import axios from 'axios';
import * as cheerio from 'cheerio';
import fs from 'fs/promises';
import path from 'path';
import { fileURLToPath } from 'url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const BASE_URL = 'http://120.236.48.169:89/HPMS/';
const START_URL = BASE_URL + 'ProjectInfoList.aspx';

// XML Encode
function xmlEncode(text) {
    return text.replace(/&/g, '&amp;').replace(/</g, '&lt;');
}

async function getEncryptedUrl(relativeUrl, origin) {
    if (!relativeUrl) {
        return '';
    }
    const urlParts = relativeUrl.split('?');
    if (urlParts.length < 2) {
        return new URL(relativeUrl, origin).href;
    }

    const path = urlParts[0];
    const queryString = urlParts[1];

    const xmlPayload = `<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<param funname="SouthDigital.BasicFun.MyEncrypt.DefaultEncrypt">
<item>${xmlEncode(queryString)}</item>
</param>`;

    const encryptionUrl = new URL('/Common/Agents/ExeFunCommon.aspx', origin).href;

    try {
        const response = await axios.post(encryptionUrl, xmlPayload, {
            headers: {
                'Content-Type': 'application/xml',
                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36',
            }
        });
        const encryptedQuery = response.data;
        if (encryptedQuery) {
            return `${new URL(path, origin).href}?${encodeURIComponent(encryptedQuery)}`;
        }
    } catch (error) {
        console.error(`加密链接失败: ${relativeUrl}`, error.message);
    }

    // Fallback to original url on error
    return new URL(relativeUrl, origin).href;
}


// 从HTML中提取表格数据的函数
async function extractDataFromHtml($, origin) {
    const rows = $('.resultlist table tr:has(td)').get();

    const dataPromises = rows.map(async (row) => {
        const columns = $(row).find('td');
        if (columns.length < 4) {
            return null;
        }

        const projectNameCell = $(columns[1]);
        const projectNameLink = projectNameCell.find('a');

        const rowData = {
            '序号': $(columns[0]).text().trim(),
            '项目名称': projectNameLink.length ? projectNameLink.text().trim() : projectNameCell.text().trim(),
            '开发企业': $(columns[2]).text().trim(),
            '项目地址': $(columns[3]).text().trim(),
            '项目链接': '',
        };

        if (projectNameLink.length) {
            const onclickAttr = projectNameLink.attr('onclick');
            if (onclickAttr) {
                const match = onclickAttr.match(/open_click\(['"]([^'"]+)['"]\)/);
                if (match && match[1]) {
                    rowData['项目链接'] = await getEncryptedUrl(match[1], origin);
                }
            }
        }
        return rowData;
    });

    const data = await Promise.all(dataPromises);
    return data.filter(item => item !== null);
}

/**
 * 抓取网站所有数据，处理分页
 * @returns {Promise<Array<Object>>} - 所有抓取的数据记录数组
 */
async function scrapeWebsite() {
    let allData = [];
    console.log('开始抓取第一页数据...');
    const origin = new URL(START_URL).origin;

    let response = await axios.get(START_URL, {
        headers: {
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36'
        }
    });

    let $ = cheerio.load(response.data);
    let firstPageData = await extractDataFromHtml($, origin);
    allData = allData.concat(firstPageData);
    console.log(`第一页抓取完成，获得 ${allData.length} 条数据。`);

    // 获取总页数
    const pageCountSpan = $('#PageNavigator1_LblPageCount');
    const totalPages = pageCountSpan.length ? parseInt(pageCountSpan.text(), 10) : 1;
    console.log(`共发现 ${totalPages} 页。`);

    // 收集表单数据，用于POST请求
    const formValues = {};
    $('input[name^="txt"], select').each((idx, el) => {
        const name = $(el).attr('name');
        if (name) {
            formValues[name] = $(el).val() || '';
        }
    });

    // 抓取其余页面
    for (let i = 2; i <= totalPages; i++) {
        console.log(`正在抓取第 ${i} 页...`);

        const viewState = $('#__VIEWSTATE').val();
        const viewStateGenerator = $('#__VIEWSTATEGENERATOR').val();
        const eventValidation = $('#__EVENTVALIDATION').val();

        if (!viewState) {
            console.log('无法找到 __VIEWSTATE，终止抓取。');
            break;
        }

        const postData = new URLSearchParams();
        postData.append('__EVENTTARGET', 'PageNavigator1$LnkBtnNext');
        postData.append('__EVENTARGUMENT', '');
        postData.append('__VIEWSTATE', viewState);
        postData.append('__VIEWSTATEGENERATOR', viewStateGenerator);
        if (eventValidation) {
            postData.append('__EVENTVALIDATION', eventValidation);
        }

        // 添加表单字段
        for (const name in formValues) {
            postData.append(name, formValues[name]);
        }
        postData.append('PageNavigator1$txtNewPageIndex', (i - 1).toString());

        response = await axios.post(START_URL, postData, {
            headers: {
                'Content-Type': 'application/x-www-form-urlencoded',
                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36',
                'Referer': START_URL,
            }
        });

        $ = cheerio.load(response.data);
        const nextPageData = await extractDataFromHtml($, origin);
        console.log(`第 ${i} 页抓取完成，获得 ${nextPageData.length} 条数据。`);

        if (nextPageData.length === 0) {
            console.log(`第 ${i} 页没有数据，抓取结束。`);
            break;
        }
        allData = allData.concat(nextPageData);
    }
    
    console.log(`\n抓取全站数据完毕！共 ${allData.length} 条原始记录。`);
    return allData;
}

/**
 * 对抓取的数据进行后处理：
 * 1. 重新编号序号字段
 * @param {Array<Object>} allData - 原始抓取数据
 * @returns {Promise<Array<Object>>} - 处理后的数据
 */
async function processScrapedData(allData) {
    // 重新编号序号字段
    for (let i = 0; i < allData.length; i++) {
        allData[i]['序号'] = (i + 1).toString();
    }
    console.log('序号字段已重新编号。');

    return allData;
}

// 主函数
async function main() {
    try {
        const allData = await scrapeWebsite();
        const processedData = await processScrapedData(allData);

        // 保存为JSON文件
        await fs.writeFile(path.join(__dirname, 'data.json'), JSON.stringify(processedData, null, 4), 'utf-8');
        console.log('项目数据已保存至 data.json 文件。');

        console.log('\n所有数据抓取和处理任务已完成。');

    } catch (error) {
        console.error('抓取或处理过程中发生错误:', error.message);
        if (error.response) {
            console.error('Status:', error.response.status);
        }
    }
}

main();