/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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 "rcv.h"
#include "extern.h"

/*
 * Mail -- a mail program
 *
 * Still more user commands.
 */

/*
 * Process a shell escape by saving signals, ignoring signals,
 * and forking a sh -c
 */
int
shell(void *str)
{
        sig_t sigint = signal(SIGINT, SIG_IGN);
        char *sh;
        char cmd[BUFSIZ];

        if (strlcpy(cmd, str, sizeof(cmd)) >= sizeof(cmd))
                return (1);
        if (bangexp(cmd, sizeof(cmd)) < 0)
                return (1);
        if ((sh = value("SHELL")) == NULL)
                sh = _PATH_CSHELL;
        (void)run_command(sh, 0, -1, -1, "-c", cmd, NULL);
        (void)signal(SIGINT, sigint);
        printf("!\n");
        return (0);
}

/*
 * Fork an interactive shell.
 */
/*ARGSUSED*/
int
dosh(void *str __unused)
{
        sig_t sigint = signal(SIGINT, SIG_IGN);
        char *sh;

        if ((sh = value("SHELL")) == NULL)
                sh = _PATH_CSHELL;
        (void)run_command(sh, 0, -1, -1, NULL);
        (void)signal(SIGINT, sigint);
        printf("\n");
        return (0);
}

/*
 * Expand the shell escape by expanding unescaped !'s into the
 * last issued command where possible.
 */
int
bangexp(char *str, size_t strsize)
{
        char bangbuf[BUFSIZ];
        static char lastbang[BUFSIZ];
        char *cp, *cp2;
        int n, changed = 0;

        cp = str;
        cp2 = bangbuf;
        n = sizeof(bangbuf);
        while (*cp != '\0') {
                if (*cp == '!') {
                        if (n < (int)strlen(lastbang)) {
overf:
                                printf("Command buffer overflow\n");
                                return (-1);
                        }
                        changed++;
                        if (strlcpy(cp2, lastbang, sizeof(bangbuf) - (cp2 - bangbuf))
                            >= sizeof(bangbuf) - (cp2 - bangbuf))
                                goto overf;
                        cp2 += strlen(lastbang);
                        n -= strlen(lastbang);
                        cp++;
                        continue;
                }
                if (*cp == '\\' && cp[1] == '!') {
                        if (--n <= 1)
                                goto overf;
                        *cp2++ = '!';
                        cp += 2;
                        changed++;
                }
                if (--n <= 1)
                        goto overf;
                *cp2++ = *cp++;
        }
        *cp2 = 0;
        if (changed) {
                printf("!%s\n", bangbuf);
                (void)fflush(stdout);
        }
        if (strlcpy(str, bangbuf, strsize) >= strsize)
                goto overf;
        if (strlcpy(lastbang, bangbuf, sizeof(lastbang)) >= sizeof(lastbang))
                goto overf;
        return (0);
}

/*
 * Print out a nice help message from some file or another.
 */

int
help(void *arg __unused)
{
        int c;
        FILE *f;

        if ((f = Fopen(_PATH_HELP, "r")) == NULL) {
                warn("%s", _PATH_HELP);
                return (1);
        }
        while ((c = getc(f)) != EOF)
                putchar(c);
        (void)Fclose(f);
        return (0);
}

/*
 * Change user's working directory.
 */
int
schdir(void *v)
{
        char **arglist = v;
        char *cp;

        if (*arglist == NULL) {
                if (homedir == NULL)
                        return (1);
                cp = homedir;
        } else
                if ((cp = expand(*arglist)) == NULL)
                        return (1);
        if (chdir(cp) < 0) {
                warn("%s", cp);
                return (1);
        }
        return (0);
}

int
respond(void *v)
{
        int *msgvec = v;

        if (value("Replyall") == NULL && value("flipr") == NULL)
                return (dorespond(msgvec));
        else
                return (doRespond(msgvec));
}

/*
 * Reply to a list of messages.  Extract each name from the
 * message header and send them off to mail1()
 */
int
dorespond(int *msgvec)
{
        struct message *mp;
        char *cp, *rcv, *replyto;
        char **ap;
        struct name *np;
        struct header head;

        if (msgvec[1] != 0) {
                printf("Sorry, can't reply to multiple messages at once\n");
                return (1);
        }
        mp = &message[msgvec[0] - 1];
        touch(mp);
        dot = mp;
        if ((rcv = skin(hfield("from", mp))) == NULL)
                rcv = skin(nameof(mp, 1));
        if ((replyto = skin(hfield("reply-to", mp))) != NULL)
                np = extract(replyto, GTO);
        else if ((cp = skin(hfield("to", mp))) != NULL)
                np = extract(cp, GTO);
        else
                np = NULL;
        np = elide(np);
        /*
         * Delete my name from the reply list,
         * and with it, all my alternate names.
         */
        np = delname(np, myname);
        if (altnames)
                for (ap = altnames; *ap != NULL; ap++)
                        np = delname(np, *ap);
        if (np != NULL && replyto == NULL)
                np = cat(np, extract(rcv, GTO));
        else if (np == NULL) {
                if (replyto != NULL)
                        printf("Empty reply-to field -- replying to author\n");
                np = extract(rcv, GTO);
        }
        head.h_to = np;
        if ((head.h_subject = hfield("subject", mp)) == NULL)
                head.h_subject = hfield("subj", mp);
        head.h_subject = reedit(head.h_subject);
        if (replyto == NULL && (cp = skin(hfield("cc", mp))) != NULL) {
                np = elide(extract(cp, GCC));
                np = delname(np, myname);
                if (altnames != 0)
                        for (ap = altnames; *ap != NULL; ap++)
                                np = delname(np, *ap);
                head.h_cc = np;
        } else
                head.h_cc = NULL;
        head.h_bcc = NULL;
        head.h_smopts = NULL;
        head.h_replyto = value("REPLYTO");
        head.h_inreplyto = skin(hfield("message-id", mp));
        mail1(&head, 1);
        return (0);
}

/*
 * Modify the message subject to begin with "Re:" if
 * it does not already.
 */
char *
reedit(char *subj)
{
        char *newsubj;

        if (subj == NULL)
                return (NULL);
        if ((subj[0] == 'r' || subj[0] == 'R') &&
            (subj[1] == 'e' || subj[1] == 'E') &&
            subj[2] == ':')
                return (subj);
        newsubj = salloc(strlen(subj) + 5);
        sprintf(newsubj, "Re: %s", subj);
        return (newsubj);
}

/*
 * Preserve the named messages, so that they will be sent
 * back to the system mailbox.
 */
int
preserve(void *v)
{
        int *msgvec = v;
        int *ip, mesg;
        struct message *mp;

        if (edit) {
                printf("Cannot \"preserve\" in edit mode\n");
                return (1);
        }
        for (ip = msgvec; *ip != 0; ip++) {
                mesg = *ip;
                mp = &message[mesg-1];
                mp->m_flag |= MPRESERVE;
                mp->m_flag &= ~MBOX;
                dot = mp;
        }
        return (0);
}

/*
 * Mark all given messages as unread.
 */
int
unread(void *v)
{
        int *msgvec = v;
        int *ip;

        for (ip = msgvec; *ip != 0; ip++) {
                dot = &message[*ip-1];
                dot->m_flag &= ~(MREAD|MTOUCH);
                dot->m_flag |= MSTATUS;
        }
        return (0);
}

/*
 * Print the size of each message.
 */
int
messize(void *v)
{
        int *msgvec = v;
        struct message *mp;
        int *ip, mesg;

        for (ip = msgvec; *ip != 0; ip++) {
                mesg = *ip;
                mp = &message[mesg-1];
                printf("%d: %ld/%ld\n", mesg, mp->m_lines, mp->m_size);
        }
        return (0);
}

/*
 * Quit quickly.  If we are sourcing, just pop the input level
 * by returning an error.
 */
int
rexit(void *v)
{
        if (sourcing)
                return (1);
        exit(0);
        /*NOTREACHED*/
}

/*
 * Set or display a variable value.  Syntax is similar to that
 * of csh.
 */
int
set(void *v)
{
        char **arglist = v;
        struct var *vp;
        char *cp, *cp2;
        char varbuf[BUFSIZ], **ap, **p;
        int errs, h, s;

        if (*arglist == NULL) {
                for (h = 0, s = 1; h < HSHSIZE; h++)
                        for (vp = variables[h]; vp != NULL; vp = vp->v_link)
                                s++;
                ap = (char **)salloc(s * sizeof(*ap));
                for (h = 0, p = ap; h < HSHSIZE; h++)
                        for (vp = variables[h]; vp != NULL; vp = vp->v_link)
                                *p++ = vp->v_name;
                *p = NULL;
                sort(ap);
                for (p = ap; *p != NULL; p++)
                        printf("%s\t%s\n", *p, value(*p));
                return (0);
        }
        errs = 0;
        for (ap = arglist; *ap != NULL; ap++) {
                cp = *ap;
                cp2 = varbuf;
                while (cp2 < varbuf + sizeof(varbuf) - 1 && *cp != '=' && *cp != '\0')
                        *cp2++ = *cp++;
                *cp2 = '\0';
                if (*cp == '\0')
                        cp = "";
                else
                        cp++;
                if (equal(varbuf, "")) {
                        printf("Non-null variable name required\n");
                        errs++;
                        continue;
                }
                assign(varbuf, cp);
        }
        return (errs);
}

/*
 * Unset a bunch of variable values.
 */
int
unset(void *v)
{
        char **arglist = v;
        struct var *vp, *vp2;
        int errs, h;
        char **ap;

        errs = 0;
        for (ap = arglist; *ap != NULL; ap++) {
                if ((vp2 = lookup(*ap)) == NULL) {
                        if (getenv(*ap)) 
                                unsetenv(*ap);
                        else if (!sourcing) {
                                printf("\"%s\": undefined variable\n", *ap);
                                errs++;
                        }
                        continue;
                }
                h = hash(*ap);
                if (vp2 == variables[h]) {
                        variables[h] = variables[h]->v_link;
                        vfree(vp2->v_name);
                        vfree(vp2->v_value);
                        (void)free(vp2);
                        continue;
                }
                for (vp = variables[h]; vp->v_link != vp2; vp = vp->v_link)
                        ;
                vp->v_link = vp2->v_link;
                vfree(vp2->v_name);
                vfree(vp2->v_value);
                (void)free(vp2);
        }
        return (errs);
}

/*
 * Put add users to a group.
 */
int
group(void *v)
{
        char **argv = v;
        struct grouphead *gh;
        struct group *gp;
        char **ap, *gname, **p;
        int h, s;

        if (*argv == NULL) {
                for (h = 0, s = 1; h < HSHSIZE; h++)
                        for (gh = groups[h]; gh != NULL; gh = gh->g_link)
                                s++;
                ap = (char **)salloc(s * sizeof(*ap));
                for (h = 0, p = ap; h < HSHSIZE; h++)
                        for (gh = groups[h]; gh != NULL; gh = gh->g_link)
                                *p++ = gh->g_name;
                *p = NULL;
                sort(ap);
                for (p = ap; *p != NULL; p++)
                        printgroup(*p);
                return (0);
        }
        if (argv[1] == NULL) {
                printgroup(*argv);
                return (0);
        }
        gname = *argv;
        h = hash(gname);
        if ((gh = findgroup(gname)) == NULL) {
                if ((gh = calloc(1, sizeof(*gh))) == NULL)
                        err(1, "Out of memory");
                gh->g_name = vcopy(gname);
                gh->g_list = NULL;
                gh->g_link = groups[h];
                groups[h] = gh;
        }

        /*
         * Insert names from the command list into the group.
         * Who cares if there are duplicates?  They get tossed
         * later anyway.
         */

        for (ap = argv+1; *ap != NULL; ap++) {
                if ((gp = calloc(1, sizeof(*gp))) == NULL)
                        err(1, "Out of memory");
                gp->ge_name = vcopy(*ap);
                gp->ge_link = gh->g_list;
                gh->g_list = gp;
        }
        return (0);
}

/*
 * Sort the passed string vecotor into ascending dictionary
 * order.
 */
void
sort(char **list)
{
        char **ap;

        for (ap = list; *ap != NULL; ap++)
                ;
        if (ap-list < 2)
                return;
        qsort(list, ap-list, sizeof(*list), diction);
}

/*
 * Do a dictionary order comparison of the arguments from
 * qsort.
 */
int
diction(const void *a, const void *b)
{
        return (strcmp(*(const char **)a, *(const char **)b));
}

/*
 * The do nothing command for comments.
 */

/*ARGSUSED*/
int
null(void *arg __unused)
{
        return (0);
}

/*
 * Change to another file.  With no argument, print information about
 * the current file.
 */
int
file(void *arg)
{
        char **argv = arg;

        if (argv[0] == NULL) {
                newfileinfo(0);
                return (0);
        }
        if (setfile(*argv) < 0)
                return (1);
        announce();
        return (0);
}

/*
 * Expand file names like echo
 */
int
echo(void *arg)
{
        char **argv = arg;
        char **ap, *cp;

        for (ap = argv; *ap != NULL; ap++) {
                cp = *ap;
                if ((cp = expand(cp)) != NULL) {
                        if (ap != argv)
                                printf(" ");
                        printf("%s", cp);
                }
        }
        printf("\n");
        return (0);
}

int
Respond(void *msgvec)
{
        if (value("Replyall") == NULL && value("flipr") == NULL)
                return (doRespond(msgvec));
        else
                return (dorespond(msgvec));
}

/*
 * Reply to a series of messages by simply mailing to the senders
 * and not messing around with the To: and Cc: lists as in normal
 * reply.
 */
int
doRespond(int msgvec[])
{
        struct header head;
        struct message *mp;
        int *ap;
        char *cp, *mid;

        head.h_to = NULL;
        for (ap = msgvec; *ap != 0; ap++) {
                mp = &message[*ap - 1];
                touch(mp);
                dot = mp;
                if ((cp = skin(hfield("from", mp))) == NULL)
                        cp = skin(nameof(mp, 2));
                head.h_to = cat(head.h_to, extract(cp, GTO));
                mid = skin(hfield("message-id", mp));
        }
        if (head.h_to == NULL)
                return (0);
        mp = &message[msgvec[0] - 1];
        if ((head.h_subject = hfield("subject", mp)) == NULL)
                head.h_subject = hfield("subj", mp);
        head.h_subject = reedit(head.h_subject);
        head.h_cc = NULL;
        head.h_bcc = NULL;
        head.h_smopts = NULL;
        head.h_replyto = value("REPLYTO");
        head.h_inreplyto = mid;
        mail1(&head, 1);
        return (0);
}

/*
 * Conditional commands.  These allow one to parameterize one's
 * .mailrc and do some things if sending, others if receiving.
 */
int
ifcmd(void *arg)
{
        char **argv = arg;
        char *cp;

        if (cond != CANY) {
                printf("Illegal nested \"if\"\n");
                return (1);
        }
        cond = CANY;
        cp = argv[0];
        switch (*cp) {
        case 'r': case 'R':
                cond = CRCV;
                break;

        case 's': case 'S':
                cond = CSEND;
                break;

        default:
                printf("Unrecognized if-keyword: \"%s\"\n", cp);
                return (1);
        }
        return (0);
}

/*
 * Implement 'else'.  This is pretty simple -- we just
 * flip over the conditional flag.
 */
int
elsecmd(void *arg __unused)
{

        switch (cond) {
        case CANY:
                printf("\"Else\" without matching \"if\"\n");
                return (1);

        case CSEND:
                cond = CRCV;
                break;

        case CRCV:
                cond = CSEND;
                break;

        default:
                printf("Mail's idea of conditions is screwed up\n");
                cond = CANY;
                break;
        }
        return (0);
}

/*
 * End of if statement.  Just set cond back to anything.
 */
int
endifcmd(void *arg __unused)
{

        if (cond == CANY) {
                printf("\"Endif\" without matching \"if\"\n");
                return (1);
        }
        cond = CANY;
        return (0);
}

/*
 * Set the list of alternate names.
 */
int
alternates(void *arg)
{
        char **namelist = arg;
        int c;
        char **ap, **ap2, *cp;

        c = argcount(namelist) + 1;
        if (c == 1) {
                if (altnames == 0)
                        return (0);
                for (ap = altnames; *ap != NULL; ap++)
                        printf("%s ", *ap);
                printf("\n");
                return (0);
        }
        if (altnames != 0)
                (void)free(altnames);
        if ((altnames = calloc((unsigned)c, sizeof(char *))) == NULL)
                err(1, "Out of memory");
        for (ap = namelist, ap2 = altnames; *ap != NULL; ap++, ap2++) {
                cp = calloc((unsigned)strlen(*ap) + 1, sizeof(char));
                strcpy(cp, *ap);
                *ap2 = cp;
        }
        *ap2 = 0;
        return (0);
}