/*
*   Copyright 2010 Matteo Agostinelli <agostinelli@gmail.com>
*
*   This program is free software; you can redistribute it and/or modify
*   it under the terms of the GNU Library General Public License as
*   published by the Free Software Foundation; either version 2 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 Library General Public
*   License along with this program; if not, write to the
*   Free Software Foundation, Inc.,
*   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "qalculate_engine.h"

#include <libqalculate/Calculator.h>
#include <libqalculate/ExpressionItem.h>
#include <libqalculate/Unit.h>
#include <libqalculate/Prefix.h>
#include <libqalculate/Variable.h>
#include <libqalculate/Function.h>

#include <QFile>
#include <QApplication>
#include <QClipboard>

#include <KDebug>
#include <KLocale>

QAtomicInt QalculateEngine::s_counter;

QalculateEngine::QalculateEngine(QObject* parent):
    QObject(parent)
{
    m_lastResult = "";
    s_counter.ref();
    if (!CALCULATOR) {
        new Calculator();
        CALCULATOR->terminateThreads();
        CALCULATOR->loadGlobalDefinitions();
        CALCULATOR->loadLocalDefinitions();
        CALCULATOR->loadGlobalCurrencies();
        CALCULATOR->loadExchangeRates();
    }
}

QalculateEngine::~QalculateEngine()
{
    if (s_counter.deref()) {
        delete CALCULATOR;
        CALCULATOR = NULL;
    }
}

QString QalculateEngine::evaluate(const QString& expression)
{
    if (expression.isEmpty()) {
        return QString();
    }

    QString input = expression;
    QByteArray ba = input.replace(QChar(0xA3), "GBP").replace(QChar(0xA5), "JPY").replace('$', "USD").replace(QChar(0x20AC), "EUR").toLatin1();

    m_lastResult = QString();
    try {
        CALCULATOR->terminateThreads();
        EvaluationOptions eo;

        eo.auto_post_conversion = POST_CONVERSION_BEST;
        eo.keep_zero_units = false;

        eo.parse_options.angle_unit = ANGLE_UNIT_RADIANS;
        eo.structuring = STRUCTURING_SIMPLIFY;

        MathStructure result = CALCULATOR->calculate(ba.constData(), eo);

        PrintOptions po;
        po.number_fraction_format = FRACTION_DECIMAL;
        po.indicate_infinite_series = false;
        po.use_all_prefixes = false;
        po.use_denominator_prefix = true;
        po.negative_exponents = false;
        po.lower_case_e = true;
        po.base_display = BASE_DISPLAY_NORMAL;

        result.format(po);

        m_lastResult = result.print(po).c_str();
    } catch(std::exception &err) {
        kDebug() << err.what();
    } catch (...) {
        kDebug() << "Exception raised";
    }

    return m_lastResult;
}

void QalculateEngine::copyToClipboard(bool flag)
{
    Q_UNUSED(flag);

    QApplication::clipboard()->setText(m_lastResult);
}