<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Cache;

class AIService
{
    /**
     * 当前使用的服务
     */
    protected $currentService;

    /**
     * 服务配置
     */
    protected $config;

    /**
     * 构造函数
     */
    public function __construct()
    {
        $this->config = config('ai');
        $this->currentService = $this->config['default'];
    }

    /**
     * 聊天对话
     */
    public function chat(array $messages, array $options = []): array
    {
        $cacheKey = $this->getCacheKey('chat', $messages, $options);
        
        // 检查缓存
        if ($this->config['cache']['enabled']) {
            $cached = Cache::get($cacheKey);
            if ($cached) {
                return $cached;
            }
        }

        $result = $this->callService('chat', $messages, $options);

        // 缓存结果
        if ($this->config['cache']['enabled'] && $result['success']) {
            Cache::put($cacheKey, $result, $this->config['cache']['ttl']);
        }

        return $result;
    }

    /**
     * 调用AI服务
     */
    protected function callService(string $action, array $data, array $options = []): array
    {
        $serviceConfig = $this->getServiceConfig();
        
        // 记录请求日志
        if ($this->config['logging']['enabled'] && $this->config['logging']['log_requests']) {
            Log::info('AI服务请求', [
                'service' => $this->currentService,
                'action' => $action,
                'data' => $this->filterSensitiveData($data),
            ]);
        }

        try {
            $response = $this->makeRequest($serviceConfig, $data, $options);
            
            // 记录响应日志
            if ($this->config['logging']['enabled'] && $this->config['logging']['log_responses']) {
                Log::info('AI服务响应', [
                    'service' => $this->currentService,
                    'action' => $action,
                    'response' => $this->filterSensitiveData($response),
                ]);
            }

            return $response;
        } catch (\Exception $e) {
            // 记录错误日志
            if ($this->config['logging']['enabled'] && $this->config['logging']['log_errors']) {
                Log::error('AI服务错误', [
                    'service' => $this->currentService,
                    'action' => $action,
                    'error' => $e->getMessage(),
                ]);
            }

            // 尝试降级服务
            if ($this->config['fallback']['enabled']) {
                return $this->fallbackService($action, $data, $options);
            }

            return [
                'success' => false,
                'error' => 'AI服务暂时不可用: ' . $e->getMessage(),
                'service' => $this->currentService,
            ];
        }
    }

    /**
     * 发送HTTP请求
     */
    protected function makeRequest(array $serviceConfig, array $data, array $options): array
    {
        $url = $serviceConfig['api_url'];
        $timeout = $serviceConfig['timeout'] ?? 30;
        
        $headers = $this->buildHeaders($serviceConfig);
        $body = $this->buildRequestBody($serviceConfig, $data, $options);

        $response = Http::withHeaders($headers)
            ->timeout($timeout)
            ->post($url, $body);

        if ($response->successful()) {
            return $this->parseResponse($serviceConfig, $response->json());
        } else {
            throw new \Exception('API请求失败: ' . $response->status() . ' - ' . $response->body());
        }
    }

    /**
     * 构建请求头
     */
    protected function buildHeaders(array $serviceConfig): array
    {
        $headers = [
            'Content-Type' => 'application/json',
        ];

        switch ($this->currentService) {
            case 'openai':
                $headers['Authorization'] = 'Bearer ' . $serviceConfig['api_key'];
                break;
            case 'azure_openai':
                $headers['api-key'] = $serviceConfig['api_key'];
                break;
            case 'anthropic':
                $headers['x-api-key'] = $serviceConfig['api_key'];
                $headers['anthropic-version'] = '2023-06-01';
                break;
            case 'aliyun_qwen':
                $headers['Authorization'] = 'Bearer ' . $serviceConfig['api_key'];
                break;
        }

        return $headers;
    }

    /**
     * 构建请求体
     */
    protected function buildRequestBody(array $serviceConfig, array $data, array $options): array
    {
        $body = [];

        switch ($this->currentService) {
            case 'openai':
            case 'local':
                $body = [
                    'model' => $serviceConfig['model'],
                    'messages' => $data['messages'] ?? [],
                    'max_tokens' => $options['max_tokens'] ?? $serviceConfig['max_tokens'],
                    'temperature' => $options['temperature'] ?? $serviceConfig['temperature'],
                    'stream' => $options['stream'] ?? false,
                ];
                break;
            case 'azure_openai':
                $body = [
                    'messages' => $data['messages'] ?? [],
                    'max_tokens' => $options['max_tokens'] ?? $serviceConfig['max_tokens'],
                    'temperature' => $options['temperature'] ?? $serviceConfig['temperature'],
                    'stream' => $options['stream'] ?? false,
                ];
                break;
            case 'anthropic':
                $body = [
                    'model' => $serviceConfig['model'],
                    'messages' => $data['messages'] ?? [],
                    'max_tokens' => $options['max_tokens'] ?? $serviceConfig['max_tokens'],
                    'temperature' => $options['temperature'] ?? $serviceConfig['temperature'],
                    'stream' => $options['stream'] ?? false,
                ];
                break;
            case 'aliyun_qwen':
                $body = [
                    'model' => $serviceConfig['model'],
                    'messages' => $data['messages'] ?? [],
                    'max_tokens' => $options['max_tokens'] ?? $serviceConfig['max_tokens'],
                    'temperature' => $options['temperature'] ?? $serviceConfig['temperature'],
                    'stream' => $options['stream'] ?? false,
                ];
                break;
        }

        return $body;
    }

    /**
     * 解析响应
     */
    protected function parseResponse(array $serviceConfig, array $response): array
    {
        switch ($this->currentService) {
            case 'openai':
            case 'azure_openai':
            case 'local':
                $content = $response['choices'][0]['message']['content'] ?? '';
                $tokens = $response['usage']['total_tokens'] ?? 0;
                break;
            case 'anthropic':
                $content = $response['content'][0]['text'] ?? '';
                $tokens = $response['usage']['input_tokens'] + $response['usage']['output_tokens'] ?? 0;
                break;
            case 'aliyun_qwen':
                $content = $response['choices'][0]['message']['content'] ?? '';
                $tokens = $response['usage']['total_tokens'] ?? 0;
                break;
            default:
                $content = '';
                $tokens = 0;
        }

        return [
            'success' => true,
            'content' => $content,
            'tokens' => $tokens,
            'raw_response' => $response,
        ];
    }

    /**
     * 降级服务
     */
    protected function fallbackService(string $action, array $data, array $options): array
    {
        $services = $this->config['fallback']['service_order'];
        $currentIndex = array_search($this->currentService, $services);
        
        if ($currentIndex === false || $currentIndex >= count($services) - 1) {
            return [
                'success' => false,
                'error' => '所有AI服务都不可用',
            ];
        }

        // 切换到下一个服务
        $nextService = $services[$currentIndex + 1];
        $this->currentService = $nextService;
        
        Log::warning('AI服务降级', [
            'from' => $services[$currentIndex],
            'to' => $nextService,
            'action' => $action,
        ]);

        // 重试请求
        return $this->callService($action, $data, $options);
    }

    /**
     * 获取服务配置
     */
    protected function getServiceConfig(): array
    {
        $serviceConfig = $this->config['services'][$this->currentService] ?? [];
        
        if (empty($serviceConfig)) {
            throw new \Exception("AI服务配置不存在: {$this->currentService}");
        }

        return $serviceConfig;
    }

    /**
     * 过滤敏感数据
     */
    protected function filterSensitiveData(array $data): array
    {
        if (!$this->config['security']['filter_sensitive_data']) {
            return $data;
        }

        $filtered = $data;
        $sensitiveKeywords = $this->config['security']['sensitive_keywords'];

        array_walk_recursive($filtered, function (&$value, $key) use ($sensitiveKeywords) {
            foreach ($sensitiveKeywords as $keyword) {
                if (stripos($key, $keyword) !== false || stripos($value, $keyword) !== false) {
                    $value = '***FILTERED***';
                    break;
                }
            }
        });

        return $filtered;
    }

    /**
     * 生成缓存键
     */
    protected function getCacheKey(string $action, array $data, array $options): string
    {
        $prefix = $this->config['cache']['prefix'];
        $hash = md5(serialize([$action, $data, $options, $this->currentService]));
        
        return $prefix . $hash;
    }

    /**
     * 获取当前服务
     */
    public function getCurrentService(): string
    {
        return $this->currentService;
    }

    /**
     * 设置服务
     */
    public function setService(string $service): void
    {
        if (isset($this->config['services'][$service])) {
            $this->currentService = $service;
        } else {
            throw new \Exception("不支持的AI服务: {$service}");
        }
    }

    /**
     * 获取可用服务列表
     */
    public function getAvailableServices(): array
    {
        return array_keys($this->config['services']);
    }

    /**
     * 测试服务连接
     */
    public function testConnection(): array
    {
        try {
            $testMessages = [
                ['role' => 'system', 'content' => '你是一个测试助手'],
                ['role' => 'user', 'content' => '请回复"OK"'],
            ];

            $result = $this->chat($testMessages, [
                'max_tokens' => 10,
                'temperature' => 0.1,
            ]);

            return [
                'success' => $result['success'],
                'service' => $this->currentService,
                'response_time' => '正常',
                'message' => $result['success'] ? '连接正常' : ($result['error'] ?? '连接失败'),
            ];
        } catch (\Exception $e) {
            return [
                'success' => false,
                'service' => $this->currentService,
                'error' => $e->getMessage(),
                'message' => '连接失败',
            ];
        }
    }

    /**
     * 获取服务状态
     */
    public function getServiceStatus(): array
    {
        $services = [];
        
        foreach ($this->config['services'] as $name => $config) {
            $originalService = $this->currentService;
            $this->currentService = $name;
            
            try {
                $testResult = $this->testConnection();
                $services[$name] = [
                    'status' => $testResult['success'] ? 'online' : 'offline',
                    'message' => $testResult['message'],
                ];
            } catch (\Exception $e) {
                $services[$name] = [
                    'status' => 'error',
                    'message' => $e->getMessage(),
                ];
            }
            
            $this->currentService = $originalService;
        }

        return $services;
    }
}