/*
 *  © 2022, Chris Harlow. All rights reserved.
 *  
 *  This file is part of DCC++EX API
 *
 *  This is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  It 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 CommandStation.  If not, see <https://www.gnu.org/licenses/>.
 */
#ifndef IO_LEWDUINO_h
 #define IO_LEWDUINO_h
#include <Arduino.h>
#include "defines.h"
#include "IODevice.h"

#define PIN_MASK(bit) (0x80>>(bit%8))
#define GET_BIT(x) (_pinValues[(x)/8] & PIN_MASK((x)) )
#define SET_BIT(x) _pinValues[(x)/8] |= PIN_MASK((x))
#define CLR_BIT(x) _pinValues[(x)/8] &= ~PIN_MASK((x))
#define DIAG_IO



class IO_LEWDUINO : public IODevice {

public:
  IO_LEWDUINO(VPIN firstVpin, int nPins, 
                byte clockPin, byte latchPin, byte dataPin, 
                const byte* pinmap) :
    IODevice(firstVpin, nPins) {
 
   _latchPin=latchPin;
    _clockPin=clockPin;
    _dataPin=dataPin;
    _pinMap=pinmap;
    _nShiftBytes=(nPins+7)/8; // rounded up to multiples of 8 bits
    _pinValues=(byte*) calloc(_nShiftBytes,1);  
    // Connect to HAL so my _write, _read and _loop will be called as required.
    IODevice::addDevice(this);  
  }

// Called by HAL to start handling this device
  void _begin() override {
     _deviceState = DEVSTATE_NORMAL;
    pinMode(_latchPin,OUTPUT);
    pinMode(_clockPin,OUTPUT);
    pinMode(_dataPin,_pinMap?INPUT_PULLUP:OUTPUT);
    _display();
  }

// loop called by HAL supervisor 
void _loop(unsigned long currentMicros) override {
    if (_pinMap) _loopInput(currentMicros);
    else if (_xmitPending) _loopOutput();
}

void _loopInput(unsigned long currentMicros)  {
   
   if (currentMicros-_prevMicros < POLL_MICROS) return; // Nothing to do
    _prevMicros=currentMicros;
   
    //set latch to HIGH to freeze & store parallel data
   ArduinoPins::fastWriteDigital(_latchPin, HIGH);
   delayMicroseconds(50);
   //set latch to LOW to enable the data to be transmitted serially
   ArduinoPins::fastWriteDigital(_latchPin, LOW);
   delayMicroseconds(50);

  // stream in the bitmap useing mapping order provided at constructor   
  for (int xmitByte=0;xmitByte<_nShiftBytes; xmitByte++) {
      byte newByte=0;
      for (int xmitBit=0;xmitBit<8; xmitBit++) {
        ArduinoPins::fastWriteDigital(_clockPin, LOW);
        delayMicroseconds(20);
        bool data = ArduinoPins::fastReadDigital(_dataPin);  
        byte map=_pinMap[xmitBit];
        if (data)  newByte |= map;
            else   newByte &= ~map;
        ArduinoPins::fastWriteDigital(_clockPin, HIGH); 
        delayMicroseconds(20);   
      }
      _pinValues[xmitByte]=newByte;
      DIAG(F("DIN %x=%x"),xmitByte, newByte);
    }
  }

void _loopOutput()  {
    // stream out the bitmap (highest pin first)
    _xmitPending=false; 
    ArduinoPins::fastWriteDigital(_latchPin, LOW);
    for (int xmitBit=_nShiftBytes*8 -1; xmitBit>=0; xmitBit--) {
        ArduinoPins::fastWriteDigital(_dataPin,GET_BIT(xmitBit));
        ArduinoPins::fastWriteDigital(_clockPin,HIGH);
        ArduinoPins::fastWriteDigital(_clockPin,LOW);
    }  
    digitalWrite(_latchPin, HIGH);
  }

  int _read(VPIN vpin) override {
    int pin=vpin - _firstVpin;
    bool b=GET_BIT(pin);
    return b?1:0;
  }

  void _write(VPIN vpin, int value) override {
    int pin = vpin - _firstVpin;
    bool oldval=GET_BIT(pin);
    bool newval=value!=0;
    if (newval==oldval) return; // no change  
    if (newval) SET_BIT(pin);
           else CLR_BIT(pin);
    _xmitPending=true;  // shift register will be sent on next _loop()
  }

  void _display() override {
      DIAG(F("IO_LEWDUINO %SPUT Configured on VPins:%d-%d shift=%d"), 
      _pinMap?F("IN"):F("OUT"),
      (int)_firstVpin, 
      (int)_firstVpin+_nPins-1, _nShiftBytes*8);
  }

private:
  static const unsigned long POLL_MICROS=1000000; // 10 / S
  unsigned long _prevMicros; 
  int  _nShiftBytes=0; 
  VPIN _latchPin,_clockPin,_dataPin;
  byte* _pinValues;
  bool _xmitPending; // Only relevant in output mode
  const byte* _pinMap;  // NULL in output mode 
};

class IO_DNIN8  {
public:
  static void create(VPIN firstVpin, int nPins, byte clockPin, byte latchPin, byte dataPin ) 
  {
      // input arrives as board pin 0,7,6,5,1,2,3,4 
      static const byte pinmap[8]={0x80,0x01,0x02,0x04,0x40,0x20,0x10,0x08};
      if (IODevice::checkNoOverlap(firstVpin,nPins))
        new IO_LEWDUINO( firstVpin,  nPins,  clockPin,  latchPin,   dataPin,pinmap);
  }

};

class IO_DNIN8K  {
public:
  static void create(VPIN firstVpin, int nPins, byte clockPin, byte latchPin, byte dataPin ) 
  {
      // input arrives as board pin 0, 1, 2, 3, 4, 5, 6, 7
      static const byte pinmap[8]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80}; 
       if (IODevice::checkNoOverlap(firstVpin,nPins))
        new IO_LEWDUINO( firstVpin,  nPins, clockPin, latchPin, dataPin,pinmap);
  }
};

class IO_DNOUT8 {
public:
  static void create(VPIN firstVpin, int nPins, byte clockPin, byte latchPin, byte dataPin ) 
  {
        if (IODevice::checkNoOverlap(firstVpin,nPins))
         new IO_LEWDUINO( firstVpin,  nPins,  clockPin, latchPin,   dataPin,NULL);
  }

};
#endif