/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.krakenapps.http.internal.handler;

import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.ServletConfig;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletRequestWrapper;

import org.krakenapps.http.internal.context.KrakenServletContext;

import java.io.IOException;

public final class ServletHandler extends AbstractHandler implements Comparable<ServletHandler> {
	private final String alias;
	private final Servlet servlet;

	public ServletHandler(KrakenServletContext context, Servlet servlet, String alias) {
		super(context);
		this.alias = alias;
		this.servlet = servlet;
	}

	public String getAlias() {
		return this.alias;
	}

	public Servlet getServlet() {
		return this.servlet;
	}

	public void init() throws ServletException {
		String name = "servlet_" + getId();
		ServletConfig config = new ServletConfigImpl(name, getContext(), getInitParams());
		this.servlet.init(config);
	}

	public void destroy() {
		this.servlet.destroy();
	}

	public boolean matches(String uri) {
		if (this.alias.equals("/")) {
			return uri.startsWith(this.alias);
		} else {
			return uri.equals(this.alias) || uri.startsWith(this.alias + "/");
		}
	}

	public boolean handle(HttpServletRequest req, HttpServletResponse res) throws ServletException,
			IOException {
		final boolean matches = matches(req.getPathInfo());
		if (matches) {
			doHandle(req, res);
		}

		return matches;
	}

	private void doHandle(HttpServletRequest req, HttpServletResponse res) throws ServletException,
			IOException {
		if (!getContext().handleSecurity(req, res)) {
			if (!res.isCommitted()) {
				res.sendError(HttpServletResponse.SC_FORBIDDEN);
			}
		} else {
			this.servlet.service(new RequestWrapper(req), res);
		}
	}

	public int compareTo(ServletHandler other) {
		return other.alias.length() - this.alias.length();
	}

	private final class RequestWrapper extends HttpServletRequestWrapper {
		private String pathInfo;
		private boolean pathInfoComputed = false;

		public RequestWrapper(HttpServletRequest req) {
			super(req);
		}

		@Override
		public String getPathInfo() {
			if (!this.pathInfoComputed) {
				final int servletPathLength = getServletPath().length();
				this.pathInfo = getRequestURI().substring(getContextPath().length()).replaceAll(
						"[/]{2,}", "/").substring(servletPathLength);

				if ("".equals(this.pathInfo) && servletPathLength != 0) {
					this.pathInfo = null;
				}

				this.pathInfoComputed = true;
			}

			return this.pathInfo;
		}

		@Override
		public String getPathTranslated() {
			final String info = getPathInfo();
			return (null == info) ? null : getRealPath(info);
		}

		@Override
		public String getServletPath() {
			return alias;
		}
	}

	@Override
	public String toString() {
		return "ServletHandler [alias=" + alias + ", servlet=" + servlet + "]";
	}
}