from datetime import date

import pytest

from finbot.parser import parse_date_hint, parse_expense

TODAY = date(2026, 8, 15)  # a Saturday


class TestParseDateHint:
    def test_defaults_to_today(self):
        resolved, span = parse_date_hint("coffee 250", TODAY)
        assert resolved == TODAY
        assert span is None

    @pytest.mark.parametrize(
        "text,expected",
        [
            ("lunch yesterday", date(2026, 8, 14)),
            ("coffee today", TODAY),
            ("dinner day before yesterday", date(2026, 8, 13)),
            ("paid 3 days ago", date(2026, 8, 12)),
            ("rent on 2026-08-01", date(2026, 8, 1)),
            ("bought 12 aug", date(2026, 8, 12)),
            ("bought aug 12", date(2026, 8, 12)),
        ],
    )
    def test_resolves(self, text, expected):
        resolved, span = parse_date_hint(text, TODAY)
        assert resolved == expected
        assert span is not None

    def test_future_dates_roll_back_a_year(self):
        # "12 dec" typed in August means last December, not a future spend.
        resolved, _ = parse_date_hint("gift 12 dec", TODAY)
        assert resolved == date(2025, 12, 12)

    def test_bare_weekday_means_the_most_recent_past_one(self):
        # TODAY is a Saturday; "friday" is yesterday.
        resolved, _ = parse_date_hint("drinks friday", TODAY)
        assert resolved == date(2026, 8, 14)

    def test_same_weekday_goes_back_a_full_week(self):
        resolved, _ = parse_date_hint("shopping saturday", TODAY)
        assert resolved == date(2026, 8, 8)

    def test_day_first_preferred_for_ambiguous_slashes(self):
        resolved, _ = parse_date_hint("paid 03/04", TODAY)
        assert resolved == date(2026, 4, 3)

    def test_falls_back_to_month_first_when_day_first_impossible(self):
        # 25 is not a month, so 12/25 can only be December 25th.
        resolved, _ = parse_date_hint("gift 12/25", TODAY)
        assert resolved == date(2025, 12, 25)

    def test_invalid_date_does_not_crash(self):
        resolved, _ = parse_date_hint("paid 2026-02-30", TODAY)
        assert resolved == TODAY


class TestParseExpense:
    def test_returns_none_without_an_amount(self):
        assert parse_expense("hello there", "INR", TODAY) is None

    def test_returns_none_for_empty(self):
        assert parse_expense("", "INR", TODAY) is None
        assert parse_expense("   ", "INR", TODAY) is None

    def test_simple_entry(self):
        draft = parse_expense("coffee 250", "INR", TODAY)
        assert draft is not None
        assert draft.amount_minor == 25000
        assert draft.currency == "INR"
        assert "coffee" in draft.description
        assert draft.category == "food_dining"
        assert draft.occurred_on == TODAY

    def test_strips_the_amount_from_the_description(self):
        draft = parse_expense("₹1,200 groceries at bigbasket", "INR", TODAY)
        assert draft is not None
        assert "1" not in draft.description
        assert "₹" not in draft.description
        assert draft.category == "groceries"

    def test_strips_filler_words(self):
        draft = parse_expense("spent 500 on dinner", "INR", TODAY)
        assert draft is not None
        assert draft.description == "dinner"

    def test_date_phrase_leaves_the_description(self):
        draft = parse_expense("45.50 lunch yesterday", "INR", TODAY)
        assert draft is not None
        assert draft.occurred_on == date(2026, 8, 14)
        assert "yesterday" not in draft.description
        assert draft.description == "lunch"

    def test_hashtag_overrides_the_keyword_guess(self):
        draft = parse_expense("320 lunch #transport", "INR", TODAY)
        assert draft is not None
        # "lunch" would normally be food_dining; the tag wins.
        assert draft.category == "transport"
        assert "#" not in draft.description

    def test_unknown_hashtag_falls_back_to_other(self):
        draft = parse_expense("100 thing #nonsense", "INR", TODAY)
        assert draft is not None
        assert draft.category == "other"

    def test_explicit_currency_beats_the_default(self):
        draft = parse_expense("€40 dinner", "INR", TODAY)
        assert draft is not None
        assert draft.currency == "EUR"
        assert draft.amount_minor == 4000

    def test_description_never_empty(self):
        draft = parse_expense("250", "INR", TODAY)
        assert draft is not None
        assert draft.description == "unlabelled"

    def test_keeps_the_raw_input(self):
        draft = parse_expense("  coffee 250  ", "INR", TODAY)
        assert draft is not None
        assert draft.raw == "coffee 250"


class TestZeroAmounts:
    """Zero is not an expense -- otherwise ordinary sentences get logged."""

    @pytest.mark.parametrize("text", ["question 0", "0", "round 0 of talks", "0.00"])
    def test_zero_is_rejected(self, text):
        assert parse_expense(text, "INR", TODAY) is None

    def test_positive_amounts_still_parse(self):
        assert parse_expense("coffee 1", "INR", TODAY).amount_minor == 100