package lt.insoft.commons.zk.util;

import java.net.URL;
import java.util.List;
import java.util.Locale;
import java.util.Set;

import org.apache.commons.lang.reflect.FieldUtils;
import org.zkoss.util.resource.LabelLocator;
import org.zkoss.util.resource.Labels;
import org.zkoss.util.resource.Locator;
import org.zkoss.util.resource.Locators;
import org.zkoss.util.resource.impl.LabelLoader;
import org.zkoss.web.util.resource.ServletLabelLocator;
import org.zkoss.zk.ui.WebApp;
import org.zkoss.zk.ui.util.WebAppInit;

import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

public class FixLabelLoadersInit implements WebAppInit {
	private static final String ZK_CLASS_PATH_PREFIX = "~.";

	@Override
	public void init(WebApp wapp) throws Exception {
		LabelLoader loader = (LabelLoader) FieldUtils.readStaticField(Labels.class, "_loader", true);
		@SuppressWarnings("unchecked")
		Set<Object> locators = (Set<Object>) FieldUtils.readField(loader, "_locators", true);
		List<Object> list = Lists.newArrayList(locators);
		boolean modified = false;
		for (int i = 0; i < list.size(); i++) {
			Object element = list.get(i);
			if (element instanceof ServletLabelLocator) {
				String path = (String) FieldUtils.readField(element, "_path", true);
				if (path != null && path.startsWith(ZK_CLASS_PATH_PREFIX)) {
					list.set(i, new ExtraLabelLocator(path));
					modified = true;
				}
			}
		}
		
		if (modified) {
			FieldUtils.writeField(loader, "_locators", Sets.newLinkedHashSet(list), true);
		}
	}
	
	private static class ExtraLabelLocator implements LabelLocator {
		private final String path;

		public ExtraLabelLocator(String path) {
			this.path = path;
		}

		@Override
		public URL locate(Locale locale) throws Exception {
			String propertiesPath = path;
			final int j = propertiesPath.lastIndexOf('.');
			final String prefix = j >= 0 ? propertiesPath.substring(0, j) : propertiesPath;
			final String suffix = j >= 0 ? propertiesPath.substring(j) : "";
			propertiesPath = locale == null ? prefix + suffix : prefix + '_' + locale + suffix;

			final Locator locator = Locators.getDefault();
			return locator.getResource(propertiesPath.replace(ZK_CLASS_PATH_PREFIX, ""));
		}
	}

}