#include <ftdi.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// FTDI Vendor ID
#define VID 0x0403
// FTDI Product ID
#define PID 0x6001

#define DMX_CHANNELS 512
// One "official" DMX frame can take (1s/44Hz) = 22727272ns
#define DMX_FRAMETIME 22727272
#define DMX_BREAK 110000
#define DMX_MAB 16000

#define MAX_STR 64

inline void ts_diffadd(struct timespec *res, struct timespec *a, struct timespec *b, struct timespec *c) {
        time_t rem;

        res->tv_nsec=a->tv_nsec-b->tv_nsec+c->tv_nsec;
        rem=res->tv_nsec/1000000000;
        res->tv_nsec=res->tv_nsec%1000000000;
        res->tv_sec=a->tv_sec-b->tv_sec+c->tv_sec+rem;

        if (res->tv_nsec<0 && res->tv_sec>0) res->tv_sec--; res->tv_nsec+=1000000000;
        if (res->tv_nsec>0 && res->tv_sec<0) res->tv_nsec-=1000000000; res->tv_sec++;
}

void e(int res, const char *funcname, struct ftdi_context *ftdi, int exit_val) {
	char *reason;

	if ( res < 0 ) {
		reason=ftdi_get_error_string(ftdi);
		fprintf(stderr, "Error in %s : %s\n", funcname, reason);
		exit(exit_val);
	}

}

/*
struct ftdi_device_list
{
    // pointer to next entry
    struct ftdi_device_list *next;
    // pointer to libusb's usb_device
    struct usb_device *dev;
}
*/

int main() {
	int res;

	char *manufacturer, *description, *serial;
	char universe[DMX_CHANNELS+1];

	struct ftdi_context ftdi;
	struct ftdi_device_list *devlist=NULL;
	struct usb_device *dev=NULL;

	struct timespec ts_frame_time, ts_dmx_break, ts_dmx_mab, ts_to_sleep, ts_trame_begin, ts_now;

	ts_frame_time.tv_sec=0;
	ts_frame_time.tv_nsec=DMX_FRAMETIME;
	ts_dmx_break.tv_sec=0;
	ts_dmx_break.tv_nsec=DMX_BREAK;
	ts_dmx_mab.tv_sec=0;
	ts_dmx_mab.tv_nsec=DMX_MAB;
	
	(void) memset(universe, 0, DMX_CHANNELS);
	(void) memset(&ftdi, 0, sizeof(ftdi));
	universe[DMX_CHANNELS]=0;

	manufacturer=malloc(MAX_STR);
	description=malloc(MAX_STR);
	serial=malloc(MAX_STR);

	e(ftdi_init(&ftdi),"ftdi_init",&ftdi,10);
	e(ftdi_usb_find_all(&ftdi, &devlist, VID, PID),"ftdi_usb_find_all",&ftdi,11);

	//Always take the first device
	if (devlist==NULL || devlist->dev==NULL) {
		fprintf(stderr, "No usb device detected (looking for 0x%04X:0x%04X)\n", VID, PID);
		exit(2);
	}
	dev=devlist->dev;

//	fprintf(stderr, "DEBUG : next==%p\n", devlist->next);
	
	e(ftdi_usb_get_strings(&ftdi, dev, manufacturer, MAX_STR, description, MAX_STR, serial, MAX_STR),"ftdi_usb_get_strings",&ftdi,12);
	fprintf(stderr, "Connecting to USB device ('%s','%s','%s')\n", manufacturer, description, serial);
	e(ftdi_usb_open_dev(&ftdi,dev),"ftdi_usb_open_dev",&ftdi,13);
	fprintf(stderr, "Connected\n");
	
	//Init the device
	e(ftdi_usb_reset(&ftdi),"ftdi_usb_reset",&ftdi,15);
	e(ftdi_set_baudrate(&ftdi, 250000),"ftdi_set_baudrate",&ftdi,16);
	e(ftdi_set_line_property(&ftdi, BITS_8, STOP_BIT_2, NONE),"ftdi_set_line_property",&ftdi,17);
	e(ftdi_setflowctrl(&ftdi, SIO_DISABLE_FLOW_CTRL),"ftdi_setflowctrl",&ftdi,18);
	e(ftdi_usb_purge_buffers(&ftdi),"ftdi_usb_purge_buffers",&ftdi,19);
	e(ftdi_setrts(&ftdi, 0),"ftdi_setrts",&ftdi,20);

	// 1ms pause for initialization completion
	ts_to_sleep.tv_sec=0;
	ts_to_sleep.tv_nsec=1000000;
	nanosleep(&ts_to_sleep,NULL);

	ts_trame_begin.tv_sec=0;
	ts_trame_begin.tv_nsec=0;

	// Wait the end of the previous timeslot
	clock_gettime(CLOCK_MONOTONIC, &ts_now);
	ts_diffadd(&ts_to_sleep,&ts_frame_time,&ts_now,&ts_trame_begin);
	nanosleep(&ts_to_sleep,NULL);

	clock_gettime(CLOCK_MONOTONIC, &ts_trame_begin);

	e(ftdi_set_line_property2(&ftdi, BITS_8, STOP_BIT_2, NONE, BREAK_ON),"ftdi_set_line_property2",&ftdi,30);
	nanosleep(&ts_dmx_break,NULL);
	e(ftdi_set_line_property2(&ftdi, BITS_8, STOP_BIT_2, NONE, BREAK_OFF),"ftdi_set_line_property2",&ftdi,31);
	nanosleep(&ts_dmx_mab,NULL);



	// Tests
	universe[2]=120;
	universe[3]=120;
	universe[4]=120;


	//e(ftdi_write_data(&ftdi, universe, DMX_CHANNELS),"ftdi_write_data",&ftdi,32);
	res=ftdi_write_data(&ftdi, universe, DMX_CHANNELS);
	
	//fprintf(stderr, "DEBUG : to_sleep=={%li,%li}\n", ts_to_sleep.tv_sec, ts_to_sleep.tv_nsec);
	fprintf(stderr, "DEBUG : res==%i\n", res);
//	fprintf(stderr, "DEBUG : universe==%s\n", universe);

	e(ftdi_usb_close(&ftdi),"ftdi_usb_close",&ftdi,50);
	ftdi_list_free(&devlist);
	ftdi_deinit(&ftdi);


	free(manufacturer);
	free(description);
	free(serial);

	exit(0);
}