#include<stdio.h>
#include<string.h>
#include<ctype.h>
#define BS 128

/* Program slouci vice souboru dohromady a zase je umi extrahovat.
 * Vice info vizte pack.c, tato verze se lisi tim, ze umi sloucit
 * i soubory s mezerama v nazvu, napr.:
 *
 * ./pack2 -s zapack.pack prvni.txt druhy\ s\ mezerou.txt 
 * zapackovavame... prvni.txt
 * zapackovavame... druhy s mezerou.txt
 *
 * ./pack2 -r zapack.pack 
 * depackovavame... prvni.txt
 * depackovavame... druhy s mezerou.txt
 */

int main(int argc, char**argv) {
	if (argc < 3) {	// osetreni spatneho spusteni bez parametru
		fprintf(stderr, "Chyba!... navodek na pouziti!\n");
		return 1;
	}
	char buf[BS];
	if (!strcmp(argv[1], "-s")) {		// sbal
		FILE *fout = fopen(argv[2], "wb");
		for (int i = 3; i < argc; ++i) {
			printf("zapackovavame... %s\n", argv[i]);

			FILE *fin = fopen(argv[i], "rb");
			fseek(fin, 0, SEEK_END);
			fprintf(fout, "%ld ", strlen(argv[i]));
			fputs(argv[i], fout);
			fprintf(fout, "%ld ", ftell(fin));
			rewind(fin);
			size_t precteno;
			do {
				precteno = fread(buf, 1, BS, fin);
				fwrite(buf, 1, precteno, fout);
			} while (precteno == BS);

			fclose(fin);
		}

		fclose(fout);
	} else if (!strcmp(argv[1], "-r")) { 	// rozbal
		FILE *fin = fopen(argv[2], "rb");
		char fnazev[257];
		long int fdelka;
		int delka_jmena;
		while (1 == fscanf(fin, "%d%*c", &delka_jmena) 
			&& NULL != fgets(fnazev, delka_jmena+1, fin) // fgets cte o 1 mene
			&& 1 == fscanf(fin, "%ld%*c", &fdelka) 
			&& strlen(fnazev) > 0
		) {
			printf("depackovavame... %s\n", fnazev);
			FILE *fout = fopen(fnazev, "wb");
			size_t precteno;
			do {
				precteno = fread(buf, 1, 
						fdelka > BS ? BS : fdelka, fin);
				fwrite(buf, 1, precteno, fout);
				
				fdelka -= BS;
			} while (fdelka > 0); 
			fclose(fout);
		}
		fclose(fin);
	} else {
		fprintf(stderr, "Chybny prepinac: %s\n", argv[1]);
		return 2;
	}

	return 0;
}