/* scan_args.c */

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

#include "pcode.h"

#define PCODE_VERSION_BLURB                                               \
"pcode " PCODE_VERSION_STR ", " PCODE_DATE_STR "\n"                       \
"Copyright 2004 Andy Goth <unununium@openverse.com>.\n"                   \
"Adapted from pcode2.c by Agnieszka Szczurowska, 2000.\n"                 \
"Implements pcode as described by Bruce J. MacLennan, 1999.\n"            \
"Check for updates at <URL:http://ioioio.net/school/pcode/>.\n"           \
"pcode is free software, covered by the GNU General Public License; you\n"\
"are welcome to change and/or distribute it under certain conditions.\n"  \
"There is absolutely no warranty for pcode.  See COPYING for details.\n"

#define PCODE_HELP_BLURB                                                  \
"Usage: %s [OPTION] ...\n"                                                \
"Interprets a pcode program.\n"                                           \
"\n"                                                                      \
"  -iFILE   Read input data from FILE.\n"                                 \
"  -oFILE   Write output data to FILE.\n"                                 \
"  -d       Execute program interactively (debug mode).\n"                \
"  -c       Colorize debug display.\n"                                    \
"  -h       Print this message.\n"                                        \
"  -V       Display version and copyright information.\n"                 \
"\n"                                                                      \
"If FILE is `-' or not specified, stdin or stdout is used.\n"             \
"\n"                                                                      \
"Report bugs to Andy Goth <unununium@openverse.com>.\n"

int scan_args(int argc, char** argv, interp_t* interp)
{
    int i, have_input = 0, have_output = 0, debug = 0, color = 0, *have;
    int retval = 0;
    FILE* input = stdin, *output = stdout, **file, *def;
    char opt, *progname, *string, *mode;

    /* Get program name. */
    progname = strrchr(argv[0], '/');
    if (progname != NULL) ++progname;
    else                  progname = argv[0];

    /* Scan command line arguments.  Too bad getopt_long(3) is GNU-only... */
    for (i = 1; i < argc; ++i) {
        if (argv[i][0] == '-') opt = argv[i][1];
        else                   opt = 0; /* Invalid; handled below. */

        switch (opt) {
        case 'i': case 'o':
            if (argv[i][2] != 0) {
                /* `-ifilename' or `-ofilename' */
                string = &argv[i][2];
            } else {
                /* `-i filename' or `-o filename' */
                ++i;
                if (i == argc) {
                    fprintf(stderr, "Option `-%c' requires argument\n", opt);
                    retval = -1; goto end;
                }
                string = argv[i];
            }

            have = opt == 'i' ? &have_input : &have_output;
            file = opt == 'i' ? &input      : &output     ;
            def  = opt == 'i' ? stdin       : stdout      ;
            mode = opt == 'i' ? "r"         : "w"         ;

            if (*have) {
                fprintf(stderr, "Too many `-%c' options\n", opt);
                retval = -1; goto end;
            }

            *have = 1;
            if (strcmp(string, "-") == 0) {
                *file = def;
            } else {
                *file = fopen(string, mode);
                if (*file == NULL) {
                    fprintf(stderr, "`%s': %s\n", string, strerror(errno));
                    retval = -1; goto end;
                }
            }
            break;
        case 'd': debug = 1; break;
        case 'c': color = 1; break;
        case 'h': printf(PCODE_HELP_BLURB, progname); retval = 1; goto end;
        case 'V': printf(PCODE_VERSION_BLURB       ); retval = 1; goto end;
        default:
            fprintf(stderr, "Invalid argument `%s'\n", argv[i]);
            fprintf(stderr, "Try `%s -h' for more information\n", progname);
            retval = -1; goto end;
        }
    }

end:
    /* Store results. */
    if (retval == 0 && debug && input == stdin) {
        fprintf(stderr, "In debug mode, cannot use stdin for program input\n");
        retval = -1;
    }

    interp->input  = input;
    interp->output = output;
    interp->debug  = debug;
    interp->color  = color;

    return retval;
}

/* vim: set ts=4 sts=4 sw=4 tw=80 et: */