import axios from './axios.js';
import * as cheerio from 'cheerio';
import fs from 'fs/promises';
import path from 'path';
import { fileURLToPath } from 'url'; // Add fileURLToPath import
import { getEncryptedUrl } from './getEncryptedUrl.js'; // Import shared encryption function

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

const BASE_URL = 'http://120.236.48.169:89/HEMS/';
const START_URL = BASE_URL + 'CompanyList.aspx';

/**
 * Extracts company data from HTML content.
 * @param {object} $ - Cheerio object.
 * @param {string} origin - The origin URL for resolving relative links.
 * @returns {Promise<Array<Object>>} - An array of company data records.
 */
async function extractDataFromHtml($, origin) {
    const dataPromises = $('.resultlist table tr:has(td)').get().map(async (row) => {
        const columns = $(row).find('td');
        if (columns.length < 5) { // Expecting 5 columns: 序号, 营业执照注册号, 企业名称, 法人代表, 地址
            return null;
        }

        const companyNameCell = $(columns[2]); // 企业名称 is the 3rd column
        const companyNameLink = companyNameCell.find('a');

        const rowData = {
            '序号': $(columns[0]).text().trim(),
            '营业执照注册号': $(columns[1]).text().trim(),
            '企业名称': companyNameLink.length ? companyNameLink.text().trim() : companyNameCell.text().trim(),
            '法人代表': $(columns[3]).text().trim(),
            '地址': $(columns[4]).text().trim(),
            '企业链接': '', // Initialize
        };

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

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

/**
 * Scrapes all company data from the target website, handling pagination.
 * @returns {Promise<Array<Object>>} - An array of all scraped data records.
 */
async function scrapeWebsite() {
    let allData = [];
    const origin = new URL(START_URL).origin;

    console.log('开始抓取公司列表第一页数据...');
    let response = await axios.get(START_URL);

    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 ${firstPageData.length} 条数据。`);

    // Get total pages for pagination
    const totalRecordsSpan = $('#PageNavigator1_LblRecordCount');
    const totalPagesSpan = $('#PageNavigator1_LblPageCount');

    const totalRecords = totalRecordsSpan.length ? parseInt(totalRecordsSpan.text(), 10) : 0;
    const totalPages = totalPagesSpan.length ? parseInt(totalPagesSpan.text(), 10) : 1;
    console.log(`共发现 ${totalRecords} 条记录，分为 ${totalPages} 页。`);

    // Collect form data for POST requests
    const formValues = {};
    $('input[name^="txt"], select').each((idx, el) => {
        const name = $(el).attr('name');
        if (name) {
            formValues[name] = $(el).val() || '';
        }
    });

    // Scrape remaining pages
    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);
        }
        
        // Add form fields
        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',
                '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抓取全站公司数据完毕！共 ${allData.length} 条原始记录。`);
    return allData;
}

/**
 * Performs post-processing on the scraped data:
 * 1. Re-indexes "序号" sequentially.
 * @param {Array<Object>} allData - The raw scraped data.
 * @returns {Array<Object>} - The processed data.
 */
function processScrapedData(allData) {
    // Re-index "序号" sequentially
    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;
}

// Main function to orchestrate the scraping and saving process
export async function main() {
    try {
        console.log('🚀 开始抓取普宁房地产开发企业列表...');
        const allData = await scrapeWebsite();
        const processedData = processScrapedData(allData);

        const dataPath = path.join(__dirname, '..', 'data', 'companies.json');
        await fs.mkdir(path.dirname(dataPath), { recursive: true }); // Ensure data directory exists
        await fs.writeFile(dataPath, JSON.stringify(processedData, null, 4), 'utf-8');
        console.log(`✅ 公司列表数据已保存至 data/companies.json 文件。`);

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

    } catch (error) {
        console.error('❌ 抓取或处理公司列表过程中发生错误:', error.message);
        if (error.response) {
            console.error('Status:', error.response.status);
            console.error('Data:', error.response.data);
        }
        process.exit(1); // Exit with error code
    }
}

// Self-execution logic
if (__filename === process.argv[1]) {
    main();
}