"""Tests for the life-events → cashflow-array helper."""
from __future__ import annotations

import numpy as np
import pytest

from fire_planner.life_events import EventInput, events_to_cashflow_array


def test_empty_events_yield_zero_array() -> None:
    arr = events_to_cashflow_array([], horizon_years=5)
    np.testing.assert_array_equal(arr, np.zeros(5))


def test_one_time_event_lands_at_year_start() -> None:
    arr = events_to_cashflow_array(
        [EventInput(year_start=3, one_time_amount_gbp=250_000)],
        horizon_years=10,
    )
    expected = np.zeros(10)
    expected[3] = 250_000
    np.testing.assert_array_equal(arr, expected)


def test_ranged_delta_applied_inclusive() -> None:
    arr = events_to_cashflow_array(
        [EventInput(year_start=2, year_end=5, delta_gbp_per_year=-10_000)],
        horizon_years=10,
    )
    expected = np.zeros(10)
    expected[2:6] = -10_000  # 2,3,4,5 inclusive
    np.testing.assert_array_equal(arr, expected)


def test_year_end_none_is_one_time() -> None:
    """Ranged events default year_end == year_start."""
    arr = events_to_cashflow_array(
        [EventInput(year_start=4, year_end=None, delta_gbp_per_year=-5_000)],
        horizon_years=10,
    )
    expected = np.zeros(10)
    expected[4] = -5_000
    np.testing.assert_array_equal(arr, expected)


def test_disabled_events_skipped() -> None:
    arr = events_to_cashflow_array(
        [
            EventInput(year_start=0, one_time_amount_gbp=1_000_000, enabled=False),
            EventInput(year_start=1, delta_gbp_per_year=-50_000, year_end=3, enabled=False),
        ],
        horizon_years=5,
    )
    np.testing.assert_array_equal(arr, np.zeros(5))


def test_events_past_horizon_clipped() -> None:
    """Events starting at or beyond the horizon don't apply at all;
    ranged events that overlap the horizon get clipped to the last year."""
    arr = events_to_cashflow_array(
        [
            EventInput(year_start=10, one_time_amount_gbp=100_000),
            EventInput(year_start=8, year_end=15, delta_gbp_per_year=-5_000),
        ],
        horizon_years=10,
    )
    # First event: year 10 is outside (horizon 0..9), so nothing.
    # Second event: clipped to years 8..9.
    expected = np.zeros(10)
    expected[8] = -5_000
    expected[9] = -5_000
    np.testing.assert_array_equal(arr, expected)


def test_multiple_events_sum() -> None:
    arr = events_to_cashflow_array(
        [
            EventInput(year_start=0, year_end=4, delta_gbp_per_year=-12_000),
            EventInput(year_start=2, one_time_amount_gbp=50_000),
            EventInput(year_start=3, delta_gbp_per_year=20_000, year_end=10),
        ],
        horizon_years=10,
    )
    expected = np.zeros(10)
    expected[0:5] += -12_000  # event 1: years 0..4
    expected[2] += 50_000  # event 2: year 2 lump sum
    expected[3:10] += 20_000  # event 3: years 3..9 (clipped from 3..10)
    np.testing.assert_array_equal(arr, expected)


def test_negative_year_start_clipped_to_zero() -> None:
    arr = events_to_cashflow_array(
        [EventInput(year_start=-2, year_end=2, delta_gbp_per_year=-1_000)],
        horizon_years=5,
    )
    expected = np.zeros(5)
    expected[0:3] = -1_000  # 0,1,2
    np.testing.assert_array_equal(arr, expected)


@pytest.mark.parametrize("amount", [0, 0.0, None])
def test_zero_or_none_one_time_amount_skipped(amount: float | None) -> None:
    arr = events_to_cashflow_array(
        [EventInput(year_start=2, one_time_amount_gbp=amount)],
        horizon_years=5,
    )
    np.testing.assert_array_equal(arr, np.zeros(5))