package org.gcube.data.access.storagehub.services.admin;

import static org.gcube.data.access.storagehub.Roles.INFRASTRUCTURE_MANAGER_ROLE;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.StringReader;
import java.io.StringWriter;

import javax.inject.Inject;
import javax.jcr.Node;
import javax.servlet.ServletContext;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;

import org.apache.cxf.io.ReaderInputStream;
import org.apache.jackrabbit.api.JackrabbitSession;
import org.gcube.common.authorization.control.annotations.AuthorizationControl;
import org.gcube.common.authorization.library.AuthorizedTasks;
import org.gcube.common.authorization.library.provider.AuthorizationProvider;
import org.gcube.common.storagehub.model.Paths;
import org.gcube.data.access.storagehub.PathUtil;
import org.gcube.data.access.storagehub.StorageHubAppllicationManager;
import org.gcube.data.access.storagehub.accounting.AccountingHandler;
import org.gcube.data.access.storagehub.exception.MyAuthException;
import org.gcube.data.access.storagehub.handlers.CredentialHandler;
import org.gcube.data.access.storagehub.handlers.items.ItemHandler;
import org.gcube.data.access.storagehub.handlers.items.builders.FileCreationParameters;
import org.gcube.data.access.storagehub.handlers.items.builders.ItemsParameterBuilder;
import org.gcube.data.access.storagehub.scripting.AbstractScript;
import org.gcube.data.access.storagehub.scripting.ScriptUtil;
import org.gcube.data.access.storagehub.services.RepositoryInitializer;
import org.glassfish.jersey.media.multipart.FormDataContentDisposition;
import org.glassfish.jersey.media.multipart.FormDataParam;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Path("admin/script")
public class ScriptManager {


	private static Logger log = LoggerFactory.getLogger(ScriptManager.class);

	private RepositoryInitializer repository = StorageHubAppllicationManager.repository;

	@Inject 
	AccountingHandler accountingHandler;

	@Context 
	ServletContext context;
	
	@Inject
	ScriptUtil scriptUtil;

	@Inject
	ItemHandler itemHandler;
	
	@Inject
	PathUtil pathUtil;

	@POST
	@Path("execute")
	@AuthorizationControl(allowedRoles = {INFRASTRUCTURE_MANAGER_ROLE},exception=MyAuthException.class)
	@Consumes(MediaType.MULTIPART_FORM_DATA)
	public String run( @FormDataParam("name") String name,
			@FormDataParam("asynch") Boolean asynch,
			@FormDataParam("destinationFolderId") String destinationFolderId,
			@FormDataParam("file") InputStream stream,
			@FormDataParam("file") FormDataContentDisposition fileDetail) {
		try {
			ScriptClassLoader scriptClassLoader = new ScriptClassLoader(Thread.currentThread().getContextClassLoader());
			Class<?> scriptClass = uploadClass(stream, scriptClassLoader, fileDetail.getFileName().replace(".class", ""));
			return run(scriptClass, name, destinationFolderId, asynch!=null? asynch : false);
		}catch(Throwable e) {
			log.error("error executing script {}", name,e);
			throw new WebApplicationException("error loading class",e);
		}
	}


	private Class<?> uploadClass(InputStream stream, ScriptClassLoader classLoader, String name) throws Throwable {
		try(ByteArrayOutputStream buffer = new ByteArrayOutputStream()){
			int nRead;
			byte[] data = new byte[1024];
			while ((nRead = stream.read(data, 0, data.length)) != -1) 
				buffer.write(data, 0, nRead);

			buffer.flush();
			byte[] byteArray = buffer.toByteArray();
			return classLoader.findClass(name, byteArray);
		}

	}

	private String run(Class<?> clazz, String name, String destinationFolderId, boolean asynch) throws Throwable {
		String login = AuthorizationProvider.instance.get().getClient().getId();
		log.info("script {} called by {}", clazz.getSimpleName(), login);
		JackrabbitSession ses = null;

		try {
			ses = (JackrabbitSession) repository.getRepository().login(CredentialHandler.getAdminCredentials(context));

			String parentId = destinationFolderId!=null ? destinationFolderId : ses.getNode(pathUtil.getWorkspacePath(login).toPath()).getIdentifier();
			Node parentNode = ses.getNodeByIdentifier(parentId);
			String parentPath = parentNode.getPath(); 

			if (AbstractScript.class.isAssignableFrom(clazz)) {
				AbstractScript scriptInstance = (AbstractScript) clazz.newInstance();

				RealRun realRun = new RealRun(ses, scriptInstance, login, parentId, name);
				if (asynch) { 
					new Thread(AuthorizedTasks.bind(realRun)).start();
				}else realRun.run();
				
			} else throw new Exception("class "+clazz.getSimpleName()+" not implements AbstractScript");

			return Paths.append(Paths.getPath(parentPath), name).toPath();

		}catch (Throwable e) {
			if (ses !=null && ses.isLive())
				ses.logout();
			throw e;
		}


	}


	class RealRun implements Runnable{

		private JackrabbitSession ses;
		AbstractScript instance;
		String login;
		String parentId;
		String name;

		public RealRun(JackrabbitSession ses, AbstractScript instance, String login, String parentId, String name) {
			super();
			this.ses = ses;
			this.instance = instance;
			this.login = login;
			this.parentId = parentId;
			this.name = name;
		}


		@Override
		public void run() {
			try{
				String result ="";
				try {
					result = instance.run(ses, null, scriptUtil);
					log.info("result is {}",result);
				}catch(Throwable t) {
					StringWriter sw = new StringWriter();
					PrintWriter pw = new PrintWriter(sw, true);
					t.printStackTrace(pw);
					result+= "\n"+sw.toString();
				}
				
				try( InputStream stream = new ReaderInputStream(new StringReader(result))){
					ItemsParameterBuilder<FileCreationParameters> builder = FileCreationParameters.builder().name(name).description("result of script execution "+name)
							.stream(stream).on(parentId).with(ses).author(login);
					itemHandler.create(builder.build());
				} catch (Throwable e) {
					log.error("error saving script result {} in the Workspace",name, e);
				}
				
			} finally {
				if (ses!=null)
					ses.logout();
			}

		}

	}

	class ScriptClassLoader extends ClassLoader{

		public ScriptClassLoader(ClassLoader parent) {
			super(parent);
		}

		public Class<?> findClass(String name, byte[] b) {
			return defineClass(name, b, 0, b.length);
		}
	}

}