#define MAX_DATA_LINES 5
#define TEXT_BUFFER 256


String smsArr[MAX_DATA_LINES];
int smsArrIndex;
char sbuff[TEXT_BUFFER];
char inchar;
int count;
int smsIndex;
boolean found=false;

int led = 13;
int onModulePin = 2;        // the pin to switch on the module (without press on button)

void switchModule(){
    digitalWrite(onModulePin,HIGH);
    delay(2000);
    digitalWrite(onModulePin,LOW);
}

void setup(){
    Serial.begin(115200);                // UART baud rate
    pinMode(led, OUTPUT);
    pinMode(onModulePin, OUTPUT);
    switchModule();                    // switches the module ON
    Serial.println("SWITCHING ON");

    for (int i=25;i>0;i--){
      Serial.println(i);
      delay(1000);
    }

    Serial.println("AT+CMGF=1");         // sets the SMS mode to text
    delay(100);
    Serial.println("AT+CNMI=2,1,0,0,0");         // sets the SMS mode to text
    while(Serial.read()!='K');
    Serial.println("AT+CPMS=\"SM\",\"SM\",\"SM\"");    //selects SIM memory
    while(Serial.read()!='K');
    Serial.println("DELETING...");
    Serial.println("AT+CMGD=,4");
    while(Serial.read()!='K');
    Serial.println("READY...");
    Serial.flush();
}

void loop(){
  do{
    count=0;
    while(true){
      while(!Serial.available());
      inchar=Serial.read();
      if(inchar==10||inchar==13)
        break;
      sbuff[count]=inchar;
      count++;
    }
    sbuff[count]='\0';
  }while(!startsWith(sbuff,"+CMTI:"));
  char tmp[4];
  int offset=String(sbuff).indexOf(",")+1;
  tmp[0]=sbuff[offset];
  tmp[1]=sbuff[offset+1];
  tmp[2]=sbuff[offset+2];
  tmp[3]=sbuff[offset+3];
  smsIndex=atoi(tmp);
  readSMS();

}

boolean startsWith(String string, char key[]){
  return string.startsWith(key);
}

boolean startsWith(char string[], char key[]){
  for(int i=0;i<sizeof(key);i++){
    if(string[i]!=key[i])
      return false;
  }
  return true;
}

void readSMS(){
  //Serial.println("Reading sms");
  String s="AT+CMGR=";
  s=s+smsIndex;
  Serial.println(s);
  smsArrIndex=0;
  found=false;
  do{
    String tmp;
    do{
      count=0;
      while(true){
        while(!Serial.available());
        inchar=Serial.read();
        if(inchar==10||inchar==13)
          break;
        sbuff[count]=inchar;
        count++;
      }
      sbuff[count]='\0';
      tmp=String(sbuff);
      if(startsWith(tmp,"+CMGR:"))
        found=true;
    }while(!startsWith(tmp,"+CMGR:")&&!found);

    smsArr[smsArrIndex]=String(sbuff);
    Serial.print("PACKET Return ");
    Serial.print(smsArrIndex);
    Serial.print(" :");
    Serial.println(smsArr[smsArrIndex]);
    smsArrIndex++;
  }while(!(startsWith(smsArr[smsArrIndex-1],"OK")||startsWith(smsArr[smsArrIndex-1],"ERROR"))&&smsArrIndex<=MAX_DATA_LINES);
  smsArrIndex--;
  if(startsWith(smsArr[smsArrIndex],"ERROR")){
    Serial.println("Error has occured with AT+CMGR=1");
  }
  else if(startsWith(smsArr[smsArrIndex],"OK")){
    if(startsWith(smsArr[0],"+CMGR:")){
      Serial.print("Number: ");
      int offset=smsArr[0].indexOf(",")+4;
      Serial.println(smsArr[0].substring(offset,offset+10));
    }
    Serial.print("MSG: ");
    Serial.println(smsArr[1]);
  }
  else{
    Serial.println("Error with returned data length");
    for(int i=0;i<MAX_DATA_LINES;i++)
      Serial.println(smsArr[i]);
  }

   //Serial.println("AT+CMGD=1");
   //Serial.println("----FINISH-----");
}