    """
    conn.execute("DELETE FROM corp_presence")
    conn.execute("DELETE FROM brand_inputs")
    conn.execute("DELETE FROM brand_products")
    conn.execute("DELETE FROM system_fiscal")
    conn.execute("DELETE FROM corp_financial_state")
    conn.execute("DELETE FROM corp_lifecycle_events")
    conn.execute("DELETE FROM chain_inputs")
    conn.execute("DELETE FROM production_chains")
    # specialization_vocabulary FK-references commodities — clear it
    # before commodities so the FK-on delete does not fail (D-237).
    conn.execute("DELETE FROM specialization_vocabulary")
    conn.execute("DELETE FROM commodities")
    conn.execute("DELETE FROM gate_links")