Require Extent report to work in Offline Mode entirely due to internet restrictions

Question

I am working on Java Selenium TestNG. Selenium 4.10.0 TestNG 7.8.0

I am trying to generate Extent Reports, but the CSS properties are not loaded, probably because of the internet restrictions I have. The github CDN from which the CSS are taken are blocked in my organization, and would not be whitelisted. Is there a way where I can get the reports working good without internet? Any jars for css,etc are available? Or is there any alternative? Please help!

Note: I cannot use Maven, so all jars must be downloaded and then loaded into my IDE (IntelliJ)

Extent Report dependencies (jar files): extentreports-4.0.9 freemarker-2.3.23 bson-3.3.0 gson-2.8.5 httpclient-4.5.2 httpcore-4.4.4 httpmime-4.5.2 mongodb-driver-3.3.0 mongodb-driver-core-3.3.0 commons-codec-1.9.0 commons-logging-1.2

Code I tried: TestBase.java (Base Class)

package tests;

import com.aventstack.extentreports.ExtentReports;
import com.aventstack.extentreports.ExtentTest;
import org.apache.commons.io.FileUtils;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.edge.EdgeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.testng.ITestContext;
import org.testng.annotations.Listeners;
import utils.ExtentManager;
import utils.ExtentTestManager;
import utils.TestListener;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.time.Duration;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.Set;

@Listeners(TestListener.class)
public class TestBase {
    public static WebDriver driver;
    public static Properties prop;

    public static int TIMEOUT = 60;

    public TestBase() {
        try {
            prop = new Properties();
            FileInputStream fis = new FileInputStream(System.getProperty("user.dir") + "/src/testDAta/config.properties");
            prop.load(fis);
        } catch (Exception e) {
            System.out.println("Exception: " + e.getMessage());
        }
    }

    public void setup(ITestContext context) {
        System.setProperty("webdriver.edge.driver", System.getProperty("user.dir") + prop.getProperty("edge.path"));
        driver = new EdgeDriver();
        driver.manage().window().maximize();
        context.setAttribute("driver", driver);
    }
    public void getURL(String url){
        if (url.equalsIgnoreCase("google")) {
            driver.get(prop.getProperty("web.urlG"));
        } else if (url.equalsIgnoreCase("yahoo")) {
            driver.get(prop.getProperty("web.urlY"));
        } else {
            System.out.println("none!");
        }
    }

    public void waitAndClickElement(WebElement element) {
        WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(TIMEOUT));
        wait.until(ExpectedConditions.elementToBeClickable(element)).click();
    }
    public void waitForElementToAppear(WebElement element){
        WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(TIMEOUT));
        wait.until(ExpectedConditions.visibilityOf(element));
    }

    public void switchWindow(int idx){
        Set<String> allHandles = driver.getWindowHandles();
        List<String> handlesList = new ArrayList<>(allHandles);
        System.out.println("Handles: " + handlesList);
        driver.switchTo().window(handlesList.get(idx));

    }
    public void captureScreenshot(String screenshotName){
        try{
            TakesScreenshot ts = (TakesScreenshot) driver;
            File srcFile = ts.getScreenshotAs(OutputType.FILE);
            String destPath = System.getProperty("user.dir") + "/screenshots/" + screenshotName + ".png";
            File destFile = new File(destPath);
            FileUtils.copyFile(srcFile, destFile);
        }catch (IOException e){
            e.printStackTrace();
        }
    }
}

HomePage.java (PageObject file)

package pages;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;
import tests.TestBase;

public class HomePage extends TestBase {
    public WebDriver driver;
    public HomePage(WebDriver driver){
//        this.driver = driver;
        PageFactory.initElements(driver, this);
    }

    @FindBy(id = "getwebsitebtn")
    WebElement txtLink;

    @FindBy(xpath = "//*[text()='Get Started for Free']")
    WebElement getFreeBtn;

    public void linkTest(){
        waitAndClickElement(txtLink);
        switchWindow(1);
        waitAndClickElement(getFreeBtn);
    }

}

TestFile.java (Test file)

package tests;

import com.aventstack.extentreports.ExtentTest;
import com.aventstack.extentreports.Status;
import org.testng.ITestContext;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
import pages.HomePage;
import utils.ExtentTestManager;

import java.io.IOException;

public class TestFile extends TestBase{


    @BeforeClass
    public void setItUp(ITestContext context){
        setup(context);
    }

    public static ExtentTest extentTest;
    @Test
    public void urlTest() throws IOException {
//        extentTest = ExtentTestManager.getTest();
        // Call the setup method to initialize the driver
//        getURL("Yahoo"); // You can change this to "Google" or other URLs as needed
        extentTest = ExtentTestManager.getTest();
        getURL("Yahoo");

        HomePage hp = new HomePage(driver); // Initialize the HomePage object after the driver is set up
        hp.linkTest();
        extentTest.log(Status.INFO, "Clicked on Links");
        captureScreenshot("snap1");
        System.out.println(System.getProperty("user.dir"));
        extentTest.addScreenCaptureFromPath(System.getProperty("user.dir") + "/screenshots/snap1.png", "snapshot");
        ExtentTestManager.endTest();
    }

}

testng.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="All Test Suite">
    <test verbose="2" preserve-order="true" name="E:/MyCode/frmwrk">
        <classes><class name="tests.TestFile">
            <methods><include name="urlTest"/>
            </methods>
        </class>
        </classes>
    </test>
</suite>

ExtentManager.java

package utils;

import java.io.File;

import com.aventstack.extentreports.ExtentReports;
import com.aventstack.extentreports.reporter.ExtentSparkReporter;
import com.aventstack.extentreports.reporter.configuration.Theme;

public class ExtentManager {
    private static ExtentReports extent;
    private static String reportFileName = "Test-Automaton-Report" + ".html";
    private static String fileSeperator = System.getProperty("file.separator");
    private static String reportFilepath = System.getProperty("user.dir") + fileSeperator + "TestReport";
    private static String reportFileLocation = reportFilepath + fileSeperator + reportFileName;

    public static ExtentReports getInstance() {
        if (extent == null)
            createInstance();
        return extent;
    }

    // Create an extent report instance
    public static ExtentReports createInstance() {
        String fileName = getReportPath(reportFilepath);

        ExtentSparkReporter htmlReporter = new ExtentSparkReporter(fileName);
        htmlReporter.config().setTheme(Theme.DARK);
        htmlReporter.config().setDocumentTitle(reportFileName);
        htmlReporter.config().setReportName(reportFileName);
        htmlReporter.config().setTimeStampFormat("MMM dd, yyyy HH:mm:ss");

        extent = new ExtentReports();
        extent.attachReporter(htmlReporter);

        return extent;
    }

    // Create the report path
    private static String getReportPath(String path) {
        File testDirectory = new File(path);
        if (!testDirectory.exists()) {
            if (testDirectory.mkdir()) {
                System.out.println("Directory: " + path + " is created!");
                return reportFileLocation;
            } else {
                System.out.println("Failed to create directory: " + path);
                return System.getProperty("user.dir");
            }
        } else {
            System.out.println("Directory already exists: " + path);
        }
        return reportFileLocation;
    }
}

ExtentTestManager.java

package utils;

import java.util.HashMap;
import java.util.Map;

import com.aventstack.extentreports.ExtentReports;
import com.aventstack.extentreports.ExtentTest;


public class ExtentTestManager {
    static Map<Long, ExtentTest> extentTestMap = new HashMap<>();
    static ExtentReports extent = ExtentManager.getInstance();

    public static synchronized ExtentTest getTest() {
        return extentTestMap.get(Thread.currentThread().getId());
    }

    public static synchronized void endTest() {
        extent.flush();
    }

    public static synchronized ExtentTest startTest(String testName) {
        ExtentTest test = extent.createTest(testName);
        extentTestMap.put(Thread.currentThread().getId(), test);
        return test;
    }
}

TestListener.java

package utils;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;

import org.apache.commons.io.FileUtils;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.testng.ITestContext;
import org.testng.ITestListener;
import org.testng.ITestResult;

import com.aventstack.extentreports.Status;

import tests.TestBase;
import utils.ExtentManager;
import utils.ExtentTestManager;

public class TestListener extends TestBase implements ITestListener {

    public void onStart(ITestContext context) {
        System.out.println("*** Test Suite " + context.getName() + " started ***");
        System.setProperty("org.freemarker.loggerLibrary", "none");
    }

    public void onFinish(ITestContext context) {
        System.out.println(("*** Test Suite " + context.getName() + " ending ***"));
        ExtentTestManager.endTest();
        ExtentManager.getInstance().flush();
    }

    public void onTestStart(ITestResult result) {
        System.out.println(("*** Running test method " + result.getMethod().getMethodName() + "..."));
        ExtentTestManager.startTest(result.getMethod().getMethodName());
    }

    public void onTestSuccess(ITestResult result) {
        System.out.println("*** Executed " + result.getMethod().getMethodName() + " test successfully...");
        ExtentTestManager.getTest().log(Status.PASS, "Test passed");
    }

    public void onTestFailure(ITestResult result) {
        System.out.println("*** Executed " + result.getMethod().getMethodName() + " test FAILED...");
        ExtentTestManager.getTest().log(Status.FAIL, "Test Failed");
        ExtentTestManager.getTest().fail(result.getThrowable());

        StringWriter sw = new StringWriter();
        result.getThrowable().printStackTrace(new PrintWriter(sw));
        sw = null;

        WebDriver driver = (WebDriver) result.getTestContext().getAttribute("driver");
        String root = System.getProperty("user.dir");
        TakesScreenshot ts = (TakesScreenshot) driver;
        File ss = ts.getScreenshotAs(OutputType.FILE);
        long random = System.currentTimeMillis();
        String des = root + "//target//screenshots//ss" + result.getMethod().getMethodName() + random + ".png";

        try {
            FileUtils.copyFile(ss, new File(des));
        } catch (IOException e) {
            e.printStackTrace();
        }

        ExtentTestManager.getTest().fail("Test skipped");
        try {
            ExtentTestManager.getTest().addScreenCaptureFromPath(des);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }

    public void onTestSkipped(ITestResult result) {
        System.out.println("*** Test " + result.getMethod().getMethodName() + " skipped...");
        ExtentTestManager.getTest().log(Status.SKIP, "Test Skipped");
    }

    public void onTestFailedButWithinSuccessPercentage(ITestResult result) {
        System.out.println("*** Test failed but within percentage % " + result.getMethod().getMethodName());
    }

}