<?php

declare(strict_types=1);

namespace Tez\Utils\Tests\Enum;

use PHPUnit\Framework\TestCase;
use Tez\Utils\Enum\BackedEnumTrait;
use Tez\Utils\Enum\BitFlagTrait;

enum Permission: int
{
    use BackedEnumTrait;
    use BitFlagTrait;

    case Read   = 1;
    case Write  = 2;
    case Delete = 4;
    case Admin  = 8;
}

final class BitFlagTraitTest extends TestCase
{
    // -------------------------------------------------------------------------
    // combine()
    // -------------------------------------------------------------------------

    public function testCombineWithNoArgumentsReturnsZero(): void
    {
        self::assertSame(0, Permission::combine());
    }

    public function testCombineWithSingleCase(): void
    {
        self::assertSame(1, Permission::combine(Permission::Read));
    }

    public function testCombineWithTwoCases(): void
    {
        self::assertSame(3, Permission::combine(Permission::Read, Permission::Write));
    }

    public function testCombineWithAllCases(): void
    {
        self::assertSame(15, Permission::combine(
            Permission::Read,
            Permission::Write,
            Permission::Delete,
            Permission::Admin,
        ));
    }

    public function testCombineIsDeduplicated(): void
    {
        self::assertSame(1, Permission::combine(Permission::Read, Permission::Read));
    }

    // -------------------------------------------------------------------------
    // fromBitmask()
    // -------------------------------------------------------------------------

    public function testFromBitmaskWithZeroReturnsEmptyArray(): void
    {
        self::assertSame([], Permission::fromBitmask(0));
    }

    public function testFromBitmaskWithSingleBitReturnsSingleCase(): void
    {
        self::assertSame([Permission::Read], Permission::fromBitmask(1));
    }

    public function testFromBitmaskWithCombinedMaskReturnsMatchingCases(): void
    {
        $mask = Permission::combine(Permission::Read, Permission::Write);

        self::assertSame([Permission::Read, Permission::Write], Permission::fromBitmask($mask));
    }

    public function testFromBitmaskWithAllBitsReturnsAllCases(): void
    {
        $mask = Permission::combine(
            Permission::Read,
            Permission::Write,
            Permission::Delete,
            Permission::Admin,
        );

        self::assertSame(
            [Permission::Read, Permission::Write, Permission::Delete, Permission::Admin],
            Permission::fromBitmask($mask),
        );
    }

    // -------------------------------------------------------------------------
    // isSetIn()
    // -------------------------------------------------------------------------

    public function testIsSetInReturnsTrueWhenBitIsPresent(): void
    {
        $mask = Permission::combine(Permission::Read, Permission::Write);

        self::assertTrue(Permission::Read->isSetIn($mask));
        self::assertTrue(Permission::Write->isSetIn($mask));
    }

    public function testIsSetInReturnsFalseWhenBitIsAbsent(): void
    {
        $mask = Permission::combine(Permission::Read, Permission::Write);

        self::assertFalse(Permission::Delete->isSetIn($mask));
        self::assertFalse(Permission::Admin->isSetIn($mask));
    }

    public function testIsSetInReturnsFalseForZeroMask(): void
    {
        self::assertFalse(Permission::Read->isSetIn(0));
    }

    // -------------------------------------------------------------------------
    // addTo()
    // -------------------------------------------------------------------------

    public function testAddToSetsBit(): void
    {
        $mask = Permission::combine(Permission::Read);
        $mask = Permission::Write->addTo($mask);

        self::assertSame(3, $mask);
        self::assertTrue(Permission::Write->isSetIn($mask));
    }

    public function testAddToIsIdempotent(): void
    {
        $mask = Permission::combine(Permission::Read);
        $mask = Permission::Read->addTo($mask);

        self::assertSame(1, $mask);
    }

    public function testAddToOnEmptyMask(): void
    {
        self::assertSame(4, Permission::Delete->addTo(0));
    }

    // -------------------------------------------------------------------------
    // removeFrom()
    // -------------------------------------------------------------------------

    public function testRemoveFromClearsBit(): void
    {
        $mask = Permission::combine(Permission::Read, Permission::Write);
        $mask = Permission::Write->removeFrom($mask);

        self::assertSame(1, $mask);
        self::assertFalse(Permission::Write->isSetIn($mask));
    }

    public function testRemoveFromIsIdempotent(): void
    {
        $mask = Permission::combine(Permission::Read);
        $mask = Permission::Write->removeFrom($mask);

        self::assertSame(1, $mask);
    }

    public function testRemoveFromOnZeroMaskReturnsZero(): void
    {
        self::assertSame(0, Permission::Read->removeFrom(0));
    }

    // -------------------------------------------------------------------------
    // Workflow: add then remove
    // -------------------------------------------------------------------------

    public function testAddThenRemoveRestoresOriginalMask(): void
    {
        $original = Permission::combine(Permission::Read, Permission::Delete);
        $modified = Permission::Write->addTo($original);
        $restored = Permission::Write->removeFrom($modified);

        self::assertSame($original, $restored);
    }
}