import sqlite3
from version import __version__
from pathlib import Path
import logging
from logging_config import setup_logging
import os

APP_ENV = os.environ.get("APP_ENV", "dev")
logger = setup_logging(APP_ENV)

logger.info(f"Starting migration - APP-Version {__version__}")

logger = logging.getLogger(__name__)


BASE_DIR = Path(__file__).resolve().parents[1]
DB_DIR = BASE_DIR / "data"
DB_PATH = DB_DIR / "app.db"
MIGRATIONS_DIR = BASE_DIR / "migrations"



def get_connection() -> sqlite3.Connection:
    DB_DIR.mkdir(exist_ok=True)
    conn = sqlite3.connect(DB_PATH)
    return conn

def get_applied_versions(conn: sqlite3.Connection) -> set[str]:
    """
    Ließt aus schema_version, welche Migrationen schon gelaufen sind.
    Falls die Tabelle noch nicht existiert → leeres Set.
    """
    try:
        cur = conn.execute("SELECT version FROM schema_version")
        rows = cur.fetchall()
        return {r[0] for r in rows}
    except sqlite3.OperationalError:
        # Tabelle existiert noch nicht (z.B. bei initialer DB)
        
        return set()

def apply_migrations():
    if not MIGRATIONS_DIR.exists():
        raise SystemExit(f"Migrations-Ordner nicht gefunden: {MIGRATIONS_DIR}")

    conn = get_connection()

    try:
        applied = get_applied_versions(conn)

        # Alle .sql-Dateien alphabetisch sortiert
        sql_files = sorted(MIGRATIONS_DIR.glob("*.sql"))

        if not sql_files:
            logger.info("Keine Migrationsdateien gefunden.")
            return

        for path in sql_files:
            version = path.stem  # z.B. '20250220_120000_initial'

            if version in applied:
                logger.info(f"[SKIP] {version} (bereits angewendet)")
                continue

            logger.info(f"[APPLY] {version}")
            sql = path.read_text(encoding="utf-8")

            try:
                # Eine Transaktion pro Datei
                with conn:
                    conn.executescript(sql)
            except Exception as e:
                logger.info(f"Fehler in Migration {version}: {e}")
                # hier nicht weiter machen
                raise
        logger.info(f"Migrationen abgeschlossen. DB: {DB_PATH}")
        #print(f"Migrationen abgeschlossen. DB: {DB_PATH}")

    finally:
        conn.close()


if __name__ == "__main__":
    apply_migrations()