where.h

#ifndef _WHERE_H
#define _WHERE_H
/*
 * Fledge storage client.
 *
 * Copyright (c) 2018 OSisoft, LLC
 *
 * Released under the Apache 2.0 Licence
 *
 * Author: Mark Riddoch, Massimiliano Pinto
 */
#include <string>
#include <vector>
#include <stdexcept>

typedef enum Conditional {
    Older,
    Newer,
    Equals,
    NotEquals,
    GreaterThan,
    LessThan,
    In,
    IsNull,
    NotNull
} Condition;

class Where {
    public:
        Where(const std::string& column, const Condition condition, const std::string& value) :
                m_column(column), m_condition(condition), m_and(0), m_or(0)
        {
            if (condition != In)
            {
                m_value = value;
            }
            else
            {
                m_in.push_back(value);
            }
        };
        Where(const std::string& column, const Condition condition, const std::string& value, Where *andCondition) :
                m_column(column), m_condition(condition), m_and(andCondition), m_or(0)
        {
            if (condition != In)
            {
                m_value = value;
            }
            else
            {
                m_in.push_back(value);
            }
        };
        Where(const std::string& column, const Condition condition) :
                m_column(column), m_condition(condition), m_and(0), m_or(0)
        {
            if (condition != IsNull && condition != NotNull)
            {
                throw std::runtime_error("Missing value in where clause");
            }
        };
        Where(const std::string& column, const Condition condition, Where *andCondition) :
                m_column(column), m_condition(condition), m_and(andCondition), m_or(0)
        {
            if (condition != IsNull && condition != NotNull)
            {
                throw std::runtime_error("Missing value in where clause");
            }
        };
        ~Where();
        void        andWhere(Where *condition) { m_and = condition; };
        void        orWhere(Where *condition) { m_or = condition; };
        void        addIn(const std::string& value)
        {
            if (m_condition == In)
            {
                m_in.push_back(value);
            }
        };
        const std::string   toJSON() const;
    private:
        Where(const Where&);
        Where&          operator=(Where const&);
        const std::string   m_column;
        const Condition     m_condition;
        std::string     m_value;
        Where           *m_and;
        Where           *m_or;
        std::vector<std::string>
                    m_in;
};
#endif