"""Default data seeding — EUR currency, 19% and 7% tax rates."""

from __future__ import annotations

import logging
import uuid

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.currency import Currency
from app.models.tax import TaxRate

logger = logging.getLogger(__name__)


async def seed_default_data(db: AsyncSession, tenant_id: uuid.UUID | None = None) -> None:
    """Seed default currency and tax rates for a tenant.

    Idempotent: checks if data already exists before inserting.
    If tenant_id is None, seeds for all existing tenants.
    """
    from app.models.tenant import Tenant

    if tenant_id is not None:
        tenant_ids = [tenant_id]
    else:
        result = await db.execute(select(Tenant.id))
        tenant_ids = [row[0] for row in result.all()]

    for tid in tenant_ids:
        await _seed_currencies(db, tid)
        await _seed_tax_rates(db, tid)

    await db.flush()
    logger.info(f"Seeded default data for {len(tenant_ids)} tenant(s)")


async def _seed_currencies(db: AsyncSession, tenant_id: uuid.UUID) -> None:
    """Seed EUR as default currency if no currencies exist for this tenant."""
    existing = await db.execute(
        select(Currency).where(
            Currency.tenant_id == tenant_id,
            Currency.deleted_at.is_(None),
        )
    )
    if existing.scalars().first() is not None:
        return

    eur = Currency(
        tenant_id=tenant_id,
        code="EUR",
        name="Euro",
        symbol="€",
        is_default=True,
    )
    db.add(eur)
    logger.info(f"Seeded EUR currency for tenant {tenant_id}")


async def _seed_tax_rates(db: AsyncSession, tenant_id: uuid.UUID) -> None:
    """Seed 19% and 7% tax rates if no tax rates exist for this tenant."""
    existing = await db.execute(
        select(TaxRate).where(
            TaxRate.tenant_id == tenant_id,
            TaxRate.deleted_at.is_(None),
        )
    )
    if existing.scalars().first() is not None:
        return

    vat_19 = TaxRate(
        tenant_id=tenant_id,
        name="Mehrwertsteuer 19%",
        rate=19.00,
        is_default=True,
    )
    vat_7 = TaxRate(
        tenant_id=tenant_id,
        name="Mehrwertsteuer 7%",
        rate=7.00,
        is_default=False,
    )
    db.add(vat_19)
    db.add(vat_7)
    logger.info(f"Seeded 19% and 7% tax rates for tenant {tenant_id}")