/***************************************************************************
 *   Copyright (c) 2015 Eivind Kvedalen <eivind@kvedalen.name>             *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   This library 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 of the License, or (at your option) any later version.      *
 *                                                                         *
 *   This library  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 Library General Public License for more details.                  *
 *                                                                         *
 *   You should have received a copy of the GNU Library General Public     *
 *   License along with this library; see the file COPYING.LIB. If not,    *
 *   write to the Free Software Foundation, Inc., 51 Franklin Street,      *
 *   Fifth Floor, Boston, MA  02110-1301, USA                              *
 *                                                                         *
 ***************************************************************************/

#include "PreCompiled.h"
#ifndef _PreComp_
# include <QPixmapCache>
#endif
#include "ExpressionBinding.h"
#include "BitmapFactory.h"
#include "Command.h"
#include <App/Expression.h>
#include <App/DocumentObject.h>
#include <Base/Tools.h>
#include <Base/Console.h>
#include <App/ObjectIdentifier.h>
#include <App/Document.h>
#include <App/Application.h>
#include <boost/bind.hpp>

FC_LOG_LEVEL_INIT("Expression",true,true)

using namespace Gui;
using namespace App;

ExpressionBinding::ExpressionBinding()
    : iconLabel(0)
    , iconHeight(-1)
    , m_autoApply(false)
{
}


ExpressionBinding::~ExpressionBinding()
{
}

bool ExpressionBinding::isBound() const
{
    return path.getDocumentObject() != 0;
}

void Gui::ExpressionBinding::setExpression(boost::shared_ptr<Expression> expr)
{
    DocumentObject * docObj = path.getDocumentObject();

    if (expr) {
        const std::string error = docObj->ExpressionEngine.validateExpression(path, expr);

        if (error.size())
            throw Base::RuntimeError(error.c_str());

    }

    lastExpression = getExpression();

    bool transaction = !App::GetApplication().getActiveTransaction();
    if(transaction) {
        std::ostringstream ss;
        ss << (expr?"Set":"Discard") << " expression " << docObj->Label.getValue();
        App::GetApplication().setActiveTransaction(ss.str().c_str());
    }

    docObj->ExpressionEngine.setValue(path, expr);

    if(m_autoApply)
        apply();
    
    if(transaction)
        App::GetApplication().closeActiveTransaction();

}

void ExpressionBinding::bind(const App::ObjectIdentifier &_path)
{
    const Property * prop = _path.getProperty();

    Q_ASSERT(prop != 0);

    path = prop->canonicalPath(_path);
    
    //connect to be informed about changes
    DocumentObject * docObj = path.getDocumentObject();
    connection = docObj->ExpressionEngine.expressionChanged.connect(boost::bind(&ExpressionBinding::expressionChange, this, _1));
}

void ExpressionBinding::bind(const Property &prop)
{
    bind(App::ObjectIdentifier(prop));
}

bool ExpressionBinding::hasExpression() const
{
    return isBound() && getExpression() != 0;
}

boost::shared_ptr<App::Expression> ExpressionBinding::getExpression() const
{
    DocumentObject * docObj = path.getDocumentObject();

    Q_ASSERT(isBound() && docObj != 0);

    return docObj->getExpression(path).expression;
}

std::string ExpressionBinding::getExpressionString(bool no_throw) const
{
    try {
        if (!getExpression())
            throw Base::RuntimeError("No expression found.");
        return getExpression()->toString();
    } catch (Base::Exception &e) {
        if(no_throw)
            FC_ERR("failed to get expression string: " << e.what());
        else
            throw;
    } catch (std::exception &e) {
        if(no_throw)
            FC_ERR("failed to get expression string: " << e.what());
        else
            throw;
    } catch (...) {
        if(no_throw)
            FC_ERR("failed to get expression string: unknown exception");
        else
            throw;
    }
    return std::string();
}

std::string ExpressionBinding::getEscapedExpressionString() const
{
    return Base::Tools::escapedUnicodeFromUtf8(getExpressionString(false).c_str());
}

QPixmap ExpressionBinding::getIcon(const char* name, const QSize& size) const
{
    QString key = QString::fromLatin1("%1_%2x%3")
        .arg(QString::fromLatin1(name))
        .arg(size.width())
        .arg(size.height());
    QPixmap icon;
    if (QPixmapCache::find(key, icon))
        return icon;

    icon = BitmapFactory().pixmapFromSvg(name, size);
    if (!icon.isNull())
        QPixmapCache::insert(key, icon);
    return icon;
}

bool ExpressionBinding::apply(const std::string & propName)
{
    Q_UNUSED(propName); 
    if (hasExpression()) {
        DocumentObject * docObj = path.getDocumentObject();

        if (!docObj)
            throw Base::RuntimeError("Document object not found.");

        bool transaction = !App::GetApplication().getActiveTransaction();
        if(transaction) {
            std::ostringstream ss;
            ss << "Set expression " << docObj->Label.getValue();
            App::GetApplication().setActiveTransaction(ss.str().c_str());
        }
        Gui::Command::doCommand(Gui::Command::Doc,"App.getDocument('%s').%s.setExpression('%s', u'%s')",
                                docObj->getDocument()->getName(),
                                docObj->getNameInDocument(),
                                path.toEscapedString().c_str(),
                                getEscapedExpressionString().c_str());
        if(transaction)
            App::GetApplication().closeActiveTransaction();
        return true;
    }
    else {
        if (isBound()) {
            DocumentObject * docObj = path.getDocumentObject();

            if (!docObj)
                throw Base::RuntimeError("Document object not found.");

            if (lastExpression) {
                bool transaction = !App::GetApplication().getActiveTransaction();
                if(transaction) {
                    std::ostringstream ss;
                    ss << "Discard expression " << docObj->Label.getValue();
                    App::GetApplication().setActiveTransaction(ss.str().c_str());
                }
                Gui::Command::doCommand(Gui::Command::Doc,"App.getDocument('%s').%s.setExpression('%s', None)",
                                        docObj->getDocument()->getName(),
                                        docObj->getNameInDocument(),
                                        path.toEscapedString().c_str());
                if(transaction)
                    App::GetApplication().closeActiveTransaction();
            }
        }

        return false;
    }
}

bool ExpressionBinding::apply()
{
    Property * prop(path.getProperty());

    assert(prop != 0);
    Q_UNUSED(prop);

    DocumentObject * docObj(path.getDocumentObject());

    if (!docObj)
        throw Base::RuntimeError("Document object not found.");

    /* Skip updating read-only properties */
    if (prop->isReadOnly())
        return true;
    
    return apply(Gui::Command::getObjectCmd(docObj) + "." + getPath().toEscapedString());
}

void ExpressionBinding::expressionChange(const ObjectIdentifier& id) {

    if(id==path)
        onChange();
}