"""Apply slot-core SQL migrations in sorted order (REQ-006).

Idempotent: every migration uses CREATE TABLE IF NOT EXISTS / CREATE INDEX
IF NOT EXISTS, so re-running against an existing database is a no-op.
"""
from __future__ import annotations

from pathlib import Path
from typing import Any

_SQL_DIR = Path(__file__).resolve().parent / "sql"


def migration_files() -> list[Path]:
    return sorted(_SQL_DIR.glob("*.sql"))


def apply_migrations(dsn: str, *, psycopg_module: Any = None) -> list[str]:
    """Apply all migrations to `dsn`. Returns the list of applied filenames."""
    if psycopg_module is None:
        import psycopg  # type: ignore[import-not-found]

        psycopg_module = psycopg
    applied: list[str] = []
    with psycopg_module.connect(dsn, autocommit=False) as conn:
        for path in migration_files():
            with conn.cursor() as cur:
                cur.execute(path.read_text())
            applied.append(path.name)
        conn.commit()
    return applied