#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <math.h>

const unsigned char TEXT[] = "\
ESXISTXFÜNF\
ZEHNZWANZIG\
DREIVIERTEL\
VORGESTNACH\
HALBXELFÜNF\
EINSXLEZWEI\
DREIXTXVIER\
SECHSXXACHT\
SIEBENZWÖLF\
ZEHNEUNXUHR";

typedef unsigned long long uint64;
typedef unsigned __int128 uint128;

#define ES_IST		((uint128) 0b11 << 0 | 0b111 << 3 )
#define FÜNF_PRE	((uint128) 0b1111			<< 7  )
#define FÜNFZEHN	((uint128) 0b11111111		<< 7  )
#define ZEHN_PRE	((uint128) 0b1111			<< 11 )
#define ZWANZIG		((uint128) 0b1111111		<< 15 )
#define DREIVIERTEL	((uint128) 0b11111111111	<< 22 )
#define VIERTEL		((uint128) 0b1111111		<< 26 )
#define VOR			((uint128) 0b111			<< 33 )
#define NACH		((uint128) 0b1111			<< 40 )
#define HALB		((uint128) 0b1111			<< 44 )
#define ELF			((uint128) 0b111			<< 49 )
#define FÜNF_UHR	((uint128) 0b1111			<< 51 )
#define EINS		((uint128) 0b1111			<< 55 )
#define ZWEI		((uint128) 0b1111			<< 62 )
#define DREI		((uint128) 0b1111			<< 66 )
#define VIER		((uint128) 0b1111			<< 73 )
#define SECHS		((uint128) 0b11111			<< 77 )
#define ACHT		((uint128) 0b1111			<< 84 )
#define SIEBEN		((uint128) 0b111111			<< 88 )
#define ZWÖLF		((uint128) 0b11111			<< 94 )
#define ZEHN_UHR	((uint128) 0b1111			<< 99 )
#define NEUN		((uint128) 0b1111			<< 102)
#define UHR			((uint128) 0b111			<< 107)
#define STELLE		((uint128) 0b11 << 38 | 0b11 << 49 | 0b11 << 60)
#define GESTELLT	((uint128) 0b1111 << 36 | 0b11 << 49 | 0b1 << 60 | 0b1 << 71)

uint128 HOURS[] = {
	ZWÖLF, EINS, ZWEI, DREI, VIER, FÜNF_UHR,
	SECHS, SIEBEN, ACHT, NEUN, ZEHN_UHR, ELF
};
uint128 PARTS[] = {
	UHR, FÜNF_PRE, ZEHN_PRE, VIERTEL,
	ZWANZIG, FÜNF_PRE | HALB, HALB
};

uint128 active = 0;

void print128(uint128 n) {
	printf("0x%016llx%016llx\n",
		(uint64) (n >> 64), (uint64) n & 0xFFFFFFFFFFFFFFFF);
}

void set(uint128 seg) {
	active |= seg;
}

void reset(void) {
	active = 0;
	set(ES_IST);
}

void settime(time_t ts) {

	unsigned int second = ts % 60;

	unsigned int minute = (ts / 60) % 60;
	float fminute = (float) minute + (float) second / 60;
	minute = 5 * (unsigned int) roundf(fminute / 5);

	unsigned int hour   = (ts / (60*60) + 1) % 12;

	//printf("%02d:%02d\n", hour, minute);

	int before = 0;

	if (minute >= 25) {
		hour = (hour+1) % 12;
		before = 1;
		minute = 60-minute;
		if (minute == 35) {
			minute = 25;
			before = 0;
		}
	}

	//printf("%02d %s %02d\n", minute, before ? "vor" : "nach", hour);

	if (minute == 25)
		before = !before;

	reset();

	if (minute != 0 && minute != 30)
		set(before ? (uint128) VOR : (uint128) NACH);

	set((uint128) HOURS[hour]);
	set((uint128) PARTS[minute/5]);

}

void dump() {

	const int ROWS = 10;
	const int COLS = 11;

	const char WHITE[] = "\033[1;37m";
	const char  GRAY[] = "\033[0;30m";

	uint128 buffer = active;

	int ci = 0;

	for (int bi = 0; bi < sizeof(TEXT); bi++) {

		// utf8 tail byte
		if (TEXT[bi] >> 6 == 0b10) {
			putc(TEXT[bi], stdout);
			continue;
		}

		int col = ci % COLS;
		int row = ci / COLS;
		if (col == 0)
			printf("\n ");

		const char* color = (buffer & (uint128) 1) ? WHITE : GRAY;

		printf("  %s%c", color, TEXT[bi]);

		buffer = buffer >> 1;
		ci++;

	}

	#define RESET_COLORS "\033[0m"
	printf(RESET_COLORS "\n");

}

int main(int argc, char* argv[]) {

	int demo = 0;
	int live = 0;
	if (argc > 1) {
		if (strncmp(argv[1], "demo", 5) == 0)
			demo = 1;
		else if (strncmp(argv[1], "live", 5) == 0)
			live = 1;
		else
			active = atol(argv[1]);
	}

	time_t ts = time(NULL);

	while (1) {
		printf("\033c");
		if (demo) printf("DEMO Mode!\n");
		ts = demo ? ts + 5 * 60 : time(NULL);
		settime(ts);
		dump();

		if (!live) return 0;

		sleep(5);
	};

	return 0;

}