import sys
import os
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "../../")))

from sqlalchemy import create_engine, MetaData
from sqlalchemy.orm import sessionmaker
from config import Config
from dotenv import load_dotenv
load_dotenv()

# Źródło: SQLite
sqlite_engine = create_engine("sqlite:///instance/baza.db")
sqlite_meta = MetaData()
sqlite_meta.reflect(bind=sqlite_engine)

# Cel: PostgreSQL
pg_engine = create_engine(Config.SQLALCHEMY_DATABASE_URI)
pg_meta = MetaData()
pg_meta.reflect(bind=pg_engine)

# Sesje
SQLiteSession = sessionmaker(bind=sqlite_engine)
PGSession = sessionmaker(bind=pg_engine)

sqlite_session = SQLiteSession()
pg_session = PGSession()

def migrate_table(table_name):
    print("➡️  Używana baza docelowa:", Config.SQLALCHEMY_DATABASE_URI)
    print(f"\n➡️  Migruję tabelę: {table_name}")
    source_table = sqlite_meta.tables.get(table_name)
    target_table = pg_meta.tables.get(table_name)

    if source_table is None or target_table is None:
        print(f"⚠️  Pominięto: {table_name} (brak w jednej z baz)")
        return

    rows = sqlite_session.execute(source_table.select()).fetchall()
    if not rows:
        print("ℹ️  Brak danych do migracji.")
        return

    insert_data = [dict(row._mapping) for row in rows]

    try:
        with pg_engine.begin() as conn:
            conn.execute(target_table.delete())
            conn.execute(target_table.insert(), insert_data)
        print(f"✅ Przeniesiono: {len(rows)} rekordów")
    except Exception as e:
        print(f"❌ Błąd przy migracji {table_name}: {e}")


def main():
    tables = ["user", "shopping_list", "item", "expense", "receipt", "suggested_product"]
    for table in tables:
        migrate_table(table)
    print("\n🎉 Migracja zakończona pomyślnie.")

if __name__ == "__main__":
    main()