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

use Ds\Map;
use Ds\Seq;
use Ds\Set;
use Kadet\Functional\Collections as c;

class CollectorsTest extends \PHPUnit\Framework\TestCase
{
    private static function gen(iterable $entries): \Generator
    {
        foreach ($entries as $key => $value) {
            yield $key => $value;
        }
    }

    public function testKeyByLastWins()
    {
        $map = c\keyBy(fn ($v) => $v['id'])([['id' => 1, 'n' => 'a'], ['id' => 2, 'n' => 'b'], ['id' => 1, 'n' => 'c']]);

        $this->assertInstanceOf(Map::class, $map);
        $this->assertSame(2, $map->count());
        $this->assertSame('c', $map->get(1)['n']);
        $this->assertSame([1, 2], $map->keys()->toArray());
    }

    public function testKeyBySelectorReceivesKey()
    {
        $map = c\keyBy(fn ($v, $k) => $k . $v)(['a' => 'x']);

        $this->assertSame(['ax' => 'x'], $map->toArray());
    }

    public function testKeyByAcceptsInternalFunction()
    {
        $this->assertSame(['A' => 'a'], c\keyBy(strtoupper(...))(['a'])->toArray());
    }

    public function testGroupByKeepsOrderAndUsesSeq()
    {
        $map = c\groupBy(fn ($v) => $v % 2)([1, 2, 3, 4]);

        $this->assertEquals(new Map([1 => new Seq([1, 3]), 0 => new Seq([2, 4])]), $map);
        $this->assertSame([1, 0], $map->keys()->toArray());
        $this->assertInstanceOf(Seq::class, $map->get(1));
    }

    public function testToSeqDropsKeys()
    {
        $this->assertSame([1, 2], c\toSeq()(['a' => 1, 'b' => 2])->toArray());
    }

    public function testToMapPreservesGeneratorKeys()
    {
        $key = new \stdClass();
        $map = c\toMap()((static function () use ($key) {
            yield 'a' => 1;
            yield 5 => 2;
            yield $key => 3;
        })());

        $this->assertInstanceOf(Map::class, $map);
        $this->assertSame(1, $map->get('a'));
        $this->assertSame(2, $map->get(5));
        $this->assertSame(3, $map->get($key));
    }

    public function testToSet()
    {
        $set = c\toSet()(['a' => 1, 'b' => 1, 'c' => 2]);

        $this->assertInstanceOf(Set::class, $set);
        $this->assertSame([1, 2], $set->toArray());
    }

    public function testToArrayPreservesKeys()
    {
        $this->assertSame(['a' => 1, 5 => 2], c\toArray()(self::gen(['a' => 1, 5 => 2])));
        $this->assertSame(['a' => 1], c\toArray()(new Map(['a' => 1])));
        $this->assertSame([1, 2], c\toArray()(new Seq([1, 2])));
    }

    public function testToArrayRejectsObjectKeys()
    {
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('toArray(): key of type stdClass cannot be an array key');

        $map = new Map();
        $map->put(new \stdClass(), 1);

        c\toArray()($map);
    }

    public function testCollectorsAcceptLazyInput()
    {
        $map = c\keyBy(fn ($v) => $v * 10)(self::gen([1, 2]));

        $this->assertSame([10 => 1, 20 => 2], $map->toArray());
        $this->assertSame([0 => [1, 3], 1 => [2, 4]], c\groupBy(fn ($v) => $v % 2 ? 0 : 1)(self::gen([1, 2, 3, 4]))->map(fn ($k, $v) => $v->toArray())->toArray());
    }
}