/*
 *  © 2024, Travis Farmer. All rights reserved.
 *  © 2024, Chris Bulliner. All rights reserved. https://github.com/CMB27
 *   
 *  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/>.
 */

/*
 * RSproto
 * =======
 * To define a RSproto, example syntax:
 *    RSproto::create(serial, baud[, cycletime[, pin]]);
 * 
 * serial = serial port to be used (e.g. Serial3)
 * baud = baud rate (9600, 19200, 28800, 57600 or 115200)
 * cycletime = minimum time between successive updates/reads of a node in millisecs (default 500ms)
 * pin = pin number connected to RSproto module's DE and !RE terminals for half-duplex operation (default VPIN_NONE)
 *
 * 
 * RSprotoNode
 * ========
 * To define a RSproto node and associate it with a RSproto bus,
 *    RSprotonode::create(firstVPIN, numVPINs, nodeID);
 * 
 * firstVPIN = first vpin in block allocated to this device
 * numVPINs = number of vpins
 * nodeID = 0-254
 */

#ifndef IO_RS485_H
#define IO_RS485_H

#include "IODevice.h"

class RSproto;
class RSprotonode;

#ifndef COMMAND_BUFFER_SIZE
 #define COMMAND_BUFFER_SIZE 100
#endif
#ifndef RS485_SERIAL
 #define RS485_SERIAL Serial1
#endif
class taskBuffer
{
private:
static taskBuffer *first;
  RSprotonode *node;
  Stream * serial;
  uint8_t _txPin;
  uint8_t _nodeID;
  uint8_t _commandType;
  byte bufferLength;
  byte buffer[COMMAND_BUFFER_SIZE]; 
  taskBuffer *next;
  uint8_t endChar[1] = {0xFE};
  byte inCommandPayload;
  // EX-IOExpander protocol flags
  enum {
    EXIOINIT = 0xE0,    // Flag to initialise setup procedure
    EXIORDY = 0xE1,     // Flag we have completed setup procedure, also for EX-IO to ACK setup
    EXIODPUP = 0xE2,    // Flag we're sending digital pin pullup configuration
    EXIOVER = 0xE3,     // Flag to get version
    EXIORDAN = 0xE4,    // Flag to read an analogue input
    EXIOWRD = 0xE5,     // Flag for digital write
    EXIORDD = 0xE6,     // Flag to read digital input
    EXIOENAN = 0xE7,    // Flag to enable an analogue pin
    EXIOINITA = 0xE8,   // Flag we're receiving analogue pin mappings
    EXIOPINS = 0xE9,    // Flag we're receiving pin counts for buffers
    EXIOWRAN = 0xEA,   // Flag we're sending an analogue write (PWM)
    EXIOERR = 0xEF,     // Flag we've received an error
  };
  // RSproto protocol frame bytes
  enum {
    STARTBYTE = 0xFD,
    ENDBYTE = 0xFE,
  };
  void doCommand2(uint8_t *commandBuffer=NULL, int commandSize=0);
  void loop2();
  void parseRx(uint8_t *buf);
  void parseOne(uint8_t *buf);
public:
  taskBuffer(Stream * myserial);
  ~taskBuffer();
  static void doCommand(uint8_t *commandBuffer=NULL, int commandSize=0);
  static void init(unsigned long baud, int8_t txPin=-1);
  static void loop();
};






/**********************************************************************
 * RSprotonode class
 * 
 * This encapsulates the state associated with a single RSproto node, 
 * which includes the nodeID, number of discrete inputs and coils, and
 * the states of the discrete inputs and coils.
 **********************************************************************/
class RSprotonode : public IODevice {
private:
  uint8_t _busNo;
  uint8_t _nodeID;
  char _type;
  RSprotonode *_next = NULL;
  bool _initialised = false;
  RSproto *bus;
  taskBuffer *task;
  HardwareSerial* _serial;
  // EX-IOExpander protocol flags
  enum {
    EXIOINIT = 0xE0,    // Flag to initialise setup procedure
    EXIORDY = 0xE1,     // Flag we have completed setup procedure, also for EX-IO to ACK setup
    EXIODPUP = 0xE2,    // Flag we're sending digital pin pullup configuration
    EXIOVER = 0xE3,     // Flag to get version
    EXIORDAN = 0xE4,    // Flag to read an analogue input
    EXIOWRD = 0xE5,     // Flag for digital write
    EXIORDD = 0xE6,     // Flag to read digital input
    EXIOENAN = 0xE7,    // Flag to enable an analogue pin
    EXIOINITA = 0xE8,   // Flag we're receiving analogue pin mappings
    EXIOPINS = 0xE9,    // Flag we're receiving pin counts for buffers
    EXIOWRAN = 0xEA,   // Flag we're sending an analogue write (PWM)
    EXIOERR = 0xEF,     // Flag we've received an error
  };
  
public:
  static RSprotonode *_nodeList;
  enum ProfileType : int {
    Instant = 0,  // Moves immediately between positions (if duration not specified)
    UseDuration = 0, // Use specified duration
    Fast = 1,     // Takes around 500ms end-to-end
    Medium = 2,   // 1 second end-to-end
    Slow = 3,     // 2 seconds end-to-end
    Bounce = 4,   // For semaphores/turnouts with a bit of bounce!!
    NoPowerOff = 0x80, // Flag to be ORed in to suppress power off after move.
  };

  uint8_t _numDigitalPins = 0;
  uint8_t _numAnaloguePins = 0;
  uint8_t _majorVer = 0;
  uint8_t _minorVer = 0;
  uint8_t _patchVer = 0;
  uint8_t* _digitalInputStates  = NULL;
  uint8_t* _analogueInputStates = NULL;
  uint8_t* _analogueInputBuffer = NULL;  // buffer for I2C input transfers
  uint8_t _readCommandBuffer[4];
  uint8_t _digitalPinBytes = 0;   // Size of allocated memory buffer (may be longer than needed)
  uint8_t _analoguePinBytes = 0;  // Size of allocated memory buffer (may be longer than needed)
  uint8_t* _analoguePinMap = NULL;
  int  resFlag = 0;
  bool _initalized;
  static void create(VPIN firstVpin, int nPins, uint8_t nodeID) {
    if (checkNoOverlap(firstVpin, nPins)) new RSprotonode(firstVpin, nPins, nodeID);
  }
  RSprotonode(VPIN firstVpin, int nPins, uint8_t nodeID);

  uint8_t getNodeID() {
    return _nodeID;
  }
  
  RSprotonode *getNext() {
    return _next;
  }
 
  void setNext(RSprotonode *node) {
    _next = node;
  }
  bool isInitialised() {
    return _initialised;
  }
  void setInitialised() {
    _initialised = true;
  }
  
  bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) override;
  int _configureAnalogIn(VPIN vpin) override;
  void _begin() override;
  int _read(VPIN vpin) override;
  void _write(VPIN vpin, int value) override;
  int _readAnalogue(VPIN vpin) override;
  void _writeAnalogue(VPIN vpin, int value, uint8_t profile, uint16_t duration) override;

  uint8_t getBusNumber() {
    return _busNo;
  }
 
  void _display() override {
    DIAG(F("EX-IOExpander485 node:%d v%d.%d.%d Vpins %u-%u %S"), _nodeID, _majorVer, _minorVer, _patchVer, (int)_firstVpin, (int)_firstVpin+_nPins-1, _deviceState == DEVSTATE_FAILED ? F("OFFLINE") : F(""));
  }
  
};

/**********************************************************************
 * RSproto class
 * 
 * This encapsulates the properties state of the bus and the
 * transmission and reception of data across that bus.  Each RSproto
 * object owns a set of RSprotonode objects which represent the nodes
 * attached to that bus.
 **********************************************************************/
class RSproto : public IODevice {
private:
  // Here we define the device-specific variables.  
  uint8_t _busNo;
  taskBuffer *task;
  unsigned long _cycleStartTime = 0;
  unsigned long _timeoutStart = 0;
  unsigned long _cycleTime; // target time between successive read/write cycles, microseconds
  unsigned long _timeoutPeriod; // timeout on read responses, in microseconds.
  unsigned long _currentMicros;  // last value of micros() from _loop function.
  unsigned long _postDelay; // delay time after transmission before switching off transmitter (in us)
  unsigned long _byteTransmitTime; // time in us for transmission of one byte
  int _operationCount = 0;
  int _refreshOperation = 0;

  static RSproto *_busList; // linked list of defined bus instances
  bool waitReceive = false;
  int _waitCounter = 0;
  int _waitCounterB = 0;
  int _waitA;
  unsigned long _charTimeout;
  unsigned long _frameTimeout;
  enum {RDS_IDLE, RDS_DIGITAL, RDS_ANALOGUE};  // Read operation states
  uint8_t _readState = RDS_IDLE;
  
  unsigned long _lastDigitalRead = 0;
  unsigned long _lastAnalogueRead = 0;
  const unsigned long _digitalRefresh = 10000UL;    // Delay refreshing digital inputs for 10ms
  const unsigned long _analogueRefresh = 50000UL;   // Delay refreshing analogue inputs for 50ms


  
  
  RSprotonode *_nodeListStart = NULL, *_nodeListEnd = NULL;
  RSprotonode *_currentNode = NULL;
  uint16_t _receiveDataIndex = 0;  // Index of next data byte to be received.
  RSproto *_nextBus = NULL;  // Pointer to next bus instance in list.
  
// Helper function for error handling
  void reportError(uint8_t status, bool fail=true) {
    DIAG(F("EX-IOExpander485 Node:%d Error"), _currentNode->getNodeID());
    if (fail)
    _deviceState = DEVSTATE_FAILED;
  }

public:
  static void create(unsigned long baud, int8_t txPin=-1) {
    new RSproto(baud, txPin);
  }

  int _CommMode = 0;
  int _opperation = 0;
  uint16_t _pullup;
  uint16_t _pin;
  int8_t _txPin;
  bool _busy = false;
  unsigned long _baud;
  int taskCnt = 0;
  uint8_t initBuffer[1] = {0xFE};

  // Device-specific initialisation
  void _begin() override {

  #if defined(RSproto_STM_OK)
    pinMode(RSproto_STM_OK, OUTPUT);
    ArduinoPins::fastWriteDigital(RSproto_STM_OK,LOW);
  #endif
  #if defined(RSproto_STM_FAIL)
    pinMode(RSproto_STM_FAIL, OUTPUT);
    ArduinoPins::fastWriteDigital(RSproto_STM_FAIL,LOW);
  #endif
  #if defined(RSproto_STM_COMM)
    pinMode(RSproto_STM_COMM, OUTPUT);
    ArduinoPins::fastWriteDigital(RSproto_STM_COMM,LOW);
  #endif
  
  #if defined(DIAG_IO)
    _display();
  #endif
  }


  // Loop function (overriding IODevice::_loop(unsigned long))
  void _loop(unsigned long currentMicros) override;

  // Display information about the device
  void _display() override {
    DIAG(F("EX-IOExpander485 Configured on Vpins:%d-%d %S"), _firstVpin, _firstVpin+_nPins-1,
      _deviceState == DEVSTATE_FAILED ? F("OFFLINE") : F("OK"));
  }

  // Locate RSprotonode object with specified nodeID.
  RSprotonode *findNode(uint8_t nodeID) {
    for (RSprotonode *node = _nodeListStart; node != NULL; node = node->getNext()) {
      if (node->getNodeID() == nodeID) 
        return node;
    }
    return NULL;
  }

  bool nodesInitialized() {
    bool retval = true;
    for (RSprotonode *node = _nodeListStart; node != NULL; node = node->getNext()) {
      if (node->_initalized == false) 
        retval = false;
    }
    return retval;
  }
  // Add new RSprotonode to the list of nodes for this bus.
  void addNode(RSprotonode *newNode) {
    if (!_nodeListStart)
      _nodeListStart = newNode;
    if (!_nodeListEnd) 
      _nodeListEnd = newNode;
    else
      _nodeListEnd->setNext(newNode);
  //DIAG(F("RSproto: 260h nodeID:%d _nodeListStart:%d _nodeListEnd:%d"), newNode, _nodeListStart, _nodeListEnd);
  }

protected:
  RSproto(unsigned long baud, int8_t txPin);

public:
  
  uint8_t getBusNumber() {
    return _busNo;
  }
  RSproto *getNext() {
    return _nextBus;
  }
  static RSproto *findBus(uint8_t busNo) {
    for (RSproto *bus = _busList; bus != NULL; bus = bus->getNext()) {
      if (bus->getBusNumber() == busNo) 
        return bus;
    }
    return NULL;
  }
};


#endif // IO_RSproto_H