/*
 * (C) 2018 The University of Chicago
 * 
 * See COPYRIGHT in top-level directory.
 */
#ifndef __HEPNOS_KEYVAL_CONTAINER_H
#define __HEPNOS_KEYVAL_CONTAINER_H

#include <memory>
#include <string>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/serialization/string.hpp>
#include <hepnos/Demangle.hpp>
#include <hepnos/Exception.hpp>

namespace hepnos {

class KeyValueContainer {

    public:

    /**
     * @brief Default constructor.
     */
    KeyValueContainer() = default;

    /**
     * @brief Copy constructor.
     */
    KeyValueContainer(const KeyValueContainer& other) = default;

    /**
     * @brief Move constructor.
     */
    KeyValueContainer(KeyValueContainer&& other) = default;

    /**
     * @brief Copy-assignment operator.
     */
    KeyValueContainer& operator=(const KeyValueContainer& other) = default;

    /**
     * @brief Move-assignment operator.
     */
    KeyValueContainer& operator=(KeyValueContainer&& other) = default;

    /**
     * @brief Destructor.
     */
    virtual ~KeyValueContainer() = default;

    /**
     * @brief Stores raw key/value data in this KeyValueContainer.
     * This function is virtual and must be overloaded in the child class.
     *
     * @param key Key
     * @param buffer Value
     *
     * @return true if the key did not already exist, false otherwise.
     */
    virtual bool storeRawData(const std::string& key, const std::vector<char>& buffer) = 0;

    /**
     * @brief Loads raw key/value data from this KeyValueContainer.
     * This function is virtual and must be overloaded in the child class.
     *
     * @param key Key
     * @param buffer Buffer used to hold the value.
     *
     * @return true if the key exists, false otherwise.
     */
    virtual bool loadRawData(const std::string& key, std::vector<char>& buffer) const = 0;

    /**
     * @brief Stores a key/value pair into the KeyValueContainer.
     * The type of the key should have operator<< available
     * to stream it into a std::stringstream for the purpose
     * of converting it into an std::string. The resulting
     * string must not have the "/", or "%" characters. The
     * type of the value must be serializable using Boost.
     *
     * @tparam K type of the key.
     * @tparam V type of the value.
     * @param key Key to store.
     * @param value Value to store.
     *
     * @return true if the key was found. false otherwise.
     */
    template<typename K, typename V>
    bool store(const K& key, const V& value) {
        std::stringstream ss_value;
        std::stringstream ss_key;
        ss_key << key << "#" << demangle<V>();
        boost::archive::binary_oarchive oa(ss_value);
        try {
            oa << value;
        } catch(...) {
            throw Exception("Exception occured during serialization");
        }
        std::string serialized = ss_value.str();
        std::vector<char> buffer(serialized.begin(), serialized.end());
        return storeRawData(ss_key.str(), buffer);
    }

    /**
     * @brief Loads a value associated with a key from the 
     * KeyValueContainer. The type of the key should have 
     * operator<< available to stream it into a std::stringstream 
     * for the purpose of converting it into an std::string. 
     * The resulting string must not have the "/" or "%" characters.
     * The type of the value must be serializable using Boost.
     *
     * @tparam K type of the key.
     * @tparam V type of the value.
     * @param key Key to load.
     * @param value Value to load.
     *
     * @return true if the key exists and was loaded. False otherwise.
     */
    template<typename K, typename V>
    bool load(const K& key, V& value) const {
        std::vector<char> buffer;
        std::stringstream ss_key;
        ss_key << key << "#" << demangle<V>();
        if(!loadRawData(ss_key.str(), buffer)) {
            return false;
        }
        try {
            std::string serialized(buffer.begin(), buffer.end());
            std::stringstream ss(serialized);
            boost::archive::binary_iarchive ia(ss);
            ia >> value;
        } catch(...) {
            throw Exception("Exception occured during serialization");
        }
        return true;
    }
};

}

#endif