<?php

declare(strict_types=1);

namespace Weerscherm\Tests;

use PHPUnit\Framework\TestCase;
use Weerscherm\RainCalculator;

final class RainCalculatorTest extends TestCase
{
    private \DateTimeZone $tz;

    protected function setUp(): void
    {
        $this->tz = new \DateTimeZone('Europe/Berlin');
    }

    /** @return array<string, mixed> */
    private function fixture(string $name): array
    {
        return json_decode((string) file_get_contents(__DIR__ . "/fixtures/$name.json"), true)['body'];
    }

    private function now(string $s): \DateTimeImmutable
    {
        return new \DateTimeImmutable($s, $this->tz);
    }

    public function testNormalWeek(): void
    {
        $r = RainCalculator::compute($this->fixture('getmeasure'), $this->now('2026-09-11 14:32'), 9.9);

        self::assertSame(2.4, $r['today']);
        self::assertSame([
            ['date' => '2026-09-08', 'mm' => 1.2],
            ['date' => '2026-09-09', 'mm' => 6.8],
            ['date' => '2026-09-10', 'mm' => 0.0],
        ], $r['previous_days']);
        self::assertEqualsWithDelta(38.5, $r['month_total'], 0.0001);
    }

    public function testMissingPreviousDayIsNullAndExcludedFromTotal(): void
    {
        $body = $this->fixture('getmeasure');
        $sep9 = (string) $this->now('2026-09-09 03:17')->getTimestamp();
        unset($body[$sep9]);

        $r = RainCalculator::compute($body, $this->now('2026-09-11 14:32'), null);

        self::assertNull($r['previous_days'][1]['mm']);
        self::assertSame('2026-09-09', $r['previous_days'][1]['date']);
        self::assertEqualsWithDelta(31.7, $r['month_total'], 0.0001);
    }

    public function testMissingTodayFallsBackToSumRain24(): void
    {
        $body = $this->fixture('getmeasure');
        unset($body[(string) $this->now('2026-09-11 03:17')->getTimestamp()]);

        self::assertSame(2.4, RainCalculator::compute($body, $this->now('2026-09-11 14:32'), 2.4)['today']);
        self::assertNull(RainCalculator::compute($body, $this->now('2026-09-11 14:32'), null)['today']);
    }

    public function testMonthBoundaryKeepsPreviousDaysButNotInMonthTotal(): void
    {
        $r = RainCalculator::compute($this->fixture('getmeasure-month'), $this->now('2026-10-02 09:00'), null);

        self::assertSame(5.0, $r['today']);
        self::assertSame([
            ['date' => '2026-09-29', 'mm' => 2.0],
            ['date' => '2026-09-30', 'mm' => 3.0],
            ['date' => '2026-10-01', 'mm' => 4.0],
        ], $r['previous_days']);
        self::assertEqualsWithDelta(9.0, $r['month_total'], 0.0001);
    }

    public function testDaylightSavingTransitionMapsTimestampsToLocalDates(): void
    {
        $r = RainCalculator::compute($this->fixture('getmeasure-dst'), $this->now('2026-10-25 12:00'), null);

        self::assertSame(4.0, $r['today'], 'meting om 01:30 lokaal (nog zomertijd) hoort bij 25 oktober');
        self::assertSame([
            ['date' => '2026-10-22', 'mm' => 1.0],
            ['date' => '2026-10-23', 'mm' => 2.0],
            ['date' => '2026-10-24', 'mm' => 3.0],
        ], $r['previous_days']);
        self::assertEqualsWithDelta(10.0, $r['month_total'], 0.0001, '26 oktober telt niet mee, ook al ligt de timestamp op 25 oktober in UTC');
    }

    public function testEmptyBodyGivesNulls(): void
    {
        $r = RainCalculator::compute([], $this->now('2026-09-11 14:32'), null);

        self::assertNull($r['today']);
        self::assertSame([null, null, null], array_column($r['previous_days'], 'mm'));
        self::assertNull($r['month_total']);
    }

    public function testDateBeginIsMinOfFirstOfMonthAndThreeDaysAgo(): void
    {
        self::assertSame('2026-09-01 00:00:00', RainCalculator::dateBegin($this->now('2026-09-15 14:32'))->format('Y-m-d H:i:s'));
        self::assertSame('2026-09-29 00:00:00', RainCalculator::dateBegin($this->now('2026-10-02 09:00'))->format('Y-m-d H:i:s'));
        self::assertSame('Europe/Berlin', RainCalculator::dateBegin($this->now('2026-10-02 09:00'))->getTimezone()->getName());
    }
}