from decimal import Decimal
import xml.etree.ElementTree as ET

from invoice_logic import (
    berechne_faelligkeit,
    kaufmaennisches_runden,
    clean_german_float,
    extract_invoice_items_pure_python,
    map_unece_unit_code,
    parse_to_strict_xml_date,
    generate_compliant_xrechnung,
    generate_compliant_zugferd_cii,
    VERKAEUFER_IBAN,
    PAYMENT_MEANS_CODES,
    aggregate_tax_subtotals,
    compute_invoice_totals,
)


def _single_rate_invoice():
    """Eine einfache Einzelsteuersatz-Rechnung, wie main.py sie vor Phase 1 erzeugt hat."""
    items = [
        {"name": "Beratung", "description": "", "quantity": 2.0, "unit": "Std.",
         "unit_price": 100.0, "total_amount": 200.0},
    ]
    return {
        "invoice_type_code": "380",
        "invoice_number": "R26-001",
        "invoice_date": "2026-01-15",
        "delivery_date": "",
        "buyer_reference": "",
        "customer_number": "",
        "recipient_name": "Test GmbH",
        "recipient_email": "kunde@example.com",
        "recipient_street": "Musterweg 1",
        "recipient_zip": "12345",
        "recipient_city": "Berlin",
        "items": items,
        "total_net_amount": 200.0,
        "total_vat_amount": 38.0,
        "vat_rate_percent": 19.0,
        "total_gross_amount": 238.0,
        "iban": VERKAEUFER_IBAN,
        "delivery_note_id": "",
        "order_id": "",
        "contract_id": "",
        "service_start_date": "",
        "service_end_date": "",
        "payment_term_days": "14",
        "invoice_note": "",
    }


def test_generate_compliant_xrechnung_single_rate_unchanged():
    xml_str = generate_compliant_xrechnung(_single_rate_invoice())
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"cbc": "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2",
          "cac": "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"}
    assert root.find("cbc:ID", ns).text == "R26-001"
    tax_amount = root.find(".//cac:TaxTotal/cbc:TaxAmount", ns).text
    assert tax_amount == "38.00"
    payable = root.find(".//cac:LegalMonetaryTotal/cbc:PayableAmount", ns).text
    assert payable == "238.00"


def test_generate_compliant_zugferd_cii_single_rate_unchanged():
    xml_str = generate_compliant_zugferd_cii(_single_rate_invoice())
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"ram": "urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100"}
    grand_total = root.find(".//ram:SpecifiedTradeSettlementHeaderMonetarySummation/ram:GrandTotalAmount", ns).text
    assert grand_total == "238.00"


def test_berechne_faelligkeit_basic():
    assert berechne_faelligkeit("2026-01-15", "14") == "2026-01-29"


def test_kaufmaennisches_runden_half_up():
    assert kaufmaennisches_runden(1.005) == 1.01


def test_clean_german_float_thousands_and_comma():
    assert clean_german_float("1.234,56") == 1234.56


def test_extract_invoice_items_pure_python_basic():
    text = "1\nBeratung\n2,00 Std.\n100,00\n200,00\n"
    items = extract_invoice_items_pure_python(text)
    assert items[0]["name"] == "Beratung"
    assert items[0]["quantity"] == 2.0
    assert items[0]["unit_price"] == 100.0


def test_map_unece_unit_code_hours():
    assert map_unece_unit_code("Std.") == "HUR"


def test_parse_to_strict_xml_date_german_format():
    assert parse_to_strict_xml_date("15.01.2026") == "2026-01-15"


def test_payment_means_codes_contains_expected_entries():
    assert PAYMENT_MEANS_CODES["58"] == "SEPA-Überweisung"
    assert set(["30", "31", "42", "48", "58"]).issubset(PAYMENT_MEANS_CODES.keys())


def test_generate_compliant_xrechnung_uses_dynamic_payment_means_code():
    data = _single_rate_invoice()
    data["payment_means_code"] = "31"
    xml_str = generate_compliant_xrechnung(data)
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"cbc": "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2",
          "cac": "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"}
    code = root.find(".//cac:PaymentMeans/cbc:PaymentMeansCode", ns).text
    assert code == "31"


def test_generate_compliant_xrechnung_defaults_payment_means_code_to_58():
    xml_str = generate_compliant_xrechnung(_single_rate_invoice())
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"cbc": "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2",
          "cac": "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"}
    code = root.find(".//cac:PaymentMeans/cbc:PaymentMeansCode", ns).text
    assert code == "58"


def test_generate_compliant_zugferd_cii_uses_dynamic_payment_means_code():
    data = _single_rate_invoice()
    data["payment_means_code"] = "48"
    xml_str = generate_compliant_zugferd_cii(data)
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"ram": "urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100"}
    code = root.find(".//ram:SpecifiedTradeSettlementPaymentMeans/ram:TypeCode", ns).text
    assert code == "48"


def test_aggregate_tax_subtotals_single_rate():
    items = [{"total_amount": 200.0, "vat_rate_percent": 19.0}]
    buckets = aggregate_tax_subtotals(items)
    assert buckets == [{"rate": 19.0, "category": "S", "taxable_amount": 200.0, "tax_amount": 38.0}]


def test_aggregate_tax_subtotals_mixed_rates():
    items = [
        {"total_amount": 100.0, "vat_rate_percent": 19.0},
        {"total_amount": 50.0, "vat_rate_percent": 7.0},
        {"total_amount": 30.0, "vat_rate_percent": 0.0},
    ]
    buckets = aggregate_tax_subtotals(items)
    assert buckets == [
        {"rate": 0.0, "category": "E", "taxable_amount": 30.0, "tax_amount": 0.0},
        {"rate": 7.0, "category": "S", "taxable_amount": 50.0, "tax_amount": 3.5},
        {"rate": 19.0, "category": "S", "taxable_amount": 100.0, "tax_amount": 19.0},
    ]


def test_compute_invoice_totals_mixed_rates_no_discount():
    items = [
        {"total_amount": 100.0, "vat_rate_percent": 19.0},
        {"total_amount": 50.0, "vat_rate_percent": 7.0},
    ]
    totals = compute_invoice_totals(items)
    assert totals["line_net_total"] == 150.0
    assert totals["allowance_amount"] == 0.0
    assert totals["tax_basis_total"] == 150.0
    assert totals["total_vat_amount"] == 22.5
    assert totals["total_gross_amount"] == 172.5


def test_compute_invoice_totals_single_rate_matches_old_behavior():
    items = [{"total_amount": 200.0, "vat_rate_percent": 19.0}]
    totals = compute_invoice_totals(items)
    assert totals["tax_basis_total"] == 200.0
    assert totals["total_vat_amount"] == 38.0
    assert totals["total_gross_amount"] == 238.0


def _mixed_rate_invoice():
    data = _single_rate_invoice()
    items = [
        {"name": "Beratung", "description": "", "quantity": 2.0, "unit": "Std.",
         "unit_price": 100.0, "total_amount": 200.0, "vat_rate_percent": 19.0},
        {"name": "Buch", "description": "", "quantity": 1.0, "unit": "Stk.",
         "unit_price": 50.0, "total_amount": 50.0, "vat_rate_percent": 7.0},
    ]
    totals = compute_invoice_totals(items)
    data["items"] = items
    data["tax_buckets"] = totals["tax_buckets"]
    data["line_net_total"] = totals["line_net_total"]
    data["allowance_amount"] = totals["allowance_amount"]
    data["total_net_amount"] = totals["tax_basis_total"]
    data["total_vat_amount"] = totals["total_vat_amount"]
    data["total_gross_amount"] = totals["total_gross_amount"]
    return data


def test_generate_compliant_xrechnung_mixed_rates_two_tax_subtotals():
    xml_str = generate_compliant_xrechnung(_mixed_rate_invoice())
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"cbc": "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2",
          "cac": "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"}
    subtotals = root.findall(".//cac:TaxTotal/cac:TaxSubtotal", ns)
    assert len(subtotals) == 2
    percents = sorted(st.find("cac:TaxCategory/cbc:Percent", ns).text for st in subtotals)
    assert percents == ["19.00", "7.00"] or percents == ["7.00", "19.00"]
    lines = root.findall(".//cac:InvoiceLine", ns)
    line_percents = [ln.find(".//cbc:Percent", ns).text for ln in lines]
    assert set(line_percents) == {"19.00", "7.00"}


def test_generate_compliant_zugferd_cii_mixed_rates_two_header_taxes():
    xml_str = generate_compliant_zugferd_cii(_mixed_rate_invoice())
    root = ET.fromstring(xml_str.encode("utf-8"))
    ns = {"ram": "urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100"}
    header_taxes = root.findall(
        ".//ram:ApplicableHeaderTradeSettlement/ram:ApplicableTradeTax", ns)
    assert len(header_taxes) == 2