require('dotenv').config(); //載入.env環境檔
const { initDrive } = require("./tools/initDrive.js");
const { crawlerFB } = require("./tools/crawlerFB.js");
const { crawlerIG } = require("./tools/crawlerIG.js");

async function crawler () {

    const driver = await initDrive();
    if (!driver) {//driver不存在就結束程式
        return
    }
    //因為有些人是用FB帳號登入IG，為了避免增加FB登出的動作，所以採取先對IG進行爬蟲
    await crawlerIG(driver)
    await crawlerFB(driver)

    driver.quit();
}

crawler()

const fb_username = process.env.FB_USERNAME
const fb_userpass = process.env.FB_PASSWORD
const { By, until } = require('selenium-webdriver') // 從套件中取出需要用到的功能
exports.crawlerFB = crawlerFB;//讓其他程式在引入時可以使用這個函式

// FB有經典版以及新版的區分，兩者的爬蟲路徑不同，我們藉由函式取得各自的路徑
const { fb_head_path, fb_trace_path } = getCrawlerPath();

function getCrawlerPath () {
    if (process.env.FB_VERSION === 'new') {//如果是新版FB
        return {
            "fb_head_path": `//*[contains(@class,"fzdkajry")]`,
            "fb_trace_path": `//*[contains(@class,"knvmm38d")]`
        }
    } else {//如果為設定皆默認為舊版
        return {
            "fb_head_path": `//*[contains(@class,"_1vp5")]`,
            "fb_trace_path": `//*[@id="PagesProfileHomeSecondaryColumnPagelet"]//*[contains(@class,"_4bl9")]`
        }
    }
}

async function crawlerFB(driver) {    
    await loginFacebook(driver)
    const fanpage = "https://www.facebook.com/baobaonevertell/"
    await goFansPage(driver, fanpage)
    await driver.sleep(3000)
    await getTrace(driver)
}

async function loginFacebook(driver) {
    const web = 'https://www.facebook.com/login';//我們要前往FB
    await driver.get(web)//在這裡要用await確保打開完網頁後才能繼續動作

    //填入fb登入資訊
    const fb_email_ele = await driver.wait(until.elementLocated(By.xpath(`//*[@id="email"]`)));
    fb_email_ele.sendKeys(fb_username)
    const fb_pass_ele = await driver.wait(until.elementLocated(By.xpath(`//*[@id="pass"]`)));
    fb_pass_ele.sendKeys(fb_userpass)

    //抓到登入按鈕然後點擊
    const login_elem = await driver.wait(until.elementLocated(By.xpath(`//*[@id="loginbutton"]`)))
    login_elem.click()

    //因為登入這件事情要等server回應，你直接跳轉粉絲專頁會導致登入失敗
    //用登入後才有的元件，來判斷是否登入
    await driver.wait(until.elementLocated(By.xpath(fb_head_path)))
}

async function goFansPage(driver, web_url) {
    //登入成功後要前往粉專頁面
    await driver.get(web_url)
}

async function getTrace(driver) {
    let fb_trace = 0;//這是紀錄FB追蹤人數
    
    //因為考慮到登入之後每個粉專顯示追蹤人數的位置都不一樣，所以就採用全抓在分析    
    const fb_trace_eles = await driver.
        wait(until.elementsLocated(By.xpath(fb_trace_path)))
    for (const fb_trace_ele of fb_trace_eles) {
        const fb_text = await fb_trace_ele.getText()
        if (fb_text.includes('人在追蹤')) {
            fb_trace = fb_text.replace(/\D/g, '')//只取數字
            break
        }
    }
    console.log(`FB追蹤人數：${fb_trace}`)
}

exports.initDrive = initDrive;//讓其他程式在引入時可以使用這個函式

const webdriver = require('selenium-webdriver') // 加入虛擬網頁套件
const chrome = require('selenium-webdriver/chrome');
const options = new chrome.Options();
options.setUserPreferences({ 'profile.default_content_setting_values.notifications': 1 });//因為FB會有notifications干擾到爬蟲，所以要先把它關閉

const path = require('path');//用於處理文件路徑的小工具
const fs = require("fs");//讀取檔案用

async function initDrive () {
    if (!checkDriver()) {// 檢查Driver是否是設定，如果無法設定就結束程式
        return
    }
    
    // 建立這個broswer的類型
    let driver = await new webdriver.Builder().forBrowser("chrome").withCapabilities(options).build();
    
    //考慮到ig在不同螢幕寬度時的Xpath不一樣，所以我們要在這裡設定統一的視窗大小
    await driver.manage().window().setRect({ width: 1280, height: 800, x: 0, y: 0 });

    return driver
}

function checkDriver() {
    try {
        chrome.getDefaultService()//確認是否有預設
    } catch {
        console.warn('找不到預設driver!');
        //'../chromedriver.exe'記得調整成自己的路徑
        const file_path = '../chromedriver.exe'
        //請確認印出來日誌中的位置是否與你路徑相同
        console.log(path.join(__dirname, file_path));
        
        //確認路徑下chromedriver.exe是否存在            
        if (fs.existsSync(path.join(__dirname, file_path))) {
            const service = new chrome.ServiceBuilder(path.join(__dirname, file_path)).build();//設定driver路徑
            chrome.setDefaultService(service);
            console.log('設定driver路徑');
            return true
        } else {
            console.error('無法設定driver路徑');
            return false
        }
    }
    return true
}