<?php

namespace App\Clients;

use App\Services\ConfigService;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\RateLimiter;
use RuntimeException;

class AiClient
{
    private ConfigService $configService;
    private ?array $currentProvider = null;

    public function __construct(ConfigService $configService)
    {
        $this->configService = $configService;
    }

    /**
     * 获取所有配置的 AI 提供商
     */
    public function getProviders(): array
    {
        $providers = $this->configService->get('log_analysis.ai_providers', []);

        // 如果数据库没有配置，使用 .env 默认配置
        if (empty($providers)) {
            $envConfig = config('services.ai');
            if (!empty($envConfig['api_key'])) {
                $providers = [
                    'default' => [
                        'name' => '默认 (环境变量)',
                        'endpoint' => $envConfig['endpoint'],
                        'api_key' => $envConfig['api_key'],
                        'model' => $envConfig['model'],
                        'temperature' => $envConfig['temperature'],
                        'timeout' => $envConfig['timeout'],
                        'max_tokens' => $envConfig['max_tokens'],
                        'enabled' => true,
                    ],
                ];
            }
        }

        return $providers;
    }

    /**
     * 获取当前激活的 AI 提供商
     */
    public function getActiveProvider(): ?array
    {
        if ($this->currentProvider !== null) {
            return $this->currentProvider;
        }

        $activeKey = $this->configService->get('log_analysis.active_ai_provider');
        $providers = $this->getProviders();

        if ($activeKey && isset($providers[$activeKey]) && ($providers[$activeKey]['enabled'] ?? true)) {
            $this->currentProvider = $providers[$activeKey];
            $this->currentProvider['key'] = $activeKey;
            return $this->currentProvider;
        }

        // 返回第一个启用的提供商
        foreach ($providers as $key => $provider) {
            if ($provider['enabled'] ?? true) {
                $this->currentProvider = $provider;
                $this->currentProvider['key'] = $key;
                return $this->currentProvider;
            }
        }

        return null;
    }

    /**
     * 设置当前使用的提供商
     */
    public function setActiveProvider(string $providerKey): void
    {
        $providers = $this->getProviders();
        if (!isset($providers[$providerKey])) {
            throw new RuntimeException("AI 提供商不存在: {$providerKey}");
        }

        $this->configService->set('log_analysis.active_ai_provider', $providerKey);
        $this->currentProvider = $providers[$providerKey];
        $this->currentProvider['key'] = $providerKey;
    }

    /**
     * 检查是否已配置
     */
    public function isConfigured(): bool
    {
        return $this->getActiveProvider() !== null;
    }

    /**
     * 发送聊天请求 (OpenAI 兼容接口)
     *
     * @param array $messages 消息数组
     * @param string|null $systemPrompt 系统提示词
     * @return string AI 响应内容
     */
    public function chat(array $messages, ?string $systemPrompt = null): string
    {
        $provider = $this->getActiveProvider();
        if (!$provider) {
            throw new RuntimeException('未配置 AI 服务，请在设置页面配置 AI 提供商');
        }

        // 速率限制
        $this->waitForRateLimit($provider['key'] ?? 'default');

        $allMessages = [];
        if ($systemPrompt) {
            $allMessages[] = ['role' => 'system', 'content' => $systemPrompt];
        }
        $allMessages = array_merge($allMessages, $messages);

        $endpoint = rtrim($provider['endpoint'], '/') . '/chat/completions';

        $response = Http::timeout($provider['timeout'] ?? 120)
            ->withHeaders([
                'Authorization' => 'Bearer ' . $provider['api_key'],
                'Content-Type' => 'application/json',
            ])
            ->post($endpoint, [
                'model' => $provider['model'],
                'messages' => $allMessages,
                'temperature' => $provider['temperature'] ?? 0.3,
                'max_tokens' => $provider['max_tokens'] ?? 4096,
            ]);

        if (!$response->successful()) {
            $error = $response->json('error.message') ?? $response->body();
            throw new RuntimeException("AI 请求失败: {$error}");
        }

        return $response->json('choices.0.message.content', '');
    }

    /**
     * 分析日志并返回结构化结果
     *
     * @param string $logsContent 日志内容
     * @param string|null $codeContext 相关代码上下文
     * @return array 分析结果
     */
    public function analyzeLogs(string $logsContent, ?string $codeContext = null): array
    {
        $systemPrompt = $this->buildAnalysisSystemPrompt();
        $userContent = $this->buildAnalysisUserPrompt($logsContent, $codeContext);

        $response = $this->chat([
            ['role' => 'user', 'content' => $userContent],
        ], $systemPrompt);

        return $this->parseAnalysisResponse($response);
    }

    /**
     * 测试连接
     */
    public function testConnection(): array
    {
        $provider = $this->getActiveProvider();
        if (!$provider) {
            return [
                'success' => false,
                'message' => '未配置 AI 服务',
            ];
        }

        try {
            $response = $this->chat([
                ['role' => 'user', 'content' => 'Hello, please respond with "OK" only.'],
            ]);

            return [
                'success' => true,
                'message' => '连接成功',
                'provider' => $provider['name'] ?? $provider['key'],
                'model' => $provider['model'],
            ];
        } catch (\Exception $e) {
            return [
                'success' => false,
                'message' => $e->getMessage(),
            ];
        }
    }

    private function buildAnalysisSystemPrompt(): string
    {
        return <<<'PROMPT'
你是一个专业的日志分析专家。你的任务是分析提供的日志内容，识别异常和问题，并给出分类和建议。

请按照以下 JSON 格式返回分析结果：
{
  "core_anomalies": [
    {
      "type": "error|warning|performance|security",
      "classification": "database|network|application|configuration|resource|other",
      "count": 数量,
      "sample": "示例日志内容",
      "possible_cause": "可能的原因",
      "suggestion": "建议的解决方案"
    }
  ],
  "summary": "整体分析摘要",
  "impact": "high|medium|low",
  "trends": "趋势分析（可选）"
}

分类说明：
- type: error(错误), warning(警告), performance(性能问题), security(安全问题)
- classification: database(数据库), network(网络), application(应用逻辑), configuration(配置), resource(资源), other(其他)
- impact: high(高影响), medium(中等影响), low(低影响)

请确保返回有效的 JSON 格式。
PROMPT;
    }

    private function buildAnalysisUserPrompt(string $logsContent, ?string $codeContext): string
    {
        $prompt = "请分析以下日志内容：\n\n```\n{$logsContent}\n```";

        if ($codeContext) {
            $prompt .= "\n\n相关代码上下文：\n\n```\n{$codeContext}\n```";
        }

        return $prompt;
    }

    private function parseAnalysisResponse(string $response): array
    {
        // 尝试提取 JSON
        if (preg_match('/\{[\s\S]*}/', $response, $matches)) {
            $json = $matches[0];
            $decoded = json_decode($json, true);
            if (json_last_error() === JSON_ERROR_NONE) {
                return $decoded;
            }
        }

        // 如果无法解析 JSON，返回原始响应
        return [
            'core_anomalies' => [],
            'summary' => $response,
            'impact' => 'unknown',
            'raw_response' => $response,
        ];
    }

    private function waitForRateLimit(string $providerKey): void
    {
        $key = "ai_rate_limit:{$providerKey}";

        // 每分钟最多 60 次请求
        $maxAttempts = 60;
        $decaySeconds = 60;

        if (RateLimiter::tooManyAttempts($key, $maxAttempts)) {
            $seconds = RateLimiter::availableIn($key);
            sleep($seconds);
        }

        RateLimiter::hit($key, $decaySeconds);
    }
}