<?php

namespace App\Services\Providers;

class ClaudeProvider
{
    public static function stream(string $model, array $messages, array $options, callable $onChunk): void
    {
        $provider = $options['provider'];
        $apiUrl = rtrim($provider['apiUrl'] ?? 'https://api.anthropic.com', '/');
        $apiKey = $provider['apiKey'] ?? '';
        $systemPrompt = $options['systemPrompt'] ?? '';
        $thinkingMode = $options['thinkingMode'] ?? false;

        $url = $apiUrl . '/v1/messages';

        // Claude 的 system 消息通过单独参数传递，从 messages 中排除
        $claudeMessages = array_values(array_filter($messages, function ($msg) {
            return $msg['role'] !== 'system';
        }));

        $bodyData = [
            'model' => $model,
            'max_tokens' => $thinkingMode ? 16000 : 4096,
            'messages' => $claudeMessages,
            'stream' => true
        ];

        if (!empty($systemPrompt)) {
            $bodyData['system'] = $systemPrompt;
        }

        if ($thinkingMode) {
            $bodyData['thinking'] = [
                'type' => 'enabled',
                'budget_tokens' => 10000
            ];
        }

        $body = json_encode($bodyData);

        $headers = [
            'x-api-key: ' . $apiKey,
            'anthropic-version: 2023-06-01',
            'Content-Type: application/json',
            'Accept: text/event-stream'
        ];

        $ch = curl_init($url);
        curl_setopt_array($ch, [
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => $body,
            CURLOPT_HTTPHEADER => $headers,
            CURLOPT_TIMEOUT => 120,
            CURLOPT_RETURNTRANSFER => false,
            CURLOPT_SSL_VERIFYPEER => true,
            CURLOPT_WRITEFUNCTION => function ($ch, $data) use ($onChunk) {
                $lines = explode("\n", $data);
                $currentEvent = '';

                foreach ($lines as $line) {
                    $line = trim($line);
                    if ($line === '') {
                        $currentEvent = '';
                        continue;
                    }
                    if (str_starts_with($line, 'event: ')) {
                        $currentEvent = substr($line, 7);
                        continue;
                    }
                    if (str_starts_with($line, 'data: ')) {
                        $payload = substr($line, 6);
                        $json = json_decode($payload, true);

                        if (!$json) {
                            continue;
                        }

                        switch ($currentEvent) {
                            case 'content_block_delta':
                                if (isset($json['delta'])) {
                                    $delta = $json['delta'];
                                    if (isset($delta['type']) && $delta['type'] === 'thinking_delta' && isset($delta['thinking'])) {
                                        $onChunk($delta['thinking'], 'thinking');
                                    } elseif (isset($delta['text'])) {
                                        $onChunk($delta['text'], 'content');
                                    }
                                }
                                break;
                            case 'message_stop':
                                return strlen($data);
                            case 'error':
                                if (isset($json['error']['message'])) {
                                    throw new \RuntimeException('Claude API错误: ' . $json['error']['message']);
                                }
                                break;
                        }
                    }
                }
                return strlen($data);
            }
        ]);

        $result = curl_exec($ch);
        if ($result === false) {
            $error = curl_error($ch);
            curl_close($ch);
            throw new \RuntimeException('API请求失败: ' . $error);
        }

        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($httpCode >= 400) {
            throw new \RuntimeException('API返回错误，状态码: ' . $httpCode);
        }
    }
}