#ifndef C_TIME_HISTOGRAM_H
#define C_TIME_HISTOGRAM_H
/*
 Hanoh Haim
 Ido Barnea
 Cisco Systems, Inc.
*/

/*
Copyright (c) 2015-2016 Cisco Systems, Inc.

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.
*/


#include <stdint.h>
#include <stdio.h>
#include <math.h>
#include <string>
#include <json/json.h>
#include "mbuf.h"
#include "os_time.h"

class CTimeHistogramPerPeriodData {
 public:
    void reset() {
        m_sum = 0;
        m_cnt = 0;
        m_cnt_high = 0;
        m_max = 0;
    }
    void inc_cnt() {m_cnt++;}
    void inc_high_cnt() {m_cnt_high++;}
    void update_max(dsec_t dt) {
        if (dt > m_max)
            m_max = dt;
    }
    void update_sum(dsec_t dt) {
        m_sum += dt * 1000000;
    }
    inline uint64_t get_sum() {return m_sum;}
    inline uint64_t get_cnt() {return m_cnt;}
    inline uint64_t get_high_cnt() {return m_cnt_high;}
    inline dsec_t get_max() {return m_max;}
    inline dsec_t get_max_usec() {return m_max * 1000000;}

 private:
    uint64_t m_sum; // Sum of samples
    uint64_t m_cnt;  // Number of samples
    uint64_t m_cnt_high;  // Number of samples above configured threshold
    dsec_t   m_max;  // Max sample
};

class CTimeHistogram {
public:
    enum {
        HISTOGRAM_SIZE=9,
        HISTOGRAM_SIZE_LOG=5,
        HISTOGRAM_QUEUE_SIZE=14,
    };
    bool Create(void);
    void Delete();
    void Reset();
    bool Add(dsec_t dt);
    void Dump(FILE *fd);
    void DumpWinMax(FILE *fd);
    /* should be called once each sampling period */
    void update();
    dsec_t  get_average_latency();
    /* get average of total data */
    dsec_t  get_max_latency(){
        return (get_usec(m_max_dt));
    }
    dsec_t  get_max_latency_last_update(){
        CTimeHistogramPerPeriodData &period_elem = m_period_data[get_read_period_index()];
        return period_elem.get_max_usec();
    }
    void  dump_json(std::string name,std::string & json );
    void dump_json(Json::Value & json, bool add_histogram = true);
    uint64_t get_count() {return m_total_cnt;}
    uint64_t get_high_count() {return m_total_cnt_high;}

private:
    uint32_t get_usec(dsec_t d);
    double  get_cur_average();
    void  update_average(CTimeHistogramPerPeriodData &period_elem);
    inline uint8_t get_read_period_index() {
        if (m_period == 0)
            return 1;
        else
            return 0;
    }

private:
    dsec_t   m_min_delta;/* set to 10usec*/
    // One element collects data for current period, other is saved for sending report.
    // Each period we switch between the two
    CTimeHistogramPerPeriodData m_period_data[2];
    uint8_t m_period; // 0 or 1 according to m_period_data element we currently use
    uint64_t m_total_cnt;
    uint64_t m_total_cnt_high;
    dsec_t   m_max_dt;  // Total maximum latency
    dsec_t   m_average; /* moving average */
    uint32_t m_win_cnt;
    dsec_t   m_max_ar[HISTOGRAM_QUEUE_SIZE]; // Array of maximum latencies for previous periods
    uint64_t m_hcnt[HISTOGRAM_SIZE_LOG][HISTOGRAM_SIZE] __rte_cache_aligned ;
};

#endif