/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Assistant of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qhelpsearchquerywidget.h"

#include <QtCore/QAbstractListModel>
#include <QtCore/QObject>
#include <QtCore/QStringList>
#include <QtCore/QtGlobal>

#include <QtGui/QCompleter>
#include <QtGui/QLabel>
#include <QtGui/QLayout>
#include <QtGui/QLineEdit>
#include <QtGui/QFocusEvent>
#include <QtGui/QPushButton>
#include <QtGui/QToolButton>

QT_BEGIN_NAMESPACE

class QHelpSearchQueryWidgetPrivate : public QObject
{
    Q_OBJECT

private:
    struct QueryHistory {
        explicit QueryHistory() : curQuery(-1) {}
        QList<QList<QHelpSearchQuery> > queries;
        int curQuery;
    };

    class CompleterModel : public QAbstractListModel
    {
    public:
        explicit CompleterModel(QObject *parent)
          : QAbstractListModel(parent) {}

        int rowCount(const QModelIndex &parent = QModelIndex()) const
        {
            return parent.isValid() ? 0 : termList.size();
        }

        QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const
        {
            if (!index.isValid() || index.row() >= termList.count()||
                (role != Qt::EditRole && role != Qt::DisplayRole))
                return QVariant();
            return termList.at(index.row());
        }

        void addTerm(const QString &term)
        {
            if (!termList.contains(term)) {
                termList.append(term);
                reset();
            }
        }

    private:
        QStringList termList;
    };

    QHelpSearchQueryWidgetPrivate()
        : QObject()
        , simpleSearch(true)
        , searchCompleter(new CompleterModel(this), this)
    {
        searchButton = 0;
        advancedSearchWidget = 0;
        showHideAdvancedSearchButton = 0;
        defaultQuery = 0;
        exactQuery = 0;
        similarQuery = 0;
        withoutQuery = 0;
        allQuery = 0;
        atLeastQuery = 0;
    }

    ~QHelpSearchQueryWidgetPrivate()
    {
        // nothing todo
    }

    void retranslate()
    {
        simpleSearchLabel->setText(QHelpSearchQueryWidget::tr("Search for:"));
        prevQueryButton->setToolTip(QHelpSearchQueryWidget::tr("Previous search"));
        nextQueryButton->setToolTip(QHelpSearchQueryWidget::tr("Next search"));
        searchButton->setText(QHelpSearchQueryWidget::tr("Search"));
#ifdef QT_CLUCENE_SUPPORT
        advancedSearchLabel->setText(QHelpSearchQueryWidget::tr("Advanced search"));
        similarLabel->setText(QHelpSearchQueryWidget::tr("words <B>similar</B> to:"));
        withoutLabel->setText(QHelpSearchQueryWidget::tr("<B>without</B> the words:"));
        exactLabel->setText(QHelpSearchQueryWidget::tr("with <B>exact phrase</B>:"));
        allLabel->setText(QHelpSearchQueryWidget::tr("with <B>all</B> of the words:"));
        atLeastLabel->setText(QHelpSearchQueryWidget::tr("with <B>at least one</B> of the words:"));
#endif
    }

    QStringList buildTermList(const QString query)
    {
        bool s = false;
        QString phrase;
        QStringList wordList;
        QString searchTerm = query;

        for (int i = 0; i < searchTerm.length(); ++i) {
            if (searchTerm[i] == QLatin1Char('\"') && !s) {
                s = true;
                phrase = searchTerm[i];
                continue;
            }
            if (searchTerm[i] != QLatin1Char('\"') && s)
                phrase += searchTerm[i];
            if (searchTerm[i] == QLatin1Char('\"') && s) {
                s = false;
                phrase += searchTerm[i];
                wordList.append(phrase);
                searchTerm.remove(phrase);
            }
        }
        if (s)
            searchTerm.replace(phrase, phrase.mid(1));

        const QRegExp exp(QLatin1String("\\s+"));
        wordList += searchTerm.split(exp, QString::SkipEmptyParts);
        return wordList;
    }

    void saveQuery(const QList<QHelpSearchQuery> &query, QueryHistory &queryHist)
    {
        // We only add the query to the list if it is different from the last one.
        bool insert = false;
        if (queryHist.queries.empty())
            insert = true;
        else {
            const QList<QHelpSearchQuery> &lastQuery = queryHist.queries.last();
            if (lastQuery.size() != query.size()) {
                insert = true;
            } else {
                for (int i = 0; i < query.size(); ++i) {
                    if (query.at(i).fieldName != lastQuery.at(i).fieldName
                        || query.at(i).wordList != lastQuery.at(i).wordList) {
                        insert = true;
                        break;
                    }
                }
            }
        }
        if (insert) {
            queryHist.queries.append(query);
            foreach (const QHelpSearchQuery &queryPart, query) {
                static_cast<CompleterModel *>(searchCompleter.model())->
                        addTerm(queryPart.wordList.join(" "));
            }
        }
    }

    void nextOrPrevQuery(int maxOrMinIndex, int addend, QToolButton *thisButton,
        QToolButton *otherButton)
    {
        QueryHistory *queryHist;
        QList<QLineEdit *> lineEdits;
        if (simpleSearch) {
            queryHist = &simpleQueries;
            lineEdits << defaultQuery;
        } else {
            queryHist = &complexQueries;
            lineEdits << allQuery << atLeastQuery << similarQuery
                << withoutQuery << exactQuery;
        }
        foreach (QLineEdit *lineEdit, lineEdits)
            lineEdit->clear();

        // Otherwise, the respective button would be disabled.
        Q_ASSERT(queryHist->curQuery != maxOrMinIndex);

        queryHist->curQuery += addend;
        const QList<QHelpSearchQuery> &query =
            queryHist->queries.at(queryHist->curQuery);
        foreach (const QHelpSearchQuery &queryPart, query) {
            if (QLineEdit *lineEdit = lineEditFor(queryPart.fieldName))
                lineEdit->setText(queryPart.wordList.join(" "));
        }

        if (queryHist->curQuery == maxOrMinIndex)
            thisButton->setEnabled(false);
        otherButton->setEnabled(true);
    }

    QLineEdit* lineEditFor(const QHelpSearchQuery::FieldName &fieldName) const
    {
        switch (fieldName) {
            case QHelpSearchQuery::DEFAULT:
                return defaultQuery;
            case QHelpSearchQuery::ALL:
                return allQuery;
            case QHelpSearchQuery::ATLEAST:
                return atLeastQuery;
            case QHelpSearchQuery::FUZZY:
                return similarQuery;
            case QHelpSearchQuery::WITHOUT:
                return withoutQuery;
            case QHelpSearchQuery::PHRASE:
                return exactQuery;
            default:
                Q_ASSERT(0);
        }
        return 0;
    }

    void enableOrDisableToolButtons()
    {
        const QueryHistory &queryHist = simpleSearch ? simpleQueries
            : complexQueries;
        prevQueryButton->setEnabled(queryHist.curQuery > 0);
        nextQueryButton->setEnabled(queryHist.curQuery
            < queryHist.queries.size() - 1);
    }

private slots:
    void showHideAdvancedSearch()
    {
        if (simpleSearch) {
            advancedSearchWidget->show();
            showHideAdvancedSearchButton->setText((QLatin1String("-")));
        } else {
            advancedSearchWidget->hide();
            showHideAdvancedSearchButton->setText((QLatin1String("+")));
        }

        simpleSearch = !simpleSearch;
        defaultQuery->setEnabled(simpleSearch);
        enableOrDisableToolButtons();
    }

    void searchRequested()
    {
        QList<QHelpSearchQuery> queryList;
#if !defined(QT_CLUCENE_SUPPORT)
        queryList.append(QHelpSearchQuery(QHelpSearchQuery::DEFAULT,
            QStringList(defaultQuery->text())));

#else
        if (defaultQuery->isEnabled()) {
            queryList.append(QHelpSearchQuery(QHelpSearchQuery::DEFAULT,
                buildTermList(defaultQuery->text())));
        } else {
            const QRegExp exp(QLatin1String("\\s+"));
            QStringList lst = similarQuery->text().split(exp,
                QString::SkipEmptyParts);
            if (!lst.isEmpty()) {
                QStringList fuzzy;
                foreach (const QString &term, lst)
                    fuzzy += buildTermList(term);
                queryList.append(QHelpSearchQuery(QHelpSearchQuery::FUZZY,
                    fuzzy));
            }

            lst = withoutQuery->text().split(exp, QString::SkipEmptyParts);
            if (!lst.isEmpty()) {
                QStringList without;
                foreach (const QString &term, lst)
                    without.append(term);
                queryList.append(QHelpSearchQuery(QHelpSearchQuery::WITHOUT,
                    without));
            }

            if (!exactQuery->text().isEmpty()) {
                QString phrase = exactQuery->text().remove(QLatin1Char('\"'));
                phrase = phrase.simplified();
                queryList.append(QHelpSearchQuery(QHelpSearchQuery::PHRASE,
                    QStringList(phrase)));
            }

            lst = allQuery->text().split(exp, QString::SkipEmptyParts);
            if (!lst.isEmpty()) {
                QStringList all;
                foreach (const QString &term, lst)
                    all.append(term);
                queryList.append(QHelpSearchQuery(QHelpSearchQuery::ALL, all));
            }

            lst = atLeastQuery->text().split(exp, QString::SkipEmptyParts);
            if (!lst.isEmpty()) {
                QStringList atLeast;
                foreach (const QString &term, lst)
                    atLeast += buildTermList(term);
                queryList.append(QHelpSearchQuery(QHelpSearchQuery::ATLEAST,
                    atLeast));
            }
        }
#endif
        QueryHistory &queryHist = simpleSearch ? simpleQueries : complexQueries;
        saveQuery(queryList, queryHist);
        queryHist.curQuery = queryHist.queries.size() - 1;
        if (queryHist.curQuery > 0)
            prevQueryButton->setEnabled(true);
        nextQueryButton->setEnabled(false);
    }

    void nextQuery()
    {
        nextOrPrevQuery((simpleSearch ? simpleQueries
            : complexQueries).queries.size() - 1, 1, nextQueryButton,
                prevQueryButton);
    }

    void prevQuery()
    {
        nextOrPrevQuery(0, -1, prevQueryButton, nextQueryButton);
    }

private:
    friend class QHelpSearchQueryWidget;

    bool simpleSearch;
    QLabel *simpleSearchLabel;
    QLabel *advancedSearchLabel;
    QLabel *similarLabel;
    QLabel *withoutLabel;
    QLabel *exactLabel;
    QLabel *allLabel;
    QLabel *atLeastLabel;
    QPushButton *searchButton;
    QWidget* advancedSearchWidget;
    QToolButton *showHideAdvancedSearchButton;
    QLineEdit *defaultQuery;
    QLineEdit *exactQuery;
    QLineEdit *similarQuery;
    QLineEdit *withoutQuery;
    QLineEdit *allQuery;
    QLineEdit *atLeastQuery;
    QToolButton *nextQueryButton;
    QToolButton *prevQueryButton;
    QueryHistory simpleQueries;
    QueryHistory complexQueries;
    QCompleter searchCompleter;
};

#include "qhelpsearchquerywidget.moc"


/*!
    \class QHelpSearchQueryWidget
    \since 4.4
    \inmodule QtHelp
    \brief The QHelpSearchQueryWidget class provides a simple line edit or
    an advanced widget to enable the user to input a search term in a
    standardized input mask.
*/

/*!
    \fn void QHelpSearchQueryWidget::search()

    This signal is emitted when a the user has the search button invoked.
    After reciving the signal you can ask the QHelpSearchQueryWidget for the
    build list of QHelpSearchQuery's that you may pass to the QHelpSearchEngine's
    search() function.
*/

/*!
    Constructs a new search query widget with the given \a parent.
*/
QHelpSearchQueryWidget::QHelpSearchQueryWidget(QWidget *parent)
    : QWidget(parent)
{
    d = new QHelpSearchQueryWidgetPrivate();

    QVBoxLayout *vLayout = new QVBoxLayout(this);
    vLayout->setMargin(0);

    QHBoxLayout* hBoxLayout = new QHBoxLayout();
    d->simpleSearchLabel = new QLabel(this);
    d->defaultQuery = new QLineEdit(this);
    d->defaultQuery->setCompleter(&d->searchCompleter);
    d->prevQueryButton = new QToolButton(this);
    d->prevQueryButton->setArrowType(Qt::LeftArrow);
    d->prevQueryButton->setEnabled(false);
    d->nextQueryButton = new QToolButton(this);
    d->nextQueryButton->setArrowType(Qt::RightArrow);
    d->nextQueryButton->setEnabled(false);
    d->searchButton = new QPushButton(this);
    hBoxLayout->addWidget(d->simpleSearchLabel);
    hBoxLayout->addWidget(d->defaultQuery);
    hBoxLayout->addWidget(d->prevQueryButton);
    hBoxLayout->addWidget(d->nextQueryButton);
    hBoxLayout->addWidget(d->searchButton);

    vLayout->addLayout(hBoxLayout);

    connect(d->prevQueryButton, SIGNAL(clicked()), d, SLOT(prevQuery()));
    connect(d->nextQueryButton, SIGNAL(clicked()), d, SLOT(nextQuery()));
    connect(d->searchButton, SIGNAL(clicked()), this, SIGNAL(search()));
    connect(d->defaultQuery, SIGNAL(returnPressed()), this, SIGNAL(search()));

#if defined(QT_CLUCENE_SUPPORT)
    hBoxLayout = new QHBoxLayout();
    d->showHideAdvancedSearchButton = new QToolButton(this);
    d->showHideAdvancedSearchButton->setText(QLatin1String("+"));
    d->showHideAdvancedSearchButton->setMinimumSize(25, 20);

    d->advancedSearchLabel = new QLabel(this);
    QSizePolicy sizePolicy(QSizePolicy::Maximum, QSizePolicy::Preferred);
    sizePolicy.setHeightForWidth(d->advancedSearchLabel->sizePolicy().hasHeightForWidth());
    d->advancedSearchLabel->setSizePolicy(sizePolicy);

    QFrame* hLine = new QFrame(this);
    hLine->setFrameStyle(QFrame::HLine);
    hBoxLayout->addWidget(d->showHideAdvancedSearchButton);
    hBoxLayout->addWidget(d->advancedSearchLabel);
    hBoxLayout->addWidget(hLine);

    vLayout->addLayout(hBoxLayout);

    // setup advanced search layout
    d->advancedSearchWidget = new QWidget(this);
    QGridLayout *gLayout = new QGridLayout(d->advancedSearchWidget);
    gLayout->setMargin(0);

    d->similarLabel = new QLabel(this);
    gLayout->addWidget(d->similarLabel, 0, 0);
    d->similarQuery = new QLineEdit(this);
    d->similarQuery->setCompleter(&d->searchCompleter);
    gLayout->addWidget(d->similarQuery, 0, 1);

    d->withoutLabel = new QLabel(this);
    gLayout->addWidget(d->withoutLabel, 1, 0);
    d->withoutQuery = new QLineEdit(this);
    d->withoutQuery->setCompleter(&d->searchCompleter);
    gLayout->addWidget(d->withoutQuery, 1, 1);

    d->exactLabel = new QLabel(this);
    gLayout->addWidget(d->exactLabel, 2, 0);
    d->exactQuery = new QLineEdit(this);
    d->exactQuery->setCompleter(&d->searchCompleter);
    gLayout->addWidget(d->exactQuery, 2, 1);

    d->allLabel = new QLabel(this);
    gLayout->addWidget(d->allLabel, 3, 0);
    d->allQuery = new QLineEdit(this);
    d->allQuery->setCompleter(&d->searchCompleter);
    gLayout->addWidget(d->allQuery, 3, 1);

    d->atLeastLabel = new QLabel(this);
    gLayout->addWidget(d->atLeastLabel, 4, 0);
    d->atLeastQuery = new QLineEdit(this);
    d->atLeastQuery->setCompleter(&d->searchCompleter);
    gLayout->addWidget(d->atLeastQuery, 4, 1);

    vLayout->addWidget(d->advancedSearchWidget);
    d->advancedSearchWidget->hide();

    d->retranslate();

    connect(d->exactQuery, SIGNAL(returnPressed()), this, SIGNAL(search()));
    connect(d->similarQuery, SIGNAL(returnPressed()), this, SIGNAL(search()));
    connect(d->withoutQuery, SIGNAL(returnPressed()), this, SIGNAL(search()));
    connect(d->allQuery, SIGNAL(returnPressed()), this, SIGNAL(search()));
    connect(d->atLeastQuery, SIGNAL(returnPressed()), this, SIGNAL(search()));
    connect(d->showHideAdvancedSearchButton, SIGNAL(clicked()),
        d, SLOT(showHideAdvancedSearch()));
#endif
    connect(this, SIGNAL(search()), d, SLOT(searchRequested()));
}

/*!
    Destroys the search query widget.
*/
QHelpSearchQueryWidget::~QHelpSearchQueryWidget()
{
    delete d;
}

/*!
    \since 4.8

    Expands the search query widget so that the extended search fields are shown.
*/
void QHelpSearchQueryWidget::expandExtendedSearch()
{
    if (d->simpleSearch)
        d->showHideAdvancedSearch();
}

/*!
    \since 4.8

    Collapses the search query widget so that only the default search field is
    shown.
*/
void QHelpSearchQueryWidget::collapseExtendedSearch()
{
    if (!d->simpleSearch)
        d->showHideAdvancedSearch();
}

/*!
    Returns a list of queries to use in combination with the search engines
    search(QList<QHelpSearchQuery> &queryList) function.
*/
QList<QHelpSearchQuery> QHelpSearchQueryWidget::query() const
{
    const QHelpSearchQueryWidgetPrivate::QueryHistory &queryHist =
        d->simpleSearch ? d->simpleQueries : d->complexQueries;
    return queryHist.queries.isEmpty() ?
        QList<QHelpSearchQuery>() : queryHist.queries.last();
}

/*!
    \since 4.8

    Sets the QHelpSearchQueryWidget input fields to the values specified by
    \a queryList search field name. Please note that one has to call the search
    engine's search(QList<QHelpSearchQuery> &queryList) function to perform the
    actual search.
*/
void QHelpSearchQueryWidget::setQuery(const QList<QHelpSearchQuery> &queryList)
{
    QList<QLineEdit *> lineEdits;
    lineEdits << d->defaultQuery << d->allQuery << d->atLeastQuery
        << d->similarQuery << d->withoutQuery << d->exactQuery;
    foreach (QLineEdit *lineEdit, lineEdits)
        lineEdit->clear();

    const QLatin1String space(" ");
    foreach (const QHelpSearchQuery &q, queryList) {
        if (QLineEdit *lineEdit = d->lineEditFor(q.fieldName))
            lineEdit->setText(lineEdit->text() + q.wordList.join(space) + space);
    }
    d->searchRequested();
}

/*!
    \reimp
*/
void QHelpSearchQueryWidget::focusInEvent(QFocusEvent *focusEvent)
{
    if (focusEvent->reason() != Qt::MouseFocusReason) {
        d->defaultQuery->selectAll();
        d->defaultQuery->setFocus();
    }
}

/*! \reimp
*/
void QHelpSearchQueryWidget::changeEvent(QEvent *event)
{
    if (event->type() == QEvent::LanguageChange)
        d->retranslate();
    else
        QWidget::changeEvent(event);
}

QT_END_NAMESPACE