<?php
/**
 * Copyright 2026 Kacper Donat
 *
 * @author Kacper "Kadet" Donat <kacper@kadet.net>
 *
 * Full license available in separate LICENSE file
 */

/*
 * The only test written with the pipe operator, which needs PHP 8.5 to parse. phpunit.xml loads this file only on
 * PHP 8.5 and newer, so the rest of the suite still runs on PHP 8.2-8.4.
 */

use Ds\Map;
use Kadet\Functional\Collections as c;
use Kadet\Functional\Collections\Lazy as lazy;
use Kadet\Functional\Exception\EmptyCollectionException;
use Kadet\Functional\Predicates as p;
use Kadet\Functional\Transforms as t;
use PHPUnit\Framework\Attributes\RequiresPhp;

final class PipeDeparture
{
    public function __construct(
        public readonly string $id,
        public readonly string $line,
        public readonly string $destination,
        public readonly int $delay,
    ) {
    }
}

#[RequiresPhp('>= 8.5')]
class PipeSyntaxTest extends \PHPUnit\Framework\TestCase
{
    /** @return list<PipeDeparture> */
    private static function departures(): array
    {
        return [
            new PipeDeparture('d1', '8', 'Stogi', 0),
            new PipeDeparture('d2', '8', 'Stogi', 120),
            new PipeDeparture('d3', '12', 'Oliwa', 30),
            new PipeDeparture('d4', '12', 'Oliwa', 300),
            new PipeDeparture('d5', '6', 'Łostowice', 0),
        ];
    }

    public function testRealisticPipeline()
    {
        $late = self::departures()
            |> lazy\filter(p\property('delay', p\gt(60)))
            |> c\keyBy(t\property('id'))
            |> c\map(fn (PipeDeparture $departure) => "{$departure->line} → {$departure->destination}");

        $this->assertInstanceOf(Map::class, $late);
        $this->assertSame(['d2' => '8 → Stogi', 'd4' => '12 → Oliwa'], $late->toArray());
    }

    public function testFirstRequired()
    {
        $mostDelayed = self::departures()
            |> c\sortBy(t\property('delay'), descending: true)
            |> c\first(required: true);

        $this->assertSame('d4', $mostDelayed->id);
    }

    public function testFirstRequiredThrowsWhenNothingMatches()
    {
        $this->expectException(EmptyCollectionException::class);
        $this->expectExceptionMessage('first(): no element matched');

        self::departures() |> c\first(p\property('line', p\same('2')), required: true);
    }

    public function testLazyChainReadsOnlyWhatIsNeeded()
    {
        $read = [];

        $line = self::departures()
            |> lazy\tap(function (PipeDeparture $departure) use (&$read) { $read[] = $departure->id; })
            |> lazy\map(t\property('line'))
            |> c\find(fn (string $line) => $line === '12');

        $this->assertSame('12', $line);
        $this->assertSame(['d1', 'd2', 'd3'], $read);
    }
}