// Squawk messenger. 
// Copyright (C) 2019  Yury Gubich <blue@macaw.me>
// 
// 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 3 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, see <http://www.gnu.org/licenses/>.

#ifndef LMDBDATABASE_DATABASE_H
#define LMDBDATABASE_DATABASE_H

#include <map>
#include <set>
#include <string>
#include <optional>
#include <limits>

#include <QString>
#include <QStandardPaths>
#include <QDir>

#include <lmdb.h>

#include "exceptions.h"

namespace LMDBDataBase {

class StorageBase;

template<class T>
class Serializer;

template <class K, class V>
class Storage;

template <class K, class V>
class Cache;

typedef MDB_txn* TransactionID;

class DataBase {
    friend class StorageBase;
public:

    DataBase(const QString& name, uint16_t mapSize = 10);
    ~DataBase();

    void open();
    void close();
    bool ready() const;
    bool removeDirectory();
    QString createDirectory();
    QString getName() const;
    void drop();

    TransactionID beginReadOnlyTransaction() const;
    TransactionID beginTransaction() const;
    void commitTransaction(TransactionID id) const;
    void abortTransaction(TransactionID id) const;

    template <class K, class V>
    Storage<K, V>* addTable(const std::string& name);

    template <class K, class V>
    Cache<K, V>* addCache(const std::string& name);

    template <class K, class V>
    Storage<K, V>* getTable(const std::string& name);

    template <class K, class V>
    Cache<K, V>* getCache(const std::string& name);

private:
    typedef std::map<std::string, StorageBase*> Tables;
    typedef std::set<TransactionID> Transactions;

    TransactionID beginReadOnlyTransaction(const std::string& storageName) const;
    TransactionID beginTransaction(const std::string& storageName) const;
    void commitTransaction(TransactionID id, const std::string& storageName) const;
    void abortTransaction(TransactionID id, const std::string& storageName) const;

private:
    std::string name;
    bool opened;
    uint16_t size;
    MDB_env* environment;
    Tables tables;
    Transactions* transactions;

    inline static const std::string emptyName = "";
};

}
#include "operators.hpp"

template <class K, class V>
LMDBDataBase::Storage<K, V>* LMDBDataBase::DataBase::addTable(const std::string& p_name) {
    if (opened) {
        throw Opened(name, "add table " + p_name);
    }
    Storage<K, V>* table = new Storage<K, V>(p_name, this);
    tables.insert(std::make_pair(p_name, (StorageBase*)table));
    return table;
}

template<class K, class V>
LMDBDataBase::Cache<K, V> * LMDBDataBase::DataBase::addCache(const std::string& p_name) {
    if (opened) {
        throw Opened(name, "add cache " + p_name);
    }
    Cache<K, V>* cache = new Cache<K, V>(p_name, this);
    tables.insert(std::make_pair(p_name, (StorageBase*)cache));
    return cache;
}

template <class K, class V>
LMDBDataBase::Storage<K, V>* LMDBDataBase::DataBase::getTable(const std::string& p_name) {
    return static_cast<Storage<K, V>*>(tables.at(p_name));
}

template <class K, class V>
LMDBDataBase::Cache<K, V>* LMDBDataBase::DataBase::getCache(const std::string& p_name) {
    return static_cast<Cache<K, V>*>(tables.at(p_name));
}

#endif // LMDBDATABASE_DATABASE_H