// 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/>.

#include "database.h"
#include "exceptions.h"
#include "table.h"

DataBase::DataBase(const QString& p_name, uint16_t mapSize):
    name(p_name.toStdString()),
    opened(false),
    size(mapSize),
    environment(),
    tables()
{
}

DataBase::~DataBase()
{
    close();
    for (const std::pair<const std::string, _Table*>& pair : tables) {
        delete pair.second;
    }
}

void DataBase::close()
{
    if (opened) {
        for (const std::pair<const std::string, _Table*>& pair : tables) {
            _Table* table = pair.second;
            mdb_dbi_close(environment, table->dbi);
        }
        mdb_env_close(environment);
        opened = false;
    }
}

void DataBase::open()
{
    if (!opened) {
        mdb_env_create(&environment);
        QString path(QStandardPaths::writableLocation(QStandardPaths::CacheLocation));
        path += "/" + getName();
        QDir cache(path);

        if (!cache.exists()) {
            bool res = cache.mkpath(path);
            if (!res) {
                throw Directory(path.toStdString());
            }
        }

        mdb_env_set_maxdbs(environment, tables.size());
        mdb_env_set_mapsize(environment, size * 1024UL * 1024UL);
        mdb_env_open(environment, path.toStdString().c_str(), 0, 0664);

        MDB_txn *txn;
        mdb_txn_begin(environment, NULL, 0, &txn);

        for (const std::pair<const std::string, _Table*>& pair : tables) {
            _Table* table = pair.second;
            int rc = table->createTable(txn);
            if (rc) {
                throw Unknown(name, mdb_strerror(rc));
            }

        }
        mdb_txn_commit(txn);
        opened = true;
    }
}

bool DataBase::removeDirectory()
{
    if (opened) {
        throw Opened(name, "remove database directory");
    }
    QString path(QStandardPaths::writableLocation(QStandardPaths::CacheLocation));
    path += "/" + getName();
    QDir cache(path);

    if (cache.exists()) {
        return cache.removeRecursively();
    } else {
        return true;
    }
}

QString DataBase::getName() const
{
    return QString::fromStdString(name);
}

bool DataBase::ready() const
{
    return opened;
}

void DataBase::drop()
{
    if (!opened) {
        throw Closed("drop", name);
    }

    MDB_txn *txn;
    int rc = mdb_txn_begin(environment, NULL, 0, &txn);
    if (rc) {
        throw Unknown(name, mdb_strerror(rc));
    }
    for (const std::pair<const std::string, _Table*>& pair : tables) {
        rc = pair.second->drop(txn);
        if (rc) {
            throw Unknown(name, mdb_strerror(rc), pair.first);
        }
    }

    mdb_txn_commit(txn);
}