#define F_CPU 8000000UL						/* define Clock Frequency */
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
/*#include "LCD_16x2_H_file.h"				/ * include 16x2 LCD Header file * /*/
#include "USART_Interrupt.h"				/* include USART Header file */

#define SREG   _SFR_IO8(0x3F)

void GSM_Begin();
void GSM_Calling(char *);
void GSM_HangCall();
void GSM_Response();
void GSM_Response_Display();
void GSM_Msg_Read(int);
bool GSM_Wait_for_Msg();
void GSM_Msg_Display();
void GSM_Msg_Delete(unsigned int);
void GSM_Send_Msg(char* , char*);
void GSM_Delete_All_Msg();

char buff[160];								/* buffer to store responses and messages */
char status_flag = 0;						/* for checking any new message */
volatile int buffer_pointer;
char Mobile_no[14];							/* store mobile no. of received message */
char message_received[60];					/* save received message */
int position = 0;							/* save location of current message */


int main(void)
{
    DDRD=0b11111100;
    PORTD=0x00;
    buffer_pointer = 0;
    int is_msg_arrived;
    memset(message_received, 0, 60);
    /*LCD_Init();*/
    USART_Init(9600);						    /* initialize USART communication */
    sei();
   /* LCD_String_xy(1,0,"GSM Initializing");*/
    _delay_ms(3000);
//     LCD_Clear();
//     LCD_String_xy(1,0,"AT");
    GSM_Begin();								/* check GSM responses and initialize GSM */
    /*LCD_Clear();*/
    
    while (1){
        
        /*check if any new message received */
           /* LCD_String_xy(1,0,"wait SMS codes");*/
            
            is_msg_arrived = GSM_Wait_for_Msg();		/*check for message arrival*/
            if(is_msg_arrived== true)
            {
//                 LCD_Clear();
//                 LCD_String_xy(1,0,"New SMS");		/* new message arrived */
/*                _delay_ms(1000);*/
/*                LCD_Clear();*/
                GSM_Msg_Read(position);					/* read arrived message */
               /* _delay_ms(3000);*/
                
                /*check if received message is "call me" */
                if(strstr( message_received,"PA1_on")){
                    
                    /*GSM_Calling(Mobile_no);				/ * call sender of message * /*/
//                     LCD_Clear();
//                     LCD_String_xy(1,0,"PORT is ON");
                   /* _delay_ms(1000);*/
                    PORTD|=1<<7;
                    
                }
                 if(strstr( message_received,"PA1_off")){
                    
                    /*GSM_Calling(Mobile_no);				/ * call sender of message * /*/
//                     LCD_Clear();
//                     LCD_String_xy(1,0,"PORT is OFF");
                   /* _delay_ms(1000);*/
                    PORTD&=~(1<<7);
                    
                }
                
                /*LCD_Clear();*/
                GSM_Delete_All_Msg();				/* to save SIM memory delete current message */
               /* LCD_String_xy(1,0,"Clear all SMS");*/
                GSM_Response();
                /*_delay_ms(1000);*/
                
            }
            
            
            is_msg_arrived=0;
            
            /*LCD_Clear();*/
        }
        
        memset(Mobile_no, 0, 14);
        memset(message_received, 0, 60);
        
        
    }


void GSM_Begin()
{

    while(1)
    {
        /*LCD_Command(0xc0);*/
        USART_SendString("ATE0\r");			/* send ATE0 to check module is ready or not */
        _delay_ms(500);
        if(strstr(buff,"OK"))
        {
            GSM_Response();                 /* get Response */
            memset(buff,0,160);
            break;
        }
        else
        {
            /*LCD_String("Error");*/
        }
    }
    _delay_ms(1000);

//     LCD_Clear();
//     LCD_String_xy(1,0,"Text Mode");
//     LCD_Command(0xc0);
    USART_SendString("AT+CMGF=1\r");/* select message format as text */
    GSM_Response();
    _delay_ms(1000);
}

void GSM_Msg_Delete(unsigned int position)
{
    buffer_pointer=0;
    char delete_cmd[20];
    sprintf(delete_cmd,"AT+CMGD=%d\r",position);    /* delete message at specified position */
    USART_SendString(delete_cmd);
}

void GSM_Delete_All_Msg()
{
    USART_SendString("AT+CMGDA=\"DEL ALL\"\r");		/* delete all messages of SIM */
}

bool GSM_Wait_for_Msg()
{
    char msg_location[4];
    int i;
    _delay_ms(500);
    buffer_pointer=0;

    while(1)
    {
        if(buff[buffer_pointer]=='\r' || buff[buffer_pointer]== '\n') /*eliminate "\r \n" which is start of string */
        {
            buffer_pointer++;
        }
        else
        break;
    }
    
    if(strstr(buff,"CMTI:"))                                          /* "CMTI:" to check if any new message received */
    {
        while(buff[buffer_pointer]!= ',')
        {
            buffer_pointer++;
        }
        buffer_pointer++;
        
        i=0;
        while(buff[buffer_pointer]!= '\r')
        {
            msg_location[i]=buff[buffer_pointer];				      /* copy location of received message where it is stored */
            buffer_pointer++;
            i++;
        }

        /* convert string of position to integer value */
        position = atoi(msg_location);
        
        memset(buff,0,strlen(buff));
        buffer_pointer=0;

        return true;
    }
    else
    {
        return false;
    }
}

/* ISR routine to save responses/new message */
ISR(USART_RXC_vect)
{
    buff[buffer_pointer] = UDR;							/* copy UDR(received value) to buffer */
    buffer_pointer++;
    status_flag = 1;						            /* flag for new message arrival */
}


void GSM_Send_Msg(char *num,char *sms)
{
    char sms_buffer[35];
    buffer_pointer=0;
    sprintf(sms_buffer,"AT+CMGS=\"%s\"\r",num);
    USART_SendString(sms_buffer);                       /*send command AT+CMGS="Mobile No."\r */
    _delay_ms(200);
    while(1)
    {
        if(buff[buffer_pointer]==0x3e)                  /* wait for '>' character*/
        {
            buffer_pointer = 0;
            memset(buff,0,strlen(buff));
            USART_SendString(sms);                      /* send msg to given no. */
            USART_TxChar(0x1a);                         /* send Ctrl+Z then only message will transmit*/
            break;
        }
        buffer_pointer++;
    }
    _delay_ms(300);
    buffer_pointer = 0;
    memset(buff,0,strlen(buff));
    memset(sms_buffer,0,strlen(sms_buffer));
}

// void GSM_Calling(char *Mob_no)
// {
//     char call[20];
//     sprintf(call,"ATD%s;\r",Mob_no);
//     USART_SendString(call);						        /* send command ATD<Mobile_No>; for calling*/
// }

// void GSM_HangCall()
// {
//     LCD_Clear();
//     USART_SendString("ATH\r");					        /*send command ATH\r to hang call*/
//     
// }

void GSM_Response()
{
    unsigned int timeout=0;
    int CRLF_Found=0;
    char CRLF_buff[2];
    int Response_Length=0;
    while(1)
    {
        if(timeout>=60000)								/*if timeout occur then return */
        return;
        Response_Length = strlen(buff);
        if(Response_Length)
        {
            _delay_ms(2);
            timeout++;
            if(Response_Length==strlen(buff))
            {
                for(int i=0;i<Response_Length;i++)
                {
                    memmove(CRLF_buff,CRLF_buff+1,1);
                    CRLF_buff[1]=buff[i];
                    if(strncmp(CRLF_buff,"\r\n",2))
                    {
                        if(CRLF_Found++==2)				/* search for \r\n in string */
                        {
                           /* GSM_Response_Display();		/ * display response * /*/
                            return;
                        }
                    }

                }
                CRLF_Found = 0;

            }
            
        }
        _delay_ms(1);
        timeout++;
    }
    status_flag=0;
}

// void GSM_Response_Display()
// {
//     buffer_pointer = 0;
//     int lcd_pointer = 0;
//     while(1)
//     {
//         if(buff[buffer_pointer]== '\r' || buff[buffer_pointer]== '\n')  /* search for \r\n in string */
//         {
//             buffer_pointer++;
//         }
//         else
//         break;
//     }
//     
// 
//     LCD_Command(0xc0);
//     while(buff[buffer_pointer]!='\r')								   /* display response till "\r" */
//     {
//         LCD_Char(buff[buffer_pointer]);
//         buffer_pointer++;
//         lcd_pointer++;
//         if(lcd_pointer==15)								               /* check for end of LCD line */
//         LCD_Command(0x80);
//     }
//     buffer_pointer=0;
//     memset(buff,0,strlen(buff));
// }

void GSM_Msg_Read(int position)
{
    char read_cmd[10];
    sprintf(read_cmd,"AT+CMGR=%d\r",position);
    USART_SendString(read_cmd);							/* read message at specified location/position */
/*    GSM_Msg_Display();*/									/* display message */
}

// void GSM_Msg_Display()
// {
//     _delay_ms(500);
//     if(!(strstr(buff,"+CMGR")))                         /*check for +CMGR response */
//     {
//         LCD_String_xy(1,0,"No message");
//     }
//     else
//     {
//         buffer_pointer = 0;
//         
//         while(1)
//         {
//             if(buff[buffer_pointer]=='\r' || buff[buffer_pointer]== 'n')  /*wait till \r\n not over*/
//             {
//                 buffer_pointer++;
//             }
//             else
//             break;
//         }
//         
//         /* search for 1st ',' to get mobile no.*/
//         while(buff[buffer_pointer]!=',')
//         {
//             buffer_pointer++;
//         }
//         buffer_pointer = buffer_pointer+2;
// 
//         /* extract mobile no. of message sender */
//         for(int i=0;i<=12;i++)
//         {
//             Mobile_no[i] = buff[buffer_pointer];
//             buffer_pointer++;
//         }
//         
//         do
//         {
//             buffer_pointer++;
//         }while(buff[buffer_pointer-1]!= '\n');
//         
//         LCD_Command(0xC0);
//         int i=0;
// 
//         /* display and save message */
//         while(buff[buffer_pointer]!= '\r' && i<31)
//         {
//             LCD_Char(buff[buffer_pointer]);
//             message_received[i]=buff[buffer_pointer];
//             
//             buffer_pointer++;
//             i++;
//             if(i==16)
//             LCD_Command(0x80);						/* display on 1st line */
//         }
//         
//         buffer_pointer = 0;
//         memset(buff,0,strlen(buff));
//     }
//     status_flag = 0;
// }