/*
 *  © 2020, Chris Harlow. All rights reserved.
 *  © 2020, Harald Barth
 *  
 *  This file is part of Asbelos DCC 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/>.
 */
/*
 * Truncated JMRI WiThrottle server implementation for DCC-EX command station
 * Credit is due to  Valerie Valley RR https://sites.google.com/site/valerievalleyrr/
 *  for showing how it could be done, but this code is very different to the original
 *  implementation as it is designed to run on the Arduino and not the ESP and is
 *  also calling directly into the DCCEX Api rather than  simulating JMRI text commands.
 * Refer JMRI WiFi Throttle Communications Protocol https://www.jmri.org/help/en/package/jmri/jmrit/withrottle/Protocol.shtml
 * 
 * 
 * PROTOTYPE NOTES:
 *  There will be one WiThrottle instance created for each WiThrottle client detected by the WifiInterface.
 *  Some shortcuts have been taken and there are some things that are yet to be included:
 *  e.g. Full response to adding a loco.
 *  What to do about unknown turnouts.
 *  Broadcasting to other WiThrottles when things change.  
 *    -  Bear in mind that changes may have taken place due to  
 *      other WiThrottles, OR JMRI commands received OR TPL automation. 
 *    - I suggest that at the end of parse(), then anything that has changed and is of interest could  
 *       be notified then.  (e.g loco speeds, directions or functions, turnout states.
 *       
 *  WiThrottle.h sets the max locos per client at 10, this is ok to increase but requires just an extra 3 bytes per loco per client.      
*/
#include <Arduino.h>
#include "WiThrottle.h"
#include "DCC.h"
#include "DCCWaveform.h"
#include "StringFormatter.h"
#include "Turnouts.h"
#include "DIAG.h"

#define LOOPLOCOS(THROTTLECHAR, CAB)  for (int loco=0;loco<MAX_MY_LOCO;loco++) \
      if ((myLocos[loco].throttle==THROTTLECHAR || '*'==THROTTLECHAR) && (CAB<0 || myLocos[loco].cab==CAB))

WiThrottle * WiThrottle::firstThrottle=NULL;
bool WiThrottle::annotateLeftRight=false;

WiThrottle* WiThrottle::getThrottle( int wifiClient) {
  for (WiThrottle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle)  
     if (wt->clientid==wifiClient) return wt; 
  return new WiThrottle( wifiClient);
}

bool WiThrottle::isThrottleInUse(int cab) {
  for (WiThrottle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle)  
     if (wt->areYouUsingThrottle(cab)) return true;
  return false;
}

bool WiThrottle::areYouUsingThrottle(int cab) {
  LOOPLOCOS('*', cab) { // see if I have this cab in use
      return true;
  }
  return false;
}


 // One instance of WiThrottle per connected client, so we know what the locos are 
 
WiThrottle::WiThrottle( int wificlientid) {
   DIAG(F("\nCreating new WiThrottle for client %d\n"),wificlientid); 
   nextThrottle=firstThrottle;
   firstThrottle= this;
   clientid=wificlientid;
   heartBeatEnable=false; // until client turns it on
   sendTurnoutList=false; // indicates turnout list needs to be sent to this client
   sendPowerState =false; // indicates power state  needs to be sent to this client
   for (int loco=0;loco<MAX_MY_LOCO; loco++) myLocos[loco].throttle='\0';
}

WiThrottle::~WiThrottle() {
  if (firstThrottle== this) {
    firstThrottle=this->nextThrottle;
    return;
  }
  for (WiThrottle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle) {
    if (wt->nextThrottle==this) {
      wt->nextThrottle=this->nextThrottle;
      return;  
     }
  }
}

void WiThrottle::parse(Print & stream, byte * cmdx) {
  
  // we have to take a copy of the cmd buffer as the reply will get built into the cmdx  
  byte local[50];
  for (byte i=0;i<sizeof(local);i++) {
    local[i]=cmdx[i];
    if (!cmdx[i]) break;
  }
  local[49]='\0'; // prevent runaway parser
  
  byte * cmd=local;
  
  heartBeat=millis();
  //  DIAG(F("\nWiThrottle(%d)<-[%e]\n"),clientid, cmd);

  // Send turnout list when requested (will replace list on client)
  if (sendTurnoutList) {
    StringFormatter::send(stream,F("PTL"));
    for(Turnout *tt=Turnout::firstTurnout;tt!=NULL;tt=tt->nextTurnout){
        StringFormatter::send(stream,F("]\\[%d}|{%d}|{%c"), tt->data.id, tt->data.id, Turnout::isActive(tt->data.id)?'4':'2');
    }
    StringFormatter::send(stream,F("\n"));
    sendTurnoutList = false;
  }

  // Send power state when requested
  if (sendPowerState) {
    StringFormatter::send(stream,F("PPA%x\n"),DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON);
    sendPowerState = false;  
  }

   while (cmd[0]) {
   switch (cmd[0]) {
       case '*':  // heartbeat control
            if (cmd[1]=='+') heartBeatEnable=true;
            else if (cmd[1]=='-') heartBeatEnable=false;
            break;
       case 'P':  
            if (cmd[1]=='P' && cmd[2]=='A' )  {  //PPA power mode 
              DCCWaveform::mainTrack.setPowerMode(cmd[3]=='1'?POWERMODE::ON:POWERMODE::OFF);
              StringFormatter::send(stream,F("PPA%x\n"),DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON);
            }
            else if (cmd[1]=='T' && cmd[2]=='A') { // PTA accessory toggle 
                int id=getInt(cmd+4); 
                bool newstate=false;
                Turnout * tt=Turnout::get(id);
                if (!tt) {
                  // If turnout does not exist, create it
                  int addr = ((id - 1) / 4) + 1;
                  int subaddr = (id - 1) % 4;
                  Turnout::create(id,addr,subaddr);
                  StringFormatter::send(stream, F("HMTurnout %d created\n"),id);
                }
                switch (cmd[3]) {
                    case 'T': newstate=true; break;
                    case 'C': newstate=false; break;
                    case '2': newstate=!Turnout::isActive(id);                 
                }
		            Turnout::activate(id,newstate);
                StringFormatter::send(stream, F("PTA%c%d\n"),newstate?'4':'2',id );   
                sendTurnoutList = true;
            }
            break;
       case 'N':  // Heartbeat (2)
            StringFormatter::send(stream, F("*%d\n"),HEARTBEAT_TIMEOUT); // return timeout value
            break;
       case 'M': // multithrottle
            multithrottle(stream, cmd); 
            break;
       case 'H': // send initial connection info after receiving "HU" message
            if (cmd[1] == 'U') {
              StringFormatter::send(stream,F("VN2.0\nHTDCC++EX\nRL0\nPPA%x\n"),DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON);
              if (annotateLeftRight) StringFormatter::send(stream,F("PTT]\\[Turnouts}|{Turnout]\\[Left}|{2]\\[Right}|{4\n"));
              else                   StringFormatter::send(stream,F("PTT]\\[Turnouts}|{Turnout]\\[Closed}|{2]\\[Thrown}|{4\n"));
              StringFormatter::send(stream,F("*%d\n"),HEARTBEAT_TIMEOUT);
              sendTurnoutList = true; // send turnout list on next reply (avoid msg length overflow)
            }
            break;           
      case 'Q': // 
            LOOPLOCOS('*', -1) { // tell client to drop any locos still assigned to this WiThrottle
              if (myLocos[loco].throttle!='\0') {
                StringFormatter::send(stream, F("M%c-%c%d<;>\n"), myLocos[loco].throttle, LorS(myLocos[loco].cab), myLocos[loco].cab);
              }
            }
            DIAG(F("WiThrottle(%d) Quit\n"), clientid);
            delete this; 
            break;           
   }
   // skip over cmd until 0 or past \r or \n
   while(*cmd !='\0' && *cmd != '\r' && *cmd !='\n') cmd++;
   if (*cmd!='\0') cmd++; // skip \r or \n  
   }           
}
int WiThrottle::getInt(byte * cmd) {
    int i=0;
    while (cmd[0]>='0' && cmd[0]<='9') {
      i=i*10 + (cmd[0]-'0');
      cmd++;
    }
    return i;    
}

int WiThrottle::getLocoId(byte * cmd) {
    if (cmd[0]=='*') return -1;  // match all locos 
    if (cmd[0]!='L' && cmd[0]!='S') return 0; // should not match any locos
    return getInt(cmd+1); 
}
void WiThrottle::multithrottle(Print & stream, byte * cmd){ 
          char throttleChar=cmd[1];
          int locoid=getLocoId(cmd+3); // -1 for *
          byte * aval=cmd;
          while(*aval !=';' && *aval !='\0') aval++;
          if (*aval) aval+=2;  // skip ;>

//       DIAG(F("\nMultithrottle aval=%c cab=%d"), aval[0],locoid);    
       switch(cmd[2]) {
          case '+':  // add loco request
                //return error if address zero requested
                if (locoid==0) { 
                  StringFormatter::send(stream, F("HMAddress '0' not supported!\n"), cmd[3] ,locoid);                    
                  return;
                }
                //return error if L or S from request doesn't match DCC++ assumptions
                if (cmd[3] != LorS(locoid)) { 
                  StringFormatter::send(stream, F("HMLength '%c' not valid for %d!\n"), cmd[3] ,locoid);                    
                  return;
                }
                //use first empty "slot" on this client's list, and add to registration list
                for (int loco=0;loco<MAX_MY_LOCO;loco++) {
                  if (myLocos[loco].throttle=='\0') { 
                    myLocos[loco].throttle=throttleChar;
                    myLocos[loco].cab=locoid;
                    StringFormatter::send(stream, F("M%c+%c%d<;>\n"), throttleChar, cmd[3] ,locoid); //tell client to add loco
                    // TODO... get known Fn states from DCC (need memoryStream improvements to handle data length)
                    // for(fKey=0; fKey<29; fKey++)StringFormatter::send(stream,F("M%cA%c<;>F0&s\n"),throttleChar,cmd[3],fkey);
                    StringFormatter::send(stream, F("M%cA%c%d<;>V%d\n"), throttleChar, cmd[3], locoid, DCC::getThrottleSpeed(myLocos[loco].cab));
                    StringFormatter::send(stream, F("M%cA%c%d<;>R%d\n"), throttleChar, cmd[3], locoid, DCC::getThrottleDirection(myLocos[loco].cab));
                    StringFormatter::send(stream, F("M%cA%c%d<;>s1\n"), throttleChar, cmd[3], locoid); //default speed step 128
                    break;
                  }
               }
               break;
          case '-': // remove loco(s) from this client (leave in DCC registration)
                 LOOPLOCOS(throttleChar, locoid) {
                     myLocos[loco].throttle='\0';
                     StringFormatter::send(stream, F("M%c-%c%d<;>\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab);
                  }
            
            break;
          case 'A':
              locoAction(stream,aval, throttleChar, locoid);
            }
}

void WiThrottle::locoAction(Print & stream, byte* aval, char throttleChar, int cab){
    // Note cab=-1 for all cabs in the consist called throttleChar.  
//    DIAG(F("\nLoco Action aval=%c%c throttleChar=%c, cab=%d"), aval[0],aval[1],throttleChar, cab);
     switch (aval[0]) {
           case 'V':  // Vspeed
             { 
              byte locospeed=getInt(aval+1);
              LOOPLOCOS(throttleChar, cab) {
                DCC::setThrottle(myLocos[loco].cab,locospeed, DCC::getThrottleDirection(myLocos[loco].cab));
                StringFormatter::send(stream,F("M%cA%c%d<;>V%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, DCC::getThrottleSpeed(myLocos[loco].cab));
                }
             } 
            break;
           case 'F': //F onOff function
                {
		  bool funcstate;
                  bool pressed=aval[1]=='1';
                  int fKey = getInt(aval+2);
                  LOOPLOCOS(throttleChar, cab) {
		      funcstate = DCC::changeFn(myLocos[loco].cab, fKey, pressed);
		      if(funcstate==0 || funcstate==1)
			  StringFormatter::send(stream,F("M%cA%c%d<;>F%d%d\n"), throttleChar, LorS(myLocos[loco].cab), 
						myLocos[loco].cab, funcstate, fKey);
		  }
                }
                break;  
            case 'q':
                if (aval[1]=='V') {   //qV
                  LOOPLOCOS(throttleChar, cab) {              
                    StringFormatter::send(stream,F("M%cA%c%d<;>V%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, DCC::getThrottleSpeed(myLocos[loco].cab));
                  }              
                }
                else if (aval[1]=='R') { // qR
                  LOOPLOCOS(throttleChar, cab) {              
                    StringFormatter::send(stream,F("M%cA%c%d<;>R%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, DCC::getThrottleDirection(myLocos[loco].cab));
                  }             
                }     
            break;    
            case 'R':
            { 
              bool forward=aval[1]!='0';
              LOOPLOCOS(throttleChar, cab) {              
                DCC::setThrottle(myLocos[loco].cab, DCC::getThrottleSpeed(myLocos[loco].cab), forward);
                StringFormatter::send(stream,F("M%cA%c%d<;>R%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, DCC::getThrottleDirection(myLocos[loco].cab));
              }
            }        
            break;      
            case 'X':
              //Emergency Stop  (speed code 1)
              LOOPLOCOS(throttleChar, cab) {
                DCC::setThrottle(myLocos[loco].cab,1, DCC::getThrottleDirection(myLocos[loco].cab));
              }
              break;
            case 'I': // Idle, set speed to 0
            case 'Q': // Quit, set speed to 0
              LOOPLOCOS(throttleChar, cab) {
                DCC::setThrottle(myLocos[loco].cab,1, DCC::getThrottleDirection(myLocos[loco].cab));
              }
              break;
            }               
}

void WiThrottle::loop() {
  // for each WiThrottle, check the heartbeat
  for (WiThrottle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle) 
     wt->checkHeartbeat();
}

void WiThrottle::checkHeartbeat() {
  // if 2 heartbeats missed... eSTOP all locos for this client
  if(heartBeatEnable && (millis()-heartBeat > HEARTBEAT_TIMEOUT*2000)) {
    DIAG(F("WiThrottle(%d) hearbeat missed, dropping connection"),clientid);
    LOOPLOCOS('*', -1) { //stop and drop all locos still assigned to this WiThrottle
      if (myLocos[loco].throttle!='\0') {
        DIAG(F("  dropping cab %c"),clientid, myLocos[loco].cab);
        DCC::setThrottle(myLocos[loco].cab, 1, DCC::getThrottleDirection(myLocos[loco].cab)); //eStop
      }
    }
    delete this;
  } else {
      // TODO  Check if anything has changed on my locos since last notified! 
    }
}

char WiThrottle::LorS(int cab) {
    return (cab<127)?'S':'L';
}