/**
    * Copyright (C) 2005-2009 Alfresco Software Limited.
    *
    * This file is part of the Spring Surf Extension project.
    *
    * Licensed 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.springframework.extensions.webscripts;
  
  
  /**
   * Represents a MediaType as described at
   * 
   * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
   */
  public class MediaType
  {
      private String type;
      private String subtype;
      private String params = "";
      private float quality = 1.0f;
      
  
      /**
       * Construct
       * 
       * @param  mediatype  string representation of mediatype e.g. text/html;level=1;q=0.8
       */
      public MediaType(String mediatype)
      {
          if (mediatype == null || mediatype.length() == 0)
          {
              throw new WebScriptException("Invalid mediatype: " + mediatype);
          }
          String[] parts = mediatype.split("/");
          if (parts.length != 2)
          {
              throw new WebScriptException("Invalid mediatype: " + mediatype + " does not consists of type and subtype");
          }
          
          this.type = parts[0].trim();
  
          int paramsIdx = parts[1].indexOf(';');
          if (paramsIdx == -1)
          {
              // subtype only has been specified
              this.subtype = parts[1];
          }
          else
          {
              String params = parts[1].substring(paramsIdx);
              int qualityIdx = params.lastIndexOf(";");
              String[] qualityParts = params.substring(qualityIdx +1).split("=");
              if (qualityParts.length == 2 && qualityParts[0].trim().equals("q"))
              {
                  // mediatype includes quality factor (and potentially accept-params)
                  this.subtype = parts[1].substring(0, paramsIdx).replace(" ", "");
                  this.quality = new Float(qualityParts[1].trim()).floatValue();
                  if (qualityIdx > 0)
                  {
                      this.params = params.substring(1, qualityIdx).replace(" ", "");
                  }
              }
              else
              {
                  // mediatype includes accept-params only
                  this.subtype = parts[1].substring(0, paramsIdx).replace(" ", "");
                  this.params = params.substring(1).replace(" ", "");
              }
          }
      }
      
      /**
       * @return  type
       */
      public String getType()
      {
          return type;
      }
  
      /**
       * @return  subtype
       */
      public String getSubtype()
      {
          return subtype;
      }
  
     /**
      * @return  params
      */
     public String getParams()
     {
         return params;
     }
 
     /**
      * @return  quality factory
      */
     public float getQuality()
     {
         return quality;
     }
     
     /**
      * Compare to another media type
      * 
      * @param to  media type to compare to
      * @return  score representing how close a match the compared media types are
      */
     public float compare(MediaType to)
     {
         boolean typeWildcard = to.type.equals("*");
         boolean subtypeWildcard = to.subtype.equals("*");
         boolean paramsWildcard = to.params.length() == 0;
         if (typeWildcard || type.equals(to.type))
         {
             if (subtypeWildcard || subtype.equals(to.subtype))
             {
                 if (paramsWildcard || params.equals(to.params))
                 {
                     return (typeWildcard ? 0.0f : 10.0f) + (subtypeWildcard ? 0.0f : 100.0f) + (paramsWildcard ? 0.0f : 1000f) + to.quality;
                 }
             }
         }
         return 0.0f;
     }
     
     /**
      * @return  string representation of media type in the format of type/subtype[;params]
      */
     private String toMediaType()
     {
         return type + "/" + subtype + (params.length() == 0 ? "" : ";" + params);
     }
     
     /* (non-Javadoc)
      * @see java.lang.Object#hashCode()
      */
     public int hashCode()
     {
         return toMediaType().hashCode();
     }
     
     /* (non-Javadoc)
      * @see java.lang.Object#equals(java.lang.Object)
      */
     public boolean equals(Object other)
     {
         if (other == null)
         {
             return false;
         }
         if (other instanceof MediaType)
         {
             return this.type.equals(((MediaType)other).type) && this.subtype.equals(((MediaType)other).subtype) &&
                    this.params.equals(((MediaType)other).params);
         }
         return false;
     }
     
     /* (non-Javadoc)
      * @see java.lang.Object#toString()
      */
     public String toString()
     {
         return toMediaType() + ";q=" + quality;
     }
 
     
     
     /**
      * Simple exampe usage
      * 
      * @param args
      */
     public static void main(String[] args)
     {
         MediaType one = new MediaType("*/*");
         System.out.println(one.toString());
         MediaType two = new MediaType("a/b");
         System.out.println(two.toString());
         MediaType three = new MediaType("a/*");
         System.out.println(three.toString());
         MediaType four = new MediaType("a/*;b=1");
         System.out.println(four.toString());
         MediaType five = new MediaType("a/* ; b=1");
         System.out.println(five.toString());
         System.out.println(four.equals(five));
         MediaType six = new MediaType("a/*;q=0.1");
         System.out.println(six.toString());
         MediaType seven = new MediaType("a/*;q = 0.1");
         System.out.println(seven.toString());
         MediaType eight = new MediaType("a/*; q = 0.1");
         System.out.println(eight.toString());
         MediaType nine = new MediaType("a/*;b=1; q = 0.1");
         System.out.println(nine.toString());
         MediaType ten = new MediaType("a/*;");
         System.out.println(ten.toString());
         MediaType eleven = new MediaType("a/*;b=1;c=2;q=1.0");
         System.out.println(eleven.toString());
         
         MediaType textHtmlLevel1 = new MediaType("text/html;level=1");
         MediaType textHtml = new MediaType("text/html");
         MediaType textPlain = new MediaType("text/plain");
         MediaType imageJpeg = new MediaType("image/jpeg");
         MediaType textHtmlLevel2 = new MediaType("text/html;level=2");
         MediaType textHtmlLevel3 = new MediaType("text/html;level=3");
         
         MediaType acceptTextStar = new MediaType("text/*;q=0.3");
         MediaType acceptTextHtml = new MediaType("text/html;q=0.7");
         MediaType acceptTextHtmlLevel1 = new MediaType("text/html;level=1");
         MediaType acceptTextHtmlLevel2 = new MediaType("text/html;level=2;q=0.4");
         MediaType acceptStarStar = new MediaType("*/*;q=0.5");
         
 
         MediaType[] negotiated = new MediaType[] {textHtmlLevel1, textHtml, textPlain, imageJpeg, textHtmlLevel2, textHtmlLevel3};
         MediaType[] accept = new MediaType[] {acceptTextStar, acceptTextHtml, acceptTextHtmlLevel1, acceptTextHtmlLevel2, acceptStarStar};
 
         for (MediaType neg : negotiated)
         {
             System.out.println("Testing " + neg.toMediaType());
             float q = 0.0f;
             for (MediaType acc : accept)
             {
                 float accq = neg.compare(acc);
                 System.out.println(" Compare to " + acc.toString() + " = " + accq);
                 if (accq > q)
                 {
                     q = accq;
                 }
             }
             System.out.println(" Result = " + q);
         }
     }
     
 }