<?php

declare(strict_types=1);

namespace LIT\MCP\Tests\Unit\Integrations\Divi\Release;

use ArrayObject;
use LIT\MCP\Integrations\Divi\Release\Call;
use LIT\MCP\Integrations\Divi\Release\SignatureFingerprint;
use PHPUnit\Framework\TestCase;

/** Stand-in for a Divi class: one baseline method and one variant per property the fingerprint covers. */
final class SignatureFixture
{
    public static function base(int $id, string|array $data = [], &$ref = null, ...$rest): ?bool
    {
        return null;
    }

    /** Same signature, other parameter names and other default values: no change. */
    public static function renamed(int $post, string|array $payload = '', &$out = 5, ...$more): ?bool
    {
        return null;
    }

    public static function extraRequired(int $id, string|array $data, &$ref = null, ...$rest): ?bool
    {
        return null;
    }

    public static function fewer(int $id, string|array $data = []): ?bool
    {
        return null;
    }

    public static function typeChanged(string $id, string|array $data = [], &$ref = null, ...$rest): ?bool
    {
        return null;
    }

    public static function unionWidened(int $id, string|array|int $data = [], &$ref = null, ...$rest): ?bool
    {
        return null;
    }

    public static function notNullable(int $id, string|array $data = [], &$ref = null, ...$rest): bool
    {
        return true;
    }

    public static function byValue(int $id, string|array $data = [], $ref = null, ...$rest): ?bool
    {
        return null;
    }

    public static function notVariadic(int $id, string|array $data = [], &$ref = null, $rest = null): ?bool
    {
        return null;
    }

    public static function defaultRemoved(int $id, string|array $data, &$ref, ...$rest): ?bool
    {
        return null;
    }

    public static function returnChanged(int $id, string|array $data = [], &$ref = null, ...$rest): ?int
    {
        return null;
    }

    public function notStatic(int $id, string|array $data = [], &$ref = null, ...$rest): ?bool
    {
        return null;
    }

    protected static function notPublic(int $id, string|array $data = [], &$ref = null, ...$rest): ?bool
    {
        return null;
    }

    public static function untyped($id, $data = [])
    {
        return null;
    }

    public static function mixedTyped(mixed $id, mixed $data = []): mixed
    {
        return null;
    }
}

final class SignatureFingerprintTest extends TestCase
{
    private const FIXTURE = SignatureFixture::class;

    private static function method(string $name): Call
    {
        return new Call(self::FIXTURE . '::' . $name);
    }

    public function testIsASha256OfAnExistingFunctionAndStable(): void
    {
        $hash = SignatureFingerprint::of(new Call('strlen', 1));

        self::assertMatchesRegularExpression('/^[0-9a-f]{64}$/', (string) $hash);
        self::assertSame($hash, SignatureFingerprint::of(new Call('strlen', 1)));
        self::assertNotSame($hash, SignatureFingerprint::of(new Call('str_replace', 3)));
    }

    public function testMissingSymbolsGiveNull(): void
    {
        self::assertNull(SignatureFingerprint::of(new Call('lit_mcp_missing_function')));
        self::assertNull(SignatureFingerprint::of(new Call('Missing\Klass::run')));
        self::assertNull(SignatureFingerprint::of(new Call(ArrayObject::class . '::missing')));
        self::assertNull(SignatureFingerprint::canonical(new Call('lit_mcp_missing_function')));
    }

    public function testCanonicalTextDescribesTheSignature(): void
    {
        self::assertSame(
            'public static (int, array|string=, &mixed=, ...mixed): ?bool',
            SignatureFingerprint::canonical(self::method('base'))
        );
        self::assertSame('function (string): int', SignatureFingerprint::canonical(new Call('strlen')));
        self::assertSame(
            'public (int, array|string=, &mixed=, ...mixed): ?bool',
            SignatureFingerprint::canonical(self::method('notStatic'))
        );
    }

    /** @return array<string, array{string}> */
    public static function changedSignatures(): array
    {
        return [
            'extra required parameter' => ['extraRequired'],
            'fewer parameters' => ['fewer'],
            'parameter type' => ['typeChanged'],
            'wider union' => ['unionWidened'],
            'return type loses null' => ['notNullable'],
            'by reference lost' => ['byValue'],
            'variadic lost' => ['notVariadic'],
            'default removed' => ['defaultRemoved'],
            'return type' => ['returnChanged'],
            'no longer static' => ['notStatic'],
            'no longer public' => ['notPublic'],
        ];
    }

    /** @dataProvider changedSignatures */
    public function testAnyChangeOfTheInterfaceChangesTheHash(string $variant): void
    {
        self::assertNotSame(
            SignatureFingerprint::of(self::method('base')),
            SignatureFingerprint::of(self::method($variant)),
            $variant
        );
    }

    public function testRenamedParametersAndOtherDefaultValuesKeepTheHash(): void
    {
        self::assertSame(
            SignatureFingerprint::of(self::method('base')),
            SignatureFingerprint::of(self::method('renamed'))
        );
    }

    public function testNoTypeReadsAsMixed(): void
    {
        self::assertSame(
            SignatureFingerprint::of(self::method('untyped')),
            SignatureFingerprint::of(self::method('mixedTyped'))
        );
    }

    public function testTheCallsOwnArgumentCountAndFeaturesAreNotPartOfIt(): void
    {
        self::assertSame(
            SignatureFingerprint::of(new Call(self::FIXTURE . '::base', 2)),
            SignatureFingerprint::of(new Call('\\' . self::FIXTURE . '::base', null, []))
        );
    }

    public function testAFunctionAndAMethodOfTheSameShapeDiffer(): void
    {
        self::assertNotSame(
            SignatureFingerprint::of(new Call('strlen')),
            SignatureFingerprint::of(new Call(ArrayObject::class . '::count'))
        );
    }

    public function testTheClassNeverIncludesAFile(): void
    {
        $source = (string) file_get_contents(
            dirname(__DIR__, 5) . '/src/Integrations/Divi/Release/SignatureFingerprint.php'
        );
        $forbidden = [T_INCLUDE, T_INCLUDE_ONCE, T_REQUIRE, T_REQUIRE_ONCE, T_EVAL];

        foreach (token_get_all($source) as $token) {
            self::assertFalse(is_array($token) && in_array($token[0], $forbidden, true), 'no include, require or eval');
        }
    }
}