package org.argeo.cms.ui.script;
   
   import java.io.IOException;
   import java.io.InputStreamReader;
   import java.io.Reader;
   import java.net.URL;
   
   import javax.jcr.Repository;
   import javax.script.ScriptEngine;
  import javax.script.ScriptEngineManager;
  import javax.script.ScriptException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.argeo.cms.CmsException;
  import org.eclipse.rap.rwt.application.Application;
  import org.eclipse.rap.rwt.application.ApplicationConfiguration;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.BundleException;
  import org.osgi.framework.wiring.BundleWiring;
  
  public class CmsScriptRwtApplication implements ApplicationConfiguration {
  	public final static String APP = "APP";
  	public final static String BC = "BC";
  
  	private final Log log = LogFactory.getLog(CmsScriptRwtApplication.class);
  
  	BundleContext bundleContext;
  	Repository repository;
  
  	ScriptEngine engine;
  
  	public void init(BundleContext bundleContext) {
  		this.bundleContext = bundleContext;
  		ClassLoader bundleCl = bundleContext.getBundle().adapt(BundleWiring.class).getClassLoader();
  		ClassLoader originalCcl = Thread.currentThread().getContextClassLoader();
  		try {
  //			Thread.currentThread().setContextClassLoader(bundleCl);// GraalVM needs it to be before creating manager
  //			ScriptEngineManager scriptEngineManager = new ScriptEngineManager(bundleCl);
  //			engine = scriptEngineManager.getEngineByName("JavaScript");
  //			if (engine == null) {// Nashorn
  //				Thread.currentThread().setContextClassLoader(originalCcl);
  //				scriptEngineManager = new ScriptEngineManager();
  //				Thread.currentThread().setContextClassLoader(bundleCl);
  //				engine = scriptEngineManager.getEngineByName("JavaScript");
  //			}
  			engine = loadScriptEngine(originalCcl, bundleCl);
  
  			// Load script
  			URL appUrl = bundleContext.getBundle().getEntry("cms/app.js");
  			// System.out.println("Loading " + appUrl);
  			// System.out.println("Loading " + appUrl.getHost());
  			// System.out.println("Loading " + appUrl.getPath());
  
  			CmsScriptApp app = new CmsScriptApp(engine);
  			engine.put(APP, app);
  			engine.put(BC, bundleContext);
  			try (Reader reader = new InputStreamReader(appUrl.openStream())) {
  				engine.eval(reader);
  			} catch (IOException | ScriptException e) {
  				throw new CmsException("Cannot execute " + appUrl, e);
  			}
  
  			if (log.isDebugEnabled())
  				log.debug("CMS script app initialized from " + appUrl);
  
  		} catch (Exception e) {
  			e.printStackTrace();
  		} finally {
  			Thread.currentThread().setContextClassLoader(originalCcl);
  		}
  	}
  
  	public void destroy(BundleContext bundleContext) {
  		engine = null;
  	}
  
  	@Override
  	public void configure(Application application) {
  		load(application);
  	}
  
  	void load(Application application) {
  		CmsScriptApp app = getApp();
  		app.apply(bundleContext, repository, application);
  		if (log.isDebugEnabled())
  			log.debug("CMS script app loaded to " + app.getWebPath());
  	}
  
  	CmsScriptApp getApp() {
  		if (engine == null)
  			throw new IllegalStateException("CMS script app is not initialized");
  		return (CmsScriptApp) engine.get(APP);
  	}
  
  	void update() {
  
  		try {
  			bundleContext.getBundle().update();
 		} catch (BundleException e) {
 			e.printStackTrace();
 		}
 	}
 
 	public void setRepository(Repository repository) {
 		this.repository = repository;
 	}
 
 	private static ScriptEngine loadScriptEngine(ClassLoader originalCcl, ClassLoader bundleCl) {
 		Thread.currentThread().setContextClassLoader(bundleCl);// GraalVM needs it to be before creating manager
 		ScriptEngineManager scriptEngineManager = new ScriptEngineManager(bundleCl);
 		ScriptEngine engine = scriptEngineManager.getEngineByName("JavaScript");
 		if (engine == null) {// Nashorn
 			Thread.currentThread().setContextClassLoader(originalCcl);
 			scriptEngineManager = new ScriptEngineManager();
 			Thread.currentThread().setContextClassLoader(bundleCl);
 			engine = scriptEngineManager.getEngineByName("JavaScript");
 		}
 		return engine;
 	}
 }