feat(core): add currency service

app/services/currency_service.py

@@ -0,0 +1,160 @@
+"""Currency service — CRUD, default currency management, seeding."""
+
+from __future__ import annotations
+
+import uuid
+from datetime import UTC, datetime
+from typing import Any
+
+from sqlalchemy import select, update
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.audit import log_audit
+from app.models.currency import Currency
+
+
+def _currency_to_dict(c: Currency) -> dict[str, Any]:
+    """Serialize a Currency ORM object to dict."""
+    return {
+        "id": str(c.id),
+        "code": c.code,
+        "name": c.name,
+        "symbol": c.symbol,
+        "is_default": c.is_default,
+        "created_at": c.created_at.isoformat() if c.created_at else None,
+        "updated_at": c.updated_at.isoformat() if c.updated_at else None,
+    }
+
+
+async def list_currencies(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+) -> dict[str, Any]:
+    """List all currencies for a tenant."""
+    q = select(Currency).where(
+        Currency.tenant_id == tenant_id,
+        Currency.deleted_at.is_(None),
+    ).order_by(Currency.code.asc())
+    result = await db.execute(q)
+    currencies = result.scalars().all()
+    return {
+        "items": [_currency_to_dict(c) for c in currencies],
+        "total": len(currencies),
+    }
+
+
+async def create_currency(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+    user_id: uuid.UUID,
+    data: dict[str, Any],
+) -> dict[str, Any]:
+    """Create a new currency. If is_default=True, unset other defaults first."""
+    if data.get("is_default"):
+        await db.execute(
+            update(Currency)
+            .where(Currency.tenant_id == tenant_id, Currency.is_default.is_(True))
+            .values(is_default=False)
+        )
+
+    currency = Currency(
+        tenant_id=tenant_id,
+        code=data["code"].upper(),
+        name=data["name"],
+        symbol=data["symbol"],
+        is_default=data.get("is_default", False),
+    )
+    db.add(currency)
+    await db.flush()
+    await db.refresh(currency)
+    await log_audit(
+        db, tenant_id, user_id, "create", "currency", currency.id,
+        changes={"code": currency.code},
+    )
+    return _currency_to_dict(currency)
+
+
+async def update_currency(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+    user_id: uuid.UUID,
+    currency_id: uuid.UUID,
+    data: dict[str, Any],
+) -> dict[str, Any] | None:
+    """Update a currency. If setting is_default=True, unset other defaults first."""
+    q = select(Currency).where(
+        Currency.id == currency_id,
+        Currency.tenant_id == tenant_id,
+        Currency.deleted_at.is_(None),
+    )
+    result = await db.execute(q)
+    currency = result.scalar_one_or_none()
+    if currency is None:
+        return None
+
+    if data.get("is_default") is True and not currency.is_default:
+        await db.execute(
+            update(Currency)
+            .where(
+                Currency.tenant_id == tenant_id,
+                Currency.is_default.is_(True),
+                Currency.id != currency_id,
+            )
+            .values(is_default=False)
+        )
+
+    changes: dict[str, Any] = {}
+    for field in ("code", "name", "symbol", "is_default"):
+        if field in data and data[field] is not None:
+            old_val = getattr(currency, field)
+            changes[field] = {"old": old_val, "new": data[field]}
+            setattr(currency, field, data[field])
+
+    await db.flush()
+    await db.refresh(currency)
+    await log_audit(db, tenant_id, user_id, "update", "currency", currency_id, changes=changes)
+    return _currency_to_dict(currency)
+
+
+async def delete_currency(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+    user_id: uuid.UUID,
+    currency_id: uuid.UUID,
+) -> bool:
+    """Soft-delete a currency."""
+    q = select(Currency).where(
+        Currency.id == currency_id,
+        Currency.tenant_id == tenant_id,
+        Currency.deleted_at.is_(None),
+    )
+    result = await db.execute(q)
+    currency = result.scalar_one_or_none()
+    if currency is None:
+        return False
+
+    currency.deleted_at = datetime.now(UTC)
+    await db.flush()
+    await log_audit(
+        db, tenant_id, user_id, "delete", "currency", currency_id,
+        changes={"code": currency.code},
+    )
+    return True
+
+
+async def seed_default_currencies(db: AsyncSession, tenant_id: uuid.UUID) -> None:
+    """Seed default EUR currency for a new tenant if none exist."""
+    q = select(Currency).where(Currency.tenant_id == tenant_id, Currency.deleted_at.is_(None))
+    result = await db.execute(q)
+    if result.scalars().first() is not None:
+        return
+
+    eur = Currency(
+        tenant_id=tenant_id,
+        code="EUR",
+        name="Euro",
+        symbol="€",
+        is_default=True,
+    )
+    db.add(eur)
+    await db.flush()