#ifndef __JTRIGGER__JCHECKSUM__
#define __JTRIGGER__JCHECKSUM__

#include <vector>
#include <limits>

#include "km3net-dataformat/online/JDAQ.hh"
#include "km3net-dataformat/online/JDAQClock.hh"
#include "km3net-dataformat/online/JDAQHit.hh"
#include "km3net-dataformat/online/JDAQSuperFrame.hh"

#include "JLang/JException.hh"
#include "Jeep/JStatus.hh"

/**
 * \author mdejong
 */

namespace JTRIGGER {}
namespace JPP { using namespace JTRIGGER; }

namespace JTRIGGER {

  using KM3NETDAQ::JDAQHit;
  using KM3NETDAQ::JDAQSuperFrame;
  using KM3NETDAQ::NUMBER_OF_PMTS;

  using JLANG::JValueOutOfRange;
  using JLANG::JIndexOutOfRange;
  using JEEP::JStatus;

  /**
   * Maximal frame size.
   */
  static int MAXIMAL_FRAME_SIZE = std::numeric_limits<int>::max();


  /**
   * Auxiliary class to perform check-sum on raw data.
   */
  struct JChecksum {
    /**
     * Error types.
     */
    enum error_types {
      EPMT_t = 1,      //!< PMT number error
      ETDC_t,          //!< TDC value  error
      TIME_t,          //!< Time order error
      EUDP_t,          //!< UDP packet error
      SIZE_t           //!< size       error
    };


    /**
     * Error.
     */
    struct error {
      /**
       * Default constructor.
       */
      error() :
	pos (-1),
	type(-1)
      {}


      /**
       * Constructor.
       *
       * \param  pos           index in frame
       * \param  type          error type
       */
      error(const int pos,
	    const int type) :
	pos (pos),
	type(type)
     {}

      
      int pos;            //!< index in frame
      int type;           //!< error type
    };


    /**
     * Auxiliary data structure for result of checksum.
     */
    struct result_type :
      public std::vector<error>
    {
      /**
       * Type conversion operator.
       *
       * \return               true if okay; else false
       */
      operator bool() const
      {
	return this->empty();
      }

      /**
       * Check for errors with given error mask.
       *
       * \param  mask          error mask
       * \return               true if error present; else false
       */
      bool has(const JStatus& mask) const
      {
	for (const_iterator i = this->begin(); i != this->end(); ++i) {
	  if (mask.has(i->type)) {
	    return true;
	  }
	}

	return false;
      }
    };

    typedef result_type::const_iterator                const_iterator;
    typedef result_type::const_reverse_iterator        const_reverse_iterator;


    /**
     * Default constructor.
     */
    JChecksum()
    {
      t0.resize(NUMBER_OF_PMTS, 0);
    }


    /**
     * Check sum.
     *
     * The following checks are made:
     *    -# UDP packet assembly is complete;
     *    -# PMT number greater or equals zero and less than NUMBER_OF_PMTS;
     *    -# TDC value less than frame time (with 5% margin);
     *    -# TDC values from same PMT are monotonously increasing;
     *
     * \param  frame         DAQ frame
     * \return               list of errors; empty if all okay
     */
    const result_type& operator()(const JDAQSuperFrame& frame) const
    {
      using namespace std;
      using namespace KM3NETDAQ;

      const JDAQHit::JTDC_t Tmax = (JDAQHit::JTDC_t) (getTimeSinceRTS(frame.getFrameIndex()) + 1.05 * getFrameTime());

      buffer.clear();

      for (vector<JDAQHit::JTDC_t>::iterator i = t0.begin(); i != t0.end(); ++i) {
	*i = 0;
      }

      if (frame.size() > MAXIMAL_FRAME_SIZE) {
	buffer.push_back(error(-1, SIZE_t));
      }

      if (!frame.testDAQStatus()) {
	buffer.push_back(error(-1, EUDP_t));
      }

      for (JDAQSuperFrame::const_iterator hit = frame.begin(); hit != frame.end(); ++hit) {

	const JDAQHit::JTDC_t pmt = hit->getPMT();
	const JDAQHit::JTDC_t tdc = hit->getT();

	if (pmt < NUMBER_OF_PMTS) {

	  if (tdc < t0[pmt]) {
	    buffer.push_back(error(distance(frame.begin(), hit), TIME_t));
	  }

	  if (tdc > Tmax) {
	    buffer.push_back(error(distance(frame.begin(), hit), ETDC_t));
	  }

	  t0[pmt] = tdc;

	} else {

	  buffer.push_back(error(distance(frame.begin(), hit), EPMT_t));	  
	}
      }

      return buffer;
    }

  private:
    mutable std::vector<JDAQHit::JTDC_t> t0;
    mutable result_type buffer;
  };


  /**
   * Function object to perform check-sum of raw data.
   */
  static const JChecksum checksum;
}

#endif