"""Tests for the first use case, `bank_statement_header` (spec §7)."""

from __future__ import annotations

from datetime import date
from decimal import Decimal

from ix.use_cases.bank_statement_header import BankStatementHeader, Request


class TestRequest:
    def test_defaults(self) -> None:
        r = Request()
        assert r.use_case_name == "Bank Statement Header"
        assert r.default_model == "qwen3:14b"
        # Stable substring for agent/worker tests that want to confirm the
        # prompt is what they think it is.
        assert "extract header metadata" in r.system_prompt


class TestBankStatementHeader:
    def test_all_fields_optional_except_bank_name_and_currency(self) -> None:
        # Minimal valid instance (per spec only bank_name + currency are required).
        hdr = BankStatementHeader(bank_name="UBS", currency="CHF")
        assert hdr.bank_name == "UBS"
        assert hdr.currency == "CHF"
        assert hdr.account_iban is None
        assert hdr.statement_date is None
        assert hdr.opening_balance is None

    def test_full_populated_instance_roundtrip(self) -> None:
        hdr = BankStatementHeader(
            bank_name="UBS Switzerland AG",
            account_iban="CH9300762011623852957",
            account_type="checking",
            currency="CHF",
            statement_date=date(2026, 3, 31),
            statement_period_start=date(2026, 3, 1),
            statement_period_end=date(2026, 3, 31),
            opening_balance=Decimal("1234.56"),
            closing_balance=Decimal("2345.67"),
        )
        dumped = hdr.model_dump(mode="json")
        rt = BankStatementHeader.model_validate(dumped)
        assert rt.account_type == "checking"
        assert rt.opening_balance == Decimal("1234.56")
        assert rt.statement_period_start == date(2026, 3, 1)

    def test_account_type_literal_rejects_unknown(self) -> None:
        import pytest
        from pydantic import ValidationError

        with pytest.raises(ValidationError):
            BankStatementHeader(bank_name="UBS", currency="CHF", account_type="weird")  # type: ignore[arg-type]