<?php

declare(strict_types=1);

namespace App\Services;

use App\Models\Client;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\RateLimiter;

class LlmService
{
    private const REQUEST_TIMEOUT = 30;  // 请求超时时间（秒）

    /**
     * 发送 LLM 请求
     *
     * @param Client $client 客户
     * @param string $prompt 提示词
     * @param array $options 可选参数
     * @return array{response: string, usage: array}
     * @throws \RuntimeException
     */
    public function sendRequest(Client $client, string $prompt, array $options = []): array
    {
        // 检查请求频率限制
        $key = 'llm_request_' . $client->id;
        if (RateLimiter::tooManyAttempts($key, $client->rate_limit)) {
            $seconds = RateLimiter::availableIn($key);
            throw new \RuntimeException("请求过于频繁，请在 {$seconds} 秒后重试。");
        }

        try {
            /** @var \App\Models\LlmProvider $provider */
            $provider = $client->llmProvider;

            if ($provider->status !== 'active') {
                throw new \RuntimeException('LLM 提供商当前不可用。');
            }

            // 发送请求到 LLM 提供商
            $response = Http::timeout($client->timeout)
                ->withToken($provider->api_token)
                ->withHeaders([
                    'Content-Type' => 'application/json',
                    'Accept' => 'application/json',
                ])
                ->post($provider->api_url, array_merge([
                    'prompt' => $prompt,
                ], $options));

            if (!$response->successful()) {
                Log::error('LLM provider request failed', [
                    'status' => $response->status(),
                    'body' => $response->body(),
                    'provider' => $provider->name,
                    'client_id' => $client->id,
                ]);

                throw new \RuntimeException('LLM 提供商服务异常，请稍后重试。');
            }

            // 记录成功的请求
            RateLimiter::hit($key, 60);

            $result = $response->json();

            return [
                'response' => $result['choices'][0]['text'] ?? $result['response'] ?? '',
                'usage' => $result['usage'] ?? [],
            ];

        } catch (\Illuminate\Http\Client\ConnectionException $e) {
            Log::error('LLM provider connection timeout', [
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
                'provider' => $provider->name ?? null,
                'client_id' => $client->id,
            ]);

            throw new \RuntimeException('LLM 提供商响应超时，请稍后重试。');
        }
    }
}