/*
 * 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.naming.resources;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.security.Permission;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Vector;

import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;

import org.apache.naming.JndiPermission;
import org.apache.tomcat.util.buf.UDecoder;
import org.apache.tomcat.util.buf.UEncoder;
import org.apache.tomcat.util.http.FastHttpDateFormat;

/**
 * Connection to a JNDI directory context.
 * <p/>
 * Note: All the object attribute names are the WebDAV names, not the HTTP
 * names, so this class overrides some methods from URLConnection to do the
 * queries using the right names. Content handler is also not used; the
 * content is directly returned.
 *
 * @author <a href="mailto:remm@apache.org">Remy Maucherat</a>
 */
public class DirContextURLConnection extends URLConnection {

    private static final UDecoder URL_DECODER = new UDecoder();
    private static final UEncoder URL_ENCODER = new UEncoder();

    static{
        URL_ENCODER.addSafeCharacter('/');
    }

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

    public DirContextURLConnection(DirContext context, URL url) {
        super(url);
        if (context == null)
            throw new IllegalArgumentException
                ("Directory context can't be null");
        if (org.apache.naming.Constants.IS_SECURITY_ENABLED) {
            this.permission = new JndiPermission(url.toString());
    }
        this.context = context;
    }


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


    /**
     * Directory context.
     */
    protected DirContext context;


    /**
     * Associated resource.
     */
    protected Resource resource;


    /**
     * Associated DirContext.
     */
    protected DirContext collection;


    /**
     * Other unknown object.
     */
    protected Object object;


    /**
     * Attributes.
     */
    protected Attributes attributes;


    /**
     * Date.
     */
    protected long date;


    /**
     * Permission
     */
    protected Permission permission;


    /**
     * Cache the path as it there is some processing required - particularly if
     * the context is a ProxyDirContext.
     */
    private String path = null;


    // ------------------------------------------------------------- Properties


    /**
     * Connect to the DirContext, and retrieve the bound object, as well as
     * its attributes. If no object is bound with the name specified in the
     * URL, then an IOException is thrown.
     *
     * @throws IOException Object not found
     */
    @Override
    public void connect() throws IOException {

        if (!connected) {

            try {
                date = System.currentTimeMillis();
                path = URL_DECODER.convert(getURL().getFile(), false);
                if (context instanceof ProxyDirContext) {
                    ProxyDirContext proxyDirContext =
                        (ProxyDirContext) context;
                    String hostName = proxyDirContext.getHostName();
                    String contextPath = proxyDirContext.getContextPath();
                    if (hostName != null) {
                        if (!path.startsWith("/" + hostName + "/"))
                            return;
                        path = path.substring(hostName.length()+ 1);
                    }
                    if (contextPath != null) {
                        if (!path.startsWith(contextPath + "/")) {
                            return;
                        }
                        path = path.substring(contextPath.length());
                    }
                }
                object = context.lookup(path);
                attributes = context.getAttributes(path);
                if (object instanceof Resource)
                    resource = (Resource) object;
                if (object instanceof DirContext)
                    collection = (DirContext) object;
            } catch (NamingException e) {
                // Object not found
            }

            connected = true;
        }
    }


    /**
     * Return the content length value.
     */
    @Override
    public int getContentLength() {
        return getHeaderFieldInt(ResourceAttributes.CONTENT_LENGTH, -1);
    }


    /**
     * Return the content type value.
     */
    @Override
    public String getContentType() {
        return getHeaderField(ResourceAttributes.CONTENT_TYPE);
    }


    /**
     * Return the last modified date.
     */
    @Override
    public long getDate() {
        return date;
    }


    /**
     * Return the last modified date.
     */
    @Override
    public long getLastModified() {

        if (!connected) {
            // Try to connect (silently)
            try {
                connect();
            } catch (IOException e) {
                // Ignore
            }
        }

        if (attributes == null)
            return 0;

        Attribute lastModified =
            attributes.get(ResourceAttributes.LAST_MODIFIED);
        if (lastModified != null) {
            try {
                Date lmDate = (Date) lastModified.get();
                return lmDate.getTime();
            } catch (Exception e) {
                // Ignore
            }
        }

        return 0;
    }


    protected String getHeaderValueAsString(Object headerValue) {
        if (headerValue == null) return null;
        if (headerValue instanceof Date) {
            // return date strings (ie Last-Modified) in HTTP format, rather
            // than Java format
            return FastHttpDateFormat.formatDate(
                    ((Date)headerValue).getTime(), null);
        }
        return headerValue.toString();
    }


    /**
     * Returns an unmodifiable Map of the header fields.
     */
    @Override
    public Map<String,List<String>> getHeaderFields() {

      if (!connected) {
          // Try to connect (silently)
          try {
              connect();
          } catch (IOException e) {
              //Ignore
          }
      }

      if (attributes == null)
          return (Collections.emptyMap());

      HashMap<String,List<String>> headerFields =
          new HashMap<String,List<String>>(attributes.size());
      NamingEnumeration<String> attributeEnum = attributes.getIDs();
      try {
          while (attributeEnum.hasMore()) {
              String attributeID = attributeEnum.next();
              Attribute attribute = attributes.get(attributeID);
              if (attribute == null) continue;
              ArrayList<String> attributeValueList =
                  new ArrayList<String>(attribute.size());
              NamingEnumeration<?> attributeValues = attribute.getAll();
              while (attributeValues.hasMore()) {
                  Object attrValue = attributeValues.next();
                  attributeValueList.add(getHeaderValueAsString(attrValue));
              }
              attributeValueList.trimToSize(); // should be a no-op if attribute.size() didn't lie
              headerFields.put(attributeID, Collections.unmodifiableList(attributeValueList));
          }
      } catch (NamingException ne) {
            // Shouldn't happen
      }

      return Collections.unmodifiableMap(headerFields);

    }


    /**
     * Returns the name of the specified header field.
     */
    @Override
    public String getHeaderField(String name) {

        if (!connected) {
            // Try to connect (silently)
            try {
                connect();
            } catch (IOException e) {
                // Ignore
            }
        }

        if (attributes == null)
            return (null);

        NamingEnumeration<String> attributeEnum = attributes.getIDs();
        try {
            while (attributeEnum.hasMore()) {
                String attributeID = attributeEnum.next();
                if (attributeID.equalsIgnoreCase(name)) {
                    Attribute attribute = attributes.get(attributeID);
                    if (attribute == null) return null;
                    Object attrValue = attribute.get(attribute.size()-1);
                    return getHeaderValueAsString(attrValue);
                }
            }
        } catch (NamingException ne) {
            // Shouldn't happen
        }

        return (null);

    }


    /**
     * Get object content.
     */
    @Override
    public Object getContent()
        throws IOException {

        if (!connected)
            connect();

        if (resource != null)
            return getInputStream();
        if (collection != null)
            return collection;
        if (object != null)
            return object;

        throw new FileNotFoundException(
                getURL() == null ? "null" : getURL().toString());

    }


    /**
     * Get object content.
     */
    @Override
    public Object getContent(@SuppressWarnings("rawtypes") Class[] classes)
        throws IOException {

        Object obj = getContent();

        for (int i = 0; i < classes.length; i++) {
            if (classes[i].isInstance(obj))
                return obj;
        }

        return null;

    }


    /**
     * Get input stream.
     */
    @Override
    public InputStream getInputStream() throws IOException {

        if (!connected)
            connect();

        if (resource == null) {
            throw new FileNotFoundException(
                    getURL() == null ? "null" : getURL().toString());
        }

        // Reopen resource
        try {
            resource = (Resource) context.lookup(path);
        } catch (NamingException e) {
            // Ignore
        }

        return (resource.streamContent());
    }


    /**
     * Get the Permission for this URL
     */
    @Override
    public Permission getPermission() {

        return permission;
    }


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


    /**
     * List children of this collection. The names given are relative to this
     * URI's path. The full uri of the children is then : path + "/" + name.
     */
    public Enumeration<String> list()
        throws IOException {

        if (!connected) {
            connect();
        }

        if ((resource == null) && (collection == null)) {
            throw new FileNotFoundException(
                    getURL() == null ? "null" : getURL().toString());
        }

        Vector<String> result = new Vector<String>();

        if (collection != null) {
            try {
                NamingEnumeration<NameClassPair> enumeration =
                    collection.list("/");
                while (enumeration.hasMoreElements()) {
                    NameClassPair ncp = enumeration.nextElement();
                    String s = ncp.getName();
                    result.addElement(
                            URL_ENCODER.encodeURL(s, 0, s.length()).toString());
                }
            } catch (NamingException e) {
                // Unexpected exception
                throw new FileNotFoundException(
                        getURL() == null ? "null" : getURL().toString());
            }
        }

        return result.elements();

    }


}