//================================================================================
// Name        : CaliperSensorGroup.h
// Author      : Micha Mueller
// Contact     : info@dcdb.it
// Copyright   : Leibniz Supercomputing Centre
// Description : Header file for Caliper sensor group class.
//================================================================================

//================================================================================
// This file is part of DCDB (DataCenter DataBase)
// Copyright (C) 2019-2019 Leibniz Supercomputing Centre
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//================================================================================

#ifndef CALIPER_CALIPERSENSORGROUP_H_
#define CALIPER_CALIPERSENSORGROUP_H_

#include "../../includes/SensorGroupTemplate.h"

#include "CaliperSensorBase.h"

#include <atomic>
#include <semaphore.h>
#include <unordered_map>

/**
 * @brief SensorGroupTemplate specialization for this plugin.
 *
 * @ingroup caliper
 */
class CaliperSensorGroup : public SensorGroupTemplate<CaliperSensorBase> {

/*******************************************************************************
 * Keep in sync with DcdbPusher Caliper service
 ******************************************************************************/
#define SHM_MAX_RETRIES 5
#define MAX_SYMBOL_SIZE 512
#define MAX_PATH_SIZE  4096
#define MSGQ_SIZE      8192
#define STR_PREFIX     "/cali_dcdb_"
#define SHM_SIZE       (32*1024*1024)

typedef struct {
    uintptr_t pc;
    uint64_t  ts;
    unsigned  short cpu;
} snap_data;

/* Entry for an executable symbol in the symbol table */
typedef struct {
    uintptr_t start_addr;
    uintptr_t end_addr;
    char      name[MAX_SYMBOL_SIZE];
} fsym_data;

/* Defines a contiguous executable memory block */
typedef struct {
    uintptr_t start_addr;
    uintptr_t end_addr;
    uintptr_t offset; // offset as parsed from /proc//maps
    size_t    fsym_offset; // Offset in bytes from the address of this struct
                           // to the beginning of the associated symbol section
    size_t    fsym_count; // Number of symbols in this address range
    char      pathname[MAX_PATH_SIZE]; // Filepath + name of the binary where
                                       // this memory range comes from or
                                       // "[Anonymous]" if unknown
} addr_data;

/*
 * Layout of shared-memory file used to communicate with Caliper service:
 *
 * //Communication queue, aka ring buffer:
 * size_t r_index //points to the last read element
 * size_t w_index //points to the last written element
 * sem_t  r_sem;
 * sem_t  w_sem;
 * snap_data[MSGQ_SIZE]
 *
 * //symbol lookup data
 * size_t addr_count
 * addr_data[addr_count]
 * addr_count * (fsym_data[addr_data.fsym_count])
 */
static constexpr size_t lookup_data_offset = 2*sizeof(size_t)
                                           + 2*sizeof(sem_t)
                                           + MSGQ_SIZE*sizeof(snap_data);

public:
    CaliperSensorGroup(const std::string& name);
    CaliperSensorGroup(const CaliperSensorGroup& other);
    virtual ~CaliperSensorGroup();
    CaliperSensorGroup& operator=(const CaliperSensorGroup& other);

    bool execOnStart() final override;
    void execOnStop()  final override;

    std::vector<SBasePtr>& acquireSensors() final override {
        while (_lock.test_and_set(std::memory_order_acquire)) {}
        return _baseSensors;
    }

    void releaseSensors() final override {
        _lock.clear(std::memory_order_release);
    }

    void printGroupConfig(LOG_LEVEL ll) final override;

    void setGlobalMqttPrefix(const std::string& prefix) { _globalMqttPrefix = prefix; }

private:
    void read() final override;

    int _socket;
    int _connection;
    void*  _shm;
    int    _shmFile;
    size_t _shmFailCnt;
    std::string _globalMqttPrefix;

    std::atomic_flag _lock; ///< Lock to synchronize access to associated sensors
    //TODO aggregate sensor values: store pair of S_Ptr and counter. Only push values at end of iteration
    std::unordered_map<std::string, S_Ptr> _sensorIndex; ///< Additional sensor storage for fast lookup
};

#endif /* CALIPER_CALIPERSENSORGROUP_H_ */