package org.eparapher.rcp.actions;

import java.io.File;

import org.apache.log4j.Logger;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.IJobChangeEvent;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.core.runtime.jobs.JobChangeAdapter;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.IWorkbenchWindow;
import org.eparapher.core.crypto.EPKeystoreManager;
import org.eparapher.core.encryption.DefaultEncryptionParameters;
import org.eparapher.core.encryption.GenericCypher;
import org.eparapher.core.interfaces.IUserKeystore;

public abstract class GenericDecryptionAction extends GenericAction {


	private static Logger log = Logger.getLogger(GenericDecryptionAction.class);
	
	public GenericDecryptionAction(String msignerName) {
		super(msignerName);
	}

	public GenericDecryptionAction(TreeViewer mviewer, boolean museWizard, String msignerName) {
		super(mviewer, museWizard, msignerName);
	}

	public GenericDecryptionAction(IWorkbenchWindow mwindow, String msignerName) {
		super(mwindow, msignerName);
	}

	abstract GenericCypher getCypher();

	abstract void predecryption(IProgressMonitor monitor, GenericCypher cipher, DefaultEncryptionParameters signparams);
	
	abstract void decryptFile(IProgressMonitor monitor, File file, GenericCypher cipher, DefaultEncryptionParameters signparams);

	abstract void postdecryption(IProgressMonitor monitor, GenericCypher cipher, DefaultEncryptionParameters signparams);
	
	public void run() {
		DecryptionJob job = new DecryptionJob();
		if (job != null && job.isPrivateKeyLoaded) {
			job.setUser(true);
			job.schedule();
		} else {
			log.debug("Private key is not ready : cancelling decryption");
		}
	}
	
	private class DecryptionJob extends Job {

		private String originalAlias;
		
		private boolean isPrivateKeyLoaded;

		protected GenericCypher cipher;

		private DefaultEncryptionParameters encparams;
		
		protected DecryptionJob() {

			super( actionName + " job");
			
			// Use wizard if needed for parameters
			encparams = (DefaultEncryptionParameters) getParameters();
			if (encparams==null) {
				log.info("Encryption parameters is empty");
				return;
			}
			if (encparams.getFileSelection().length==0) {
				log.info("Nothing to decrypt");
				return;
			}
			
			IUserKeystore userpkandcert = EPKeystoreManager.getInstance().getUserkeystore();
			
			if (encparams != null ) {
				originalAlias = userpkandcert.getDefaultAlias();
				if (encparams.getEncryptionAlias() != null
					&& userpkandcert.containsAlias(encparams.getEncryptionAlias()) )
					userpkandcert.setDefaultAlias(encparams.getEncryptionAlias());
				
				//Ask PIN or Passphrase and load the private key
				isPrivateKeyLoaded = userpkandcert.loadPrivateKey();
				
				if (isPrivateKeyLoaded) {
					cipher = getCypher();

					//Verify if algorithm is supported
					if (cipher.isNotSupported(encparams,userpkandcert.getX509Certificate())) {
						encparams=null;
					}

					//End Job Listener
					this.addJobChangeListener(new JobChangeAdapter() {
						public void done(IJobChangeEvent event) {
							if (event.getResult().isOK())
								log.info( actionName + " job completed successfully");
							else
								log.warn( actionName + " job did not complete successfully");
						}
					});
				}
			}
		}
		
		@SuppressWarnings("unchecked")
		@Override
		protected IStatus run(IProgressMonitor monitor) {
			
			if ( encparams != null && isPrivateKeyLoaded) {

				predecryption( monitor, cipher, encparams);

				monitor.beginTask( actionName, encparams.getFileSelection().length );
				File[] f2s = encparams.getFileSelection();
				
				for (int i = 0; i < f2s.length; i++) {
					
					decryptFile(monitor, f2s[i], cipher, encparams);

					//refresh the document view
					refreshView();
				}
				monitor.done();

				postdecryption( monitor, cipher, encparams);
				
			}
			
			//Reset the original alias
			if (originalAlias!=null)
				EPKeystoreManager.getInstance().getUserkeystore().setDefaultAlias(originalAlias);
			return Status.OK_STATUS;
		}

		private void refreshView() {
			if (viewer != null)
				Display.getDefault().asyncExec(
						new Runnable() {
							public void run() {	viewer.refresh(); }
						}
				);			
		}
	}

}