<?php

declare(strict_types=1);

namespace Magdev\WcLicensedProductClient\Tests\Security;

use Magdev\WcLicensedProductClient\Security\ResponseSignature;
use PHPUnit\Framework\Attributes\CoversClass;
use PHPUnit\Framework\Attributes\Test;
use PHPUnit\Framework\TestCase;

#[CoversClass(ResponseSignature::class)]
final class ResponseSignatureTest extends TestCase
{
    private const SECRET_KEY = 'test-secret-key-for-unit-tests';
    private const LICENSE_KEY = 'ABCD-1234-EFGH-5678';
    private const SERVER_SECRET = 'server-master-secret';

    #[Test]
    public function itSignsAndVerifiesResponse(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY);
        $timestamp = time();
        $data = ['valid' => true, 'license' => ['product_id' => 123]];

        $sig = $signature->sign($data, $timestamp);

        self::assertTrue($signature->verify($data, $sig, $timestamp));
    }

    #[Test]
    public function itRejectsInvalidSignature(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY);
        $timestamp = time();
        $data = ['valid' => true];

        self::assertFalse($signature->verify($data, 'invalid-signature', $timestamp));
    }

    #[Test]
    public function itRejectsTamperedData(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY);
        $timestamp = time();
        $originalData = ['valid' => true];
        $tamperedData = ['valid' => false];

        $sig = $signature->sign($originalData, $timestamp);

        self::assertFalse($signature->verify($tamperedData, $sig, $timestamp));
    }

    #[Test]
    public function itRejectsExpiredTimestamp(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY, timestampTolerance: 60);
        $oldTimestamp = time() - 120; // 2 minutes ago
        $data = ['valid' => true];

        $sig = $signature->sign($data, $oldTimestamp);

        self::assertFalse($signature->verify($data, $sig, $oldTimestamp));
    }

    #[Test]
    public function itAcceptsTimestampWithinTolerance(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY, timestampTolerance: 300);
        $recentTimestamp = time() - 60; // 1 minute ago
        $data = ['valid' => true];

        $sig = $signature->sign($data, $recentTimestamp);

        self::assertTrue($signature->verify($data, $sig, $recentTimestamp));
    }

    #[Test]
    public function itDerivesUniqueKeysPerLicense(): void
    {
        $key1 = ResponseSignature::deriveKey('LICENSE-001', self::SERVER_SECRET);
        $key2 = ResponseSignature::deriveKey('LICENSE-002', self::SERVER_SECRET);

        self::assertNotSame($key1, $key2);
        self::assertSame(64, strlen($key1)); // SHA256 hex = 64 chars
    }

    #[Test]
    public function itProducesDeterministicKeys(): void
    {
        $key1 = ResponseSignature::deriveKey(self::LICENSE_KEY, self::SERVER_SECRET);
        $key2 = ResponseSignature::deriveKey(self::LICENSE_KEY, self::SERVER_SECRET);

        self::assertSame($key1, $key2);
    }

    #[Test]
    public function itCreatesFromLicenseKey(): void
    {
        $signature = ResponseSignature::fromLicenseKey(self::LICENSE_KEY, self::SERVER_SECRET);
        $timestamp = time();
        $data = ['valid' => true];

        $sig = $signature->sign($data, $timestamp);

        // Verify with same derived key
        $signature2 = ResponseSignature::fromLicenseKey(self::LICENSE_KEY, self::SERVER_SECRET);
        self::assertTrue($signature2->verify($data, $sig, $timestamp));
    }

    #[Test]
    public function itExtractsSignatureFromHeaders(): void
    {
        $headers = [
            'X-License-Signature' => 'abc123',
            'Content-Type' => 'application/json',
        ];

        self::assertSame('abc123', ResponseSignature::extractSignature($headers));
    }

    #[Test]
    public function itExtractsTimestampFromHeaders(): void
    {
        $headers = [
            'X-License-Timestamp' => '1706000000',
            'Content-Type' => 'application/json',
        ];

        self::assertSame(1706000000, ResponseSignature::extractTimestamp($headers));
    }

    #[Test]
    public function itReturnsNullForMissingHeaders(): void
    {
        $headers = ['Content-Type' => 'application/json'];

        self::assertNull(ResponseSignature::extractSignature($headers));
        self::assertNull(ResponseSignature::extractTimestamp($headers));
    }

    #[Test]
    public function itHandlesLowercaseHeaders(): void
    {
        $headers = [
            'x-license-signature' => 'abc123',
            'x-license-timestamp' => '1706000000',
        ];

        self::assertSame('abc123', ResponseSignature::extractSignature($headers));
        self::assertSame(1706000000, ResponseSignature::extractTimestamp($headers));
    }

    #[Test]
    public function itProducesConsistentSignaturesForSameData(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY);
        $timestamp = 1706000000;
        $data = ['b' => 2, 'a' => 1]; // Unsorted

        $sig1 = $signature->sign($data, $timestamp);
        $sig2 = $signature->sign($data, $timestamp);

        self::assertSame($sig1, $sig2);
    }

    #[Test]
    public function itSortsKeysForConsistentSignatures(): void
    {
        $signature = new ResponseSignature(self::SECRET_KEY);
        $timestamp = 1706000000;

        $data1 = ['a' => 1, 'b' => 2];
        $data2 = ['b' => 2, 'a' => 1];

        $sig1 = $signature->sign($data1, $timestamp);
        $sig2 = $signature->sign($data2, $timestamp);

        self::assertSame($sig1, $sig2);
    }
}