<?php

namespace Tests\Unit\Scheduling;

use App\Scheduling\Cascade;
use Carbon\CarbonImmutable;
use Tests\TestCase; // Laravel TestCase: Eloquent date-casts need the connection grammar even in memory

class CascadeTest extends TestCase
{
    private function daysBefore(array $points, CarbonImmutable $due): array
    {
        return array_map(fn (CarbonImmutable $p) => (int) round($p->diffInDays($due)), $points);
    }

    public function test_no_preparation_gives_no_points(): void
    {
        $due = CarbonImmutable::parse('2026-08-14', 'UTC');
        $this->assertSame([], Cascade::points($due, $due));
    }

    public function test_halving_points(): void
    {
        $due = CarbonImmutable::parse('2026-09-30', 'UTC');

        $this->assertSame([1], $this->daysBefore(Cascade::points($due->subDay(), $due), $due));
        $this->assertSame([7, 3, 1], $this->daysBefore(Cascade::points($due->subDays(7), $due), $due));
        $this->assertSame([30, 15, 7, 3, 1], $this->daysBefore(Cascade::points($due->subDays(30), $due), $due));
        $this->assertSame([60, 30, 15, 7, 3, 1], $this->daysBefore(Cascade::points($due->subDays(60), $due), $due));
        $this->assertSame([180, 90, 45, 22, 11, 5, 2, 1], $this->daysBefore(Cascade::points($due->subDays(180), $due), $due));
    }

    public function test_points_are_local_midnights_ascending(): void
    {
        $due = CarbonImmutable::parse('2026-09-30', 'Asia/Shanghai');
        $points = Cascade::points($due->subDays(7), $due);

        $this->assertSame('2026-09-23 00:00 Asia/Shanghai', $points[0]->format('Y-m-d H:i e'));
        $this->assertSame('2026-09-29 00:00 Asia/Shanghai', $points[2]->format('Y-m-d H:i e'));
    }
}