#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

#ifdef __PROGTEST__
#define debug(...) ((void)0)
#else
#define debug(fmt, ...) fprintf(stdout, "[DEBUG %s:%d %s()] " fmt "\n", __FILE__, __LINE__, __func__, ##__VA_ARGS__)
#endif

bool is_numeric(const char* str) {
	if(*str == '\0') return false;

	for(;*str; str++) {
		if(!isdigit(*str))
			return false;
	}
	return true;
}

int invalid_input() {
	printf("Nespravny vstup.\n");
	return EXIT_FAILURE;
}

int main() {
	char* input = NULL;
	size_t len;

	int rgb[3];

	printf("Zadejte barvu v RGB formatu:\n");

	ssize_t chars_read = getline(&input, &len, stdin);

	if(chars_read == -1) {
		printf("Failed to read from stdin\n");
		return EXIT_FAILURE;
	}

	char* dst = input;
	for(char * src = input; *src; src++) {
		if(!isspace(*src)) {
			*dst++ = *src;
		}
	}
	*dst = '\0';

	int trimmed_len = strlen(input);
	if(strncmp(input, "rgb(", 4) != 0 || input[trimmed_len - 1] != ')') {
		debug("%s not in rgb(xxx) format", input);
		return invalid_input();
	}

	input[trimmed_len - 1] = '\0';
	char* slice = input + 4;

	char* token = strtok(slice, ",");

	for(int i = 0; i < 3; i++) {
		if(token == NULL) {
			debug("Too few numbers");
			return invalid_input();
		}
		if(!is_numeric(token)) {
			debug("%s is not a number", token);
			return invalid_input();
		}

		int parsed = atoi(token);

		if(parsed < 0 || parsed > 255) {
			debug("%d out of RGB range", parsed);
			return invalid_input();
		}

		rgb[i] = parsed;
		token = strtok(NULL, ",");
	}

	if(token != NULL) {
		debug("Too many numbers");
		return invalid_input();
	}

	printf("#%02X%02X%02X\n", rgb[0], rgb[1], rgb[2]);
	return EXIT_SUCCESS;
}