/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Virtual Keyboard module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL$
** 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
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** information use the contact form at https://www.qt.io/contact-us.
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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****************************************************************************/

#ifndef INPUTENGINE_H
#define INPUTENGINE_H

#include <QObject>
#include <QPointer>

namespace QtVirtualKeyboard {

class InputContext;
class SelectionListModel;
class AbstractInputMethod;
class InputEnginePrivate;
class Trace;

class InputEngine : public QObject
{
    Q_OBJECT
    Q_DISABLE_COPY(InputEngine)
    Q_DECLARE_PRIVATE(InputEngine)
    Q_FLAGS(ReselectFlags)
    Q_PROPERTY(Qt::Key activeKey READ activeKey NOTIFY activeKeyChanged)
    Q_PROPERTY(Qt::Key previousKey READ previousKey NOTIFY previousKeyChanged)
    Q_PROPERTY(QtVirtualKeyboard::AbstractInputMethod *inputMethod READ inputMethod WRITE setInputMethod NOTIFY inputMethodChanged)
    Q_PROPERTY(QList<int> inputModes READ inputModes NOTIFY inputModesChanged)
    Q_PROPERTY(InputMode inputMode READ inputMode WRITE setInputMode NOTIFY inputModeChanged)
    Q_PROPERTY(QList<int> patternRecognitionModes READ patternRecognitionModes NOTIFY patternRecognitionModesChanged)
    Q_PROPERTY(QtVirtualKeyboard::SelectionListModel *wordCandidateListModel READ wordCandidateListModel NOTIFY wordCandidateListModelChanged)
    Q_PROPERTY(bool wordCandidateListVisibleHint READ wordCandidateListVisibleHint NOTIFY wordCandidateListVisibleHintChanged)

    explicit InputEngine(InputContext *parent = 0);

public:
    enum TextCase {
        Lower,
        Upper
    };
    enum InputMode {
        Latin,
        Numeric,
        Dialable,
        Pinyin,
        Cangjie,
        Zhuyin,
        Hangul,
        Hiragana,
        Katakana,
        FullwidthLatin
    };
    enum PatternRecognitionMode {
        PatternRecognitionDisabled,
        HandwritingRecoginition
    };
    enum ReselectFlag {
        WordBeforeCursor = 0x1,
        WordAfterCursor = 0x2,
        WordAtCursor = WordBeforeCursor | WordAfterCursor
    };

    Q_ENUM(TextCase)
    Q_ENUM(InputMode)
    Q_ENUM(PatternRecognitionMode)
    Q_DECLARE_FLAGS(ReselectFlags, ReselectFlag)

public:
    ~InputEngine();

    Q_INVOKABLE bool virtualKeyPress(Qt::Key key, const QString &text, Qt::KeyboardModifiers modifiers, bool repeat);
    Q_INVOKABLE void virtualKeyCancel();
    Q_INVOKABLE bool virtualKeyRelease(Qt::Key key, const QString &text, Qt::KeyboardModifiers modifiers);
    Q_INVOKABLE bool virtualKeyClick(Qt::Key key, const QString &text, Qt::KeyboardModifiers modifiers);

    InputContext *inputContext() const;
    Qt::Key activeKey() const;
    Qt::Key previousKey() const;

    AbstractInputMethod *inputMethod() const;
    void setInputMethod(AbstractInputMethod *inputMethod);

    QList<int> inputModes() const;

    InputMode inputMode() const;
    void setInputMode(InputMode inputMode);

    SelectionListModel *wordCandidateListModel() const;
    bool wordCandidateListVisibleHint() const;

    QList<int> patternRecognitionModes() const;
    Q_INVOKABLE QtVirtualKeyboard::Trace *traceBegin(int traceId, QtVirtualKeyboard::InputEngine::PatternRecognitionMode patternRecognitionMode,
                                                     const QVariantMap &traceCaptureDeviceInfo, const QVariantMap &traceScreenInfo);
    Q_INVOKABLE bool traceEnd(QtVirtualKeyboard::Trace *trace);

    Q_INVOKABLE bool reselect(int cursorPosition, const ReselectFlags &reselectFlags);

signals:
    void virtualKeyClicked(Qt::Key key, const QString &text, Qt::KeyboardModifiers modifiers, bool isAutoRepeat);
    void activeKeyChanged(Qt::Key key);
    void previousKeyChanged(Qt::Key key);
    void inputMethodChanged();
    void inputMethodReset();
    void inputMethodUpdate();
    void inputModesChanged();
    void inputModeChanged();
    void patternRecognitionModesChanged();
    void wordCandidateListModelChanged();
    void wordCandidateListVisibleHintChanged();

private slots:
    void reset();
    void update();
    void shiftChanged();
    void updateSelectionListModels();

protected:
    void timerEvent(QTimerEvent *timerEvent);

private:
    friend class InputContext;
};

} // namespace QtVirtualKeyboard

Q_DECLARE_METATYPE(QtVirtualKeyboard::InputEngine::TextCase)
Q_DECLARE_METATYPE(QtVirtualKeyboard::InputEngine::InputMode)
Q_DECLARE_OPERATORS_FOR_FLAGS(QtVirtualKeyboard::InputEngine::ReselectFlags)

#endif