/** @file

  A brief file description

  @section license License

  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you 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.
 */

/***************************************/
/****************************************************************************
 *
 *  StatType.h - Functions for computing node and cluster stat
 *                          aggregation
 *
 *
 ****************************************************************************/

#ifndef _STATTYPE_H_
#define	_STATTYPE_H_

#include "StatXML.h"
#include "WebMgmtUtils.h"

#define BYTES_TO_MBIT_SCALE (8/1000000.0)

/* Structs used in Average Statistics calculations */
struct StatDataSamples
{
  ink_hrtime previous_time;
  ink_hrtime current_time;
  RecDataT data_type;
  RecData previous_value;
  RecData current_value;

  RecData diff_value(const char *name)
  {
    RecData tmp;

    if (data_type == RECD_NULL) {
      data_type = varType(name);
    }

    if (data_type != RECD_NULL)
      return RecDataSub(data_type, current_value, previous_value);
    else {
      RecDataClear(RECD_NULL, &tmp);
      return tmp;
    }
  }
  ink_hrtime diff_time()
  {
    return (current_time - previous_time);
  }
};

// Urgly workaround -- no optimization in HPUX
#if defined(hpux)
#define inline
#endif

#define MODULE      "StatPro"   // Statistics processor debug tag
#define MODULE_INIT "StatProInit"       // Statistics processor debug tag

/***************************************************************
 *                       StatExprToken
 * a statistics expression token can either be a binary operator,
 * name '+', '-', '*', '/', or parenthesis '(', ')' or a TS variable.
 * In the former case, the arithSymbol stores the operator or
 * paranthesis; otherwise arithSymbol is '/0';
 ***************************************************************/
class StatExprToken
{

public:

  char m_arith_symbol;
  char *m_token_name;
  RecDataT m_token_type;
  RecData m_token_value;
  RecData m_token_value_max;
  RecData m_token_value_min;
  StatDataSamples *m_token_value_delta;
  bool m_sum_var;
  bool m_node_var;

  // Member Functions
  void assignTokenName(const char *);
  bool assignTokenType();
  void print(const char *);
  short precedence();
  void copy(const StatExprToken &);

  LINK(StatExprToken, link);
  StatExprToken();
  inline ~ StatExprToken()
  {
    clean();
  };
  void clean();

  bool statVarSet(RecDataT, RecData);
};


/**
 * StatExprList
 *   simply a list of StatExprToken.
 **/
class StatExprList
{

public:

  StatExprList();
  inline ~ StatExprList()
  {
    clean();
  };
  void clean();

  void enqueue(StatExprToken *);
  void push(StatExprToken *);
  StatExprToken *dequeue();
  StatExprToken *pop();
  StatExprToken *top();
  StatExprToken *first();
  StatExprToken *next(StatExprToken *);
  unsigned count();
  void print(const char *);

private:

  size_t m_size;
  Queue<StatExprToken> m_tokenList;
};

/***************************************************************
 *                        StatObject
 * Each entry in the statistics XML file is represented by a
 * StatObject.
 ***************************************************************/
class StatObject
{

public:

  unsigned m_id;
  bool m_debug;
  char *m_expr_string;          /* for debugging using only */
  StatExprToken *m_node_dest;
  StatExprToken *m_cluster_dest;
  StatExprList *m_expression;
  StatExprList *m_postfix;
  ink_hrtime m_last_update;
  ink_hrtime m_current_time;
  ink_hrtime m_update_interval;
  RecFloat m_stats_max;
  RecFloat m_stats_min;
  bool m_has_max;
  bool m_has_min;
  bool m_has_delta;
  LINK(StatObject, link);

  // Member functions
  StatObject();
  StatObject(unsigned);
  inline ~ StatObject()
  {
    clean();
  };
  void clean();
  void assignDst(const char *, bool, bool);
  void assignExpr(char *);

  StatExprToken *StatBinaryEval(StatExprToken *, char, StatExprToken *, bool cluster = false);
  RecData NodeStatEval(RecDataT *result_type, bool cluster);
  RecData ClusterStatEval(RecDataT *result_type);
  void setTokenValue(StatExprToken *, bool cluster = false);

private:

  void infix2postfix();
};


/**
 * StatObjectList
 *    simply a list of StatObject.
 **/
class StatObjectList
{

public:

  // Member functions
  StatObjectList();
  inline ~ StatObjectList()
  {
    clean();
  };
  void clean();
  void enqueue(StatObject * object);
  StatObject *first();
  StatObject *next(StatObject * current);
  void print(const char *prefix = "");
  short Eval();                 // return the number of statistics object processed

  size_t m_size;

private:

  Queue<StatObject> m_statList;
};

#endif
