/***********************************************************************
* fkeyboard.h - Read keyboard events                                   *
*                                                                      *
* This file is part of the Final Cut widget toolkit                    *
*                                                                      *
* Copyright 2018-2019 Markus Gans                                      *
*                                                                      *
* The Final Cut 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; either version 3 of    *
* the License, or (at your option) any later version.                  *
*                                                                      *
* The Final Cut 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 program.  If not, see                        *
* <http://www.gnu.org/licenses/>.                                      *
***********************************************************************/

/*  Standalone class
 *  ════════════════
 *
 * ▕▔▔▔▔▔▔▔▔▔▔▔▏
 * ▕ FKeyboard ▏
 * ▕▁▁▁▁▁▁▁▁▁▁▁▏
 */

#ifndef FKEYBOARD_H
#define FKEYBOARD_H

#if !defined (USE_FINAL_H) && !defined (COMPILE_FINAL_CUT)
  #error "Only <final/final.h> can be included directly."
#endif

#include <sys/time.h>
#include <functional>
#include "final/fstring.h"
#include "final/ftypes.h"

namespace finalcut
{

// class forward declaration
class FApplication;
class FString;
class FTermLinux;

//----------------------------------------------------------------------
// class FKeyboardCommand
//----------------------------------------------------------------------

class FKeyboardCommand final
{
  public:
    // Constructors
    FKeyboardCommand () = default;
    explicit FKeyboardCommand (const std::function<void()>& fn)
      : handler(fn)
    { }

    // Method
    void execute()
    {
      handler();
    }

  private:
    // Data members
    std::function<void()> handler{};
};


//----------------------------------------------------------------------
// class FKeyboard
//----------------------------------------------------------------------

class FKeyboard final
{
  public:
    // Constants
    static constexpr std::size_t FIFO_BUF_SIZE{512};

    // Typedef
    typedef char keybuffer[FIFO_BUF_SIZE];

    // Constructor
    FKeyboard();

    // Disable copy constructor
    FKeyboard (const FKeyboard&) = delete;

    // Destructor
    virtual ~FKeyboard();

    // Disable assignment operator (=)
    FKeyboard& operator = (const FKeyboard&) = delete;

    // Accessors
    virtual const FString getClassName() const;
    FKey                  getKey();
    const FString         getKeyName (FKey);
    keybuffer&            getKeyBuffer();
    timeval*              getKeyPressedTime();

    // Mutators
    void                  setTermcapMap (fc::FKeyMap*);
    void                  setKeypressTimeout (const uInt64);
    void                  enableUTF8();
    void                  disableUTF8();
    void                  enableMouseSequences();
    void                  disableMouseSequences();
    void                  setPressCommand (FKeyboardCommand);
    void                  setReleaseCommand (FKeyboardCommand);
    void                  setEscPressedCommand (FKeyboardCommand);

    // Inquiry
    bool                  isInputDataPending();

    // Methods
    static void           init();
    bool&                 unprocessedInput();
    bool                  isKeyPressed();
    void                  clearKeyBuffer();
    void                  clearKeyBufferOnTimeout();
    void                  fetchKeyCode();
    void                  escapeKeyHandling();

  private:
    // Constants
    static constexpr std::size_t READ_BUF_SIZE{1024};
    static constexpr FKey NOT_SET = static_cast<FKey>(-1);

    // Accessors
    FKey                  getMouseProtocolKey();
    FKey                  getTermcapKey();
    FKey                  getMetaKey();
    FKey                  getSingleKey();

    // Mutators
    bool                  setNonBlockingInput (bool);
    bool                  setNonBlockingInput();
    bool                  unsetNonBlockingInput();

    // Inquiry
    static bool           isKeypressTimeout();

    // Methods
    FKey                  UTF8decode (const char[]);
    ssize_t               readKey();
    void                  parseKeyBuffer();
    FKey                  parseKeyString();
    FKey                  keyCorrection (const FKey&);
    void                  substringKeyHandling();
    void                  keyPressed();
    void                  keyReleased();
    void                  escapeKeyPressed();

    // Data members
    FKeyboardCommand      keypressed_cmd{};
    FKeyboardCommand      keyreleased_cmd{};
    FKeyboardCommand      escape_key_cmd{};

#if defined(__linux__)
    #undef linux
    static FTermLinux*    linux;
#endif

    static timeval        time_keypressed;
    static uInt64         key_timeout;
    fc::FKeyMap*          key_map{nullptr};
    FKey                  key{0};
    char                  read_buf[READ_BUF_SIZE]{'\0'};
    char                  fifo_buf[FIFO_BUF_SIZE]{'\0'};
    int                   fifo_offset{0};
    int                   stdin_status_flags{0};
    bool                  fifo_in_use{false};
    bool                  input_data_pending{false};
    bool                  utf8_input{false};
    bool                  mouse_support{true};
    bool                  non_blocking_stdin{false};
};

// FKeyboard inline functions
//----------------------------------------------------------------------
inline const FString FKeyboard::getClassName() const
{ return "FKeyboard"; }

//----------------------------------------------------------------------
inline FKey FKeyboard::getKey()
{ return key; }

//----------------------------------------------------------------------
inline FKeyboard::keybuffer& FKeyboard::getKeyBuffer()
{ return fifo_buf; }

//----------------------------------------------------------------------
inline timeval* FKeyboard::getKeyPressedTime()
{ return &time_keypressed; }

//----------------------------------------------------------------------
inline void FKeyboard::setKeypressTimeout (const uInt64 timeout)
{ key_timeout = timeout; }

//----------------------------------------------------------------------
inline void FKeyboard::enableUTF8()
{ utf8_input = true; }

//----------------------------------------------------------------------
inline void FKeyboard::disableUTF8()
{ utf8_input = false; }

//----------------------------------------------------------------------
inline void FKeyboard::enableMouseSequences()
{ mouse_support = true; }

//----------------------------------------------------------------------
inline void FKeyboard::disableMouseSequences()
{ mouse_support = false; }

//----------------------------------------------------------------------
inline void FKeyboard::setPressCommand (FKeyboardCommand cmd)
{ keypressed_cmd = cmd; }

//----------------------------------------------------------------------
inline void FKeyboard::setReleaseCommand (FKeyboardCommand cmd)
{ keyreleased_cmd = cmd; }

//----------------------------------------------------------------------
inline void FKeyboard::setEscPressedCommand (FKeyboardCommand cmd)
{ escape_key_cmd = cmd; }

//----------------------------------------------------------------------
inline bool FKeyboard::isInputDataPending()
{ return input_data_pending; }
//----------------------------------------------------------------------
inline bool FKeyboard::setNonBlockingInput()
{ return setNonBlockingInput(true); }

//----------------------------------------------------------------------
inline bool FKeyboard::unsetNonBlockingInput()
{ return setNonBlockingInput(false); }

}  // namespace finalcut

#endif  // FKEYBOARD_H