<?php

namespace addon\aikefu\event;

use addon\aikefu\model\Config as KefuConfigModel;
use addon\aikefu\model\Conversation as KefuConversationModel;
use addon\aikefu\model\Message as KefuMessageModel;

/**
 * 智能客服流式聊天
 */
class KefuChatStream
{
    /**
     * 处理智能客服流式聊天事件
     * @param array $data 事件数据
     * @return array
     */
    public function handle($data)
    {
        $message = $data['message'] ?? '';
        $user_id = $data['user_id'] ?? '';
        $conversation_id = $data['conversation_id'] ?? '';
        $site_id = $data['site_id'] ?? 0;
        $request_id = $data['request_id'] ?? '';

        try {
            // 验证参数
            if (empty($message)) {
                return [
                    [
                        'type' => 'error',
                        'message' => '消息内容不能为空'
                    ]
                ];
            }

            // 获取智能客服配置
            $kefu_config_model = new KefuConfigModel();
            $config_info = $kefu_config_model->getConfig($site_id)['data']['value'] ?? [];

            if (empty($config_info) || $config_info['status'] != 1) {
                return [
                    [
                        'type' => 'error',
                        'message' => '智能客服暂未启用'
                    ]
                ];
            }

            $config = $config_info;
            $apiKey = $config['api_key'];
            $baseUrl = $config['base_url'];
            $chatEndpoint = $config['chat_endpoint'];

            // 构建请求数据
            $requestData = [
                'inputs' => [],
                'query' => $message,
                'response_mode' => 'streaming',
                'user' => $user_id,
            ];

            if (!empty($conversation_id)) {
                $requestData['conversation_id'] = $conversation_id;
            }

            // 构建请求头
            $headers = [
                'Authorization: Bearer ' . $apiKey,
                'Content-Type: application/json',
                'Accept: text/event-stream',
            ];

            // 发送流式请求到Dify API
            $url = $baseUrl . $chatEndpoint;
            $result = $this->executeStreamRequest($url, $requestData, $headers);

            return $result;

        } catch (\Exception $e) {
            return [
                [
                    'type' => 'error',
                    'message' => '请求失败：' . $e->getMessage()
                ]
            ];
        }
    }

    /**
     * 执行流式请求
     */
    private function executeStreamRequest($url, $requestData, $headers)
    {
        $ch = curl_init();
        
        // 设置curl选项
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($requestData));
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_WRITEFUNCTION, [$this, 'streamCallback']);
        curl_setopt($ch, CURLOPT_TIMEOUT, 120); // 设置较长的超时时间
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);

        // 执行请求
        $result = [];
        $this->stream_buffer = '';
        $this->conversation_id = '';
        $this->current_message_id = '';
        
        $response = curl_exec($ch);
        $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $error = curl_error($ch);
        curl_close($ch);

        if ($response === false || !empty($error)) {
            return [
                [
                    'type' => 'error',
                    'message' => '请求失败：' . $error
                ]
            ];
        }

        if ($http_code >= 400) {
            return [
                [
                    'type' => 'error',
                    'message' => '服务端错误，HTTP状态码：' . $http_code
                ]
            ];
        }

        return $this->parseStreamResponse($this->stream_buffer);
    }

    /**
     * 流式回调函数
     */
    private function streamCallback($ch, $data)
    {
        $this->stream_buffer .= $data;
        return strlen($data);
    }

    /**
     * 解析流式响应
     */
    private function parseStreamResponse($response)
    {
        $result = [];
        $lines = explode("\n", $response);
        $conversation_id = '';
        $message_id = '';
        $buffer = '';

        foreach ($lines as $line) {
            $line = trim($line);
            
            if (empty($line)) {
                continue;
            }

            if (strpos($line, 'data: ') === 0) {
                $data_str = substr($line, 6);
                
                if ($data_str === '[DONE]') {
                    // 流结束，发送完成事件
                    $result[] = [
                        'type' => 'complete',
                        'conversation_id' => $conversation_id,
                        'message_id' => $message_id,
                        'content' => $buffer,
                        'finished' => true
                    ];
                    break;
                }

                $data = json_decode($data_str, true);
                if (json_last_error() === JSON_ERROR_NONE && isset($data)) {
                    // 提取会话ID和消息ID
                    if (isset($data['conversation_id'])) {
                        $conversation_id = $data['conversation_id'];
                    }
                    if (isset($data['message_id'])) {
                        $message_id = $data['message_id'];
                    }

                    // 处理内容块
                    if (isset($data['answer'])) {
                        $buffer .= $data['answer'];
                        $result[] = [
                            'type' => 'chunk',
                            'content' => $data['answer'],
                            'conversation_id' => $conversation_id,
                            'message_id' => $message_id,
                            'finished' => false
                        ];
                    }

                    // 检查是否结束
                    if (isset($data['finish_reason']) && $data['finish_reason'] !== 'null') {
                        $result[] = [
                            'type' => 'complete',
                            'conversation_id' => $conversation_id,
                            'message_id' => $message_id,
                            'content' => $buffer,
                            'finish_reason' => $data['finish_reason'],
                            'usage' => $data['usage'] ?? [],
                            'finished' => true
                        ];
                        break;
                    }
                }
            }
        }

        // 如果没有收到[DONE]信号，确保发送完成事件
        if (empty($result) || end($result)['type'] !== 'complete') {
            $result[] = [
                'type' => 'complete',
                'conversation_id' => $conversation_id,
                'message_id' => $message_id,
                'content' => $buffer,
                'finished' => true
            ];
        }

        return $result;
    }
}