<?php

namespace App\Services\LLM;

use App\Models\LlmMessage;
use App\Models\LlmSession;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Str;

class DeepSeekService
{
    public static function streamedResponseChat($llmConfig, $message, $sessionId = null): void
    {
        ini_set('output_buffering', 'off');

        $headers = [
            'Authorization' => 'Bearer ' . $llmConfig['key'],
            'Content-Type' => 'application/json',
        ];
        $body = [
            'model' => $llmConfig['model'],
            'messages' => $message,
            'stream' => true,
            'max_tokens' => 8192,
            'temperature' => 0.6,
            'top_p' => 0.7,
            "top_k"=> 50,
            "frequency_penalty" => 2
        ];

        // 保存用户消息
        $session = self::saveUserMessage($message, $sessionId, $llmConfig['model']);

        // 3. 调用DeepSeek流式API
        $response = Http::withHeaders($headers)->timeout(300)->send('POST', $llmConfig['base_url'] , [
            'json' => $body,
            'stream' => true, // 启用Guzzle流式接收
        ]);

        // 4. 流式转发数据
        $body = $response->toPsrResponse()->getBody();
        $buffer = '';
        $saveContent = '';
        $saveReasoningContent = '';
        while (true) {
            if ($body->eof() || !$body->isReadable()) {
                break;
            }
            $chunk = $body->read(500);
            $buffer .= $chunk;

            // 处理SSE事件分割
            while (($pos = strpos($buffer, "\n\n")) !== false) {
                $event = substr($buffer, 0, $pos);
                $buffer = substr($buffer, $pos + 2);

                // 解析并输出内容
                $startStr = 'data: ';
                if (str_starts_with($event, $startStr)) {
                    $jsonEvent = substr($event, strlen($startStr));
                    if ($jsonEvent === '[DONE]') {
                        break;
                    }

                    try {
                        $data = json_decode($jsonEvent, true, 512, JSON_THROW_ON_ERROR);
                        $reasoningContent = $data['choices'][0]['delta']['reasoning_content'] ?? '';
                        $content = $data['choices'][0]['delta']['content'] ?? '';
                        $saveContent.= $content;
                        $saveReasoningContent.= $reasoningContent;
                        if ($reasoningContent !== '') {
                            echo "data: " . json_encode(['reasoning_content' => $reasoningContent], JSON_UNESCAPED_UNICODE) . "\n\n";
                            ob_flush();
                            flush();
                        }
                        if ($content === '') {
                            break;
                        }
                        echo "data: " . json_encode(['content' => $content], JSON_UNESCAPED_UNICODE) . "\n\n";
                        ob_flush();
                        flush();
                    } catch (\JsonException $e) {
                        Log::error('JSON 解析失败: ' . $e->getMessage());
                    }
                }
            }
            // 与客户端连接关闭时
            if (connection_aborted()) {
                break;
            }
        }

        echo "data: [DONE]\n";
        ob_flush();
        flush();
        ob_end_flush();

        // 保存模型回复
        self::saveAssistantMessage($session->id, $saveContent, $saveReasoningContent);
    }

    /**
     * 保存用户消息并创建或获取会话
     */
    private static function saveUserMessage($messages, $sessionId = null, $model = null)
    {
        // 获取最后一条用户消息
        $userMessage = end($messages);

        // 创建或获取会话
        if (!$sessionId) {
            $title = mb_substr($userMessage['content'], 0, 50) . (mb_strlen($userMessage['content']) > 50 ? '...' : '');
            $session = LlmSession::create([
                'session_id' => Str::uuid(),
                'user_id' => Auth::id() ?? 0,
                'model' => $model,
                'title' => $title,
            ]);
        } else {
            $session = LlmSession::where('session_id', $sessionId)->firstOrFail();
            $session->updated_at = now();
            $session->save();
        }

        // 保存用户消息
        LlmMessage::create([
            'session_id' => $session->id,
            'role' => 'user',
            'content' => $userMessage['content'],
        ]);

        return $session;
    }

    /**
     * 保存模型回复
     */
    private static function saveAssistantMessage($sessionId, $content, $reasoningContent = null)
    {
        return LlmMessage::create([
            'session_id' => $sessionId,
            'role' => 'assistant',
            'content' => trim($content),
            'reasoning_content' => trim($reasoningContent),
        ]);
    }
}