package org.argeo.cms.ui.rcp;

import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.security.PrivilegedAction;
import java.util.Map;
import java.util.UUID;

import javax.security.auth.Subject;
import javax.security.auth.login.LoginContext;
import javax.security.auth.login.LoginException;

import org.argeo.api.cms.CmsApp;
import org.argeo.api.cms.CmsAuth;
import org.argeo.api.cms.CmsEventBus;
import org.argeo.api.cms.CmsLog;
import org.argeo.api.cms.CmsSession;
import org.argeo.api.cms.ux.CmsImageManager;
import org.argeo.api.cms.ux.CmsTheme;
import org.argeo.api.cms.ux.CmsView;
import org.argeo.cms.swt.AbstractSwtCmsView;
import org.argeo.cms.swt.CmsSwtUtils;
import org.argeo.cms.swt.acr.AcrSwtImageManager;
import org.eclipse.e4.ui.css.core.engine.CSSEngine;
import org.eclipse.e4.ui.css.core.engine.CSSErrorHandler;
import org.eclipse.e4.ui.css.swt.engine.CSSSWTEngineImpl;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

/** Runs a {@link CmsApp} as an SWT desktop application. */
@SuppressWarnings("restriction")
public class CmsRcpApp extends AbstractSwtCmsView implements CmsView {
	private final static CmsLog log = CmsLog.getLog(CmsRcpApp.class);

	private Shell shell;
	private CmsApp cmsApp;

	private CSSEngine cssEngine;

	private String httpServerBase;

	public CmsRcpApp(String uiName) {
		super(uiName);
		uid = UUID.randomUUID().toString();
	}

	@SuppressWarnings("rawtypes")
	public void initRcpApp() {
		imageManager = (CmsImageManager) new AcrSwtImageManager();

		display = Display.getCurrent();
		shell = new Shell(display);
		shell.setText("Argeo CMS");
		Composite parent = shell;
		parent.setLayout(CmsSwtUtils.noSpaceGridLayout());
		CmsSwtUtils.registerCmsView(shell, CmsRcpApp.this);

		try {
			loginContext = new LoginContext(CmsAuth.SINGLE_USER.getLoginContextName());
			loginContext.login();
		} catch (LoginException e) {
			throw new IllegalStateException("Could not log in.", e);
		}
		if (log.isDebugEnabled())
			log.debug("Logged in to desktop: " + loginContext.getSubject());

		Subject.doAs(loginContext.getSubject(), (PrivilegedAction<Void>) () -> {

			// TODO factorise with web app
			parent.setData(CmsApp.UI_NAME_PROPERTY, uiName);
			ui = cmsApp.initUi(parent);
			if (ui instanceof Composite)
				((Composite) ui).setLayoutData(CmsSwtUtils.fillAll());
			// we need ui to be set before refresh so that CmsView can store UI context data
			// in it.
			cmsApp.refreshUi(ui, null);

			// Styling
			CmsTheme theme = CmsSwtUtils.getCmsTheme(parent);
			if (theme != null) {
				try {
					cssEngine = new CSSSWTEngineImpl(display);
					for (String path : theme.getSwtCssPaths()) {
						try (InputStream in = theme.loadPath(path)) {
							cssEngine.parseStyleSheet(in);
						} catch (IOException e) {
							throw new IllegalStateException("Cannot load stylesheet " + path, e);
						}
					}
					cssEngine.setErrorHandler(new CSSErrorHandler() {
						public void error(Exception e) {
							log.error("SWT styling error: ", e);
						}
					});
					applyStyles(shell);
				} catch (Throwable e) {// could be a class not found error
					log.error("Cannot initialise RCP theming", e);
				}
			}
			shell.layout(true, true);

			shell.open();
			return null;
		});
	}

	/*
	 * CMS VIEW
	 */

	@Override
	public void navigateTo(String state) {
		throw new UnsupportedOperationException();
	}

	@Override
	public void authChange(LoginContext loginContext) {
	}

	@Override
	public void logout() {
		if (loginContext != null)
			try {
				loginContext.logout();
			} catch (LoginException e) {
				log.error("Cannot log out", e);
			}
	}

	@Override
	public void exception(Throwable e) {
		log.error("Unexpected exception in CMS RCP", e);
	}

	@Override
	public CmsSession getCmsSession() {
		CmsSession cmsSession = cmsApp.getCmsContext().getCmsSession(getSubject());
		return cmsSession;
	}

	@Override
	public boolean isAnonymous() {
		return false;
	}

	@Override
	public void applyStyles(Object node) {
		if (cssEngine != null)
			cssEngine.applyStyles(node, true);
	}

	public Shell getShell() {
		return shell;
	}

	@Override
	public CmsEventBus getCmsEventBus() {
		return cmsApp.getCmsContext().getCmsEventBus();
	}

	@Override
	public CmsApp getCmsApp() {
		return cmsApp;
	}

	@Override
	public URI toBackendUri(String url) {
		try {
			URI u = new URI(url);
			if (u.getHost() == null) {
				// TODO make it more robust
				u = new URI(httpServerBase + url);
			}
			return u;
		} catch (URISyntaxException e) {
			throw new IllegalArgumentException("Cannot convert " + url, e);
		}
	}

	public void setHttpServerBase(String httpServerBase) {
		this.httpServerBase = httpServerBase;
	}

	/*
	 * DEPENDENCY INJECTION
	 */
	public void setCmsApp(CmsApp cmsApp, Map<String, String> properties) {
		this.cmsApp = cmsApp;
	}

	public void unsetCmsApp(CmsApp cmsApp, Map<String, String> properties) {
		this.cmsApp = null;
	}

}