//Inculde Header Files-----------------------------------------------
#include<stdlib.h>
#include<stdio.h>
#include<errno.h>
#include<sys/time.h>
#include<unistd.h>
#include<termios.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<sys/resource.h>
#include<pthread.h>
#include<signal.h>

//Enumerations-------------------------------------------------------
typedef enum {false, true} bool; 
typedef enum {fuse_read,
		      fuse_write,
		      page_read,
		  	  page_write,
		  	  prog_check} mode;

//Constants----------------------------------------------------------
#define nibble_lo 0x0F
#define nibble_hi 0xF0
#define frame_mask 0x90
#define page_size 64

//Structs------------------------------------------------------------
typedef struct {
	char mode;
	char opt_lo;
	char opt_hi;
} cmd_t;

//Makros-------------------------------------------------------------
#define error_handler(err_no, err_str) 	\
					errno = err_no;		\
					perror(err_str);	\
					exit(EXIT_FAILURE);

//Protoypes----------------------------------------------------------
void * signal_thread(void * arg_ptr);
void set_timer(int sec, int usec);
char * cmd_build(mode cmd_mode, char cmd_option);
char * page_build(char size);
unsigned char * page_mask(char * page_build_ptr, int page_end);
int page_get(FILE * input_stream, int page_pos);

//Variables----------------------------------------------------------
char cmd_arr[3];
bool timer_state;
unsigned char page_buf[64];

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Signal Thread
void * signal_thread(void * arg_ptr){
	sigset_t * signal_ptr = (sigset_t *)arg_ptr;
	int signal_nr, signal_err;
	signal_err = sigwait(signal_ptr, &signal_nr);
	if(signal_err!=0){
		error_handler(signal_err, "Problem with Signal");
	}
	else if(signal_nr!=SIGALRM){
		fprintf(stderr, "Wrong Signal \n");
	}
	timer_state = false;
	return NULL;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Set Timer
void set_timer(int sec, int usec){
	struct itimerval timer;
	int timer_err, signal_err;
	timer.it_interval.tv_sec = sec;
	timer.it_interval.tv_usec = usec;
	timer.it_value.tv_sec = sec;
	timer.it_value.tv_usec = usec;
	timer_err = setitimer(ITIMER_REAL, &timer, NULL);
	if(timer_err!=0){
		error_handler(timer_err, "Error setting Timer");
	}
	timer_state = true;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Build Command
char * cmd_build(mode cmd_mode, char cmd_option){
	cmd_t * cmd_ptr = (cmd_t *)malloc(sizeof(cmd_t));
	(*cmd_ptr).mode = frame_mask|cmd_mode;
	(*cmd_ptr).opt_lo = frame_mask|(cmd_option&nibble_lo);
	(*cmd_ptr).opt_hi = frame_mask|((cmd_option>>4)&nibble_lo);
	char * frame_ptr = &((*cmd_ptr).mode);
	return frame_ptr;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Build Page
char * page_build(char size){
	char page[size];
	for(int i=0; i<size; i++){
		page[i] = 0xFF;
	}
	char * page_ptr = &page[0];
	return page_ptr;
}

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Mask Page
unsigned char * page_mask(char * page_build_ptr, int page_end){
	unsigned char * page_mask_ptr = (unsigned char *)
									malloc(2*page_end*sizeof(char));
	for(int i=0; i<page_end; i++){
		*page_mask_ptr = frame_mask|
								((*page_build_ptr&nibble_hi)>>4);
		*(page_mask_ptr+1) = frame_mask|(*page_build_ptr&nibble_lo);
		page_mask_ptr = page_mask_ptr + 2;
		page_build_ptr++;
	}
	return page_mask_ptr-2*page_end;
}

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Get Page
int page_get(FILE * input_stream, int p_cnt){
	int j = 0;									//init loc Variables
	int c_cnt = 0;
	if(p_cnt==0){								//check for Start
		for(int k=0; k<9; k++){
			page_buf[0] = fgetc(input_stream);
		}
	}
	else{
		c_cnt = 16;
	}
	while(j<page_size){							//get Char
		page_buf[j] = fgetc(input_stream);
		page_buf[j+1] = fgetc(input_stream);
		if(page_buf[j]==0x25){
			return j;
		}	
		if(c_cnt==16){							//check for Lineend
			c_cnt = 0;
			for(int k=0; k<11; k++){
				page_buf[j] = fgetc(input_stream);
			}
		}
		else{									//Convert to HEX
			for(int m=0; m<2; m++){
				if(page_buf[j+m]<0x3A&&page_buf[j+m]>0x2F){
						page_buf[j+m] -= 0x30;
				}
				else if(page_buf[j+m]<0x47&&page_buf[j+m]>0x40){
						page_buf[j+m] -= 0x37;
				}
			}
			page_buf[j] = ((page_buf[j]<<4)&nibble_hi)|
										(page_buf[j+1]&nibble_lo);
			c_cnt++;
			j++;
		}
	}
	return page_size;
}