package com.jamonapi.http;


import java.lang.reflect.Method;


import com.jamonapi.MonKeyImp;
import com.jamonapi.MonKey;
import com.jamonapi.MonitorFactory;
import com.jamonapi.Monitor;
import com.jamonapi.NullMonitor;
import com.jamonapi.utils.Misc;

/** Stateless class used by HttpMonRequest to represent anything a request is monitoring.
 * There will be one HttpMonItem in HttpMonFactory for each thing we are monitoring.  The state information
 * needed for monitoring a particular request is kept in HttpMonRequest.  Note any of the mehtods that take 
 * a HttpMonRequest need some form of state associated with the request.  By making HttpMonRequest stateful
 * and HttpMonItem stateless a significant number of object creations were saved.
 * 
 * @author Steven Souza
 *
 */

class HttpMonItem  {

        private boolean isTimeMon;//used in JettyHttpMonItem
        private String units="noUnitsProvided";// units used by jamon
        private String label;// label used as a base by jamon
        private String methodName;// method name that monitoring calls. getStatus, getRequestURI etc.
        private String additionToLabel="";// u=url, v=value. possibilities are empty, u,v,uv,vu
        private boolean isResponse=true;// Are we monitoring an HttpServletRequest or an HttpServletResponse
        private Method method;
        // containers put jessionid (and other params) as part of what is returned by getRequestURI, and getRequestURL.  This can make 
        // many pages not unique enough to benefit from jamon, so by default this part of the url is removed from the monitoring label
        // i.e. /myapp/mypage.jsp;jsessionid=320sljsdofou 
        //  becomes the following to jamon
        //   /myapp/mypage.jsp
        private boolean removeHttpParams=false;// remove httpParams of request from jamon label.
        private static final Monitor NULL_MON=new NullMonitor();// used when disabled

        HttpMonItem() {
        }
        
        
        /** Valid constructor arguments are case insensitive, and have to start with request, response to differentiate whether to use an object
         * that inhertis from HttpServletRequest or HttpServletResponse respectively.  This must be follwed by the methodname, units,  an optional '.value',
         * and a units.  The method name will be executed.  Note a unit of 'ms' would cause a timed monitor to be called.
         * 
         * Examples:    request.getRequestURI().ms, request.getRequestURI().ms.value, request.getRequestURI().myUnits
         *              response.getBufferSize().bytes, response.getBufferSize().bytes.value
         *
         * @param label
         */
        HttpMonItem(String label, HttpMonFactory httpMonFactory) {
            parseLabel(label, httpMonFactory);
            
        }
        
        
        
        // parse passed in string and build HttpMonItems from it to be used to monitor
        // The request. Note general form is request or response followed by a method name and units.  Special defined tokes are value, contextpath, url and units
        private void parseLabel(String localLabel, HttpMonFactory httpMonFactory) {
            String colAlias=colAlias(localLabel); // brings back anything after 'as', if it exists, null otherwise:  request.getMethod().bytes as ColName
            String nonAlias=nonAlias(localLabel); // brings back what is before 'as alias'.  i.e. request.getMethod().bytes
            
            String[] parsedLabel=nonAlias.split("[.]");
            
            label=httpMonFactory.getLabelPrefix()+".response.";// default label
           
            for (int i=0;i<parsedLabel.length;i++) {
                
                String token=parsedLabel[i].trim();
                
                if ("request".equalsIgnoreCase(token)) { // request.
                    label=httpMonFactory.getLabelPrefix()+".request.";
                    isResponse=false;
                } else if ("response".equalsIgnoreCase(token)) { // response.
                    label=httpMonFactory.getLabelPrefix()+".response.";
                    isResponse=true;
                } else if (token.indexOf("()")!=-1) { // response.methodName()
                    label+= (colAlias==null) ? token : colAlias;// if this is of the format:  response.methodName().value.ms as aliasName then use aliasName in jamon label
                    methodName=token.replaceFirst("[(][)]", "");
                } else if ("value".equalsIgnoreCase(token)) { // response.methodName().value
                    additionToLabel+="v";// indicates value
                } else if ("url".equalsIgnoreCase(token)) { // response.methodName().url (note both value and url can be on the same line)
                    additionToLabel+="u";// indicates url
                } else if ("contextpath".equalsIgnoreCase(token)) { // response.methodName().url (note both value and url can be on the same line)
                    additionToLabel+="p";// indicates path such as /jamon  
                } else if ("ms".equalsIgnoreCase(token)) { // convert ms to ms.  a unit of 'ms.' causes start/stop to be called (i.e. it is a time monitor)
                    units="ms.";
                    isTimeMon=true;
                } else { // any thing else is the units
                    units=token;
                    isTimeMon=false;
                }
                    

            }

            // gets rid of jsessionid from jamon summary labels if ignorehttpparams is true and we are monitoring 
            // the pagehits.
            if (httpMonFactory.getIgnoreHttpParams() && ("getRequestURI".equals(methodName) || "getRequestURL".equals(methodName))) 
               removeHttpParams=true;
            
        }



        String getUnits() {
            return units;
        }
 
        boolean isResponse() {
            return isResponse;
        }
        

        boolean isTimeMon() {
            return isTimeMon;
        }
     
        // This method checks to see if the size threshold has been exceeded.  If this is a time monitor and the threshold
        // has not been exceeded or if the monitor of the given time has already been created once
        // then a time monitor is started.  The method is called by HttpMonRequest for each item that is being monitored.  Due to the 
        // fact that this class has no state it is being passed in via the HttpMonRequest object.
        void start(HttpMonRequest httpMonBase) {
            
          if (isTimeMon) {
            Monitor timeMon=null;
            // if this element puts number of monitors over the threshold size then don't create a new monitor.
            if (sizeThresholdExceeded(httpMonBase)) {
              createSizeThresholdExceededMon(httpMonBase);
              timeMon=NULL_MON;
            }
          
            if (timeMon==null) {
              timeMon=startTimeMon(httpMonBase);
            }
            
            httpMonBase.setTimeMon(timeMon);
          }
        }
        
        
        // Stop any started monitors.
        void stop(HttpMonRequest httpMonBase) {
            if (isTimeMon) {
                stopTimeMon(httpMonBase);
            } else if (sizeThresholdExceeded(httpMonBase)) {// note thresholds indicators have already been created for time monitors
                createSizeThresholdExceededMon(httpMonBase);
            } else {
               MonitorFactory.add(getMonKey(httpMonBase), getValueToAdd(httpMonBase));
            }
        }
        
        
        // This method is needed as the jetty version of HttpMonItem has to track time differently. 
        Monitor startTimeMon(HttpMonRequest httpMonBase) {
            return MonitorFactory.start(getMonKey(httpMonBase));
        }
        
        // This method is also needed as the jetty version of HttpMonItem tracks time differently
        void stopTimeMon(HttpMonRequest httpMonBase) {
            httpMonBase.stopTimeMon();
        }
        
        private boolean sizeThresholdExceeded(HttpMonRequest httpMonBase) {
            // if number of jamon rows is greater than configured size (as well as size has been defined i.e. > 0) then don't create a monitor.
            // if the monitor already exists then you can proceed as no more monitors will be created.
            return MonitorFactory.getNumRows()>httpMonBase.getSize() && httpMonBase.getSize()>0 && !MonitorFactory.exists(getMonKey(httpMonBase));
        }
        
        // Track anytime the monitor threshold has been exceeded.
        private void createSizeThresholdExceededMon(HttpMonRequest httpMonBase) {
            String label=new StringBuffer(httpMonBase.getLabelPrefix()).append(".HttpMonFactory.sizeExceeded.").append(httpMonBase.getSize()).toString();
            String detailLabel=new StringBuffer(getLabel(httpMonBase)).append(", ").append(httpMonBase.getRequestURI()).append(", ").append(getUnits()).toString();
            MonitorFactory.add(new MonKeyImp(label, detailLabel, "Count"), httpMonBase.getSize());
        }
        
        

        // return key.  note we are passing in details that can be used in the detail buffer.  Details consist of the uri as well as a stack trace
        // if one occured.  
        MonKey getMonKey(HttpMonRequest httpMonBase) {
            return new MonKeyImp(getLabel(httpMonBase), httpMonBase.getDetails(), getUnits());
        }
        
        /** If a value label is to be used then append it to the end of the label, else just return the label.  The results will be used to create
         * a jamon record.  Ex:  request.getMethod() or request.getMethod().post 
         * @return
         */
        String getLabel(HttpMonRequest httpMonBase) {
            if ("".equals(additionToLabel))
              return label;
            
            // add value and/or url if they are required in the label.
            StringBuffer sb=new StringBuffer(label);
            if ( !(label.charAt(label.length()-1)=='.'))// in some cases if this isn't done then the label has no dots, or 2 consecutive ones.
                sb.append(".");
            
            for (int i=0;i<additionToLabel.length();i++) {
                if (i>=1)// i.e. both u and v are specified
                  sb.append(", ");
                
                if (additionToLabel.charAt(i)=='v')//value
                  sb.append("value: ").append(getValueLabel(httpMonBase));
                else if (additionToLabel.charAt(i)=='u')//url
                  sb.append("url: ").append(httpMonBase.getKeyReadyURI());
                else if (additionToLabel.charAt(i)=='p')//path
                  sb.append("contextpath: ").append(httpMonBase.getContextPath());
                
            }
            
            return sb.toString();
        }
        
        /** Used to create a jamon label like request.getMethod().post */

        Object getValueLabel(HttpMonRequest httpMonBase) {
          Object valLabel=executeMethod(httpMonBase);
          if (removeHttpParams)
            valLabel=removeHttpParams(valLabel);
              
          return valLabel;    
        }
 
        /* Return value to be added to jamon.  Note this is not called when it is a time monitor.  If the object returned is a number
         * then add that value to jamon else just add the number 1. */
        double getValueToAdd(HttpMonRequest httpMonBase) {
            Object obj=executeMethod(httpMonBase);
            if (obj instanceof Number)
              return ((Number)obj).doubleValue();
            else 
              return 1.0;
        }
        
        // Execute the request or responses method.
        private Object executeMethod(HttpMonRequest httpMonBase) {
            Object retValue=null;
            try {
                retValue = getMethod(httpMonBase).invoke(getObjectToExecute(httpMonBase), (Object[])null);// null is noargs.
            } catch (Throwable e) {// note I don't want the program to abort due to monitoring so the exception is not being passed upstream
                MonitorFactory.add(new MonKeyImp(httpMonBase.getLabelPrefix()+".monError", new Object[]{this, Misc.getExceptionTrace(e)}, "Exception"),1);
            }
            
            return retValue;
            
        }
        
        // return method that we are getting monitoring info from.
        Method getMethod(HttpMonRequest httpMonBase) {

           try {
              if (method==null)
                method = getObjectToExecute(httpMonBase).getClass().getMethod(methodName, (Class[])null);
            } catch (NoSuchMethodException e) {
            }
            
            return method;

        }
        
        // get the object we are calling the monitoring method from 
        Object getObjectToExecute(HttpMonRequest httpMonBase) {
            if (isResponse())
              return httpMonBase.getResponse();
            else
              return httpMonBase.getRequest();
        }
        

        
        public String toString() {
            return new StringBuffer("label=").append(label).append(", units=").append(units).append(", methodName=").append(methodName).toString();
        }
        
        // get alias portion of 'request.getRequestURI() AS myAlias.
        // this is used to put a more descriptive name in jamon.
        private static String colAlias(String str) {
            if (str==null)
              return null;
            
            String[] arr=str.split(" [aA][sS] ");
            if (arr.length==2) // returns pageHits when 'request.getRequestURI() as pageHits' is passed
              return arr[1].trim();
            else
              return null;  // returns request.getRequestURI() (no alias was used)
        }
        
        // return nonalias portion of string.
        private static String nonAlias(String str) {
            if (str==null)
              return null;
              
            String[] arr=str.split(" [aA][sS] ");
            return arr[0].trim();  // returns request.getRequestURI() (no alias was used)

        }
        
        // passing this: http://www.mypage.com:8080/page;jsessionid=5akalsdjfflj;other=9s0f0udsf?pageName=my.jsp
        // would return this: http://www.mypage.com:8080/page
        // used to remove jsessionid from page hits.
        private static String removeHttpParams(Object url) {
            if (url==null)
              return null;
            
            String urlStr=url.toString();
            int paramIndex = urlStr.indexOf(";");
            if (paramIndex == -1)// ; isn't in string
                return urlStr;
            else
                return urlStr.substring(0, paramIndex);
                
        }
        

        
        public static void main(String[] args) {
            
            System.out.println(colAlias("request.getMethod().units.value as MyLabel"));
            System.out.println(colAlias("request.getMethod().units.value"));  // null no alias
            System.out.println(colAlias("request.getMethod()"));// null no alias
            System.out.println(nonAlias("request.getMethod().units.value as MyLabel"));
            
            System.out.println(removeHttpParams("http://www.mypage.com:8080/page;jsessionid=5akalsdjfflj;other=9s0f0udsf?pageName=my.jsp"));
            System.out.println(removeHttpParams("http://www.mypage.com:8080/page?pageName=my.jsp"));
  
             
          }
        

        
}