/*
 * LMDB Abstraction Layer.
 * Copyright (C) 2023  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 "storage.h"

#define UNUSED(x) (void)(x)

LMDBAL::iStorage::iStorage(const std::string& p_name, Base* parent):
    dbi(),
    db(parent),
    name(p_name)
{}

LMDBAL::iStorage::~iStorage() {}

void LMDBAL::iStorage::drop() {
    ensureOpened(dropMethodName);

    TransactionID txn = db->beginTransaction();
    int rc = iStorage::drop(txn);
    if (rc != MDB_SUCCESS) {
        abortTransaction(txn);
        throw Unknown(db->name, mdb_strerror(rc), name);
    }

    db->commitTransaction(txn);
}

int LMDBAL::iStorage::drop(TransactionID transaction) {
    return mdb_drop(transaction, dbi, 0);
}

void LMDBAL::iStorage::ensureOpened(const std::string& methodName) const {
    if (!db->opened)
        throw Closed(methodName, db->name, name);
}

LMDBAL::SizeType LMDBAL::iStorage::count() const {
    ensureOpened(countMethodName);

    TransactionID txn = beginReadOnlyTransaction();
    SizeType amount;
    try {
        amount = count(txn);
    } catch (...) {
        abortTransaction(txn);
        throw;
    }
    abortTransaction(txn);

    return amount;
}

LMDBAL::SizeType LMDBAL::iStorage::count(TransactionID txn) const {
    MDB_stat stat;
    int rc = mdb_stat(txn, dbi, &stat);
    if (rc != MDB_SUCCESS)
        throw Unknown(db->name, mdb_strerror(rc), name);

    return stat.ms_entries;
}

void LMDBAL::iStorage::throwDuplicateOrUnknown(int rc, TransactionID txn, const std::string& key) const {
    abortTransaction(txn);
    throwDuplicateOrUnknown(rc, key);
}

void LMDBAL::iStorage::throwNotFoundOrUnknown(int rc, LMDBAL::TransactionID txn, const std::string& key) const {
    abortTransaction(txn);
    throwNotFoundOrUnknown(rc, key);
}

void LMDBAL::iStorage::throwDuplicateOrUnknown(int rc, const std::string& key) const {
    if (rc == MDB_KEYEXIST)
        throwDuplicate(key);
    else
        throwUnknown(rc);
}

void LMDBAL::iStorage::throwNotFoundOrUnknown(int rc, const std::string& key) const {
    if (rc == MDB_NOTFOUND)
        throwNotFound(key);
    else
        throwUnknown(rc);
}

void LMDBAL::iStorage::throwUnknown(int rc, LMDBAL::TransactionID txn) const {
    abortTransaction(txn);
    throwUnknown(rc);
}

const std::string & LMDBAL::iStorage::dbName() const {
    return db->name;}

bool LMDBAL::iStorage::isDBOpened() const {
    return db->opened;}

void LMDBAL::iStorage::throwUnknown(int rc) const {
    throw Unknown(db->name, mdb_strerror(rc), name);}

void LMDBAL::iStorage::throwDuplicate(const std::string& key) const {
    throw Exist(key, db->name, name);}

void LMDBAL::iStorage::throwNotFound(const std::string& key) const {
    throw NotFound(key, db->name, name);}

LMDBAL::TransactionID LMDBAL::iStorage::beginReadOnlyTransaction() const {
    return db->beginPrivateReadOnlyTransaction(name);}

LMDBAL::TransactionID LMDBAL::iStorage::beginTransaction() const {
    return db->beginPrivateTransaction(name);}

void LMDBAL::iStorage::abortTransaction(LMDBAL::TransactionID id) const {
    db->abortPrivateTransaction(id, name);}

void LMDBAL::iStorage::commitTransaction(LMDBAL::TransactionID id) {
    db->commitPrivateTransaction(id, name);}

void LMDBAL::iStorage::transactionStarted(LMDBAL::TransactionID txn, bool readOnly) const {
    UNUSED(txn);
    UNUSED(readOnly);
}
void LMDBAL::iStorage::transactionCommited(LMDBAL::TransactionID txn) {
    UNUSED(txn);}

void LMDBAL::iStorage::transactionAborted(LMDBAL::TransactionID txn) const {
    UNUSED(txn);}