/*
 * barrier -- mouse and keyboard sharing utility
 * Copyright (C) 2012-2016 Symless Ltd.
 * Copyright (C) 2004 Chris Schoeneman
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package 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 General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "barrier/IKeyState.h"
#include "barrier/KeyMap.h"

//! Core key state
/*!
This class provides key state services.  Subclasses must implement a few
platform specific methods.
*/
class KeyState : public IKeyState {
public:
    KeyState(IEventQueue* events);
    KeyState(IEventQueue* events, barrier::KeyMap& keyMap);
    virtual ~KeyState();

    //! @name manipulators
    //@{

    //! Handle key event
    /*!
    Sets the state of \p button to down or up and updates the current
    modifier state to \p newState.  This method should be called by
    primary screens only in response to local events.  For auto-repeat
    set \p down to \c true.  Overrides must forward to the superclass.
    */
    virtual void        onKey(KeyButton button, bool down,
                            KeyModifierMask newState);

    //! Post a key event
    /*!
    Posts a key event.  This may adjust the event or post additional
    events in some circumstances.  If this is overridden it must forward
    to the superclass.
    */
    virtual void        sendKeyEvent(void* target,
                            bool press, bool isAutoRepeat,
                            KeyID key, KeyModifierMask mask,
                            SInt32 count, KeyButton button);

    //@}
    //! @name accessors
    //@{

    //@}

    // IKeyState overrides
    virtual void        updateKeyMap();
    virtual void        updateKeyState();
    virtual void        setHalfDuplexMask(KeyModifierMask);
    virtual void        fakeKeyDown(KeyID id, KeyModifierMask mask,
                            KeyButton button);
    virtual bool        fakeKeyRepeat(KeyID id, KeyModifierMask mask,
                            SInt32 count, KeyButton button);
    virtual bool        fakeKeyUp(KeyButton button);
    virtual void        fakeAllKeysUp();
    virtual bool        fakeCtrlAltDel() = 0;
    virtual bool        fakeMediaKey(KeyID id);

    virtual bool        isKeyDown(KeyButton) const;
    virtual KeyModifierMask
                        getActiveModifiers() const;
    virtual KeyModifierMask
                        pollActiveModifiers() const = 0;
    virtual SInt32        pollActiveGroup() const = 0;
    virtual void        pollPressedKeys(KeyButtonSet& pressedKeys) const = 0;

    SInt32 getKeyState(KeyButton keyButton) { return m_keys[keyButton]; }

protected:
    typedef barrier::KeyMap::Keystroke Keystroke;

    //! @name protected manipulators
    //@{

    //! Get the keyboard map
    /*!
    Fills \p keyMap with the current keyboard map.
    */
    virtual void        getKeyMap(barrier::KeyMap& keyMap) = 0;

    //! Fake a key event
    /*!
    Synthesize an event for \p keystroke.
    */
    virtual void        fakeKey(const Keystroke& keystroke) = 0;

    //! Get the active modifiers
    /*!
    Returns the modifiers that are currently active according to our
    shadowed state.  The state may be modified.
    */
    virtual KeyModifierMask&
                        getActiveModifiersRValue();

    //@}
    //! @name protected accessors
    //@{

    //! Compute a group number
    /*!
    Returns the number of the group \p offset groups after group \p group.
    */
    SInt32                getEffectiveGroup(SInt32 group, SInt32 offset) const;

    //! Check if key is ignored
    /*!
    Returns \c true if and only if the key should always be ignored.
    The default returns \c true only for the toggle keys.
    */
    virtual bool        isIgnoredKey(KeyID key, KeyModifierMask mask) const;

    //! Get button for a KeyID
    /*!
    Return the button mapped to key \p id in group \p group if any,
    otherwise returns 0.
    */
    KeyButton            getButton(KeyID id, SInt32 group) const;

    //@}

private:
    typedef barrier::KeyMap::Keystrokes Keystrokes;
    typedef barrier::KeyMap::ModifierToKeys ModifierToKeys;
public:
    struct AddActiveModifierContext {
    public:
        AddActiveModifierContext(SInt32 group, KeyModifierMask mask,
                            ModifierToKeys&    activeModifiers);

    public:
        SInt32            m_activeGroup;
        KeyModifierMask    m_mask;
        ModifierToKeys&    m_activeModifiers;

    private:
        // not implemented
        AddActiveModifierContext(const AddActiveModifierContext&);
        AddActiveModifierContext& operator=(const AddActiveModifierContext&);
    };
private:

    class ButtonToKeyLess {
    public:
        bool operator()(const barrier::KeyMap::ButtonToKeyMap::value_type& a,
                        const barrier::KeyMap::ButtonToKeyMap::value_type b) const
        {
            return (a.first < b.first);
        }
    };

    // not implemented
    KeyState(const KeyState&);
    KeyState& operator=(const KeyState&);

    // called by all ctors.
    void                init();

    // adds alias key sequences.  these are sequences that are equivalent
    // to other sequences.
    void                addAliasEntries();

    // adds non-keypad key sequences for keypad KeyIDs
    void                addKeypadEntries();

    // adds key sequences for combination KeyIDs (those built using
    // dead keys)
    void                addCombinationEntries();

    // synthesize key events.  synthesize auto-repeat events count times.
    void                fakeKeys(const Keystrokes&, UInt32 count);

    // update key state to match changes to modifiers
    void                updateModifierKeyState(KeyButton button,
                            const ModifierToKeys& oldModifiers,
                            const ModifierToKeys& newModifiers);

    // active modifiers collection callback
    static void            addActiveModifierCB(KeyID id, SInt32 group,
                            barrier::KeyMap::KeyItem& keyItem, void* vcontext);

private:
    // must be declared before m_keyMap. used when this class owns the key map.
    barrier::KeyMap*            m_keyMapPtr;

    // the keyboard map
    barrier::KeyMap&            m_keyMap;

    // current modifier state
    KeyModifierMask        m_mask;

    // the active modifiers and the buttons activating them
    ModifierToKeys        m_activeModifiers;

    // current keyboard state (> 0 if pressed, 0 otherwise).  this is
    // initialized to the keyboard state according to the system then
    // it tracks synthesized events.
    SInt32                m_keys[kNumButtons];

    // synthetic keyboard state (> 0 if pressed, 0 otherwise).  this
    // tracks the synthesized keyboard state.  if m_keys[n] > 0 but
    // m_syntheticKeys[n] == 0 then the key was pressed locally and
    // not synthesized yet.
    SInt32                m_syntheticKeys[kNumButtons];

    // client data for each pressed key
    UInt32                m_keyClientData[kNumButtons];

    // server keyboard state.  an entry is 0 if not the key isn't pressed
    // otherwise it's the local KeyButton synthesized for the server key.
    KeyButton            m_serverKeys[kNumButtons];

    IEventQueue*        m_events;
};
