from dataclasses import dataclass
from datetime import date, timedelta

import pytest

from app.services.calculations import (
    aggregate_week,
    automatic_break_minutes,
    compute_net_minutes,
    cumulative_delta,
    iso_week_bounds,
    parse_time_to_minutes,
    required_break_minutes_for_span,
)


@dataclass
class FakeEntry:
    date: date
    start_minutes: int
    end_minutes: int
    break_minutes: int


def test_compute_net_minutes_and_validation() -> None:
    assert compute_net_minutes(8 * 60, 15 * 60, 30) == 390

    with pytest.raises(ValueError):
        compute_net_minutes(8 * 60, 8 * 60, 0)

    with pytest.raises(ValueError):
        compute_net_minutes(8 * 60, 12 * 60, 300)


def test_parse_time_to_minutes() -> None:
    assert parse_time_to_minutes("08:30") == 510

    with pytest.raises(ValueError):
        parse_time_to_minutes("8:30")


def test_required_break_minutes_follow_german_thresholds() -> None:
    assert required_break_minutes_for_span(6 * 60) == 0
    assert required_break_minutes_for_span((6 * 60) + 1) == 30
    assert required_break_minutes_for_span(9 * 60) == 30
    assert required_break_minutes_for_span((9 * 60) + 1) == 45


def test_automatic_break_minutes_uses_work_span() -> None:
    assert automatic_break_minutes(8 * 60, 14 * 60) == 0
    assert automatic_break_minutes(8 * 60, (14 * 60) + 1) == 30
    assert automatic_break_minutes(8 * 60, 17 * 60) == 30
    assert automatic_break_minutes(8 * 60, (17 * 60) + 1) == 45

    with pytest.raises(ValueError):
        automatic_break_minutes(8 * 60, 8 * 60)


def test_week_aggregation_and_delta() -> None:
    week_start, _ = iso_week_bounds(date(2026, 2, 25))
    entries = [
        FakeEntry(date=week_start, start_minutes=8 * 60, end_minutes=13 * 60, break_minutes=15),
        FakeEntry(date=week_start + timedelta(days=1), start_minutes=9 * 60, end_minutes=14 * 60, break_minutes=30),
    ]

    report = aggregate_week(entries, week_start, weekly_target_minutes=1500)

    assert report["weekly_ist"] == (285 + 270)
    assert report["weekly_soll"] == 1500
    assert report["weekly_delta"] == -945


def test_cumulative_delta_multiple_weeks() -> None:
    first_week_start, _ = iso_week_bounds(date(2026, 2, 2))
    second_week_start = first_week_start + timedelta(days=7)

    entries = [
        FakeEntry(date=first_week_start, start_minutes=8 * 60, end_minutes=13 * 60, break_minutes=0),
        FakeEntry(date=second_week_start, start_minutes=8 * 60, end_minutes=16 * 60, break_minutes=30),
    ]

    result = cumulative_delta(entries, second_week_start, weekly_target_minutes=1500)

    # Woche 1: 300 - 1500, Woche 2: 450 - 1500
    assert result == -2250