nex.h

#pragma once

#include "nexGlobals.h"

// forward deklarations
//void NEX_sendCommand(const char* cmd);
bool NEX_sendCommand(const char* cmd, bool waitResponse=false);

// from mqtt.h
void subscribePage();
void unsubscribePage();

#include "page.h"

// send in HMI-file in the setup function
void NEX_begin(uint baudrate) {
  log_i("[NEX] begin...");
  Serial2.begin(baudrate, SERIAL_8N1, NEX_SER_RX, NEX_SER_TX);

  NEX_sendCommand("");        // send empty command
  // Restart the nextion, which will run the Program.s part of the HMI file.
  NEX_sendCommand("rest");    // Restart the screen
}   // init()


// Converts an little endian integer (4 bytes) from the nextion display to an int32_t
int32_t hmiIntToInt32(byte arr[], uint8_t start) {
  // numeric value sent in 4 byte 32-bit little endian order
  return int32_t(arr[start+0]) | int32_t(arr[start+1]<<8) | int32_t(arr[start+2]<<16) | int32_t(arr[start+3]<<24);
}


// Read data from the nextion display if available
bool NEX_readData(uint8_t payload[], uint64_t buffLen, uint64_t timeout) {
  uint8_t buff[1];
  int cntBytes = 0, cntFF = 0;
  uint64_t msStart = millis() + timeout;

  while (millis() <= msStart) {
    if (Serial2.available()) {
      Serial2.readBytes(buff, 1);

      payload[cntBytes] = buff[0];//### check for buffer overflow
      cntBytes++;

      if (cntBytes >= buffLen-1) {
        payload[cntBytes-1] = 0;
        log_w("\nWARN: buffer overflow! max=%llu buf=\"%s\"", buffLen, payload);
        // Nextions response on an overflow error
        payload[0] = 0x24; payload[1] = 0xFF; payload[2] = 0xFF; payload[3] = 0xFF;
        payload[4] = 0x00;
        return false;
      }

      msStart = millis() + 50;    // give serial some time for next value

      if (buff[0] == 0xFF) {
        cntFF++;
        if (cntFF == 3) {  // found the tail of the nextion message
          payload[cntBytes] = '\0';
          return true;
        }   // end of message reached
      }   // read value is FF
      else
        cntFF = 0;
    }   // if Serial2.available()
  }   // while in time

  return false;
}   // NEX_readPayload()


// void NEX_sendCommand(const char* cmd) {
//   log_d("[NEX] Send '%s'", cmd);

//   Serial2.print(cmd);
//   Serial2.write(0xFF);
//   Serial2.write(0xFF);
//   Serial2.write(0xFF);
// }   // NEX_sendCommand()
bool NEX_sendCommand(const char* cmd, bool waitResponse) {
  log_d("[NEX] Send '%s'", cmd);

  Serial2.print(cmd);
  Serial2.write(0xFF);
  Serial2.write(0xFF);
  Serial2.write(0xFF);

  uint8_t resp[11];
  if (waitResponse && NEX_readData(resp, 100, NEX_CmdRespTimeout)) {
    log_d("cmd '%s' %s(%X)", cmd, resp[0] == 1 ? "OK" : "failed", resp[0]);
    return resp[0] == 1;
  }

  return false;
}   // NEX_sendCommand()


/*  ### not used for now
// get the content of a nextion integer variable
int32_t NEX_getInt(char* varname) {
  size_t len = NEX_MAX_TEXTLEN+4;
  char buff[len+1] = {0};

  // send the command to get the value of the variable
  sprintf(buff, "get %s", varname);
  NEX_sendCommand(buff);

  memset(buff, 0, len);   // clear to reuse

  if (NEX_readPayload((uint8_t*)buff, len, 100)) {            // wait 100ms for a response
    if (buff[0] == 0x71) {    // response with data of the var : 71 [32 bit num value] FF FF FF
      return (int32_t)buff[1] + (int32_t)(buff[2]*256) + (int32_t)(buff[3]*65536) + (int32_t)(buff[4]*16777216);
      // return (int32_t)buff[1] | (int32_t)(buff[2]<<8) | (int32_t)(buff[3]<<16) | (int32_t)(buff[4]<<24);
    }
  }
  return -1;
}   // NEX_getInt()
*/

// assign the config comming from the nextion's Program.s, when nextion is rebooting
void assignConfig(char cfgStr[]) {
  log_d("    assign config...");

  #define CFG_SPLIT ";"
  #define VAL_SPLIT "&"

  char *endStr;
  char *tok = strtok_r(cfgStr, CFG_SPLIT, &endStr);
  while (tok != NULL) {
    char *endTok;
    // We know there is at least one value for the specified name
    char *tokNam = strtok_r(tok,  VAL_SPLIT, &endTok);
    char *tokVal = strtok_r(NULL, VAL_SPLIT, &endTok);

    if (tokVal != NULL) { // value specified? If not, use the default, what is allready assigned
      log_d("     '%s' = '%s'", tokNam, (strcmp("WifiPWD", tokNam) != 0) ? tokVal : "*******");

      if (strcmp("standbyDelay", tokNam) == 0) {
        NEX_cfg.standbyDelay = atoi(tokVal);
        //### if (standby inactive) reset standbytime to new value - time
      }
      else
      if (strcmp("longTouchTime", tokNam) == 0) {
        NEX_cfg.longTouchTime = atoi(tokVal);
      } else
      if (strHas(tokNam, "fmtTime")) {
        int idx = atoi(tokNam+7);
        if (idx >= 0 && idx <=3)
          strncpy(NEX_cfg.fmtTime[idx], tokVal, MAX_FMTPARAM_LEN);
        else
          log_w("WARNING: invalid format-makro name fmtTime%d in token '%s'", idx, tok);
      } else
      {
        log_w("WARNING: unhandled setup token '%s'", tok);
      }
    }   // if tokVal

    tok = strtok_r(NULL, CFG_SPLIT, &endStr);
  }   // while tok
}   // assignConfig()


void NEX_handleMsg(uint8_t payload[]) {
  int cntBytes = strlen( (char*)payload );
  char *dta = nullptr;
  // All Nexion return codes: https://nextion.tech/instruction-set/#s7

  // nextion response to a command that was not handled by NEX_SendCommand()
  if (cntBytes==4 && payload[0]>=0x00 && payload[0]<=0x23) {    // response to a command are in range 0 - 0x23
    if (payload[0] != 0x01)   // command responses is 'OK'
      log_d("--> Cmd failed: 0x%X", payload[0]);
    // else    // command responses is 'failed'
    //   log_d("--> Cmd Ok: 0x%X", payload[0]);
    return;
  };

  switch (payload[0]) {

    case 0x00:  // Returned when Nextion has started or reset
    case 0x88:  // Returned when Nextion has powered up and is now initialized successfully
    case 0x70:  // Returned when using 'get' command for a string.
    case 0x71:  // Returned when 'get' command to return a number
    case 0x66:  // Returned when 'sendme' (send page id) is set to 1 (activated)
    case 0x67:  // Returned when 'sendxy' (touchevents) is set to 1 (activated)
      break; // ignore these responses

/*  the following messages are not required at the moment
    case 0x00: { // 00 00 00 FF FF FF - Returned when Nextion has started or reset
      log_i("[Nex] Screen started or reseted!");
      break;
    }   // case 0x00


    case 0x88: {  // 88 FF FF FF - Returned when Nextion has powered up and is now initialized successfully
      log_i("[Nex] Screen Ready!");
      break;
    }


    case 0x70: { // 70 [txt data] FF FF FF - Returned when using 'get' command for a string.
      payload[cntBytes-3] = '\0';   // remove message tail
      dta = (char*)payload+1;
      log_d("[Nex] Received string data '%s'!", dta);
      break;
    }   // case 0x70


    case 0x71: {  // 71 [32 bit num value] FF FF FF - Returned when 'get' command to return a number
      int32_t num = hmiIntToInt32(payload, 1);
      log_d("[Nex] Received numeric data %d!", num);
      break;
    }


    case 0x66: {  // 66 pg FF FF FF - Returned when 'sendme' (send page id) is set to 1 (activated)
      uint8_t pg = (uint8_t)payload[1];
      // log_d("[Nex] Received page %d from sendme!", pg);
      break;
    }


    case 0x67: {  // 68 x x y y s FF FF FF - Returned when 'sendxy' (touchevents) is set to 1 (activated)
      // Hint: https://unofficialnextion.com/t/how-to-implement-swipe-up-down-using-sendxy/1383
      // coordinates are in 16 bit big endian order
      int32_t x = (int32_t)(payload[1]<<8) | (int32_t)payload[2];
      int32_t y = (int32_t)(payload[3]<<8) | (int32_t)payload[4];
      bool prsd = payload[5] == 1;
      break;
    }
 */

    case NEX_MSG_HEAD: {  // 3C Id1 Id2 data1..n FF FF FF
      char msgId[3] = {(char)payload[1], (char)payload[2], 0};

      if (strcmp("SR", msgId) == 0) {   // screen restart - send in HMI-file in 'Program.s'
        payload[cntBytes-3] = '\0';     // remove message tail
        dta = (char*)payload + 3;       // skip header
        log_i("[NEX] screen init.");

        assignConfig(dta);
      } else

      if (strcmp("MQ", msgId) == 0) {   // #### MQTT testpage - send from HMI-file
        payload[cntBytes-3] = '\0';     // remove message tail
        dta = (char*)payload + 3;       // skip header
        mqttClient.subscribe(dta, 0);
      } else

      if (strcmp("PI", msgId) == 0) {   // page init - send in HMI-file on page preinitialize
        payload[cntBytes-3] = '\0';     // remove message tail
        dta = (char*)payload + 3;       // skip header
        Page_init(dta);
      } else


      if (strcmp("PL", msgId) == 0) {   // page leave - send in HMI-file on page exit
        Page_exit();
      } else

      if (strcmp("CM", msgId) == 0) {   // custom message - send in HMI-file by buttons of a page
        switch ((char)payload[3]) {     // id of that message
          case 'B': {
            ESP.restart();   // restart ESP
            delay(1000);
            break;
          }
          // $$$ here can be implemented more with other ids!
          default:
            log_w("[NEX] Unhandled custom message '%s'", payload);
        }
      } else

      if (strcmp("TT", msgId) == 0) {   //### Temporary tests - used on page 'pgTest1'
        switch ((char)payload[3]) {     // id of that message
          case '1':   { NEX_sendCommand("t0.txt=\"I'am ESP\"", true);  break; }
          case '2':   { NEX_sendCommand("t0.txt=\"Ich bin's\"", true);  break; }
          case '3':   {   // disconnect wifi
              if (WiFi.status() == WL_CONNECTED) {
                WiFi.disconnect();
                // log_d("Disconnecting WiFi...");
              }
              break;
            }
          case '4': {  // write the message to the console in HEX format
              payload[cntBytes-3] = '\0';     // remove message tail
              dta = (char*)payload + 4;       // skip header

              log_i("\nloging testmessage in hex:");
              for (int x=0; x<strlen(dta); x++) {
                Serial.printf(" %02X,", (uint8_t)dta[x]);
              }
              Serial.println();
              Serial.printf(" as text: '%s'\n", dta);
              log_i("loging testmessage done!\n");
              break;
            }
          default:
            log_d("[NEX]### Unhandled temporary test id '%s'", payload);
        }
      }

      break;
    }   // case NEX_MSG_HEAD

    default: {
      log_w("[NEX] Unknown cmd '0x%X:\n\t", payload[0]);
      for (byte i = 0; i < cntBytes; i++) {
        Serial.print(" ");
        Serial.print(payload[i], HEX);
      }
      Serial.println("'");
    }
  }   // switch payload[0]
}   // NEX_handleMsg()