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

from app.config import settings

engine = create_engine(settings.DATABASE_URL)


def init_db():
    SQLModel.metadata.create_all(engine)


def run_migrations():
    """Run idempotent schema migrations for columns added after initial create."""
    with engine.connect() as conn:
        try:
            conn.execute(
                text(
                    "ALTER TABLE transaction ADD COLUMN IF NOT EXISTS deferred_to_next_cycle BOOLEAN NOT NULL DEFAULT false"
                )
            )
            conn.commit()
        except Exception:
            conn.rollback()

        try:
            conn.execute(text("ALTER TYPE currency ADD VALUE IF NOT EXISTS 'EUR'"))
            conn.commit()
        except Exception:
            conn.rollback()

        try:
            conn.execute(
                text("ALTER TYPE transactiontype ADD VALUE IF NOT EXISTS 'SALARY'")
            )
            conn.commit()
        except Exception:
            conn.rollback()

        try:
            conn.execute(
                text(
                    """
                    CREATE TABLE IF NOT EXISTS savingsaccrual (
                        id SERIAL PRIMARY KEY,
                        year INTEGER NOT NULL,
                        month INTEGER NOT NULL,
                        memp_amount DOUBLE PRECISION NOT NULL DEFAULT 200000,
                        mpat_amount DOUBLE PRECISION NOT NULL DEFAULT 200000,
                        trigger_transaction_id INTEGER,
                        applied_at TIMESTAMP NOT NULL DEFAULT NOW(),
                        notes TEXT,
                        CONSTRAINT savingsaccrual_year_month_key UNIQUE (year, month)
                    )
                    """
                )
            )
            conn.commit()
        except Exception:
            conn.rollback()

        try:
            conn.execute(
                text(
                    """
                    INSERT INTO savingsaccrual (year, month, memp_amount, mpat_amount, notes)
                    VALUES
                      (2026, 2, 200000, 200000, 'Seeded: historical baseline'),
                      (2026, 3, 200000, 200000, 'Seeded: historical baseline')
                    ON CONFLICT (year, month) DO NOTHING
                    """
                )
            )
            conn.commit()
        except Exception:
            conn.rollback()


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