/*      $OpenBSD: quiz.c,v 1.32 2022/08/08 17:54:08 op Exp $    */
/*      $NetBSD: quiz.c,v 1.9 1995/04/22 10:16:58 cgd Exp $     */

/*-
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jim R. Oldroyd at The Instruction Set and Keith Gabryelski at
 * Commodore Business Machines.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "pathnames.h"
#include "quiz.h"

static QE qlist;
static int catone, cattwo, tflag;
static u_int qsize;

void     downcase(char *);
void     get_cats(char *, char *);
void     get_file(const char *);
const char      *next_cat(const char *);
void     quiz(void);
void     score(u_int, u_int, u_int);
void     show_index(void);
__dead void     usage(void);

int
main(int argc, char *argv[])
{
        int ch;
        const char *indexfile;

        if (pledge("stdio rpath proc exec", NULL) == -1)
                err(1, "pledge");

        indexfile = _PATH_QUIZIDX;
        while ((ch = getopt(argc, argv, "hi:t")) != -1)
                switch(ch) {
                case 'i':
                        indexfile = optarg;
                        break;
                case 't':
                        tflag = 1;
                        break;
                case 'h':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        switch(argc) {
        case 0:
                get_file(indexfile);
                show_index();
                break;
        case 2:
                if (pledge("stdio rpath", NULL) == -1)
                        err(1, "pledge");
                get_file(indexfile);
                get_cats(argv[0], argv[1]);

                if (pledge("stdio", NULL) == -1)
                        err(1, "pledge");

                quiz();
                break;
        default:
                usage();
        }
        return 0;
}

void
get_file(const char *file)
{
        FILE *fp;
        QE *qp;
        ssize_t len;
        size_t qlen, size;
        char *lp;

        if ((fp = fopen(file, "r")) == NULL)
                err(1, "%s", file);

        /*
         * XXX
         * Should really free up space from any earlier read list
         * but there are no reverse pointers to do so with.
         */
        qp = &qlist;
        qsize = 0;
        qlen = 0;
        lp = NULL;
        size = 0;
        while ((len = getline(&lp, &size, fp)) != -1) {
                if (lp[len - 1] == '\n')
                        lp[--len] = '\0';
                if (qp->q_text)
                        qlen = strlen(qp->q_text);
                if (qlen > 0 && qp->q_text[qlen - 1] == '\\') {
                        qp->q_text[--qlen] = '\0';
                        qlen += len;
                        qp->q_text = realloc(qp->q_text, qlen + 1);
                        if (qp->q_text == NULL)
                                errx(1, "realloc");
                        strlcat(qp->q_text, lp, qlen + 1);
                } else {
                        if ((qp->q_next = malloc(sizeof(QE))) == NULL)
                                errx(1, "malloc");
                        qp = qp->q_next;
                        qp->q_text = strdup(lp);
                        if (qp->q_text == NULL)
                                errx(1, "strdup");
                        qp->q_asked = qp->q_answered = FALSE;
                        qp->q_next = NULL;
                        ++qsize;
                }
        }
        free(lp);
        if (ferror(fp))
                err(1, "getline");
        (void)fclose(fp);
}

void
show_index(void)
{
        QE *qp;
        const char *p, *s;
        FILE *pf;
        const char *pager;

        if (!isatty(1))
                pager = "/bin/cat";
        else if (!(pager = getenv("PAGER")) || (*pager == 0))
                        pager = _PATH_PAGER;
        if ((pf = popen(pager, "w")) == NULL)
                err(1, "%s", pager);
        (void)fprintf(pf, "Subjects:\n\n");
        for (qp = qlist.q_next; qp; qp = qp->q_next) {
                for (s = next_cat(qp->q_text); s; s = next_cat(s)) {
                        if (!rxp_compile(s))
                                errx(1, "%s", rxperr);
                        if ((p = rxp_expand()))
                                (void)fprintf(pf, "%s ", p);
                }
                (void)fprintf(pf, "\n");
        }
        (void)fprintf(pf, "\n%s\n%s\n%s\n",
"For example, \"quiz victim killer\" prints a victim's name and you reply",
"with the killer, and \"quiz killer victim\" works the other way around.",
"Type an empty line to get the correct answer.");
        (void)pclose(pf);
}

void
get_cats(char *cat1, char *cat2)
{
        QE *qp;
        int i;
        const char *s;

        downcase(cat1);
        downcase(cat2);
        for (qp = qlist.q_next; qp; qp = qp->q_next) {
                s = next_cat(qp->q_text);
                catone = cattwo = i = 0;
                while (s) {
                        if (!rxp_compile(s))
                                errx(1, "%s", rxperr);
                        i++;
                        if (rxp_match(cat1))
                                catone = i;
                        if (rxp_match(cat2))
                                cattwo = i;
                        s = next_cat(s);
                }
                if (catone && cattwo && catone != cattwo) {
                        if (!rxp_compile(qp->q_text))
                                errx(1, "%s", rxperr);
                        get_file(rxp_expand());
                        return;
                }
        }
        errx(1, "invalid categories");
}

void
quiz(void)
{
        QE *qp;
        int i;
        size_t size;
        ssize_t len;
        u_int guesses, rights, wrongs;
        int next;
        char *answer, *t, question[LINE_SZ];
        const char *s;

        size = 0;
        answer = NULL;

        guesses = rights = wrongs = 0;
        for (;;) {
                if (qsize == 0)
                        break;
                next = arc4random_uniform(qsize);
                qp = qlist.q_next;
                for (i = 0; i < next; i++)
                        qp = qp->q_next;
                while (qp && qp->q_answered)
                        qp = qp->q_next;
                if (!qp) {
                        qsize = next;
                        continue;
                }
                if (tflag && arc4random_uniform(100) > 20) {
                        /* repeat questions in tutorial mode */
                        while (qp && (!qp->q_asked || qp->q_answered))
                                qp = qp->q_next;
                        if (!qp)
                                continue;
                }
                s = qp->q_text;
                for (i = 0; i < catone - 1; i++)
                        s = next_cat(s);
                if (!rxp_compile(s))
                        errx(1, "%s", rxperr);
                t = rxp_expand();
                if (!t || *t == '\0') {
                        qp->q_answered = TRUE;
                        continue;
                }
                (void)strlcpy(question, t, sizeof question);
                s = qp->q_text;
                for (i = 0; i < cattwo - 1; i++)
                        s = next_cat(s);
                if (s == NULL)
                        errx(1, "too few fields in data file, line \"%s\"",
                            qp->q_text);
                if (!rxp_compile(s))
                        errx(1, "%s", rxperr);
                t = rxp_expand();
                if (!t || *t == '\0') {
                        qp->q_answered = TRUE;
                        continue;
                }
                qp->q_asked = TRUE;
                (void)printf("%s?\n", question);
                for (;; ++guesses) {
                        if ((len = getline(&answer, &size, stdin)) == -1 ||
                            answer[len - 1] != '\n') {
                                score(rights, wrongs, guesses);
                                exit(0);
                        }
                        answer[len - 1] = '\0';
                        downcase(answer);
                        if (rxp_match(answer)) {
                                (void)printf("Right!\n");
                                ++rights;
                                qp->q_answered = TRUE;
                                break;
                        }
                        if (*answer == '\0') {
                                (void)printf("%s\n", t);
                                ++wrongs;
                                if (!tflag)
                                        qp->q_answered = TRUE;
                                break;
                        }
                        (void)printf("What?\n");
                }
        }
        score(rights, wrongs, guesses);
        free(answer);
}

const char *
next_cat(const char *s)
{
        int esc;

        if (s == NULL)
                return (NULL);
        esc = 0;
        for (;;)
                switch (*s++) {
                case '\0':
                        return (NULL);
                case '\\':
                        esc = 1;
                        break;
                case ':':
                        if (!esc)
                                return (s);
                default:
                        esc = 0;
                        break;
                }
}

void
score(u_int r, u_int w, u_int g)
{
        (void)printf("Rights %d, wrongs %d,", r, w);
        if (g)
                (void)printf(" extra guesses %d,", g);
        (void)printf(" score %d%%\n", (r + w + g) ? r * 100 / (r + w + g) : 0);
}

void
downcase(char *p)
{
        int ch;

        for (; (ch = *p) != '\0'; ++p)
                if (isascii(ch) && isupper(ch))
                        *p = tolower(ch);
}

void
usage(void)
{
        (void)fprintf(stderr,
            "usage: %s [-t] [-i file] category1 category2\n", getprogname());
        exit(1);
}