import re

import numpy as np
import pytest

from pandas._libs.tslibs.timedeltas import delta_to_nanoseconds

from pandas import (
    Timedelta,
    offsets,
)


@pytest.mark.parametrize(
    "obj,expected",
    [
        (np.timedelta64(14, "D"), 14 * 24 * 3600 * 1e9),
        (Timedelta(minutes=-7), -7 * 60 * 1e9),
        (Timedelta(minutes=-7).to_pytimedelta(), -7 * 60 * 1e9),
        (Timedelta(seconds=1234e-9), 1234),  # GH43764, GH40946
        (
            Timedelta(seconds=1e-9, milliseconds=1e-5, microseconds=1e-1),
            111,
        ),  # GH43764
        (
            Timedelta(days=1, seconds=1e-9, milliseconds=1e-5, microseconds=1e-1),
            24 * 3600e9 + 111,
        ),  # GH43764
        (offsets.Nano(125), 125),
        (1, 1),
        (np.int64(2), 2),
        (np.int32(3), 3),
    ],
)
def test_delta_to_nanoseconds(obj, expected):
    result = delta_to_nanoseconds(obj)
    assert result == expected


def test_delta_to_nanoseconds_error():
    obj = np.array([123456789], dtype="m8[ns]")

    with pytest.raises(TypeError, match="<class 'numpy.ndarray'>"):
        delta_to_nanoseconds(obj)


def test_huge_nanoseconds_overflow():
    # GH 32402
    assert delta_to_nanoseconds(Timedelta(1e10)) == 1e10
    assert delta_to_nanoseconds(Timedelta(nanoseconds=1e10)) == 1e10


@pytest.mark.parametrize(
    "kwargs", [{"Seconds": 1}, {"seconds": 1, "Nanoseconds": 1}, {"Foo": 2}]
)
def test_kwarg_assertion(kwargs):
    err_message = (
        "cannot construct a Timedelta from the passed arguments, "
        "allowed keywords are "
        "[weeks, days, hours, minutes, seconds, "
        "milliseconds, microseconds, nanoseconds]"
    )

    with pytest.raises(ValueError, match=re.escape(err_message)):
        Timedelta(**kwargs)