/**
 * Funkce printf
 * Material pro cviceni z c/c++
 */

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

/**
 * Funkce na vyplneni mezerami
 */
void putSpaces(unsigned int total, unsigned int numlen) {
	unsigned int j;

	if (total > numlen)
		for (j = 0; j < total - numlen; ++j)
			putchar(' ');
}

/**
 * precte ze zadaneho vstupu cele cislo
 * vraci pocet cislic cisla
 */
unsigned readNum(char *src, unsigned *out) {
	unsigned int i = 0;
	
	*out = 0;
	while ((src[i] >= '0') && (src[i] <= '9'))
		*out = *out * 10 + src[i++];

	return i;
}

/**
 * funkce nacte potrebne formatovaci parametry a vrati pocet
 * znaku, ze kterych se formatovaci retezec skladal
 */
int getType(char *fmt, char *type, unsigned *whole, unsigned *decimal) {
	unsigned i = 0;

	if (isalpha(fmt[i])) {
		*whole = *decimal = 0;
		*type = fmt[i];
		return 1;
	}
	else {
		i += readNum(fmt, whole);

		if (fmt[i] == '.') {
			++i;
			i += readNum(&fmt[i], decimal);
		}
		else
			*decimal = 0;
		
		*type = fmt[i];
		++i;

		return i;
	}
}

/**
 * zjednodusena implementace funkce printf ze stdio.h
 */
int myprintf(char *_format, ...) {
	va_list format;
	unsigned cnt = 0;
	size_t fmtsize;
	unsigned i, j;
	size_t numsize;

	// promenne pro data z argumentu
	int intdata;
	long longdata;
	unsigned uintdata;
	unsigned long ulongdata;
	char chardata;
	char *strdata;

	//formatovaci parametry
	unsigned decimal;
	unsigned whole;
	char type;
	char buffer[256];


	//nejprve inicializujeme pomocne promene a va_list
	fmtsize = strlen(_format);
	va_start(format, _format);

	//tiskneme jednotlive znaky a v pripade, ze narazime
	// na '%', vezmeme dalsi argument a vytiskneme ho odpovidajicim
	// zpusobem
	for(i = 0; i < fmtsize; ++i) {

		//vytiskneme znak beznym zpusobem
		if (_format[i] != '%') {
			putchar(_format[i]);
			++cnt;
		}

		//musime precist typovana data z argumentu
		else {
			++i;
			i += getType(&_format[i], &type, &whole, &decimal) - 1;
			switch(type) {
				case 'd':
					intdata = va_arg(format, int);
					itoa(intdata, buffer, 10);
					numsize = strlen(buffer);

					putSpaces(whole, (unsigned)numsize);

					for (j = 0; j < numsize; ++j)
						putchar(buffer[j]);

					cnt += (unsigned)numsize;
					break;

				case 'u':
					uintdata = va_arg(format, unsigned int);
					ultoa(uintdata, buffer, 10);

					numsize = strlen(buffer);

					putSpaces(whole, (unsigned)numsize);

					for (j = 0; j < numsize; ++j)
						putchar(buffer[j]);

					cnt += (unsigned)numsize;
					break;

				case 'D':
					longdata = va_arg(format, long);
					ltoa(longdata, buffer, 10);
					numsize = strlen(buffer);

					putSpaces(whole, (unsigned)numsize);

					for (j = 0; j < numsize; ++j)
						putchar(buffer[j]);

					cnt += (unsigned)numsize;
					break;

				case 'U':
					ulongdata = va_arg(format, unsigned long);
					ultoa(ulongdata, buffer, 10);

					numsize = strlen(buffer);

					putSpaces(whole, (unsigned)numsize);

					for (j = 0; j < numsize; ++j)
						putchar(buffer[j]);

					cnt += (unsigned)numsize;
					break;

				case 'c':
					chardata = va_arg(format, char);

					putSpaces(whole, 1);
					putchar(chardata);

					cnt += 1;
					break;

				case 's':
					strdata = va_arg(format, char *);
					
					numsize = strlen(strdata);
					putSpaces(whole, (unsigned)numsize);

					for (j = 0; j < numsize; ++j)
						putchar(strdata[j]);

					cnt += (unsigned)numsize;

					break;
			}
		}
	}
	
	return cnt;
}

int main() {
	int a = 5;

	myprintf("cislo %D\n\tpismeno %c\ntext: %s\n", -1, 'w', "a sample text line");

	return 0;
}