/*
Copyright 2019 Matthew Graham <sl@airmail.cc>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
	char *buf;
	unsigned int ccase = 0;
	long size;
	int i = 1;
	FILE *fp = stdin;
	if (argv[1] && argv[1][0]=='-' && argv[1][1]) {
		switch (argv[1][1]) {
			case 'l': ccase = 'l'; break;
			case 'u': ccase = 'u'; break;
			case 's': ccase = 's'; break;
		}
	}
	else {
		fprintf(stderr, "sc: usage: sc -[ l|u|s ] [file...]\n");
		return 1;
	}
	argc--;
	argv++;

	do {
		if (argc > 1 && (fp=fopen(argv[i], "r"))==NULL) {
			fprintf(stderr, "sc: unable to open %s\n", argv[i]);
			continue;
		}
		fseek(fp, 0L, SEEK_END);
		size = ftell(fp);
		rewind(fp);
		buf = malloc(size+1);
		fread(buf, size, 1, fp);
		switch (ccase) {
		case 'l':
			for (int a=0; buf[a]; a++) {
				if (buf[a] >= 'A' && buf[a] <= 'Z')
			 		buf[a] += 32;
				putchar(buf[a]);
			}
		break;

		case 'u':
			for (int b=0; buf[b]; b++) {
				if (buf[b] >= 'a' && buf[b] <= 'z')
			 		buf[b] -= 32;
				putchar(buf[b]);
			}
		break;

		case 's':
			for (int c=0; buf[c]; c++) {
				if (buf[c] >= 'a' && buf[c] <= 'z') {
			 		buf[c] -= 32;
					putchar(buf[c]);
					continue;
				}
				else if (buf[c] >= 'A' && buf[c] <= 'Z') {
			 		buf[c] += 32;
					putchar(buf[c]);
					continue;
				}
				putchar(buf[c]);
			}
		break;
		}
	} while (++i<argc);
	return 0;
}