// 获取环境变量的服务端函数
const getServerEnvVar = (name: string, defaultValue: string = '') => {
    const value = process.env[name] || defaultValue;
    // console.log(`🌐 [DifyClient] 读取环境变量 ${name}:`, {
    //     hasValue: !!process.env[name],
    //     value: process.env[name] ? `${process.env[name].substring(0, 20)}...` : 'undefined',
    //     usingDefault: !process.env[name]
    // });
    return value;
};

// Dify API 客户端配置
const DIFY_CONFIG = {
    API_URL: getServerEnvVar('NEXT_PUBLIC_API_URL', 'https://api.dify.ai/v1'),
    API_KEY: getServerEnvVar('NEXT_PUBLIC_APP_KEY', ''),
    APP_ID: (() => {
        const rawAppId = getServerEnvVar('NEXT_PUBLIC_APP_ID', '');
        // 从完整URL中提取APP ID
        const match = rawAppId.match(/\/app\/([a-f0-9-]{36})/);
        return match ? match[1] : rawAppId;
    })(),
};

console.log('🔧 Dify Client Config:', {
    apiUrl: DIFY_CONFIG.API_URL,
    appId: DIFY_CONFIG.APP_ID,
    hasApiKey: !!DIFY_CONFIG.API_KEY,
    configComplete: !!(DIFY_CONFIG.API_URL && DIFY_CONFIG.APP_ID && DIFY_CONFIG.API_KEY)
});

// 基础请求函数
const difyFetch = async (endpoint: string, options: RequestInit = {}) => {
    const url = `${DIFY_CONFIG.API_URL}/${endpoint.replace(/^\//, '')}`;

    const headers = {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${DIFY_CONFIG.API_KEY}`,
        ...options.headers,
    };

    // console.log('🌐 Dify API Request:', {
    //     url,
    //     method: options.method || 'GET',
    //     hasAuth: !!DIFY_CONFIG.API_KEY
    // });

    const response = await fetch(url, {
        ...options,
        headers,
    });

    if (!response.ok) {
        const errorText = await response.text();
        console.error('❌ Dify API Error:', {
            status: response.status,
            statusText: response.statusText,
            error: errorText
        });
        throw new Error(`Dify API Error: ${response.status} ${response.statusText}`);
    }

    return response;
};

// 生成用户ID
const generateUserId = (sessionId: string) => {
    return `user_${DIFY_CONFIG.APP_ID}:${sessionId}`;
};

// Dify API 客户端
export const difyClient = {
    // 获取应用参数
    async getApplicationParameters(user: string) {
        const response = await difyFetch('parameters', {
            method: 'GET',
            headers: {
                'Authorization': `Bearer ${DIFY_CONFIG.API_KEY}`,
            },
        });
        return response.json();
    },

    // 获取会话列表
    async getConversations(user: string) {
        const params = new URLSearchParams({
            user,
            limit: '100',
            first_id: '',
        });

        const response = await difyFetch(`conversations?${params}`, {
            method: 'GET',
        });
        return response.json();
    },

    // 获取会话消息
    async getConversationMessages(user: string, conversationId: string) {
        const params = new URLSearchParams({
            user,
            conversation_id: conversationId,
            limit: '20',
            last_id: '',
        });

        const response = await difyFetch(`messages?${params}`, {
            method: 'GET',
        });
        return response.json();
    },

    // 发送聊天消息
    async createChatMessage(
        inputs: Record<string, any>,
        query: string,
        user: string,
        responseMode: string = 'streaming',
        conversationId?: string,
        files?: any[]
    ) {
        const body = {
            inputs,
            query,
            user,
            response_mode: responseMode,
            conversation_id: conversationId,
            files: files || [],
        };

        console.log('🌐 [DifyClient] 发送聊天消息:', {
            queryLength: query.length,
            queryPreview: query.substring(0, 100) + (query.length > 100 ? '...' : ''),
            user,
            responseMode,
            conversationId,
            hasInputs: !!inputs && Object.keys(inputs).length > 0,
            inputsKeys: inputs ? Object.keys(inputs) : [],
            hasFiles: !!files && files.length > 0,
            filesCount: files?.length || 0
        });

        const response = await difyFetch('chat-messages', {
            method: 'POST',
            body: JSON.stringify(body),
        });

        console.log('📡 [DifyClient] Dify API响应:', {
            status: response.status,
            statusText: response.statusText,
            hasBody: !!response.body,
            contentType: response.headers.get('Content-Type'),
            responseMode
        });

        // 对于流式响应，直接返回Response对象
        if (responseMode === 'streaming') {
            console.log('🌊 [DifyClient] 返回流式响应对象');
            return response;
        }

        console.log('📄 [DifyClient] 解析JSON响应');
        return response.json();
    },

    // 重命名会话
    async renameConversation(conversationId: string, name: string, user: string, autoGenerate: boolean = false) {
        const body = {
            name,
            auto_generate: autoGenerate,
            user,
        };

        const response = await difyFetch(`conversations/${conversationId}/name`, {
            method: 'POST',
            body: JSON.stringify(body),
        });
        return response.json();
    },

    // 删除会话
    async deleteConversation(conversationId: string, user: string) {
        const body = {
            user,
        };

        const response = await difyFetch(`conversations/${conversationId}`, {
            method: 'DELETE',
            body: JSON.stringify(body),
        });
        return response.json();
    },

    // 更新消息反馈
    async updateMessageFeedback(messageId: string, rating: 'like' | 'dislike' | null, user: string) {
        const body = {
            rating,
            user,
        };

        const response = await difyFetch(`messages/${messageId}/feedbacks`, {
            method: 'POST',
            body: JSON.stringify(body),
        });
        return response.json();
    },
};

// 工具函数
export const difyUtils = {
    generateUserId,
    getConfig: () => DIFY_CONFIG,
};