import datetime

import pytest
from money.currency import Currency

from xexe.currency_pair import CurrencyPair
from xexe.utils import DateRange, generate_pairs_and_dates_combinations


def test_date_range_breaks_with_reversed_dates():

    with pytest.raises(ValueError):
        DateRange(
            start_date=datetime.date(year=2024, month=1, day=3),
            end_date=datetime.date(year=2024, month=1, day=1),
        )


def test_date_range_generates_proper_dates_when_itered():

    a_range = DateRange(
        start_date=datetime.date(year=2024, month=1, day=1),
        end_date=datetime.date(year=2024, month=1, day=3),
    )

    dates = [a_date for a_date in a_range]

    assert dates[0] == datetime.date(year=2024, month=1, day=1)
    assert dates[1] == datetime.date(year=2024, month=1, day=2)
    assert dates[-1] == datetime.date(year=2024, month=1, day=3)
    assert len(dates) == 3


def test_generate_pair_and_dates_combinations_outputs_correctly():
    date_range = DateRange(
        start_date=datetime.date(year=2024, month=1, day=1),
        end_date=datetime.date(year=2024, month=1, day=3),
    )

    pairs = {
        CurrencyPair(from_currency="USD", to_currency="EUR"),
        CurrencyPair(from_currency="USD", to_currency="GBP"),
        CurrencyPair(from_currency="EUR", to_currency="GBP"),
    }

    combinations = generate_pairs_and_dates_combinations(
        pairs=pairs, date_range=date_range
    )

    assert len(combinations) == 9
    assert len({combination["date"] for combination in combinations}) == 3
    assert len({combination["from_currency"] for combination in combinations}) == 2
    assert len({combination["to_currency"] for combination in combinations}) == 2