const char Input[] PROGMEM = "Zkušební text";
char *i = Input;
char CSVline[] = "subdomain1.domain.tld,211,username,Tsa5JrHYx0gmde,/path1/path2/ ,\n";
char CharArray[] = "Proměnná s textem";
const PROGMEM char BOM[] = {0xEF, 0xBB, 0xBF, 0x2A, 0x2B,};
// const char *p;
char * ptr;

void setup() {
  Serial.begin(115200);

  // char CSVline[] = "subdomain1.domain.tld,211,username,Tsa5JrHYx0gmde,/ \n";
  
  uint8_t CSVlinelength;
  size_t pFTPport;
  size_t pFTPlogin;
  size_t pFTPpassw;
  size_t pFTPpath;
  // const char *p;
  uint16_t FTPport;
  char * ptr;
  bool Error = false;
  uint8_t param;
  uint8_t i;

  CSVlinelength = strlen(CSVline);

  size_t CurrPointer = 0;

  for (param = 1; param <= 4; param++) {
    CurrPointer = strcspn(CSVline + CurrPointer, " ,") + CurrPointer ;
    if (CurrPointer > CSVlinelength) {
      Serial.print("Parameter No. ");
      Serial.print(param);
      Serial.println(" not found.");
      Error = true;
      return;
    }
    Serial.print("Parameter No. ");
    Serial.println(param);
    CSVline[CurrPointer] = '\0';
    CurrPointer++;
    i = 0;
    while (!(isalnum(CSVline[CurrPointer + i]) || CSVline[CurrPointer + i] == '/') && (CurrPointer + i) < CSVlinelength) i++;
    CurrPointer += i;
    switch (param) {
      case 1:
        Serial.print(F("FTP URL: "));
        Serial.print(CSVline);
        Serial.println(F("«"));
        pFTPport = CurrPointer;
        break;
      case 2:
        Serial.print(F("pFTPport position: "));
        Serial.println(pFTPport);
        pFTPlogin = CurrPointer;
        FTPport = atoi(CSVline + pFTPport);
        if (FTPport == 0) {
          Serial.println("Conversion to number failed. ");
          Error = true;
        } else {
          Serial.print("FTPport: ");
          Serial.println(FTPport);
        }
        Serial.print("pFTPlogin position: ");
        Serial.println(CurrPointer);
        break;
      case 3:
        Serial.print("FTP login: ");
        Serial.print(CSVline + pFTPlogin);
        Serial.println(F("«"));
        pFTPlogin += CSVline;
        pFTPpassw = CurrPointer;
        Serial.print("pFTPpassw position: ");
        Serial.println(pFTPpassw);
        break;
      case 4:
        Serial.print("FTP password: ");
        Serial.print(CSVline + pFTPpassw);
        Serial.println(F("«"));
        pFTPpassw += CSVline;
        pFTPpath = CurrPointer;
        Serial.print("pFTPpath position: ");
        Serial.println(pFTPpath);
    }


  }
  pFTPport = strcspn(CSVline + pFTPpath, ", \n");
  if (pFTPport > 0) {
    CSVline[pFTPpath + pFTPport] = '\0';
    Serial.print("FTP path: ");
    Serial.print(CSVline + pFTPpath);
    Serial.println(F("«"));
    if (CSVline[pFTPpath] != '/') {
      Serial.println(F("File path doesn't start with '/'."));
      Error = true;
    }
    if (CSVline[pFTPpath + pFTPport - 1] != '/') {
      Serial.println(F("File path doesn't end with '/'."));
      Error = true;
    }
    pFTPpath += CSVline;
  } else {
    Serial.println("Parameter File path has zero length.");
    Error = true;
  }


  delay(2000);
  if (! Error) {
    DisplayParameters(CSVline, FTPport, pFTPlogin, pFTPpassw, pFTPpath);
  }
}

void loop() {




  // delay(3000);

}



void DisplayParameters(char text1[], uint16_t port, char text3[], char text4[], char text5[]) {
  Serial.println("\nFunction DisplayParameters with char arrays in declaration.");
  Serial.println(text1);
  Serial.println(port);
  Serial.println(text3);
  Serial.println(text4);
  Serial.println(text5);
}