/*
    This file is part of the KDE Baloo project.
    SPDX-FileCopyrightText: 2015 Vishesh Handa <vhanda@kde.org>

    SPDX-License-Identifier: LGPL-2.1-or-later
*/

#include "mtimedb.h"
#include "enginedebug.h"
#include "vectorpostingiterator.h"
#include <algorithm>

using namespace Baloo;

MTimeDB::MTimeDB(MDB_dbi dbi, MDB_txn* txn)
    : m_txn(txn)
    , m_dbi(dbi)
{
    Q_ASSERT(txn != nullptr);
    Q_ASSERT(dbi != 0);
}

MTimeDB::~MTimeDB()
{
}

MDB_dbi MTimeDB::create(MDB_txn* txn)
{
    MDB_dbi dbi = 0;
    int rc = mdb_dbi_open(txn, "mtimedb", MDB_CREATE | MDB_INTEGERKEY | MDB_DUPSORT | MDB_DUPFIXED | MDB_INTEGERDUP, &dbi);
    if (rc) {
        qCWarning(ENGINE) << "MTimeDB::create" << mdb_strerror(rc);
        return 0;
    }

    return dbi;
}

MDB_dbi MTimeDB::open(MDB_txn* txn)
{
    MDB_dbi dbi = 0;
    int rc = mdb_dbi_open(txn, "mtimedb", MDB_INTEGERKEY | MDB_DUPSORT | MDB_DUPFIXED | MDB_INTEGERDUP, &dbi);
    if (rc) {
        qCWarning(ENGINE) << "MTimeDB::open" << mdb_strerror(rc);
        return 0;
    }

    return dbi;
}

void MTimeDB::put(quint32 mtime, quint64 docId)
{
    if (!docId) {
        qCWarning(ENGINE) << "MTimeDB::put - docId == 0";
        return;
    }

    MDB_val key;
    key.mv_size = sizeof(quint32);
    key.mv_data = static_cast<void*>(&mtime);

    MDB_val val;
    val.mv_size = sizeof(quint64);
    val.mv_data = static_cast<void*>(&docId);

    int rc = mdb_put(m_txn, m_dbi, &key, &val, 0);
    if (rc) {
        qCWarning(ENGINE) << "MTimeDB::put" << mdb_strerror(rc);
    }
}

QVector<quint64> MTimeDB::get(quint32 mtime)
{
    MDB_val key;
    key.mv_size = sizeof(quint32);
    key.mv_data = static_cast<void*>(&mtime);

    QVector<quint64> values;

    MDB_cursor* cursor;
    mdb_cursor_open(m_txn, m_dbi, &cursor);

    MDB_val val{0, nullptr};
    int rc = mdb_cursor_get(cursor, &key, &val, MDB_SET);
    if (rc) {
        if (rc != MDB_NOTFOUND) {
            qCWarning(ENGINE) << "MTimeDB::get" << mtime << mdb_strerror(rc);
        }
        mdb_cursor_close(cursor);
        return values;
    }

    values << *static_cast<quint64*>(val.mv_data);

    while (1) {
        rc = mdb_cursor_get(cursor, &key, &val, MDB_NEXT_DUP);
        if (rc) {
            if (rc != MDB_NOTFOUND) {
                qCWarning(ENGINE) << "MTimeDB::get (loop)" << mtime << mdb_strerror(rc);
            }
            break;
        }
        values << *static_cast<quint64*>(val.mv_data);
    }

    mdb_cursor_close(cursor);
    std::sort(values.begin(), values.end());
    values.erase(std::unique(values.begin(), values.end()), values.end());
    return values;
}

void MTimeDB::del(quint32 mtime, quint64 docId)
{
    MDB_val key;
    key.mv_size = sizeof(quint32);
    key.mv_data = static_cast<void*>(&mtime);

    MDB_val val;
    val.mv_size = sizeof(quint64);
    val.mv_data = static_cast<void*>(&docId);

    int rc = mdb_del(m_txn, m_dbi, &key, &val);
    if (rc != 0 && rc != MDB_NOTFOUND) {
        qCWarning(ENGINE) << "MTimeDB::del" << mtime << docId << mdb_strerror(rc);
    }
}

//
// Posting Iterator
//
PostingIterator::Ptr MTimeDB::iterRange(quint32 beginTime, quint32 endTime)
{
    if (endTime < beginTime) {
        return nullptr;
    }

    MDB_val key;
    key.mv_size = sizeof(quint32);
    key.mv_data = &beginTime;

    MDB_cursor* cursor;
    mdb_cursor_open(m_txn, m_dbi, &cursor);

    MDB_val val{0, nullptr};
    int rc = mdb_cursor_get(cursor, &key, &val, MDB_SET_RANGE);
    if (rc) {
        if (rc != MDB_NOTFOUND) {
            qCWarning(ENGINE) << "MTimeDB::iterRange" << beginTime << endTime << mdb_strerror(rc);
        }
        mdb_cursor_close(cursor);
        return nullptr;
    }

    QVector<quint64> results;

    while (1) {
        quint32 time = *static_cast<quint32*>(key.mv_data);
        if (time > endTime) {
            break;
        }
        results << *static_cast<quint64*>(val.mv_data);

        rc = mdb_cursor_get(cursor, &key, &val, MDB_NEXT);
        if (rc) {
            if (rc != MDB_NOTFOUND) {
                qCWarning(ENGINE) << "MTimeDB::iterRange (loop)" << beginTime << endTime << mdb_strerror(rc);
            }
            break;
        }
    }

    mdb_cursor_close(cursor);

    if (results.isEmpty()) {
        return nullptr;
    }
    std::sort(results.begin(), results.end());
    results.erase(std::unique(results.begin(), results.end()), results.end());
    return std::make_unique<VectorPostingIterator>(results);
}

QMap<quint32, quint64> MTimeDB::toTestMap() const
{
    MDB_cursor* cursor;
    mdb_cursor_open(m_txn, m_dbi, &cursor);

    MDB_val key = {0, nullptr};
    MDB_val val;

    QMap<quint32, quint64> map;
    while (1) {
        int rc = mdb_cursor_get(cursor, &key, &val, MDB_NEXT);
        if (rc) {
            qCDebug(ENGINE) << "MTimeDB::toTestMap" << mdb_strerror(rc);
            break;
        }

        const quint32 time = *(static_cast<quint32*>(key.mv_data));
        const quint64 id = *(static_cast<quint64*>(val.mv_data));
        map.insert(time, id);
    }

    mdb_cursor_close(cursor);
    return map;
}
