package org.simpleframework.http.validate;

import java.io.InputStream;
import java.util.List;
import java.util.Map;

import org.simpleframework.http.StatusLine;
import org.simpleframework.xml.Attribute;
import org.simpleframework.xml.ElementList;
import org.simpleframework.xml.Root;
import org.simpleframework.xml.Text;

/**
 * <analyser statusCode='200' statusDescription='OK' bodyLength='1024'>
 *    <expect name='Content-Type'>text/plain</expect>
 * </analyser>
 * 
 * @author niall
 *
 */
@Root
public class Analyser {
   
   @ElementList(inline=true)
   private List<Expect> expect;
   
   @Attribute(required=false)
   private String bodyHash;
   
   @Attribute(required=false)
   private String statusDescription;
   
   @Attribute
   private int statusCode;
   
   @Attribute
   private int bodyLength;
   
   public void analyse(Result response, boolean debug) throws Exception {
      InputStream stream = response.getInputStream();
      StatusLine statusLine = response.getStatusLine();
      Map<String, String> header = response.getHeader();
      int length = stream.available();
      
      if(statusLine.getCode() != statusCode) {
         throw new IllegalStateException("Expected status code '"+statusCode+"' but got '"+statusLine.getCode()+"'");
      }
      if(statusDescription != null && !statusLine.getDescription().equals(statusDescription)) {
         throw new IllegalStateException("Expected status description '"+statusDescription+"' but got '"+statusLine.getDescription()+"'");
      }
      if(statusLine.getMajor() != 1) {
         throw new IllegalStateException("Header does not start with value 1.x HTTP version");
      }
      for(Expect entry : expect) {
         entry.check(header);
      }
      if(length!= bodyLength) {
         throw new IllegalStateException("Body length '"+length+"' does not match expectation '"+bodyLength+"'");
      }
      if(bodyHash != null) {
         String md5HashString = Digest.getSignature(Digest.Algorithm.MD5, stream);

         if(!md5HashString.equals(bodyHash)) {
            throw new Exception("Expected body MD5 hash '"+bodyHash+"' does not match computed hash '"+md5HashString+"'");                  
         }
         if(debug) {
            System.out.printf("MD5: hash ok as %s for length %s%n", md5HashString, length);
         }
      }
   }
   
   @Root
   private static class Expect{
      @Attribute
      private String name;
      @Text
      private String value;
      
      public void check(Map<String, String> response) {
         String text = response.get(name);
         
         if(value == null) {
            throw new IllegalStateException("Response does not contain header '"+name+"'");
         }
         if(!value.equals(text)) {
           throw new IllegalStateException("Response header value '"+text+"' does not match expectation '"+value+"'");  
         }
      }
   }
}