<?php

/*
 * This file is part of the official PHP MCP SDK.
 *
 * A collaboration between Symfony and the PHP Foundation.
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Mcp\Tests\Unit\Client\Transport;

use Mcp\Client\State\ClientState;
use Mcp\Client\Transport\HttpTransport;
use Mcp\Exception\InvalidArgumentException;
use Mcp\Schema\JsonRpc\Error;
use Nyholm\Psr7\Factory\Psr17Factory;
use PHPUnit\Framework\Attributes\TestDox;
use PHPUnit\Framework\TestCase;
use Psr\Http\Client\ClientInterface;
use Psr\Http\Message\StreamInterface;

final class HttpTransportTest extends TestCase
{
    private Psr17Factory $factory;

    protected function setUp(): void
    {
        $this->factory = new Psr17Factory();
    }

    #[TestDox('SSE stream is aborted before the buffer can exceed the configured cap')]
    public function testSseBufferIsBoundedByConfiguredCap(): void
    {
        $transport = $this->createTransport(maxSseBufferBytes: 64);
        $state = new ClientState();
        $state->addPendingRequest(1, 30);
        $transport->setState($state);

        // A server that streams data without ever sending the "\n\n" delimiter.
        $this->setActiveStream($transport, $this->factory->createStream(str_repeat('a', 4096)));

        $this->invokeProcessSseStream($transport);

        self::assertSame('', $this->readPrivate($transport, 'sseBuffer'), 'buffer must be cleared on abort');
        self::assertNull($this->readPrivate($transport, 'activeStream'), 'stream must be released on abort');
    }

    #[TestDox('aborting the SSE stream fails the in-flight request immediately instead of waiting for its timeout')]
    public function testAbortFailsPendingRequestFast(): void
    {
        $transport = $this->createTransport(maxSseBufferBytes: 64);
        $state = new ClientState();
        $state->addPendingRequest(1, 30);
        $transport->setState($state);

        $this->setActiveStream($transport, $this->factory->createStream(str_repeat('a', 4096)));

        $this->invokeProcessSseStream($transport);

        $response = $state->consumeResponse(1);
        self::assertInstanceOf(Error::class, $response);
        self::assertSame(Error::INTERNAL_ERROR, $response->code);
        self::assertSame(1, $response->id);
    }

    #[TestDox('well-formed delimited events are parsed and dispatched')]
    public function testWellFormedEventsStillParse(): void
    {
        $transport = $this->createTransport();
        $messages = [];
        $transport->onMessage(static function (string $message) use (&$messages): void {
            $messages[] = $message;
        });

        $this->setActiveStream($transport, $this->factory->createStream("data: hello\n\ndata: world\n\n"));

        $this->invokeProcessSseStream($transport);

        self::assertSame(['hello', 'world'], $messages);
    }

    #[TestDox('the buffer cap must be a positive number of bytes')]
    public function testRejectsNonPositiveCap(): void
    {
        $this->expectException(InvalidArgumentException::class);

        $this->createTransport(maxSseBufferBytes: 0);
    }

    private function createTransport(int $maxSseBufferBytes = 8 * 1024 * 1024): HttpTransport
    {
        return new HttpTransport(
            endpoint: 'https://example.test/mcp',
            httpClient: $this->createMock(ClientInterface::class),
            requestFactory: $this->factory,
            streamFactory: $this->factory,
            maxSseBufferBytes: $maxSseBufferBytes,
        );
    }

    private function setActiveStream(HttpTransport $transport, StreamInterface $stream): void
    {
        (new \ReflectionProperty($transport, 'activeStream'))->setValue($transport, $stream);
    }

    private function invokeProcessSseStream(HttpTransport $transport): void
    {
        (new \ReflectionMethod($transport, 'processSSEStream'))->invoke($transport);
    }

    private function readPrivate(HttpTransport $transport, string $property): mixed
    {
        return (new \ReflectionProperty($transport, $property))->getValue($transport);
    }
}