'use strict';
const axios = require('axios');
const DOCUMENT_EXTENSIONS = ['pdf', 'doc', 'docx'];
const IMAGE_EXTENSIONS = ['jpg', 'jpeg', 'png', 'webp'];

class AiDify {
    /**
     * 构造函数
     * @param {object} config
     * @param {string} config.apiKey - Dify API Key
     * @param {string} config.chatflowId - ChatFlow ID
     * @param {string} [config.baseUrl=https://api.dify.ai/v1] - Dify API 接口地址
     */
    constructor({ apiKey = 'app-fiJr1pNxjdKXpetko8ANawnY', chatflowId = '', baseUrl = 'http://workflow.smartcost.com.cn/v1' }) {
        if (!apiKey) {
            throw new Error('apiKey 不能为空');
        }

        this.apiKey = apiKey;
        this.chatflowId = chatflowId;
        this.baseUrl = baseUrl;
    }

    /**
     * 向 ChatFlow 发送请求
     * @param {string} userInput - 用户输入内容
     * @param {string} [userId='user_123'] - 用户 ID
     * @returns {Promise<object>} - Dify 返回的对象
     */
    async ask(userInput, userId = 'user_123') {
        const url = `${this.baseUrl}/chat-messages`;
        const headers = {
            'Authorization': `Bearer ${this.apiKey}`,
            'Content-Type': 'application/json',
        };

        const body = {
            inputs: {}, // 如果你的 ChatFlow 有 schema，可填写 key-value
            query: userInput,
            response_mode: 'blocking',
            user: userId,
            conversation_id: this.chatflowId,
        };

        try {
            const res = await axios.post(url, body, { headers });
            return res.data;
        } catch (err) {
            console.error('Dify 请求失败:', err.response || err.response.data || err.message);
            throw new Error('Dify 请求失败');
        }
    }

    async workflows(body) {
        const url = `${this.baseUrl}/workflows/run`;
        const headers = {
            'Authorization': `Bearer ${this.apiKey}`,
            'Content-Type': 'application/json',
        };
        try {
            const res = await axios.post(url, body, { headers });
            return res.data.data.outputs;
        } catch (err) {
            console.error('Dify 请求失败:', err.response || err.response.data || err.message);
            throw new Error('Dify 请求失败');
        }
    }

    async posCalcDetailRead(col, billsName, keyword, files, userId = `user_123`) {
        const body = {
            inputs: {
                header: col.map(x => { return x.title + (x.unit ? `(${x.unit})` : '') }).join('，'),
                billsName,
                keyword,
                imgList: [],
            },
            user: userId,
        };
        for (const f of files) {
            body.inputs.imgList.push({
                type: "image",
                transfer_method: "remote_url",
                url: f.viewpath,
            })
        }
        return await this.workflows(body);
    }

    async imageTransExcel(files, userId = `user_123`) {
        const body = {
            inputs: { imgList: [] },
            user: userId,
            response_mode: 'blocking',
        };
        for (const f of files) {
            body.inputs.imgList.push({
                type: "image",
                transfer_method: "remote_url",
                url: f.viewpath,
            })
        }
        return await this.workflows(body);
    }

    async billsIdentify(name, unit, userId = `user_123`) {
        const body = {
            inputs: { billsName: name || '' + ( unit ? `(${unit})` : '') },
            user: userId,
            response_mode: 'blocking',
        };
        return await this.workflows(body);
    }

    /**
     * 根据文件名后缀判断 Dify 的 type 字段（image / document）
     */
    resolveDifyFileType(filename = '') {
        const ext = filename ? filename.split('.').pop().toLowerCase() : '';
        if (IMAGE_EXTENSIONS.includes(ext)) return 'image';
        if (DOCUMENT_EXTENSIONS.includes(ext)) return 'document';
        // 无法判断时默认按document处理，让Dify那边自行兜底
        return 'document';
    }

    async contractTrans(file, userId = 'user_123') {
        const body = {
            inputs: { fileList: [] },
            user: userId,
            response_mode: 'blocking',
        };
        if (!file.viewpath) {
            throw new Error('文件缺少viewpath字段');
        }
        const fileType = this.resolveDifyFileType(file.filename);
        body.inputs.fileList.push({
            type: fileType,
            transfer_method: 'remote_url',
            url: file.viewpath,
        });
        return await this.workflows(body);
    }
}

module.exports = AiDify;