<?php

declare(strict_types=1);

namespace app\common\service {
    function curl_init(): \stdClass
    {
        return (object) ['options' => [], 'errno' => 0];
    }

    function curl_setopt_array(\stdClass $handle, array $options): bool
    {
        $handle->options = $options;
        return true;
    }

    function curl_exec(\stdClass $handle): string|bool
    {
        $GLOBALS['streamDeliveryExecuting'] = true;
        $options = $handle->options;
        $options[CURLOPT_HEADERFUNCTION]($handle, 'HTTP/1.1 ' . $GLOBALS['streamDeliveryStatus'] . " Fixture\r\n");
        foreach ($GLOBALS['streamDeliveryChunks'] as [$chunk, $expectedDeltas]) {
            $written = $options[CURLOPT_WRITEFUNCTION]($handle, $chunk);
            \deliveryExpect(count($GLOBALS['streamDeliveryDeltas']) === $expectedDeltas,
                'each complete upstream frame reaches the consumer before the next network read');
            if ($written !== strlen($chunk)) {
                $handle->errno = CURLE_WRITE_ERROR;
                break;
            }
        }
        $GLOBALS['streamDeliveryExecuting'] = false;
        return $handle->errno === 0 ? '' : false;
    }

    function curl_errno(\stdClass $handle): int { return $handle->errno; }
    function curl_getinfo(\stdClass $handle, int $option): int { return $GLOBALS['streamDeliveryStatus']; }
    function curl_close(\stdClass $handle): void {}
}

namespace {
    require dirname(__DIR__) . '/vendor/autoload.php';

    use app\common\service\DifyChatService;

    function deliveryExpect(bool $condition, string $message): void
    {
        if (!$condition) {
            fwrite(STDERR, "FAIL: {$message}\n");
            exit(1);
        }
    }

    function deliverFixture(string $protocol, array $chunks, int $status = 200, bool $accept = true): array
    {
        $GLOBALS['streamDeliveryStatus'] = $status;
        $GLOBALS['streamDeliveryChunks'] = $chunks;
        $GLOBALS['streamDeliveryDeltas'] = [];
        $method = (new ReflectionClass(DifyChatService::class))->getMethod('sendStreamRequest');
        return $method->invoke(null, $protocol, 'https://offline.example.test', [], 'offline-fixture', 30,
            static function (string $delta) use ($accept): bool {
                deliveryExpect($GLOBALS['streamDeliveryExecuting'], 'delta callback runs during curl_exec, before transfer completion');
                $GLOBALS['streamDeliveryDeltas'][] = $delta;
                return $accept;
            }, null);
    }

    $dify = deliverFixture('dify', [
        ["data: {\"event\":\"message\",\"answer\":\"首\"}\r\n", 0],
        ["\r\n", 1],
        ["data: {\"event\":\"message\",\r\ndata: \"answer\":\"字\"}\r\n\r\n", 2],
        ["data: {\"event\":\"message_end\"}\r\n\r\n", 2],
    ]);
    deliveryExpect($dify['content'] === '首字' && $dify['finished'], 'Dify streams complete frames in order');

    $openAi = deliverFixture('openai', [
        ["data: {\"choices\":[{\"delta\":{\"content\":\"A\"}}]}\n\n", 1],
        ["data: {\"choices\":[{\"delta\":{\"content\":\"B\"}}]}\n\n", 2],
        ["data: [DONE]\n\n", 2],
    ]);
    deliveryExpect($openAi['content'] === 'AB' && $openAi['finished'], 'OpenAI streams complete frames in order');

    $rejected = deliverFixture('dify', [
        ["data: {\"event\":\"message\",\"answer\":\"private upstream error\"}\n\n", 0],
    ], 401);
    deliveryExpect(!$rejected['emitted'] && $rejected['content'] === '', 'HTTP errors never become downstream text');

    $aborted = deliverFixture('dify', [
        ["data: {\"event\":\"message\",\"answer\":\"first\"}\n\n", 1],
        ["data: {\"event\":\"message\",\"answer\":\"late\"}\n\n", 2],
    ], 200, false);
    deliveryExpect($aborted['callback_error'] && $GLOBALS['streamDeliveryDeltas'] === ['first'],
        'consumer refusal stops the current transfer before another delta');

    echo "Dify chat stream delivery: OK\n";
}