/*
    * Copyright (c) 2002-2016, Mairie de Paris
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *  1. Redistributions of source code must retain the above copyright notice
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
   *     contributors may be used to endorse or promote products derived from
   *     this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * License 1.0
   */
  package fr.paris.lutece.plugins.swaggerui.web;
  
  import fr.paris.lutece.plugins.swaggerui.service.SwaggerFileService;
  import fr.paris.lutece.portal.service.template.AppTemplateService;
  import fr.paris.lutece.portal.service.util.AppPathService;
  import fr.paris.lutece.util.html.HtmlTemplate;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.Locale;
  import java.util.Map;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  /**
   * SwaggerServlet serve swagger files with dynamic host and base path
   */
  public class SwaggerServlet extends HttpServlet
  {
  
      private static final long serialVersionUID = -5713203328367191908L;
      private static final String CONTENT_TYPE_JSON = "application/json";
      private static final String CONTENT_TYPE_YAML = "application/x-yaml";
      private static final String MARK_HOST = "host";
      private static final String MARK_PORT = "port";
      private static final String MARK_CONTEXT = "context";
  
      /**
       * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
       *
       * @param request
       *            servlet request
       * @param response
       *            servlet response
       * @throws ServletException
       *             the servlet Exception
       * @throws IOException
       *             the io exception
       */
      protected void processRequest( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException
      {
          String strPathInfo = request.getPathInfo();
          int nPos = strPathInfo.indexOf( "/plugins" );
          String strFile = strPathInfo.substring( nPos );
          String strFileUrl = AppPathService.getAbsolutePathFromRelativePath( strFile );
          String strFileContent = readFile( strFileUrl, StandardCharsets.UTF_8 );
  
          Map<String, String> model = new ConcurrentHashMap<String, String>( );
          model.put( MARK_HOST, request.getServerName( ) );
          model.put( MARK_PORT, String.valueOf( request.getServerPort( ) ) );
          model.put( MARK_CONTEXT, request.getContextPath( ) );
  
          HtmlTemplate template = AppTemplateService.getTemplateFromStringFtl( strFileContent, Locale.getDefault( ), model );
          String strNewContent = template.getHtml( );
          
          String strContentType = CONTENT_TYPE_JSON;
          if( strFile.endsWith( SwaggerFileService.EXT_YAML))
          {
              strContentType = CONTENT_TYPE_YAML;
          }
         response.setContentType( strContentType );
 
         OutputStream out = response.getOutputStream( );
         out.write( strNewContent.getBytes( StandardCharsets.UTF_8 ) );
         out.flush( );
         out.close( );
 
     }
 
     /**
      * Read a File and returns its content as a string.
      * @param strFilePath The file path
      * @param encoding The encoding
      * @return The file content
      * @throws IOException If an error occurs
      */
     private static String readFile( String strFilePath, Charset encoding ) throws IOException
     {
         byte [ ] encoded = Files.readAllBytes( Paths.get( strFilePath ) );
         return new String( encoded, encoding );
     }
 
     /**
      * Handles the HTTP <code>GET</code> method.
      *
      * @param request
      *            servlet request
      * @param response
      *            servlet response
      * @throws ServletException
      *             the servlet Exception
      * @throws IOException
      *             the io exception
      */
     @Override
     protected void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException
     {
         processRequest( request, response );
     }
 
     /**
      * Handles the HTTP <code>POST</code> method.
      *
      * @param request
      *            servlet request
      * @param response
      *            servlet response
      * @throws ServletException
      *             the servlet Exception
      * @throws IOException
      *             the io exception
      */
     @Override
     protected void doPost( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException
     {
         processRequest( request, response );
     }
 
     /**
      * Returns a short description of the servlet.
      *
      * @return message
      */
     @Override
     public String getServletInfo( )
     {
         return "Servlet serving swagger files with dynamic host and basepath";
     }
 
 }