use tutor code from rascal project, drop dependency on rascal-tutor prokect and inject screenshotter into the tutor repl command executor

pom.xml

@@ -3,7 +3,7 @@
 
     <groupId>org.rascalmpl</groupId>
     <artifactId>rascal-maven-plugin</artifactId>
-    <version>0.28.0-RC2-SNAPSHOT</version>
+    <version>0.29.0-SNAPSHOT</version>
     <packaging>maven-plugin</packaging>
 
     <scm>
@@ -29,18 +29,15 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.release>11</maven.compiler.release>
     </properties>
 
     <dependencies>
+        <!-- https://mvnrepository.com/artifact/com.google.code.google-collections/google-collect -->
         <dependency>
             <groupId>org.rascalmpl</groupId>
             <artifactId>rascal</artifactId>
-            <version>0.40.6</version>
-        </dependency>
-        <dependency>
-            <groupId>org.rascalmpl</groupId>
-            <artifactId>rascal-tutor</artifactId>
-            <version>0.19.4</version>
+            <version>0.40.7-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.rascalmpl</groupId>
@@ -93,6 +90,17 @@
             <version>4.13.1</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.seleniumhq.selenium</groupId>
+            <artifactId>selenium-java</artifactId>
+            <version>4.22.0</version>
+            <scope>compile</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.seleniumhq.selenium</groupId>
+            <artifactId>selenium-chromium-driver</artifactId>
+            <version>4.22.0</version>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/org/rascalmpl/maven/CompileRascalDocumentation.java

@@ -58,7 +58,7 @@ public class CompileRascalDocumentation extends AbstractMojo
 	private static final String UNEXPECTED_ERROR = "unexpected error during Rascal compiler run";
 	private static final String MAIN_COMPILER_MODULE = "lang::rascal::tutor::Compiler";
 	private static final ISourceLocation[] MAIN_COMPILER_SEARCH_PATH = new ISourceLocation[] {
-		URIUtil.correctLocation("lib", "rascal-tutor", ""),
+		URIUtil.correctLocation("lib", "rascal", "/org/rascalmpl/tutor"),
 		URIUtil.correctLocation("lib", "rascal", ""),
 	};
 

src/main/java/org/rascalmpl/tutor/Screenshotter.java

@@ -0,0 +1,160 @@
+package org.rascalmpl.tutor;
+
+import java.io.File;
+import java.io.IOException;
+import java.time.Duration;
+import java.util.concurrent.TimeUnit;
+
+import org.openqa.selenium.By;
+import org.openqa.selenium.JavascriptExecutor;
+import org.openqa.selenium.OutputType;
+import org.openqa.selenium.WebElement;
+import org.openqa.selenium.chrome.ChromeDriverService;
+import org.openqa.selenium.chrome.ChromeOptions;
+import org.openqa.selenium.remote.RemoteWebDriver;
+import org.openqa.selenium.support.ui.WebDriverWait;
+import org.rascalmpl.tutor.lang.rascal.tutor.repl.ITutorScreenshotFeature;
+import org.rascalmpl.uri.URIResolverRegistry;
+import org.rascalmpl.uri.URIUtil;
+
+import io.usethesource.vallang.ISourceLocation;
+
+/**
+ * This class provides ITutorScreenshotFeature to the tutor code in the Rascal project.
+ * It depends on Selenium at compile-time which takes chrome-driver at run-time which
+ * uses Chrome again.
+ */
+public class Screenshotter implements ITutorScreenshotFeature {
+    private static final String BROWSER_BINARY = System.getProperty("webdriver.chrome.browser");
+    private static final String DRIVER_BINARY = System.getProperty("webdriver.chrome.driver");
+    private final ChromeDriverService service;
+    private final RemoteWebDriver driver; 
+
+    public Screenshotter() throws IOException {
+        String driver = DRIVER_BINARY;
+        String browser = BROWSER_BINARY;
+
+        if (driver == null) {
+            driver = inferChromeDriverBinaryLocation();
+        }
+
+        if (browser == null) {
+            browser = inferChromeBrowserBinaryLocation();
+        }
+
+        if (driver != null && browser != null) {
+            this.service = new ChromeDriverService.Builder()         
+                .usingDriverExecutable(new File(driver))         
+                .usingAnyFreePort()         
+                .build();    
+
+            this.service.start();
+            this.driver = getBrowser(service, browser);
+        }
+        else {
+            this.service = null;
+            this.driver = null;
+            printInfoMessage();
+        }
+    }
+
+    private void printInfoMessage() {
+        System.err.println("INFO: tutor screenshot feature is currently disabled. To enable:");
+        System.err.println("\t* add the folder holding `chromedriver` to your PATH;");
+        System.err.println("\t* add the foldering holding `chrome` or `Google Chrome for Testing` to your PATH;");
+        System.err.println("\t* or use: `-Dwebdriver.chrome.browser=/path/to/chrome -Dwebdriver.chrome.driver/path/to/chromedriver`");
+        System.err.println("INFO: chrome and the chromedriver need to be aligned exactly. See https://googlechromelabs.github.io/chrome-for-testing/");
+    }
+
+    private String inferChromeBrowserBinaryLocation() throws IOException {
+        ISourceLocation pathBrowser = URIUtil.correctLocation("PATH", "", "Google Chrome for Testing");
+
+        if (URIResolverRegistry.getInstance().exists(pathBrowser)) {
+            System.err.println("driver exists: " + pathBrowser);
+            return URIResolverRegistry.getInstance().logicalToPhysical(pathBrowser).getPath();
+        }
+
+        pathBrowser = URIUtil.correctLocation("PATH", "", "chrome");
+        if (URIResolverRegistry.getInstance().exists(pathBrowser)) {
+            System.err.println("driver exists: " + pathBrowser);
+            return URIResolverRegistry.getInstance().logicalToPhysical(pathBrowser).getPath();
+        }
+
+        return null;
+    }
+
+    private String inferChromeDriverBinaryLocation() throws IOException {
+        ISourceLocation pathDriver = URIUtil.correctLocation("PATH", "", "chromedriver");
+
+        if (URIResolverRegistry.getInstance().exists(pathDriver)) {
+            System.err.println("driver exists: " + pathDriver);
+            return URIResolverRegistry.getInstance().logicalToPhysical(pathDriver).getPath();
+        }
+
+        return null;
+    }
+
+    private static RemoteWebDriver getBrowser(ChromeDriverService service, String BROWSER_BINARY) {
+        ChromeOptions options = new ChromeOptions()
+            .setBinary(BROWSER_BINARY)
+            .addArguments("--headless", "--disable-gpu", "--window-size=1900,1200","--ignore-certificate-errors","--disable-extensions","--no-sandbox","--disable-dev-shm-usage")
+            .addArguments("--user-data-dir=/tmp/rascal-config/google-chrome")
+            ;
+
+        RemoteWebDriver driver = new RemoteWebDriver(service.getUrl(), options);
+        driver.manage().timeouts().pageLoadTimeout(Duration.ofSeconds(30));
+        driver.manage().timeouts().implicitlyWait(Duration.ofSeconds(30));
+        driver.manage().timeouts().scriptTimeout(Duration.ofSeconds(60));
+        driver.manage().window().maximize();
+
+        return driver;
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        if (driver != null) {
+            driver.quit();
+        }
+
+        if (service != null) {
+            service.stop();
+        }
+    }
+
+    @Override
+    public String takeScreenshotAsBase64PNG(String url) throws IOException {
+        try {
+            // load the page
+            driver.get(url);
+            driver.manage().window().maximize();
+
+            // wait for page to render completely
+            WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(15));
+            wait.until(webDriver -> "complete".equals(
+                    ((JavascriptExecutor) webDriver).executeScript("return document.readyState")
+            ));
+
+            // also wait for the body to appear completely.
+            WebElement body = wait.until(webDriver -> driver.findElement(By.tagName("body")));
+
+            String previousScreenshot;
+            String currentscreenshot = "";
+            int max = 20;
+
+            // keep taking shots until all visual elements have stopped moving 
+            do {
+                TimeUnit.SECONDS.sleep(1);
+                previousScreenshot = currentscreenshot;
+                currentscreenshot = body.getScreenshotAs(OutputType.BASE64);    
+            } while (previousScreenshot.equals(currentscreenshot) && max-- > 0);
+
+            if (currentscreenshot.isEmpty()) {
+                throw new IOException("screenshot is empty");
+            }
+
+            return currentscreenshot;
+        } catch (InterruptedException e) {
+            throw new IOException("screenshot failure", e);
+        }
+    }
+}

src/main/java/org/rascalmpl/tutor/screenshotter.config

@@ -0,0 +1 @@
+org.rascalmpl.tutor.Screenshotter