/**
 * @file llkeyboard.h
 * @brief Handler for assignable key bindings
 *
 * $LicenseInfo:firstyear=2001&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLKEYBOARD_H
#define LL_LLKEYBOARD_H

#include <map>
#include <boost/function.hpp>

#include "llstringtable.h"
#include "lltimer.h"
#include "indra_constants.h"

enum EKeystate
{
    KEYSTATE_DOWN,
    KEYSTATE_LEVEL,
    KEYSTATE_UP
};

typedef boost::function<bool(EKeystate keystate)> LLKeyFunc;
typedef std::string (LLKeyStringTranslatorFunc)(std::string_view);

enum EKeyboardInsertMode
{
    LL_KIM_INSERT,
    LL_KIM_OVERWRITE
};

class LLWindowCallbacks;

class LLKeyboard
{
public:
#ifdef LL_LINUX
    // linux relies on SDL2 which uses U32 for its native key type
    typedef U32 NATIVE_KEY_TYPE;
#else
    // on non-linux platforms we can get by with a smaller native key type
    typedef U16 NATIVE_KEY_TYPE;
#endif
    LLKeyboard();
    virtual ~LLKeyboard();

    void            resetKeyDownAndHandle();
    void            resetKeys();


    F32             getCurKeyElapsedTime()  { return getKeyDown(mCurScanKey) ? getKeyElapsedTime( mCurScanKey ) : 0.f; }
    F32             getCurKeyElapsedFrameCount()    { return getKeyDown(mCurScanKey) ? (F32)getKeyElapsedFrameCount( mCurScanKey ) : 0.f; }
    bool            getKeyDown(const KEY key) { return mKeyLevel[key]; }
    bool            getKeyRepeated(const KEY key) { return mKeyRepeated[key]; }

    bool            translateKey(const NATIVE_KEY_TYPE os_key, KEY *translated_key);
    NATIVE_KEY_TYPE inverseTranslateKey(const KEY translated_key);
    bool            handleTranslatedKeyUp(KEY translated_key, MASK translated_mask);     // Translated into "Linden" keycodes
    bool            handleTranslatedKeyDown(KEY translated_key, MASK translated_mask);   // Translated into "Linden" keycodes

    virtual bool    handleKeyUp(const NATIVE_KEY_TYPE key, MASK mask) = 0;
    virtual bool    handleKeyDown(const NATIVE_KEY_TYPE key, MASK mask) = 0;

    virtual void    handleModifier(MASK mask) { }

    // Asynchronously poll the control, alt, and shift keys and set the
    // appropriate internal key masks.
    virtual void    resetMaskKeys() = 0;
    virtual void    scanKeyboard() = 0;                                                         // scans keyboard, calls functions as necessary
    // Mac must differentiate between Command = Control for keyboard events
    // and Command != Control for mouse events.
    virtual MASK    currentMask(bool for_mouse_event) = 0;
    virtual KEY     currentKey() { return mCurTranslatedKey; }

    EKeyboardInsertMode getInsertMode() { return mInsertMode; }
    void toggleInsertMode();

    static bool     maskFromString(const std::string& str, MASK *mask);     // False on failure
    static bool     keyFromString(const std::string& str, KEY *key);            // False on failure
    static std::string stringFromKey(KEY key, bool translate = true);
    static std::string stringFromMouse(EMouseClickType click, bool translate = true);
    static std::string stringFromAccelerator( MASK accel_mask ); // separated for convinience, returns with "+": "Shift+" or "Shift+Alt+"...
    static std::string stringFromAccelerator( MASK accel_mask, KEY key );
    static std::string stringFromAccelerator(MASK accel_mask, EMouseClickType click);

    void setCallbacks(LLWindowCallbacks *cbs) { mCallbacks = cbs; }
    F32             getKeyElapsedTime( KEY key );  // Returns time in seconds since key was pressed.
    S32             getKeyElapsedFrameCount( KEY key );  // Returns time in frames since key was pressed.

    static void     setStringTranslatorFunc( LLKeyStringTranslatorFunc *trans_func );

protected:
    void            addKeyName(KEY key, const std::string& name);
    virtual MASK    updateModifiers(const MASK mask) { return mask; }

protected:
    std::map<NATIVE_KEY_TYPE, KEY>  mTranslateKeyMap;       // Map of translations from OS keys to Linden KEYs
    std::map<KEY, NATIVE_KEY_TYPE>  mInvTranslateKeyMap;    // Map of translations from Linden KEYs to OS keys
    LLWindowCallbacks *mCallbacks;

    LLTimer         mKeyLevelTimer[KEY_COUNT];  // Time since level was set
    S32             mKeyLevelFrameCount[KEY_COUNT]; // Frames since level was set
    bool            mKeyLevel[KEY_COUNT];       // Levels
    bool            mKeyRepeated[KEY_COUNT];    // Key was repeated
    bool            mKeyUp[KEY_COUNT];          // Up edge
    bool            mKeyDown[KEY_COUNT];        // Down edge
    KEY             mCurTranslatedKey;
    KEY             mCurScanKey;        // Used during the scanKeyboard()

    static LLKeyStringTranslatorFunc*   mStringTranslator;  // Used for l10n + PC/Mac/Linux accelerator labeling

    EKeyboardInsertMode mInsertMode;

    static std::map<KEY,std::string> sKeysToNames;
    static std::map<std::string,KEY> sNamesToKeys;
};

// Interface to get key from assigned command
class LLKeyBindingToStringHandler
{
public:
    virtual std::string getKeyBindingAsString(const std::string& mode, const std::string& control) const = 0;
};

extern LLKeyboard *gKeyboard;

#endif