path: root/c/irc.c

#include "resolve.h"
/* irc HOST [NICK] - a bitchx/irssi-flavored IRC client on 40x18 columns.
   The kernel owns TCP; this owns the protocol and the screen.

   UI: messages scroll above; the bottom line is an irssi-style input line
   "[#chan] text_" redrawn in place with \r (the terminal has no cursor
   addressing - \r + overprint is the entire trick). Long input scrolls
   horizontally like irssi. Keys come from the OSK (SELECT toggles it) and
   from the console ring (pollcon), so a hub can type into the client too.

   Formats, straight from the elders:
     <nick> text        channel message      * nick text   CTCP ACTION
     <nick:#c> text     msg to a non-current channel
     *nick* text        private msg          >target< text  outbound /msg
     -nick- text        notice               -!- text       server/status  */

/* seg first + large: the arg string lives at 0xA000 and the first static
   lands on it; args are copied out in main() before seg is ever written. */
static unsigned char seg[220];      /* one TCP segment from the kernel   */
static char line[240];              /* server line accumulator           */
static unsigned char llen;
static char input[140];             /* the input line being typed        */
static unsigned char inlen;
static unsigned char drawn;         /* chars currently drawn on input row */
static char nick[16];
static char target[32];             /* current channel/query, "" = none  */
static char sbuf[200];              /* outgoing IRC line builder         */
static unsigned char slen;
static unsigned char namebuf[64];
static unsigned char dst[4];
static unsigned char sock;
static unsigned char quitting;
/* A WRITABLE empty string for parse defaults. handle() writes terminators
   into pfx (bang) and txt (strip_fmt); a read-only "" literal lives in ROM
   ($4000-$5FFF), where a write is an MBC5 *RAM-bank-select* - it would swap
   the whole $A000 data bank out from under every static (instant garbage).
   A prefix-less or empty-trailing server line is enough to trigger it. */
static char empty[1];

/* ---- tiny string helpers (SDCC libc is us) ------------------------------- */
static unsigned char sceq(const char *a, const char *b) {   /* case-insens. */
    unsigned char ca, cb;
    for (;;) {
        ca = (unsigned char)*a++; cb = (unsigned char)*b++;
        if (ca >= 'a' && ca <= 'z') ca -= 32;
        if (cb >= 'a' && cb <= 'z') cb -= 32;
        if (ca != cb) return 0;
        if (!ca) return 1;
    }
}
static void scpy(char *d, const char *s, unsigned char max) {
    unsigned char i;
    for (i = 0; s[i] && i < (unsigned char)(max - 1); i++) d[i] = s[i];
    d[i] = 0;
}

/* ---- outgoing IRC lines --------------------------------------------------- */
static void sc(const char *s) {           /* append to sbuf */
    while (*s && slen < 197) sbuf[slen++] = *s++;
}
static void sfin(void) {                  /* CRLF + send */
    sbuf[slen++] = '\r'; sbuf[slen++] = '\n';
    net_send(sock, sbuf, slen);
    slen = 0;
}

/* ---- the input line ------------------------------------------------------- */
/* erase what's drawn on the bottom row, park at col 0 */
static void row_clear(void) {
    unsigned char i;
    putc('\r');
    for (i = 0; i < drawn; i++) putc(' ');
    putc('\r');
    drawn = 0;
}
/* redraw "[target] tail-of-input_"; keep total < 40 so it never wraps */
static void row_draw(void) {
    unsigned char pl, vis, i;
    const char *t = target[0] ? target : "(status)";
    row_clear();
    putc('[');
    for (pl = 0; t[pl] && pl < 12; pl++) putc(t[pl]);
    putc(']'); putc(' ');
    pl += 3;                              /* prompt width */
    vis = 39 - pl - 1;                    /* room for text (cursor gets 1) */
    i = (inlen > vis) ? (unsigned char)(inlen - vis) : 0;
    for (; i < inlen; i++) putc(input[i]);
    drawn = pl + ((inlen > vis) ? vis : inlen);
}
/* print a message line above the input line */
static void say(const char *s) {
    row_clear();
    puts(s); nl();
    row_draw();
}
static void say2(const char *a, const char *b) {
    row_clear();
    puts(a); puts(b); nl();
    row_draw();
}
static void say3(const char *a, const char *b, const char *c) {
    row_clear();
    puts(a); puts(b); puts(c); nl();
    row_draw();
}

/* ---- server line parsing -------------------------------------------------- */
/* split "pfx!user@host" -> pfx nick only (in place) */
static void bang(char *p) {
    while (*p && *p != '!') p++;
    *p = 0;
}
static unsigned char isnum(const char *c) {
    return c[0] >= '0' && c[0] <= '9';
}
static unsigned char ishex(char c) {
    return (c>='0'&&c<='9')||(c>='a'&&c<='f')||(c>='A'&&c<='F');
}

/* Strip mIRC/IRC formatting in place - crucially their *arguments*, or a
   color logo (a real MOTD!) leaves its \x03 color numbers on screen as digit
   soup. \x03 = color (up to 2 digits[,up to 2 digits]); \x04 = hex color
   (up to 6 hex[,6 hex]); \x02 bold \x0f reset \x11 mono \x16 reverse
   \x1d italic \x1e strike \x1f underline are lone toggles. Leaves \x01
   (CTCP) intact for the PRIVMSG path. */
static void strip_fmt(char *s) {
    char *w = s, *r = s;
    unsigned char c, d;
    while (*r) {
        c = (unsigned char)*r;
        if (c == 3) {
            r++; d = 0;
            while (*r>='0'&&*r<='9'&&d<2) { r++; d++; }
            if (*r==','&&r[1]>='0'&&r[1]<='9') { r++; d=0; while(*r>='0'&&*r<='9'&&d<2){r++;d++;} }
            continue;
        }
        if (c == 4) {
            r++; d = 0;
            while (ishex(*r)&&d<6) { r++; d++; }
            if (*r==','&&ishex(r[1])) { r++; d=0; while(ishex(*r)&&d<6){r++;d++;} }
            continue;
        }
        if (c==2||c==15||c==17||c==22||c==29||c==30||c==31) { r++; continue; }
        *w++ = *r++;
    }
    *w = 0;
}

static void handle(char *l) {
    char *pfx = empty, *cmd, *arg, *txt = empty;
    char *p = l;

    if (*p == ':') {                       /* :prefix */
        pfx = ++p;
        while (*p && *p != ' ') p++;
        if (*p) *p++ = 0;
    }
    cmd = p;                               /* command */
    while (*p && *p != ' ') p++;
    if (*p) *p++ = 0;
    arg = p;                               /* params, then :trailing */
    while (*p) {
        if (*p == ':' && (p == arg || p[-1] == 0)) { txt = p + 1; p[-1] = 0; break; }
        if (*p == ' ') *p = 0;
        p++;
    }
    /* arg = first param (NUL-joined list), txt = trailing */
    strip_fmt(txt);                        /* kill color/format codes + args */

    if (sceq(cmd, "PING")) {
        slen = 0; sc("PONG :"); sc(txt[0] ? txt : arg); sfin();
        say("-!- Ping? Pong!");
        return;
    }
    bang(pfx);
    if (sceq(cmd, "PRIVMSG")) {
        char *dest = arg;
        unsigned char act = 0;
        if (txt[0] == 1) {                 /* CTCP */
            char *e = txt + 1;
            while (*e && *e != 1) e++;
            *e = 0; txt++;
            if (txt[0]=='A'&&txt[1]=='C'&&txt[2]=='T'&&txt[3]=='I'&&txt[4]=='O'&&txt[5]=='N'&&txt[6]==' ') {
                act = 1; txt += 7;
            } else if (txt[0]=='V') {      /* VERSION */
                slen = 0; sc("NOTICE "); sc(pfx); sc(" :\001VERSION gbos:sl0pboy:GameBoyColor\001"); sfin();
                return;
            } else return;
        }
        row_clear();
        if (act)                { puts("* "); puts(pfx); putc(' '); }
        else if (sceq(dest, nick)) { putc('*'); puts(pfx); puts("* "); }
        else if (sceq(dest, target)) { putc('<'); puts(pfx); puts("> "); }
        else                    { putc('<'); puts(pfx); putc(':'); puts(dest); puts("> "); }
        puts(txt); nl();
        row_draw();
        return;
    }
    if (sceq(cmd, "NOTICE")) {
        row_clear();
        putc('-'); puts(pfx[0] ? pfx : "server"); puts("- "); puts(txt); nl();
        row_draw();
        return;
    }
    if (sceq(cmd, "JOIN")) {
        char *ch = txt[0] ? txt : arg;
        if (sceq(pfx, nick)) {
            scpy(target, ch, sizeof(target));
            say2("-!- now talking in ", target);
        } else say3("-!- ", pfx, " has joined");
        return;
    }
    if (sceq(cmd, "PART")) {
        if (sceq(pfx, nick)) { target[0] = 0; say("-!- you left"); }
        else say3("-!- ", pfx, " has left");
        return;
    }
    if (sceq(cmd, "QUIT")) { say3("-!- ", pfx, " has quit"); return; }
    if (sceq(cmd, "KICK")) {
        char *ch = arg, *who = arg;
        while (*who) who++;
        who++;                              /* param 2: the victim */
        if (sceq(who, nick)) { target[0] = 0; say2("-!- you were kicked from ", ch); }
        else say3("-!- ", who, " was kicked");
        return;
    }
    if (sceq(cmd, "NICK")) {
        char *nn = txt[0] ? txt : arg;
        if (sceq(pfx, nick)) scpy(nick, nn, sizeof(nick));
        row_clear();
        puts("-!- "); puts(pfx); puts(" is now known as "); puts(nn); nl();
        row_draw();
        return;
    }
    if (isnum(cmd)) {
        if (cmd[0]=='4'&&cmd[1]=='3'&&cmd[2]=='3') {   /* nick in use */
            unsigned char n = strlen(nick);
            if (n < 14) { nick[n] = '_'; nick[n+1] = 0; }
            slen = 0; sc("NICK "); sc(nick); sfin();
            say2("-!- nick in use, trying ", nick);
            return;
        }
        if (cmd[0]=='3'&&cmd[1]=='3'&&cmd[2]=='2') {   /* topic */
            say2("-!- topic: ", txt);
            return;
        }
        if (cmd[0]=='3'&&cmd[1]=='5'&&cmd[2]=='3') {   /* names */
            say2("-!- users: ", txt);
            return;
        }
        if (cmd[1]=='3'&&cmd[0]=='3') return;          /* 333 topic-by: skip */
        if (cmd[0]=='0'&&cmd[1]=='0'&&(cmd[2]=='4'||cmd[2]=='5')) return; /* MYINFO/ISUPPORT noise */
        if (txt[0]) say2("-!- ", txt);                 /* motd & friends */
        return;
    }
    /* anything else: show it raw-ish, bitchx would too */
    if (txt[0]) say3(cmd, " ", txt);
}

/* accumulate TCP bytes into lines */
static void feed(unsigned char *b, unsigned char n) {
    unsigned char i;
    for (i = 0; i < n; i++) {
        char c = (char)b[i];
        if (c == '\r') continue;
        if (c == '\n') { line[llen] = 0; if (llen) handle(line); llen = 0; }
        else if (llen < 239) line[llen++] = c;
    }
}

/* ---- typed input ---------------------------------------------------------- */
static void run_cmd(char *t) {
    char *a = t;
    while (*a && *a != ' ') a++;
    if (*a) *a++ = 0;                      /* t = /cmd, a = rest */

    if (sceq(t, "/join") || sceq(t, "/j")) {
        if (!*a) { say("-!- join what?"); return; }
        slen = 0; sc("JOIN "); sc(a); sfin();
        return;
    }
    if (sceq(t, "/part") || sceq(t, "/p")) {
        slen = 0; sc("PART "); sc(*a ? a : target); sfin();
        return;
    }
    if (sceq(t, "/msg")) {
        char *m = a;
        while (*m && *m != ' ') m++;
        if (*m) *m++ = 0;
        if (!*a || !*m) { say("-!- /msg nick text"); return; }
        slen = 0; sc("PRIVMSG "); sc(a); sc(" :"); sc(m); sfin();
        row_clear();
        putc('>'); puts(a); puts("< "); puts(m); nl();
        row_draw();
        return;
    }
    if (sceq(t, "/me")) {
        if (!target[0]) { say("-!- no channel"); return; }
        slen = 0; sc("PRIVMSG "); sc(target); sc(" :\001ACTION "); sc(a); sc("\001"); sfin();
        row_clear();
        puts("* "); puts(nick); putc(' '); puts(a); nl();
        row_draw();
        return;
    }
    if (sceq(t, "/nick")) {
        if (!*a) { say("-!- /nick newnick"); return; }
        slen = 0; sc("NICK "); sc(a); sfin();
        return;
    }
    if (sceq(t, "/quit")) {
        slen = 0; sc("QUIT :"); sc(*a ? a : "sl0pboy out"); sfin();
        quitting = 1;
        return;
    }
    if (sceq(t, "/raw") || sceq(t, "/quote")) {
        slen = 0; sc(a); sfin();
        return;
    }
    say("-!- commands: /join /part /msg /me /nick /quit /raw");
}

static void submit(void) {
    input[inlen] = 0;
    if (!inlen) return;
    if (input[0] == '/') {
        inlen = 0;
        run_cmd(input);
        row_draw();
        return;
    }
    if (!target[0]) { inlen = 0; say("-!- join a channel first (/join #gb)"); return; }
    slen = 0; sc("PRIVMSG "); sc(target); sc(" :"); sc(input); sfin();
    row_clear();
    putc('<'); puts(nick); puts("> "); puts(input); nl();
    inlen = 0;
    row_draw();
}

static void key(unsigned char c) {
    if (c == '\n' || c == '\r') { submit(); return; }
    if (c == 8 || c == 127) {
        if (inlen) { inlen--; row_draw(); }
        return;
    }
    if (c < 32) return;
    if (inlen < 139) { input[inlen++] = (char)c; row_draw(); }
}

/* ---- main ----------------------------------------------------------------- */
void main(void) {
    char *argp;
    unsigned char i, n, idle;

    /* gbos does not zero C statics (crt0 zeroes nothing; fork inherits the
       parent's RAM bank) - initialize every piece of state explicitly */
    llen = inlen = drawn = slen = quitting = 0;
    target[0] = 0;
    empty[0] = 0;                          /* gbos doesn't zero BSS */

    argp = getargs();                      /* copy args before seg is used */
    for (i = 0; argp[i] && i < 63; i++) namebuf[i] = (unsigned char)argp[i];
    namebuf[i] = 0;

    /* split "HOST [NICK]" */
    scpy(nick, "sl0pboy", sizeof(nick));
    for (i = 0; namebuf[i]; i++)
        if (namebuf[i] == ' ') {
            namebuf[i] = 0;
            if (namebuf[i+1]) scpy(nick, (char *)namebuf + i + 1, sizeof(nick));
            break;
        }
    if (!namebuf[0]) {
        puts("usage: irc HOST [NICK]     (port 6667)"); nl();
        puts("  then: /join #chan, SELECT = keyboard"); nl();
        sexit(1);
    }

    if (!resolve((char *)namebuf, dst)) {
        puts("irc: cannot resolve "); puts((char *)namebuf); nl(); sexit(1);
    }

    sock = net_socket(SOCK_TCP);
    if (sock == 0xFF) { puts("irc: no socket"); nl(); sexit(1); }
    /* vary the local port per run (DIV timer noise): a fixed port can hit a
       stale half-dead connection at the server after an unclean exit */
    net_bind(sock, 41000 + ((unsigned int)*(volatile unsigned char *)0xFF04 << 2) + getpid());
    puts("-!- connecting to "); puts((char *)namebuf); puts(":6667"); nl();
    if (net_connect(sock, dst, 6667) == 0xFF) {
        puts("irc: connect failed"); nl(); net_close(sock); sexit(1);
    }

    slen = 0; sc("NICK "); sc(nick); sfin();
    slen = 0; sc("USER gbos 0 * :sl0pboy on gbos"); sfin();
    puts("-!- registering as "); puts(nick);
    puts(" (SELECT = keyboard)"); nl();
    row_draw();

    idle = 0;
    for (;;) {
        n = net_recv_nb(sock, seg, (unsigned char)sizeof(seg));
        if (n == 0) { say("-!- disconnected"); break; }
        if (n != 0xFE && n != 0xFF) feed(seg, n);   /* render a segment if any */
        if (quitting) { say("-!- quit"); break; }

        /* Poll input EVERY pass, even mid-flood: otherwise a big MOTD (or a
         * busy channel) starves the keyboard for its whole duration - the OSK
         * won't even open, and keystrokes are dropped. That's what made
         * '/join #sl0p right after connect' look broken. */
        i = pollin();                      /* OSK */
        if (!i) i = pollcon();             /* hub-injected console bytes */
        if (i) key(i);

        if (n == 0xFE || n == 0xFF) {      /* nothing received this pass */
            if (!i && ++idle >= 4) { msleep(20); idle = 4; }
        } else {
            idle = 0;                      /* actively receiving; don't sleep */
        }
    }
    net_close(sock);
    row_clear();
    sexit(0);
}