"""Tests für CSV-Parser Foundation (Issue #21)."""

import pytest

from csv_parser.core import (
    decode_raw_bytes,
    sniff_delimiter,
    parse_csv_sample,
    column_signature,
    headers_signature_match_score,
    get_csv_import_limits,
    iter_csv_dict_rows,
)
from csv_parser.type_converter import convert_value, build_row_after_mapping


def test_decode_bom_utf8():
    raw = "\ufeffa;b;c\n1;2;3".encode("utf-8-sig")
    t = decode_raw_bytes(raw)
    assert not t.startswith("\ufeff")
    assert "a;b;c" in t


def test_sniff_delimiter():
    assert sniff_delimiter("a;b;c;d") == ";"
    assert sniff_delimiter("a,b,c") == ","


def test_parse_csv_sample_header():
    text = "Date;kcal\n2024-01-01;2000\n"
    headers, rows, delim = parse_csv_sample(text, delimiter=";", max_data_rows=3)
    assert headers == ["Date", "kcal"]
    assert delim == ";"
    assert rows[0]["Date"] == "2024-01-01"
    assert rows[0]["kcal"] == "2000"


def test_column_signature_sorted_unique():
    sig = column_signature(["B", "a", "a"])
    assert sig == ["a", "b"]


def test_jaccard():
    s1 = column_signature(["Date", "Calories"])
    s2 = column_signature(["Date", "Calories", "Fat"])
    assert headers_signature_match_score(s1, s2) == pytest.approx(2 / 3)


def test_get_csv_import_limits_default():
    assert get_csv_import_limits(None)["max_rows_per_file"] == 50_000


def test_convert_date_and_kcal_factor():
    d = convert_value("15.01.2024", "date", {"type": "date", "format": "dd.mm.yyyy"})
    assert d.year == 2024 and d.month == 1 and d.day == 15

    k = convert_value("8000", "kcal", {"type": "float", "conversion_factor": 0.239, "decimal_separator": "."})
    assert abs(k - 8000 * 0.239) < 0.01


def test_iter_csv_dict_rows_full_file():
    text = "a;b\n1;2\n3;4\n"
    rows = list(iter_csv_dict_rows(text, ";", has_header=True))
    assert rows == [{"a": "1", "b": "2"}, {"a": "3", "b": "4"}]


def test_build_row_after_mapping():
    csv_row = {"Datum": "01.01.2024", "kj": "4200"}
    fm = {"Datum": "date", "kj": "kcal"}
    tc = {
        "date": {"type": "date", "format": "dd.mm.yyyy"},
        "kcal": {"type": "float", "conversion_factor": 0.239, "decimal_separator": "."},
    }
    out = build_row_after_mapping(csv_row, fm, tc)
    assert out["date"].month == 1
    assert out["kcal"] is not None


def test_build_row_fddb_raw_header_keys_match_normalized_template():
    """FDDB: DictReader liefert deutsche Überschrift, Seed nutzt normalisierten Key."""
    csv_row = {
        "Datum Tag Monat Jahr Stunde Minute": "01.01.2024 8:30",
        "kJ": "42000",
        "Fett (g)": "50",
        "KH (g)": "200",
        "Protein (g)": "100",
    }
    fm = {
        "datum_tag_monat_jahr_stunde_minute": "date",
        "kj": "kcal",
        "fett_g": "fat_g",
        "kh_g": "carbs_g",
        "protein_g": "protein_g",
    }
    tc = {
        "date": {"type": "date", "format": "dd.mm.yyyy HH:MM", "extract": "date_only"},
        "kcal": {
            "type": "float",
            "conversion_factor": 0.239,
            "decimal_separator": ",",
        },
        "fat_g": {"type": "float", "decimal_separator": ","},
        "carbs_g": {"type": "float", "decimal_separator": ","},
        "protein_g": {"type": "float", "decimal_separator": ","},
    }
    out = build_row_after_mapping(csv_row, fm, tc)
    assert out["date"].year == 2024 and out["date"].month == 1 and out["date"].day == 1


def test_convert_date_ddmm_with_seconds():
    d = convert_value(
        "15.01.2024 14:30:00",
        "date",
        {"type": "date", "format": "dd.mm.yyyy HH:MM", "extract": "date_only"},
    )
    assert d.month == 1 and d.day == 15


def test_float_decimal_separator_auto_eu_us():
    assert abs(convert_value("1.234,56", "x", {"type": "float", "decimal_separator": "auto"}) - 1234.56) < 1e-9
    assert abs(convert_value("1,234.56", "x", {"type": "float", "decimal_separator": "auto"}) - 1234.56) < 1e-9
    assert abs(convert_value("1234,5", "x", {"type": "float", "decimal_separator": "auto"}) - 1234.5) < 1e-9


def test_float_flexible_falls_back_to_auto():
    spec = {"type": "float", "decimal_separator": ",", "flexible": True}
    assert abs(convert_value("1234.56", "x", spec) - 1234.56) < 1e-9


def test_date_flexible_iso_while_primary_ddmm():
    spec = {
        "type": "date",
        "format": "dd.mm.yyyy",
        "flexible": True,
        "extract": "date_only",
    }
    d1 = convert_value("2024-03-15", "d", spec)
    d2 = convert_value("15.03.2024", "d", spec)
    assert d1 == d2


def test_date_extra_formats_without_days_in_name():
    spec = {
        "type": "date",
        "format": "yyyy-mm-dd",
        "formats": ["%d.%m.%Y"],
        "extract": "date_only",
    }
    assert convert_value("08.04.2026", "d", spec).day == 8


def test_int_flexible_thousands():
    assert convert_value("1.234", "n", {"type": "int", "flexible": True}) == 1234


def test_datetime_flexible():
    spec = {"type": "datetime", "format": "yyyy-mm-dd HH:MM:SS", "flexible": True}
    dtv = convert_value("15.01.2024 14:30:00", "t", spec)
    assert dtv.month == 1 and dtv.day == 15 and dtv.hour == 14