#include <libgimp/gimp.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>

//Functions needed by gimp

//This one is called mainly when Gimp starts
static void query (void);

//This one is called when the users clicks on "Colors"->"Read color from sensor..."
static void run (
	const gchar      *name,
	gint              nparams,
	const GimpParam  *param,
	gint             *nreturn_vals,
	GimpParam       **return_vals
);

/*
 * Opens the /dev/ttyACM0 serial port
 * Pre: the /dev/ttyACM0 port is avaiable
 */
static int open_port(void);

/*
 * Sends a signal to the Arduino, get the color code and returns it in the GimpRGB format
 * Pre: the /dev/ttyACM0 port is avaiable and Arduino send a proper hexadecimal color code
 */
static GimpRGB read_color(void);

/*
 * Converts an exadecimal digit to an integer
 * Pre: the input char is a valid exadecimal digit
 */
static int hex2int(char c);

GimpPlugInInfo PLUG_IN_INFO = {
	NULL,
	NULL,
	query,
	run
};

MAIN()

static void query (void) {
	static GimpParamDef args[] = {
		{
			GIMP_PDB_INT32,
			"run-mode",
			"Run mode"
		},
		{
			GIMP_PDB_IMAGE,
			"image",
			"Input image"
		},
		{
			GIMP_PDB_DRAWABLE,
			"drawable",
			"Input drawable"
		}
	};

	gimp_install_procedure (
		"plug-in-real-colors",
		"Real colors",
		"Reads a color and changes the palette foreground color to it",
		"Giulio Martella",
		"Copyright Giulio Martella",
		"2015",
		"_Read color from sensor...",
		"RGB*, GRAY*",
		GIMP_PLUGIN,
		G_N_ELEMENTS (args), 0,
		args, NULL
	);

	gimp_plugin_menu_register (
		"plug-in-real-colors",
		"<Image>/Colors"
	);
}

static void run (
	const gchar      *name,
	gint              nparams,
	const GimpParam  *param,
	gint             *nreturn_vals,
	GimpParam       **return_vals
) {
	static GimpParam  values[1];
	GimpPDBStatusType status = GIMP_PDB_SUCCESS;
	GimpRunMode       run_mode;

	/* Setting mandatory output values */
	*nreturn_vals = 1;
	*return_vals  = values;

	values[0].type = GIMP_PDB_STATUS;
	values[0].data.d_status = status;

	run_mode = param[0].data.d_int32;
	
	GimpRGB color = read_color();
	gimp_palette_set_foreground(&color);
}

static int open_port(void) {
	int fd; /* File descriptor for the port */
	struct termios options;

	fd = open("/dev/ttyACM0", O_RDWR | O_NOCTTY | O_NDELAY);
	if (fd == -1) {
		/*
		* Could not open the port.
		*/

		perror("open_port: Unable to open /dev/ttyf1 - ");
	} else
		fcntl(fd, F_SETFL, 0);
	
	tcgetattr(fd, &options);
	
	cfsetispeed(&options, B9600);
	cfsetospeed(&options, B9600);

	options.c_cflag     &=  ~PARENB;
	options.c_cflag     &=  ~CSTOPB;
	options.c_cflag     &=  ~CSIZE;
	options.c_cflag     |=  CS8;

	options.c_cflag     &=  ~CRTSCTS;
	options.c_cc[VMIN]   =  1;
	options.c_cc[VTIME]  =  5;
	options.c_cflag     |=  CREAD | CLOCAL;

	cfmakeraw(&options);

	tcflush(fd, TCIFLUSH);
	
	tcsetattr(fd, TCSANOW, &options);
	
	return (fd);
}

static GimpRGB read_color(void) {
	GimpRGB color;
	int fd = open_port();
	
	int n = 0, 
		i = 0;
		
	char buf = '\0';
	
	write(fd, "A", 1);
	
	do {
		n = read( fd, &buf, 1 );
		
		if( i == 0 ) 
			color.r = hex2int(buf) * 16;
		else if( i == 1 )
			color.r += hex2int(buf);
		else if( i == 2 )
			color.g = hex2int(buf) * 16;
		else if( i == 3 )
			color.g += hex2int(buf);
		else if( i == 4 )
			color.b = hex2int(buf) * 16;
		else if( i == 5 )
			color.b += hex2int(buf);
		
		i++;
	} while (buf != '\r' && n > 0);
	
	close(fd);
	
	color.r /= 255;
	color.g /= 255;
	color.b /= 255;
	color.a = 1.0;
	
	return color;
}

static int hex2int( char c ) {
	int ret = 0;
	if( c >= '0' && c <= '9' ) {
		ret = c - 48;
	} else if( c >= 'A' && c <= 'F' )  {
		ret = c - 55;
	} else if( c >= 'a' && c <= 'f' )  {
		ret = c - 87;
	}
	return ret;
	
}