//
//  ========================================================================
//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.server;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;
import java.util.ArrayList;
import java.util.Collections;
import java.util.EnumSet;
import java.util.Enumeration;
import java.util.Locale;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletOutputStream;
import javax.servlet.SessionTrackingMode;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.eclipse.jetty.http.HttpCookie;
import org.eclipse.jetty.http.HttpFields;
import org.eclipse.jetty.http.HttpHeaderValues;
import org.eclipse.jetty.http.HttpHeaders;
import org.eclipse.jetty.http.HttpStatus;
import org.eclipse.jetty.http.HttpURI;
import org.eclipse.jetty.http.HttpVersions;
import org.eclipse.jetty.http.MimeTypes;
import org.eclipse.jetty.io.BufferCache.CachedBuffer;
import org.eclipse.jetty.server.handler.ContextHandler;
import org.eclipse.jetty.util.ByteArrayISO8859Writer;
import org.eclipse.jetty.util.QuotedStringTokenizer;
import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.URIUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Response.
 * <p>
 * Implements {@link javax.servlet.http.HttpServletResponse} from the <code>javax.servlet.http</code> package.
 * </p>
 */
public final class Response implements HttpServletResponse
{
	private static final Logger LOG = LoggerFactory.getLogger(Response.class);

	
	public static final int
		NONE=0,
		STREAM=1,
		WRITER=2;

	/**
	 * If a header name starts with this string,  the header (stripped of the prefix)
	 * can be set during include using only {@link #setHeader(String, String)} or
	 * {@link #addHeader(String, String)}.
	 */
	public final static String SET_INCLUDE_HEADER_PREFIX = "org.eclipse.jetty.server.include.";

	/**
	 * If this string is found within the comment of a cookie added with {@link #addCookie(Cookie)}, then the cookie 
	 * will be set as HTTP ONLY.
	 */
	public final static String HTTP_ONLY_COMMENT="__HTTP_ONLY__";
	
	private final AbstractHttpConnection _connection;
	private int _status = SC_OK;
	private String _reason;
	private Locale _locale;
	private String _mimeType;
	private CachedBuffer _cachedMimeType;
	private String _characterEncoding;
	private boolean _explicitEncoding;
	private String _contentType;
	private volatile int _outputState;
	private PrintWriter _writer;

	public Response(AbstractHttpConnection connection)
	{
		_connection = connection;
	}

	public void addCookie(HttpCookie cookie)
	{
		_connection._responseFields.addSetCookie(cookie);
	}
	
	@Override
	public void addCookie(Cookie cookie)
	{
		String comment=cookie.getComment();
		boolean http_only=false;
		
		if (comment!=null)
		{
			int i=comment.indexOf(HTTP_ONLY_COMMENT);
			if (i>=0)
			{
				http_only=true;
				comment=comment.replace(HTTP_ONLY_COMMENT,"").trim();
				if (comment.length()==0)
					comment=null;
			}
		}
		_connection._responseFields.addSetCookie(cookie.getName(),
				cookie.getValue(),
				cookie.getDomain(),
				cookie.getPath(),
				cookie.getMaxAge(),
				comment,
				cookie.getSecure(),
				http_only || cookie.isHttpOnly(),
				cookie.getVersion());
	}

	@Override
	public boolean containsHeader(String name)
	{
		return _connection._responseFields.containsKey(name);
	}

	@Override
	public String encodeURL(String url)
	{
		throw new UnsupportedOperationException();
	}

	@Override
	public String encodeRedirectURL(String url)
	{
		throw new UnsupportedOperationException();
	}

	@Override
	@Deprecated
	public String encodeUrl(String url)
	{
		throw new UnsupportedOperationException();
	}

	@Override
	@Deprecated
	public String encodeRedirectUrl(String url)
	{
		throw new UnsupportedOperationException();
	}

	@Override
	public void sendError(int code, String message) throws IOException
	{
		if (isCommitted())
			LOG.warn("Committed before "+code+" "+message);

		resetBuffer();
		_characterEncoding = null;
		setHeader(HttpHeaders.EXPIRES,null);
		setHeader(HttpHeaders.LAST_MODIFIED,null);
		setHeader(HttpHeaders.CACHE_CONTROL,null);
		setHeader(HttpHeaders.CONTENT_TYPE,null);
		setHeader(HttpHeaders.CONTENT_LENGTH,null);

		_outputState = NONE;
		setStatus(code,message);

		if (message==null)
			message=HttpStatus.getMessage(code);

		// If we are allowed to have a body
		if (code!=SC_NO_CONTENT &&
			code!=SC_NOT_MODIFIED &&
			code!=SC_PARTIAL_CONTENT &&
			code>=SC_OK)
		{
			Request request = _connection.getRequest();

			setHeader(HttpHeaders.CACHE_CONTROL, "must-revalidate,no-cache,no-store");
			setContentType(MimeTypes.TEXT_HTML_8859_1);
			ByteArrayISO8859Writer writer= new ByteArrayISO8859Writer(2048);
			if (message != null)
			{
				message= StringUtil.replace(message, "&", "&amp;");
				message= StringUtil.replace(message, "<", "&lt;");
				message= StringUtil.replace(message, ">", "&gt;");
			}
			String uri= request.getRequestURI();
			if (uri!=null)
			{
				uri= StringUtil.replace(uri, "&", "&amp;");
				uri= StringUtil.replace(uri, "<", "&lt;");
				uri= StringUtil.replace(uri, ">", "&gt;");
			}

			writer.write("<html>\n<head>\n<meta http-equiv=\"Content-Type\" content=\"text/html;charset=ISO-8859-1\"/>\n");
			writer.write("<title>Error ");
			writer.write(Integer.toString(code));
			writer.write(' ');
			if (message==null)
				message=HttpStatus.getMessage(code);
			writer.write(message);
			writer.write("</title>\n</head>\n<body>\n<h2>HTTP ERROR: ");
			writer.write(Integer.toString(code));
			writer.write("</h2>\n<p>Problem accessing ");
			writer.write(uri);
			writer.write(". Reason:\n<pre>    ");
			writer.write(message);
			writer.write("</pre>");
			writer.write("</p>\n<hr /><i><small>Powered by Jetty://</small></i>");

			for (int i= 0; i < 20; i++)
				writer.write("\n                                                ");
			writer.write("\n</body>\n</html>\n");

			writer.flush();
			setContentLength(writer.size());
			writer.writeTo(getOutputStream());
			writer.destroy();
		}
		else if (code!=SC_PARTIAL_CONTENT)
		{
			_connection._requestFields.remove(HttpHeaders.CONTENT_TYPE);
			_connection._requestFields.remove(HttpHeaders.CONTENT_LENGTH);
			_characterEncoding = null;
			_mimeType = null;
			_cachedMimeType = null;
		}

		complete();
	}

	@Override
	public void sendError(int sc) throws IOException
	{
		sendError(sc,null);
	}

	@Override
	public void sendRedirect(String location) throws IOException
	{
		if (location==null)
			throw new IllegalArgumentException();

		if (!URIUtil.hasScheme(location))
		{
			StringBuilder buf = _connection.getRequest().getRootURL();
			if (location.startsWith("/"))
				buf.append(location);
			else
			{
				String path=_connection.getRequest().getRequestURI();
				String parent=(path.endsWith("/"))?path:URIUtil.parentPath(path);
				location=URIUtil.addPaths(parent,location);
				if(location==null)
					throw new IllegalStateException("path cannot be above root");
				if (!location.startsWith("/"))
					buf.append('/');
				buf.append(location);
			}

			location=buf.toString();
			HttpURI uri = new HttpURI(location);
			String path=uri.getDecodedPath();
			String canonical=URIUtil.canonicalPath(path);
			if (canonical==null)
				throw new IllegalArgumentException();
			if (!canonical.equals(path))
			{
				buf = _connection.getRequest().getRootURL();
				buf.append(URIUtil.encodePath(canonical));
				String param=uri.getParam();
				if (param!=null)
				{
					buf.append(';');
					buf.append(param);
				}
				String query=uri.getQuery();
				if (query!=null)
				{
					buf.append('?');
					buf.append(query);
				}
				String fragment=uri.getFragment();
				if (fragment!=null)
				{
					buf.append('#');
					buf.append(fragment);
				}
				location=buf.toString();
			}
		}
		
		resetBuffer();
		setHeader(HttpHeaders.LOCATION,location);
		setStatus(HttpServletResponse.SC_MOVED_TEMPORARILY);
		complete();

	}

	@Override
	public void setDateHeader(String name, long date)
	{
		_connection._responseFields.putDateField(name, date);
	}

	@Override
	public void addDateHeader(String name, long date)
	{
		_connection._responseFields.addDateField(name, date);
	}

	@Override
	public void setHeader(String name, String value)
	{
		if (HttpHeaders.CONTENT_TYPE.equalsIgnoreCase(name))
			setContentType(value);
		else
		{
			_connection._responseFields.put(name, value);
			if (HttpHeaders.CONTENT_LENGTH.equalsIgnoreCase(name))
			{
				if (value==null)
					_connection._generator.setContentLength(-1);
				else
					_connection._generator.setContentLength(Long.parseLong(value));
			}
		}
	}


	@Override
	public Collection<String> getHeaderNames()
	{
		final HttpFields fields=_connection._responseFields;
		return fields.getFieldNamesCollection();
	}
	
	@Override
	public String getHeader(String name)
	{
		return _connection._responseFields.getStringField(name);
	}

	@Override
	public Collection<String> getHeaders(String name)
	{
		final HttpFields fields=_connection._responseFields;
		Collection<String> i = fields.getValuesCollection(name);
		if (i==null)
			return Collections.EMPTY_LIST;
		return i;
	}

	@Override
	public void addHeader(String name, String value)
	{

		if (HttpHeaders.CONTENT_TYPE.equalsIgnoreCase(name))
		{
			setContentType(value);
			return;
		}
		
		_connection._responseFields.add(name, value);
		if (HttpHeaders.CONTENT_LENGTH.equalsIgnoreCase(name))
			_connection._generator.setContentLength(Long.parseLong(value));
	}

	@Override
	public void setIntHeader(String name, int value)
	{
		_connection._responseFields.putLongField(name, value);
		if (HttpHeaders.CONTENT_LENGTH.equalsIgnoreCase(name))
			_connection._generator.setContentLength(value);
	}

	@Override
	public void addIntHeader(String name, int value)
	{
		_connection._responseFields.addLongField(name, value);
		if (HttpHeaders.CONTENT_LENGTH.equalsIgnoreCase(name))
			_connection._generator.setContentLength(value);
	}

	@Override
	public void setStatus(int sc)
	{
		setStatus(sc,null);
	}

	@Override
	public void setStatus(int sc, String sm)
	{
		if (sc<=0)
			throw new IllegalArgumentException();
		_status = sc;
		_reason = sm;
	}

	@Override
	public String getCharacterEncoding()
	{
		if (_characterEncoding==null)
			_characterEncoding = StringUtil.__ISO_8859_1;
		return _characterEncoding;
	}
	
	@Override
	public String getContentType()
	{
		return _contentType;
	}

	@Override
	public ServletOutputStream getOutputStream() throws IOException
	{
		if (_outputState!=NONE && _outputState!=STREAM)
			throw new IllegalStateException("WRITER");

		ServletOutputStream out = _connection.getOutputStream();
		_outputState = STREAM;
		return out;
	}

	@Override
	public PrintWriter getWriter() throws IOException
	{
		if (_outputState!=NONE && _outputState!=WRITER)
			throw new IllegalStateException("STREAM");

		/* if there is no writer yet */
		if (_writer==null)
		{
			/* get encoding from Content-Type header */
			String encoding = _characterEncoding;

			if (encoding==null)
			{
				/* implementation of educated defaults */
				if(_cachedMimeType != null)
					encoding = MimeTypes.getCharsetFromContentType(_cachedMimeType);

				if (encoding==null)
					encoding = StringUtil.__ISO_8859_1;

				setCharacterEncoding(encoding);
			}

			/* construct Writer using correct encoding */
			_writer = _connection.getPrintWriter(encoding);
		}
		_outputState=WRITER;
		return _writer;
	}

	@Override
	public void setCharacterEncoding(String encoding)
	{
		if (this._outputState==0 && !isCommitted())
		{
			_explicitEncoding = true;

			if (encoding==null)
			{
				// Clear any encoding.
				if (_characterEncoding!=null)
				{
					_characterEncoding=null;
					if (_cachedMimeType!=null)
						_contentType = _cachedMimeType.toString();
					else if (_mimeType!=null)
						_contentType = _mimeType;
					else
						_contentType = null;

					if (_contentType==null)
						_connection._responseFields.remove(HttpHeaders.CONTENT_TYPE);
					else
						_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
				}
			}
			else
			{
				// No, so just add this one to the mimetype
				_characterEncoding=encoding;
				if (_contentType!=null)
				{
					int i0=_contentType.indexOf(';');
					if (i0<0)
					{
						_contentType=null;
						if(_cachedMimeType!=null)
						{
							CachedBuffer content_type = _cachedMimeType.getAssociate(_characterEncoding);
							if (content_type!=null)
							{
								_contentType = content_type.toString();
								_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
							}
						}

						if (_contentType==null)
						{
							_contentType = _mimeType+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
							_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
						}
					}
					else
					{
						int i1=_contentType.indexOf("charset=",i0);
						if (i1<0)
						{
							_contentType = _contentType+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
						}
						else
						{
							int i8=i1+8;
							int i2=_contentType.indexOf(" ",i8);
							if (i2<0)
								_contentType=_contentType.substring(0,i8)+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
							else
								_contentType=_contentType.substring(0,i8)+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ")+_contentType.substring(i2);
						}
						_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
					}
				}
			}
		}
	}

	@Override
	public void setContentLength(int len)
	{
		// Protect from setting after committed as default handling
		// of a servlet HEAD request ALWAYS sets _content length, even
		// if the getHandling committed the response!
		if (isCommitted())
			return;
		_connection._generator.setContentLength(len);
		if (len>0)
		{
			_connection._responseFields.putLongField(HttpHeaders.CONTENT_LENGTH, len);
			if (_connection._generator.isAllContentWritten())
			{
				if (_outputState==WRITER)
					_writer.close();
				else if (_outputState==STREAM)
				{
					try
					{
						getOutputStream().close();
					}
					catch(IOException e)
					{
						throw new RuntimeException(e);
					}
				}
			}
		}
	}

	@Override
	public void setContentType(String contentType)
	{
		if (isCommitted())
			return;

		// Yes this method is horribly complex.... but there are lots of special cases and
		// as this method is called on every request, it is worth trying to save string creation.
		//

		if (contentType==null)
		{
			if (_locale==null)
				_characterEncoding = null;
			_mimeType = null;
			_cachedMimeType = null;
			_contentType=null;
			_connection._responseFields.remove(HttpHeaders.CONTENT_TYPE);
		}
		else
		{
			// Look for encoding in contentType
			int i0=contentType.indexOf(';');

			if (i0>0)
			{
				// we have content type parameters

				// Extract params off mimetype
				_mimeType = contentType.substring(0,i0).trim();
				_cachedMimeType = MimeTypes.CACHE.get(_mimeType);

				// Look for charset
				int i1=contentType.indexOf("charset=",i0+1);
				if (i1>=0)
				{
					_explicitEncoding = true;
					int i8=i1+8;
					int i2 = contentType.indexOf(' ',i8);

					if (_outputState==WRITER)
					{
						// strip the charset and ignore;
						if ((i1==i0+1 && i2<0) || (i1==i0+2 && i2<0 && contentType.charAt(i0+1)==' '))
						{
							if (_cachedMimeType!=null)
							{
								CachedBuffer content_type = _cachedMimeType.getAssociate(_characterEncoding);
								if (content_type!=null)
								{
									_contentType=content_type.toString();
									_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
								}
								else
								{
									_contentType = _mimeType+";charset="+_characterEncoding;
									_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
								}
							}
							else
							{
								_contentType = _mimeType+";charset="+_characterEncoding;
								_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
							}
						}
						else if (i2<0)
						{
							_contentType=contentType.substring(0,i1)+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
							_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
						}
						else
						{
							_contentType=contentType.substring(0,i1)+contentType.substring(i2)+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
							_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
						}
					}
					else if ((i1==i0+1 && i2<0) || (i1==i0+2 && i2<0 && contentType.charAt(i0+1)==' '))
					{
						// The params are just the char encoding
						_cachedMimeType = MimeTypes.CACHE.get(_mimeType);
						_characterEncoding = QuotedStringTokenizer.unquote(contentType.substring(i8));

						if (_cachedMimeType!=null)
						{
							CachedBuffer content_type = _cachedMimeType.getAssociate(_characterEncoding);
							if (content_type!=null)
							{
								_contentType=content_type.toString();
								_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
							}
							else
							{
								_contentType=contentType;
								_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
							}
						}
						else
						{
							_contentType=contentType;
							_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
						}
					}
					else if (i2>0)
					{
						_characterEncoding = QuotedStringTokenizer.unquote(contentType.substring(i8,i2));
						_contentType=contentType;
						_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
					}
					else
					{
						_characterEncoding = QuotedStringTokenizer.unquote(contentType.substring(i8));
						_contentType=contentType;
						_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
					}
				}
				else // No encoding in the params.
				{
					_cachedMimeType = null;
					_contentType=_characterEncoding==null?contentType:contentType+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
					_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
				}
			}
			else // No params at all
			{
				_mimeType = contentType;
				_cachedMimeType = MimeTypes.CACHE.get(_mimeType);

				if (_characterEncoding!=null)
				{
					if (_cachedMimeType!=null)
					{
						CachedBuffer content_type = _cachedMimeType.getAssociate(_characterEncoding);
						if (content_type!=null)
						{
							_contentType=content_type.toString();
							_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
						}
						else
						{
							_contentType = _mimeType+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
							_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
						}
					}
					else
					{
						_contentType=contentType+";charset="+QuotedStringTokenizer.quoteIfNeeded(_characterEncoding,";= ");
						_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
					}
				}
				else if (_cachedMimeType!=null)
				{
					_contentType = _cachedMimeType.toString();
					_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
				}
				else
				{
					_contentType=contentType;
					_connection._responseFields.put(HttpHeaders.CONTENT_TYPE,_contentType);
				}
			}
		}
	}

	@Override
	public void setBufferSize(int size)
	{
		throw new UnsupportedOperationException();
	}

	@Override
	public int getBufferSize()
	{
		return _connection._generator.getContentBufferSize();
	}

	@Override
	public void flushBuffer() throws IOException
	{
		_connection.flushResponse();
	}

	@Override
	public void reset()
	{
		resetBuffer();
		fwdReset();
		_status = 200;
		_reason = null;
		
		HttpFields response_fields=_connection._responseFields;
		
		response_fields.clear();
		String connection=_connection._requestFields.getStringField(HttpHeaders.CONNECTION);
		if (connection!=null)
		{
			String[] values = connection.split(",");
			for  (int i=0;values!=null && i<values.length;i++)
			{
				int cb = HttpHeaderValues.CACHE.getOrdinal(values[0].trim());

				if (cb != -1)
				{
					switch(cb)
					{
						case HttpHeaderValues.CLOSE_ORDINAL:
							response_fields.put(HttpHeaders.CONNECTION,HttpHeaderValues.CLOSE);
							break;

						case HttpHeaderValues.KEEP_ALIVE_ORDINAL:
							if (HttpVersions.HTTP_1_0.equalsIgnoreCase(_connection.getRequest().getProtocol()))
								response_fields.put(HttpHeaders.CONNECTION,HttpHeaderValues.KEEP_ALIVE);
							break;
						case HttpHeaderValues.TE_ORDINAL:
							response_fields.put(HttpHeaders.CONNECTION,HttpHeaderValues.TE);
							break;
					}
				}
			}
		}
	}
	
	
	private void fwdReset()
	{
		resetBuffer();

		_writer=null;
		_outputState=NONE;
	}

	@Override
	public void resetBuffer()
	{
		if (isCommitted())
			throw new IllegalStateException("Committed");
		_connection._generator.resetBuffer();
	}

	@Override
	public boolean isCommitted()
	{
		return _connection._generator.isCommitted();
	}


	@Override
	public void setLocale(Locale locale)
	{
		if (locale == null || isCommitted())
			return;

		_locale = locale;
		_connection._responseFields.put(HttpHeaders.CONTENT_LANGUAGE,locale.toString().replace('_','-'));
	}

	@Override
	public Locale getLocale()
	{
		if (_locale==null)
			return Locale.getDefault();
		return _locale;
	}

	/* ------------------------------------------------------------ */
	/**
	 * @return The HTTP status code that has been set for this request. This will be <code>200<code>
	 *    ({@link HttpServletResponse#SC_OK}), unless explicitly set through one of the <code>setStatus</code> methods.
	 */
	public int getStatus()
	{
		return _status;
	}

	/* ------------------------------------------------------------ */
	/**
	 * @return The reason associated with the current {@link #getStatus() status}. This will be <code>null</code>,
	 *    unless one of the <code>setStatus</code> methods have been called.
	 */
	public String getReason()
	{
		return _reason;
	}

	public void complete()
		throws IOException
	{
		_connection.completeResponse();
	}

	/* ------------------------------------------------------------- */
	/**
	 * @return the number of bytes actually written in response body
	 */
	public long getContentCount()
	{
		if (_connection==null)
			return -1;
		return _connection._generator.getContentWritten();
	}

	public HttpFields getHttpFields()
	{
		return _connection._responseFields;
	}

	@Override
	public String toString()
	{
		return "HTTP/1.1 "+_status+" "+ (_reason==null?"":_reason) +System.getProperty("line.separator")+
		_connection._responseFields.toString();
	}
	
}