//=======================================================================================================================================
// SMS_BT_IOT
// This code implements a BT receiver  on an Arduino Mega board fitted with a HC06 BT shield set to 115200 baud
// Seria1 is usd to communicate to the BT shield
// when it receives a message from the BT, it parses its contents and in the password is correct, actuates the commands in the message
// at commands completion it sends back a message with status of the controlled actuators
// every two seconds it sends a "alive" character to the gateway to retrigger its watchdog. if not sent the Gateway retries 
// the BT synchronization.
// 
// Author : Ugo Schiara
// Ver_01 : 02/01/2021  first release  WARNING though I have written a more complex code, based on the same structure, and it works
//                                     correctly, this is ONLY the structure:  you have to complete it with YOUR code
//========================================================================================================================================
#include <string.h>

#define DEBUG 1
#define TRUE 1
#define FALSE 0
#define LIMITE 128
#define SECTIONS 6

//Globals
unsigned long parte;
char comando[LIMITE];
String password= "";
String Str_Command[SECTIONS];
int puntabuffer = 0;



//==============================================================================================================
void setup() 
{
  char chk = ' ';                                // empty char
  
  Serial.begin(115200);                          // init serial toward PC
  Serial1.begin(115200);                         // init serial toward BT (HC05 or HC06 shall be set accordingly) 

  chk =' ';
  while (chk != '!')                             // wait for trigger character
  {   if(Serial1.available())                    // anything from BT ?       
    {
       chk = Serial1.read();                     // yes, get it
#ifdef DEBUG       
       Serial.println(chk);                      // echo to PC
#endif       
    }   
  }                                              // end while  
  parte = millis();                              // start timer for the "alive character" to the  app
}



//=============================================================================================================
void loop() 
{
bool ce = FALSE;
                                          
        ce = Wait_for_SMS();                            // anything from BT ?
        if (ce == TRUE)                                 // yes, analyze the message 
        {   
            Parse_Command();                            // creates an array of strings str[6] whose first is the password         
            if (password == "Your_Write_Password")      // now fixed in the code: better to be retrieved from the EEPROM
            {
               Actuate();                               // write password correct, do the actuation and send message to BT
            }
            else  if (password == "Your_Read_Password") // now fixed in the code: better to be retrieved from the EEPROM
                 {
                   Read_Actuate();                      // read password correct, collect status and send message to BT
                 }
        }  
        if ((millis() - parte) >= (unsigned long)2000)  // two seconds elapsed ?
          {
              parte = millis();                         // retrigger the timer 
              Simcmd("$");                              // send "alive" character to the Gateway                               
          }
}


//================================================================================================================
// Write command received, put here the actuation commands, then send the feedback.
//================================================================================================================
void Actuate()
{
  // put here your actuation code
      Send_Config(); 
}

//================================================================================================================
//  Read Status and send it on BT to the gateway 
//================================================================================================================
void Read_Actuate()
{
   // Collect_Status();                                     // Read the status of commands
   Send_Config();                                        // send  using BT  to the Gateway to send then via SMS
}


//================================================================================================================
// If a valid command has been received, parse its contents e creates the # SECTIONS command strings 
//================================================================================================================
void Parse_Command()

{
  password = "Extracted from the SMS received";
  Str_Command[0] = "Extracted from the SMS received";   // the same applies for all SECTIONS
}



//=======================================================================================================================================
// Verify if any SMS from BT
// If none, return FALSE
//=======================================================================================================================================
bool Wait_for_SMS()
{
       byte i;
       byte ritch;
       char scarto;                                                  

       if(Serial1.available() == 0 )                         // any characters from BT ?
       {
        return FALSE;                                        // no characters, nothing to do and returns false
       }
       
       for(i = 0; i<LIMITE;i++) comando[i] = 0x1a;           // something arrived, clears the receiving buffer to all  ctrl-z
       i=0;                                                  // initialize counter of received characters 
       while(Serial1.available() != 0)                       // until caracters are available, gets them
        {
          if(i<LIMITE)                                       // more than the limit, still accept character but do not overflow the buffer
          {
            comando[i] = Serial1.read();                     // number of characters < limit, accept it and store in buffer
            i++;                                             // next byte
          }
          else
          {
            scarto = Serial1.read();                         // too many charactes, discard them
            scarto = scarto;                                 // dummy operation to avoid compiler warning
           }
         for (ritch = 0;ritch < 50;ritch++) delayMicroseconds(10);  // allows 500 microseconds between characters                                                                      
        }
        puntabuffer = i-1;                                   // last character received = index-1
        return TRUE;                                         // message received, return true                                              
}



//================================================================================================================
//  parameter 1 = messagge to send to PC
//================================================================================================================           
void Simcmd(String atcomm)
{ 
        Serial1.println(atcomm);                 // send command on BT to the Gateway
}


//================================================================================================================
//  Send to caller via BT the Status of the commands. Wait before and 
//  after to give time to the app 
//================================================================================================================
void Send_Config()
{
  String moment;

       moment = "compose the status";
       Delay(1000);                              // give time to app                                    
       Simcmd(moment); 
       Delay(1000);                              // give time to app
       parte = millis();                         // restars the timer to transmit the "$" to retrigger Clock3 of the app  
}


//================================================================================================================
// This delay function allows interrupts; param: quanto = number of milliseconds to wait for
//================================================================================================================
void Delay(int quanto)
{  int i;
        for (i=1;i<quanto;i++) delayMicroseconds(1000);       
}