"""Tests for utility functions."""

import pytest

from src.utils import (
    UNECE_UNIT_CODES,
    amounts_match,
    parse_german_date,
    parse_german_number,
    round_decimal,
    translate_unit_code,
)


class TestTranslateUnitCode:
    """Tests for translate_unit_code function."""

    def test_translates_known_codes(self):
        """Test translation of known UN/ECE unit codes."""
        assert translate_unit_code("C62") == "Stück"
        assert translate_unit_code("H87") == "Stück"
        assert translate_unit_code("KGM") == "Kilogramm"
        assert translate_unit_code("GRM") == "Gramm"
        assert translate_unit_code("TNE") == "Tonne"
        assert translate_unit_code("MTR") == "Meter"
        assert translate_unit_code("KMT") == "Kilometer"
        assert translate_unit_code("MTK") == "Quadratmeter"
        assert translate_unit_code("LTR") == "Liter"
        assert translate_unit_code("MLT") == "Milliliter"
        assert translate_unit_code("DAY") == "Tag"
        assert translate_unit_code("HUR") == "Stunde"
        assert translate_unit_code("MON") == "Monat"
        assert translate_unit_code("ANN") == "Jahr"
        assert translate_unit_code("SET") == "Set"
        assert translate_unit_code("PCE") == "Stück"
        assert translate_unit_code("EA") == "Stück"

    def test_returns_original_code_for_unknown(self):
        """Test that unknown codes are returned unchanged."""
        assert translate_unit_code("UNKNOWN") == "UNKNOWN"
        assert translate_unit_code("XYZ") == "XYZ"

    def test_all_unit_codes_defined(self):
        """Verify all 17 unit codes from spec are defined."""
        expected_codes = {
            "C62",
            "H87",
            "KGM",
            "GRM",
            "TNE",
            "MTR",
            "KMT",
            "MTK",
            "LTR",
            "MLT",
            "DAY",
            "HUR",
            "MON",
            "ANN",
            "SET",
            "PCE",
            "EA",
        }
        assert set(UNECE_UNIT_CODES.keys()) == expected_codes


class TestAmountsMatch:
    """Tests for amounts_match function."""

    def test_exact_match(self):
        """Test that exact amounts match."""
        assert amounts_match(100.0, 100.0) is True
        assert amounts_match(123.45, 123.45) is True

    def test_within_tolerance(self):
        """Test amounts within default tolerance match."""
        assert amounts_match(100.00, 100.01) is True
        assert amounts_match(100.00, 99.99) is True
        assert amounts_match(123.45, 123.44) is True
        assert amounts_match(123.45, 123.46) is True

    def test_at_tolerance_boundary(self):
        """Test amounts exactly at tolerance boundary."""
        assert amounts_match(100.00, 100.01) is True  # difference = 0.01
        assert amounts_match(100.01, 100.00) is True  # difference = 0.01

    def test_beyond_tolerance(self):
        """Test amounts beyond tolerance do not match."""
        assert amounts_match(100.00, 100.02) is False
        assert amounts_match(100.00, 99.98) is False
        assert amounts_match(0.00, 0.02) is False

    def test_with_custom_tolerance(self):
        """Test with custom tolerance values."""
        assert amounts_match(100.0, 100.05, tolerance=0.05) is True
        assert amounts_match(100.0, 100.06, tolerance=0.05) is False

    def test_negative_amounts(self):
        """Test with negative amounts."""
        assert amounts_match(-100.00, -100.01) is True
        assert amounts_match(-100.00, -99.99) is True
        assert amounts_match(-100.00, -100.02) is False

    def test_zero_amounts(self):
        """Test with zero amounts."""
        assert amounts_match(0.00, 0.01) is True
        assert amounts_match(0.00, 0.00) is True


class TestParseGermanNumber:
    """Tests for parse_german_number function."""

    def test_integer_without_separator(self):
        """Test parsing integer without separators."""
        assert parse_german_number("123") == 123.0
        assert parse_german_number("0") == 0.0

    def test_decimal_without_thousands(self):
        """Test parsing decimal without thousands separator."""
        assert parse_german_number("123,45") == 123.45
        assert parse_german_number("0,99") == 0.99

    def test_with_thousands_separator(self):
        """Test parsing with German thousands separator (dot)."""
        assert parse_german_number("1.234,56") == 1234.56
        assert parse_german_number("12.345,67") == 12345.67
        assert parse_german_number("123.456,78") == 123456.78

    def test_large_number(self):
        """Test parsing large numbers with multiple thousands separators."""
        assert parse_german_number("1.234.567,89") == 1234567.89

    def test_round_number(self):
        """Test parsing round numbers with decimal zero."""
        assert parse_german_number("1.234,00") == 1234.0

    def test_negative_number(self):
        """Test parsing negative numbers."""
        assert parse_german_number("-1.234,56") == -1234.56
        assert parse_german_number("-123,45") == -123.45


class TestParseGermanDate:
    """Tests for parse_german_date function."""

    def test_standard_date(self):
        """Test parsing standard German date format."""
        assert parse_german_date("04.02.2025") == "2025-02-04"
        assert parse_german_date("01.01.2024") == "2024-01-01"
        assert parse_german_date("31.12.2023") == "2023-12-31"

    def test_single_digit_day_or_month(self):
        """Test with single digit day or month."""
        assert parse_german_date("4.2.2025") == "2025-02-04"
        assert parse_german_date("1.1.2024") == "2024-01-01"
        assert parse_german_date("4.12.2025") == "2025-12-04"
        assert parse_german_date("04.2.2025") == "2025-02-04"

    def test_already_iso_format(self):
        """Test that already ISO formatted dates are returned unchanged."""
        assert parse_german_date("2025-02-04") == "2025-02-04"
        assert parse_german_date("2024-12-31") == "2024-12-31"

    def test_invalid_format(self):
        """Test invalid date formats."""
        assert parse_german_date("invalid") == "invalid"
        assert parse_german_date("01/02/2025") == "01/02/2025"

    def test_only_dots_not_triple(self):
        """Test date with dots but not three parts."""
        assert parse_german_date("01.02") == "01.02"


class TestRoundDecimal:
    """Tests for round_decimal function."""

    def test_default_two_places(self):
        """Test rounding to default 2 decimal places."""
        assert round_decimal(123.456) == 123.46
        assert round_decimal(123.454) == 123.45
        assert round_decimal(123.455) == 123.46  # Standard rounding
        assert round_decimal(123.445) == 123.45  # Standard rounding

    def test_custom_places(self):
        """Test rounding to custom decimal places."""
        assert round_decimal(123.4567, 3) == 123.457
        assert round_decimal(123.4567, 0) == 123.0
        assert round_decimal(123.4567, 4) == 123.4567

    def test_rounding_up(self):
        """Test rounding up cases."""
        assert round_decimal(123.449, 2) == 123.45
        assert round_decimal(123.994, 2) == 123.99

    def test_rounding_down(self):
        """Test rounding down cases."""
        assert round_decimal(123.444, 2) == 123.44
        assert round_decimal(123.004, 2) == 123.0

    def test_negative_numbers(self):
        """Test rounding negative numbers."""
        assert round_decimal(-123.456) == -123.46
        assert round_decimal(-123.454) == -123.45

    def test_zero(self):
        """Test rounding zero."""
        assert round_decimal(0.0) == 0.0
        assert round_decimal(0.004) == 0.0