/*
 * 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.apache.jasper.servlet;


import java.io.File;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Set;
import java.util.Vector;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.RequestDispatcher;
import javax.servlet.Servlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;


/**
 * Simple <code>ServletContext</code> implementation without
 * HTTP-specific methods.
 *
 * @author Peter Rossbach (pr@webapp.de)
 */

public class JspCServletContext implements ServletContext {


    // ----------------------------------------------------- Instance Variables


    /**
     * Servlet context attributes.
     */
    protected Hashtable myAttributes;


    /**
     * Servlet context initialization parameters.
     */
    private final ConcurrentHashMap<String,String> myParameters;


    /**
     * The log writer we will write log messages to.
     */
    protected PrintWriter myLogWriter;


    /**
     * The base URL (document root) for this context.
     */
    protected URL myResourceBaseURL;


    // ----------------------------------------------------------- Constructors


    /**
     * Create a new instance of this ServletContext implementation.
     *
     * @param aLogWriter PrintWriter which is used for <code>log()</code> calls
     * @param aResourceBaseURL Resource base URL
     */
    public JspCServletContext(PrintWriter aLogWriter, URL aResourceBaseURL) {

        myAttributes = new Hashtable();
        myParameters = new ConcurrentHashMap<String,String>();
        myLogWriter = aLogWriter;
        myResourceBaseURL = aResourceBaseURL;

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Return the specified context attribute, if any.
     *
     * @param name Name of the requested attribute
     */
    public Object getAttribute(String name) {

        return (myAttributes.get(name));

    }


    /**
     * Return an enumeration of context attribute names.
     */
    public Enumeration getAttributeNames() {

        return (myAttributes.keys());

    }


    /**
     * Return the servlet context for the specified path.
     *
     * @param uripath Server-relative path starting with '/'
     */
    public ServletContext getContext(String uripath) {

        return (null);

    }


    /**
     * Return the context path.
     */
    public String getContextPath() {

        return (null);

    }


    /**
     * Return the specified context initialization parameter.
     *
     * @param name Name of the requested parameter
     */
    public String getInitParameter(String name) {
        return myParameters.get(name);
    }


    /**
     * Return an enumeration of the names of context initialization
     * parameters.
     */
    public Enumeration getInitParameterNames() {
        return myParameters.keys();
    }


    /**
     * Return the Servlet API major version number.
     */
    public int getMajorVersion() {

        return (2);

    }


    /**
     * Return the MIME type for the specified filename.
     *
     * @param file Filename whose MIME type is requested
     */
    public String getMimeType(String file) {

        return (null);

    }


    /**
     * Return the Servlet API minor version number.
     */
    public int getMinorVersion() {

        return (3);

    }


    /**
     * Return a request dispatcher for the specified servlet name.
     *
     * @param name Name of the requested servlet
     */
    public RequestDispatcher getNamedDispatcher(String name) {

        return (null);

    }


    /**
     * Return the real path for the specified context-relative
     * virtual path.
     *
     * @param path The context-relative virtual path to resolve
     */
    public String getRealPath(String path) {

        if (!myResourceBaseURL.getProtocol().equals("file"))
            return (null);
        if (!path.startsWith("/"))
            return (null);
        try {
            return
                (getResource(path).getFile().replace('/', File.separatorChar));
        } catch (Throwable t) {
            return (null);
        }

    }


    /**
     * Return a request dispatcher for the specified context-relative path.
     *
     * @param path Context-relative path for which to acquire a dispatcher
     */
    public RequestDispatcher getRequestDispatcher(String path) {

        return (null);

    }


    /**
     * Return a URL object of a resource that is mapped to the
     * specified context-relative path.
     *
     * @param path Context-relative path of the desired resource
     *
     * @exception MalformedURLException if the resource path is
     *  not properly formed
     */
    public URL getResource(String path) throws MalformedURLException {

        if (!path.startsWith("/"))
            throw new MalformedURLException("Path '" + path +
                                            "' does not start with '/'");
        URL url = new URL(myResourceBaseURL, path.substring(1));
        InputStream is = null;
        try {
            is = url.openStream();
        } catch (Throwable t) {
            url = null;
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (Throwable t2) {
                    // Ignore
                }
            }
        }
        return url;

    }


    /**
     * Return an InputStream allowing access to the resource at the
     * specified context-relative path.
     *
     * @param path Context-relative path of the desired resource
     */
    public InputStream getResourceAsStream(String path) {

        try {
            return (getResource(path).openStream());
        } catch (Throwable t) {
            return (null);
        }

    }


    /**
     * Return the set of resource paths for the "directory" at the
     * specified context path.
     *
     * @param path Context-relative base path
     */
    public Set getResourcePaths(String path) {

        Set thePaths = new HashSet();
        if (!path.endsWith("/"))
            path += "/";
        String basePath = getRealPath(path);
        if (basePath == null)
            return (thePaths);
        File theBaseDir = new File(basePath);
        if (!theBaseDir.exists() || !theBaseDir.isDirectory())
            return (thePaths);
        String theFiles[] = theBaseDir.list();
        for (int i = 0; i < theFiles.length; i++) {
            File testFile = new File(basePath + File.separator + theFiles[i]);
            if (testFile.isFile())
                thePaths.add(path + theFiles[i]);
            else if (testFile.isDirectory())
                thePaths.add(path + theFiles[i] + "/");
        }
        return (thePaths);

    }


    /**
     * Return descriptive information about this server.
     */
    public String getServerInfo() {

        return ("JspCServletContext/1.0");

    }


    /**
     * Return a null reference for the specified servlet name.
     *
     * @param name Name of the requested servlet
     *
     * @deprecated This method has been deprecated with no replacement
     */
    public Servlet getServlet(String name) throws ServletException {

        return (null);

    }


    /**
     * Return the name of this servlet context.
     */
    public String getServletContextName() {

        return (getServerInfo());

    }


    /**
     * Return an empty enumeration of servlet names.
     *
     * @deprecated This method has been deprecated with no replacement
     */
    public Enumeration getServletNames() {

        return (new Vector().elements());

    }


    /**
     * Return an empty enumeration of servlets.
     *
     * @deprecated This method has been deprecated with no replacement
     */
    public Enumeration getServlets() {

        return (new Vector().elements());

    }


    /**
     * Log the specified message.
     *
     * @param message The message to be logged
     */
    public void log(String message) {

        myLogWriter.println(message);

    }


    /**
     * Log the specified message and exception.
     *
     * @param exception The exception to be logged
     * @param message The message to be logged
     *
     * @deprecated Use log(String,Throwable) instead
     */
    public void log(Exception exception, String message) {

        log(message, exception);

    }


    /**
     * Log the specified message and exception.
     *
     * @param message The message to be logged
     * @param exception The exception to be logged
     */
    public void log(String message, Throwable exception) {

        myLogWriter.println(message);
        exception.printStackTrace(myLogWriter);

    }


    /**
     * Remove the specified context attribute.
     *
     * @param name Name of the attribute to remove
     */
    public void removeAttribute(String name) {

        myAttributes.remove(name);

    }


    /**
     * Set or replace the specified context attribute.
     *
     * @param name Name of the context attribute to set
     * @param value Corresponding attribute value
     */
    public void setAttribute(String name, Object value) {

        myAttributes.put(name, value);

    }


    public boolean setInitParameter(String name, String value) {
        return myParameters.putIfAbsent(name, value) == null;
    }
}