<?php

declare(strict_types=1);

namespace CondorcetPHP\Condorcet\Tests\Algo\Tools;

use CondorcetPHP\Condorcet\Algo\Tools\Permutations;
use CondorcetPHP\Condorcet\Throwable\Internal\{CondorcetInternalException, IntegerOverflowException};
use PHPUnit\Framework\TestCase;

class PermutationsTest extends TestCase
{
    protected function tearDown(): void
    {
        Permutations::$useBigIntegerIfAvailable = true;
    }

    public function testCountPossiblePermutations(): void
    {
        self::assertSame(6, Permutations::getPossibleCountOfPermutations(3));

        Permutations::$useBigIntegerIfAvailable = false;
        self::assertSame(6, Permutations::getPossibleCountOfPermutations(3));

        $this->expectException(CondorcetInternalException::class);
        Permutations::getPossibleCountOfPermutations(0);
    }

    public function testIntegerOverflowWithBigInt(): void
    {
        $this->expectException(IntegerOverflowException::class);
        Permutations::getPossibleCountOfPermutations(42);
    }

    public function testIntegerOverflowWithoutBigInt(): void
    {
        Permutations::$useBigIntegerIfAvailable = false;

        $this->expectException(IntegerOverflowException::class);
        Permutations::getPossibleCountOfPermutations(42);
    }

    public function testPermutationsAllResultsFor3(): void
    {
        $p = new Permutations([0, 1, 2]);

        $r = $p->getResults();

        self::assertInstanceOf(\SplFixedArray::class, $r);
        self::assertSame(6, $r->getSize());

        self::assertSame(
            [[1=>0, 2=>1, 3=>2],
                [1=>1, 2=>0, 3=>2],
                [1=>1, 2=>2, 3=>0],
                [1=>0, 2=>2, 3=>1],
                [1=>2, 2=>0, 3=>1],
                [1=>2, 2=>1, 3=>0],
            ],
            $r->toArray()
        );
    }

    public function testPermutationsAllResultsFor1(): void
    {
        $p = new Permutations([42]);

        $r = $p->getResults();

        self::assertInstanceOf(\SplFixedArray::class, $r);
        self::assertSame(1, $r->getSize());

        self::assertSame([[1=>42]], $r->toArray());
    }
}