/*
 * wmh.c -- window front-end to nmh
 *
 * $Id$
 *
 * This code is Copyright (c) 2002, by the authors of nmh.  See the
 * COPYRIGHT file in the root directory of the nmh distribution for
 * complete copyright information.
 */

/*
 * TODO:
 * Pass signals to client during execution
 *
 * Figure out a way for the user to say how big the Scan/Display
 * windows should be, and where all the windows should be.
 */

#include <h/mh.h>
#include <h/signals.h>
#include <h/vmhsbr.h>
#include <errno.h>
#include <setjmp.h>
#include <signal.h>

#include <sys/uio.h>
#include <vt.h>
#include <bitmap.h>
#include <tools.h>

#define	ALARM ((unsigned int) 10)
#define	PAUSE ((unsigned int) 2)

#define	SZ(a) (sizeof a / sizeof a[0])

static struct swit switches[] = {
#define	PRMPTSW            0
    { "prompt string", 6 },
#define	PROGSW             1
    { "vmhproc program", 7 },
#define	NPROGSW            2
    { "novmhproc", 9 },
#define VERSIONSW          3
    { "version", 0 },
#define	HELPSW             4
    { "help", 0 },
    { NULL, NULL }
};
					/* PEERS */
static int PEERpid = NOTOK;

static jmp_buf PEERctx;


					/* WINDOWS */
static int dfd = NOTOK;
static int twd = NOTOK;
static char *myprompt = "(%s) ";

struct line {
    int l_no;
    char *l_buf;
    struct line *l_prev;
    struct line *l_next;
};

#define	W_NULL	0x00
#define	W_CMND	0x01
#define	W_FAKE	0x02
#define	W_EBAR	0x04

typedef struct {
    int	w_fd;
    int	w_flags;
    int	w_wd;
    struct wstate w_ws;
    char *w_eb;
    int	w_ebloc;
    int	w_ebsize;
    int	w_cbase;
    int	w_height;
    int	w_cheight;
    int	w_width;
    int	w_cwidth;
    struct line *w_head;
    struct line *w_top;
    struct line *w_bottom;
    struct line *w_tail;
    char w_buffer[BUFSIZ];
    int	w_bufpos;
} WINDOW;


static WINDOW *Scan;
static WINDOW *Status;
static WINDOW *Display;
static WINDOW *Command;

#define	NWIN 4
static int numwins;
WINDOW *windows[NWIN + 1];

WINDOW *WINnew ();


#ifdef HAVE_TERMIOS_H
static struct termios tio;
# define ERASE tio.c_cc[VERASE]
# define KILL  tio.c_cc[VKILL]
# define INTR  tio.c_cc[VINTR]
#else
# ifdef HAVE_TERMIO_H
static struct termio tio;
#  define ERASE tio.c_cc[VERASE]
#  define KILL  tio.c_cc[VKILL]
#  define INTR  tio.c_cc[VINTR]
# else
static struct sgttyb tio;
static struct tchars tc;
#  define ERASE tio.sg_erase
#  define KILL  tio.sg_kill
#  define INTR  tc.t_intrc
#  define EOFC  tc.t_eofc
# endif
#endif

#define	WERASC ltc.t_werasc
static struct ltchars ltc;

extern int errno;

int ALRMser (), PIPEser (), SIGser ();
int ADJser (), REFser ();

/*
 * static prototypes
 */
static void adorn(char *, char *, ...);


int
main (int argc, char **argv)
{
    int vecp = 1, nprog = 0;
    char *cp, buffer[BUFSIZ], **argp;
    char **arguments, *vec[MAXARGS];

#ifdef LOCALE
    setlocale(LC_ALL, "");
#endif
    invo_name = r1bindex (argv[0], '/');

    /* read user profile/context */
    context_read();

    arguments = getarguments (invo_name, argc,argv, 1);
    argp = arguments;

    while ((cp = *argp++))
	if (*cp == '-')
	    switch (smatch (++cp, switches)) {
		case AMBIGSW: 
		    ambigsw (cp, switches);
		    done (1);
		case UNKWNSW: 
		    vec[vecp++] = --cp;
		    continue;

		case HELPSW: 
		    snprintf (buffer, sizeof(buffer), "%s [switches for vmhproc]",
			invo_name);
		    print_help (buffer, switches, 1);
		    done (1);
		case VERSIONSW:
		    print_version(invo_name);
		    done (1);

		case PRMPTSW:
		    if (!(myprompt = *argp++) || *myprompt == '-')
			adios (NULL, "missing argument to %s", argp[-2]);
		    continue;

		case PROGSW: 
		    if (!(vmhproc = *argp++) || *vmhproc == '-')
			adios (NULL, "missing argument to %s", argp[-2]);
		    continue;
		case NPROGSW:
		    nprog++;
		    continue;
	    }
	else
	    vec[vecp++] = cp;

    SIGinit ();
    if (WINinit (nprog) == NOTOK) {
	vec[vecp] = NULL;

	vec[0] = r1bindex (vmhproc, '/');
	execvp (vmhproc, vec);
	adios (vmhproc, "unable to exec");
    }
    PEERinit (vecp, vec);

    vmh ();

    return done (0);
}


static void
vmh (void)
{
    char buffer[BUFSIZ], prompt[BUFSIZ];

    for (;;) {
	pLOOP (RC_QRY, NULL);

	snprintf (prompt, sizeof(prompt), myprompt, invo_name);

	switch (WINgetstr (Command, prompt, buffer)) {
	    case NOTOK: 
		break;

	    case OK: 
		done (0);	/* NOTREACHED */

	    default: 
		if (*buffer)
		    pLOOP (RC_CMD, buffer);
		break;
	}
    }
}

/* PEERS */

static int
PEERinit (int vecp, char *vec[])
{
    int	pfd0[2], pfd1[2];
    char buf1[BUFSIZ], buf2[BUFSIZ];
    register WINDOW **w;

    SIGNAL (SIGPIPE, PIPEser);

    if (pipe (pfd0) == NOTOK || pipe (pfd1) == NOTOK)
	adios ("pipe", "unable to");
    switch (PEERpid = vfork ()) {
	case NOTOK: 
	    adios ("vfork", "unable to");/* NOTREACHED */

	case OK: 
	    for (w = windows; *w; w++)
		if ((*w)->w_fd != NOTOK)
		    close ((*w)->w_fd);
	    close (pfd0[0]);
	    close (pfd1[1]);

	    vec[vecp++] = "-vmhread";
	    snprintf (buf1, sizeof(buf1), "%d", pfd1[0]);
	    vec[vecp++] = buf1;
	    vec[vecp++] = "-vmhwrite";
	    snprintf (buf2, sizeof(buf2), "%d", pfd0[1]);
	    vec[vecp++] = buf2;
	    vec[vecp] = NULL;

	    SIGNAL (SIGINT, SIG_DFL);
	    SIGNAL (SIGQUIT, SIG_DFL);
	    SIGNAL (SIGTERM, SIG_DFL);

	    vec[0] = r1bindex (vmhproc, '/');
	    execvp (vmhproc, vec);
	    perror (vmhproc);
	    _exit (-1);		/* NOTREACHED */

	default: 
	    close (pfd0[1]);
	    close (pfd1[0]);

	    rcinit (pfd0[0], pfd1[1]);
	    return pINI ();
    }
}


static int
pINI (void)
{
    int len, buflen;
    char *bp, buffer[BUFSIZ];
    struct record rcs, *rc;
    WINDOW **w;

    rc = &rcs;
    initrc (rc);

    /* Get buffer ready to go */
    bp = buffer;
    buflen = sizeof(buffer);

    snprintf (bp, buflen, "%d %d", RC_VRSN, numwins);
    len = strlen (bp);
    bp += len;
    buflen -= len;

    for (w = windows; *w; w++) {
	snprintf (bp, buflen, " %d", (*w)->w_height);
	len = strlen (bp);
	bp += len;
	buflen -= len;
    }

    switch (str2rc (RC_INI, buffer, rc)) {
	case RC_ACK: 
	    return OK;

	case RC_ERR: 
	    if (rc->rc_len)
		adios (NULL, "%s", rc->rc_data);
	    else
		adios (NULL, "pINI peer error");

	case RC_XXX: 
	    adios (NULL, "%s", rc->rc_data);

	default:
	    adios (NULL, "pINI protocol screw-up");
    }
/* NOTREACHED */
}


static int
pLOOP (char code, char *str)
{
    int	i;
    struct record rcs, *rc;
    WINDOW *w;

    rc = &rcs;
    initrc (rc);

    str2peer (code, str);
    for (;;)
	switch (peer2rc (rc)) {
	    case RC_TTY:
		if (pTTY () == NOTOK)
		    return NOTOK;
		break;

	    case RC_WIN:
		if (sscanf (rc->rc_data, "%d", &i) != 1
			|| i <= 0
			|| i > numwins) {
		    fmt2peer (RC_ERR, "no such window \"%s\"", rc->rc_data);
		    return NOTOK;
		}
		if ((w = windows[i - 1])->w_flags & W_CMND) {
		    fmt2peer (RC_ERR, "not a display window \"%s\"", rc->rc_data);
		    return NOTOK;
		}
		if (pWIN (w) == NOTOK)
		    return NOTOK;
		break;

	    case RC_EOF:
		return OK;

	    case RC_ERR:
		if (rc->rc_len)
		    adorn (NULL, "%s", rc->rc_data);
		else
		    adorn (NULL, "pLOOP(%s) peer error",
			    code == RC_QRY ? "QRY" : "CMD");
		return NOTOK;

	    case RC_FIN:
		if (rc->rc_len)
		    adorn (NULL, "%s", rc->rc_data);
		rcdone ();
		i = pidwait (PEERpid, OK);
		PEERpid = NOTOK;
		done (i);

	    case RC_XXX: 
		adios (NULL, "%s", rc->rc_data);

	    default:
		adios (NULL, "pLOOP(%s) protocol screw-up",
			code == RC_QRY ? "QRY" : "CMD");
	}
}


static int
pTTY (void)
{
    SIGNAL_HANDLER hstat, istat, qstat, tstat;
    struct record rcs, *rc;

    rc = &rcs;
    initrc (rc);

    if (ChangeWindowDepth (dfd, twd, 0) == NOTOK)
	adios ("failed", "ChangeWindowDepth");

    /* should block here instead of ignore */
    hstat = SIGNAL (SIGHUP, SIG_IGN);
    istat = SIGNAL (SIGINT, SIG_IGN);
    qstat = SIGNAL (SIGQUIT, SIG_IGN);
    tstat = SIGNAL (SIGTERM, SIG_IGN);

    rc2rc (RC_ACK, 0, NULL, rc);

    SIGNAL (SIGHUP, hstat);
    SIGNAL (SIGINT, istat);
    SIGNAL (SIGQUIT, qstat);
    SIGNAL (SIGTERM, tstat);

    switch (rc->rc_type) {
	case RC_EOF: 
	    rc2peer (RC_ACK, 0, NULL);
	    return OK;

	case RC_ERR: 
	    if (rc->rc_len)
		adorn (NULL, "%s", rc->rc_data);
	    else
		adorn (NULL, "pTTY peer error");
	    return NOTOK;

	case RC_XXX: 
	    adios (NULL, "%s", rc->rc_data);

	default:
	    adios (NULL, "pTTY protocol screw-up");
    }
/* NOTREACHED */
}


static int
pWIN (WINDOW *w)
{
    int i;

    if ((i = pWINaux (w)) == OK)
	WINless (w);

    return i;
}


static int
pWINaux (WINDOW *w)
{
    register int n;
    register char *bp;
    register struct line *lp, *mp;
    struct record rcs, *rc;

    rc = &rcs;
    initrc (rc);

    for (lp = w->w_head; lp; lp = mp) {
	mp = lp->l_next;
	free (lp->l_buf);
	free ((char *) lp);
    }
    w->w_head = w->w_top = w->w_bottom = w->w_tail = NULL;
    w->w_bufpos = 0;

    for (;;)
	switch (rc2rc (RC_ACK, 0, NULL, rc)) {
	    case RC_DATA: 
		for (bp = rc->rc_data, n = rc->rc_len; n-- > 0; )
		    WINputc (w, *bp++);
		break;

	    case RC_EOF: 
		rc2peer (RC_ACK, 0, NULL);
		if (w->w_bufpos)
		    WINputc (w, '\n');
		return OK;

	    case RC_ERR: 
		if (rc->rc_len)
		    adorn (NULL, "%s", rc->rc_data);
		else
		    adorn (NULL, "pWIN peer error");
		return NOTOK;

	    case RC_XXX: 
		adios (NULL, "%s", rc->rc_data);

	    default:
		adios (NULL, "pWIN protocol screw-up");
	}
/* NOTREACHED */
}


static int
pFIN (void)
{
    int status;

    if (PEERpid <= OK)
	return OK;

    rc2peer (RC_FIN, 0, NULL);
    rcdone ();

    switch (setjmp (PEERctx)) {
	case OK: 
	    SIGNAL (SIGALRM, ALRMser);
	    alarm (ALARM);

	    status = pidwait (PEERpid, OK);

	    alarm (0);
	    break;

	default: 
	    kill (PEERpid, SIGKILL);
	    status = NOTOK;
	    break;
    }
    PEERpid = NOTOK;

    return status;
}

/* WINDOWS */

/* should dynamically determine all this stuff from gconfig... */

#define	MyX	20		/* anchored hpos */
#define	MyY	40		/*   .. vpos */
#define	MyW	800		/*   .. width */
#define	MyH	500		/*   .. height */
#define	MyS	30		/*   .. height for Status, about one line */


#define	MySlop	45		/* slop */

#define	EWIDTH	25		/* Width of vertical EBAR */
#define	ESLOP	5		/*   .. slop */


static intWINinit (nprog) {
    short wx, wy, wh, sy;
    struct gconfig gc;

    if (GetGraphicsConfig (fileno (stderr), &gc) == NOTOK)
	if (nprog)
	    return NOTOK;
	else
	    adios (NULL, "not a window");

    if ((dfd = open ("/dev/ttyw0", O_RDWR)) == NOTOK)
	adios ("/dev/ttyw0", "unable to open");

    if ((twd = GetTopWindow (dfd)) == NOTOK)
	adios ("failed", "GetTopWindow");

    BlockRefreshAdjust (1);

    numwins = 0;

    wx = gc.w - (MyX + MyW + EWIDTH + ESLOP);
    Scan = WINnew (wx, wy = MyY, MyW, wh = MyH * 2 / 3, "Scan", W_EBAR);

    wy += wh + MySlop;
    Status = WINnew (wx, sy = wy, MyW, wh = MyS, "Status", W_FAKE);

    wy += wh + MySlop;
    Display = WINnew (wx, wy, MyW, MyH, "Display", W_EBAR);

    Command = WINnew (wx, sy, MyW, MyS, invo_name, W_CMND);

    windows[numwins] = NULL;

    return OK;
}


WINDOW *
WINnew (short wx, short wy, short ww, short wh, char *name, int flags)
{
    register WINDOW *w;

    if ((w = (WINDOW *) calloc (1, sizeof *w)) == NULL)
	adios (NULL, "unable to allocate window");

    if ((w->w_flags = flags) & W_FAKE) {
	w->w_fd = NOTOK;
	w->w_height = 1;

	goto out;
    }

    if (w->w_flags & W_EBAR)
	ww += EWIDTH + ESLOP;
    else
	wx += EWIDTH + ESLOP;

    if ((w->w_fd = OpenWindow (wx, wy, ww, wh, name)) == NOTOK)
	adios ("failed", "OpenWindow");
    if ((w->w_wd = GetTopWindow (dfd)) == NOTOK)
	adios ("failed", "GetTopWindow");
    if (GetWindowState (w->w_fd, &w->w_ws) == NOTOK)
	adios ("failed", "GetWindowState");
    if (SetLineDisc (w->w_fd, TWSDISC) == NOTOK)
	adios ("failed", "SetLineDisc");

    SetBuf (w->w_fd, 1024);
    SetAdjust (w->w_fd, numwins, ADJser);
    SetRefresh (w->w_fd, numwins, REFser);

    SetAddressing (w->w_fd, VT_ABSOLUTE);

    if (w->w_flags & W_EBAR) {
	w->w_eb = CreateElevatorBar (w->w_fd, 0, 0, EWIDTH,
			w->w_ws.height, VT_Gray50, 1, EB_VERTICAL,
			EB_ARROWS, w->w_ebloc = 0, w->w_ebsize = EB_MAX,
			VT_White);
	if (w->w_eb == NULL)
	    adios (NULL, "CreateElevatorBar failed");
	RefreshElevatorBar (w->w_eb);
    }

    if ((w->w_cbase = CharacterBaseline (w->w_ws.font)) <= 0)
	w->w_cbase = 14;

    if ((w->w_cheight = CharacterHeight (w->w_ws.font)) <= 0)
	w->w_cheight = 20;
    w->w_height = w->w_ws.height / w->w_cheight;
    if (w->w_height < 1)
	w->w_height = 1;

						/* 1 em */
    if ((w->w_cwidth = CharacterWidth (w->w_ws.font, 'm')) <= 0)
	w->w_cwidth = 10;
    w->w_width = (w->w_ws.width - (w->w_eb ? (EWIDTH + ESLOP) : 0))
		    / w->w_cwidth;
    if (w->w_width < 1)
	w->w_width = 1;

out: ;
    windows[numwins++] = w;

    return w;
}


static int
WINgetstr (WINDOW *w, char *prompt, char *buffer)
{
    register int c;
    register char *bp, *ip;
    char image[BUFSIZ];
    struct vtseq vts;
    register struct vtseq  *vt = &vts;

    if (w->w_eb != NULL)
	adios (NULL, "internal error--elevator bar found");

    if (w->w_head == NULL
	    && (w->w_head = (struct line *) calloc (1, sizeof *w->w_head))
		== NULL)
	adios (NULL, "unable to allocate line storage");
    w->w_head->l_buf = image;
    w->w_top = w->w_bottom = w->w_tail = w->w_head;

    if (ChangeWindowDepth (dfd, w->w_wd, 0) == NOTOK)
	adios ("failed", "ChangeWindowDepth");

    strncpy (image, prompt, sizeof(image));
    bp = ip = image + strlen (image);

    Redisplay (w, 0);

    for (;;)
	switch (getvtseq (w->w_fd, vt)) {
	    case VT_HARDKEY: 
		DisplayStatus (w->w_fd, "no hardkeys, please");
		break;

	    case VT_ASCII: 
		switch (c = toascii (vt->u.ascii)) {
		    case '\f': 	/* refresh? */
			break;

		    case '\r': 
		    case '\n': 
			strcpy (buffer, ip);
			return DONE;

		    default: 
			if (c == INTR) {
			    adorn (NULL, "Interrupt");
			    return NOTOK;
			}

			if (c == EOFC) {
			    if (bp <= ip)
				return OK;
			    break;
			}

			if (c == ERASE) {
			    if (bp <= ip)
				continue;
			    bp--;
			    break;
			}

			if (c == KILL) {
			    if (bp <= ip)
				continue;
			    bp = ip;
			    break;
			}

			if (c == WERASC) {
			    if (bp <= ip)
				continue;
			    do {
				bp--;
			    } while (isspace (*bp) && bp > ip);
			    if (bp > ip) {
				do {
				    bp--;
				} while (!isspace (*bp) && bp > buffer);
				if (isspace (*bp))
				    bp++;
			    }
			    break;
			}

			if (c < ' ' || c >= '\177')
			    continue;
			*bp++ = c;
			break;
		}
		*bp = NULL;
		Redisplay (w, 0);
		break;

	    case VT_MOUSE: 
		switch (vt->u.mouse.buttons
			& (VT_MOUSE_LEFT | VT_MOUSE_MIDDLE | VT_MOUSE_RIGHT)) {
		    case VT_MOUSE_LEFT: 
			DisplayStatus (w->w_fd, "use middle or right button");
			break;

#define	WPOP	"WMH\0Advance\0Burst\0Exit\0EOF\0"
		    case VT_MOUSE_MIDDLE: 
			SetPosition (w->w_fd, vt->u.mouse.x,
				vt->u.mouse.y);
			switch (DisplayPopUp (w->w_fd, WPOP)) {
			    case 1: /* Advance */
			do_advance: ;
				strcpy (buffer, "advance");
				return DONE;

			    case 2: /* Burst */
				strcpy (buffer, "burst");
				return DONE;

			    case 3: /* Exit */
				strcpy (buffer, "exit");
				return DONE;

			    case 4: /* EOF */
				return OK;

			    default: /* failed or none taken */
				break;
			}
			break;
#undef	WPOP

		    case VT_MOUSE_RIGHT: 
			goto do_advance;
		}
		break;

	    case VT_EOF: 
		adios (NULL, "end-of-file on window");/* NOTREACHED */

	    default: 
		DisplayStatus (w->w_fd, "unknown VT sequence");
		break;
	}
}


static int
WINputc (WINDOW *w, char c)
{
    register int i;
    register char *cp;
    register struct line *lp;

    switch (c) {
	default: 
	    if (!isascii (c)) {
		if (WINputc (w, 'M') == NOTOK || WINputc (w, '-') == NOTOK)
		    return NOTOK;
		c = toascii (c);
	    }
	    else
		if (c < ' ' || c == '\177') {
		    if (WINputc (w, '^') == NOTOK)
			return NOTOK;
		    c ^= 0100;
		}
	    break;

	case '\t': 
	    for (i = 8 - (w->w_bufpos & 0x07); i > 0; i--)
		if (WINputc (w, ' ') == NOTOK)
		    return NOTOK;
	    return OK;

	case '\b':
	    if (w->w_bufpos > 0)
		w->w_bufpos--;
	    return OK;

	case '\n': 
	    break;
    }

    if (c != '\n') {
	w->w_buffer[w->w_bufpos++] = c;
	return OK;
    }

    w->w_buffer[w->w_bufpos] = NULL;
    w->w_bufpos = 0;

    if ((lp = (struct line *) calloc (1, sizeof *lp)) == NULL)
	adios (NULL, "unable to allocate line storage");

    lp->l_no = (w->w_tail ? w->w_tail->l_no : 0) + 1;
    lp->l_buf = getcpy (w->w_buffer);
    for (cp = lp->l_buf + strlen (lp->l_buf) - 1; cp >= lp->l_buf; cp--)
	if (isspace (*cp))
	    *cp = NULL;
	else
	    break;

    if (w->w_head == NULL)
	w->w_head = lp;
    if (w->w_top == NULL)
	w->w_top = lp;
    if (w->w_bottom == NULL)
	w->w_bottom = lp;
    if (w->w_tail)
	w->w_tail->l_next = lp;
    lp->l_prev = w->w_tail;
    w->w_tail = lp;

    return DONE;
}

#define	PSLOP	2


static char mylineno[5];

static bool cancel[] =  { 1 };
static struct choice mychoices[] = { LABEL, "cancel", VT_White };

static struct question myquestions[] = {
    STRING, "Line", SZ (mylineno), (struct choice *) 0,

    TOGGLE, "", SZ (mychoices),  mychoices
};

static struct menu mymenu = { "Goto", SZ (myquestions), myquestions };

static int *myanswers[] = { (int *) mylineno, (int *) cancel };


static void
WINless (WINDOW *w)
{
    int clear, pos, forw, refresh;
    struct vtseq vts;
    register struct vtseq *vt = &vts;

    if (w->w_fd == NOTOK) {
	if (w->w_head)
	    DisplayStatus (dfd, w->w_top->l_buf);
	else
	    RemoveStatus (dfd);

	return;
    }

    if (ChangeWindowDepth (dfd, w->w_wd, 0) == NOTOK)
	adios ("failed", "ChangeWindowDepth");

    Redisplay (w, 0);

    if (w->w_bottom == w->w_tail)
	return;

    if (w->w_eb == NULL)
	adios (NULL, "internal error--no elevator bar");

    for (clear = refresh = 0, forw = 1;;) {
	if (clear) {
	    RemoveStatus (w->w_fd);
	    clear = 0;
	}
	if (refresh) {
	    Redisplay (w, 0);
	    refresh = 0;
	}

	switch (getvtseq (w->w_fd, vt)) {
	    case VT_HARDKEY: 
	    case VT_ASCII: 
		DisplayStatus (w->w_fd, "use the mouse");
		clear++;
		break;

	    case VT_MOUSE: 
		switch (vt->u.mouse.buttons
			& (VT_MOUSE_LEFT | VT_MOUSE_MIDDLE | VT_MOUSE_RIGHT)) {
		    case VT_MOUSE_LEFT: 
			if ((pos = vt->u.mouse.x) < EWIDTH) {
			    pos = w->w_ebloc = DoElevatorBar (w->w_eb, pos,
				    vt->u.mouse.y);
			    refresh = WINgoto (w, ((pos * (w->w_tail->l_no
						- w->w_head->l_no))
					/ EB_MAX) + w->w_head->l_no);
			}
			break;

#define	WPOP "Paging\0Next\0Prev\0Left\0Right\0First\0Last\0Goto ...\0Exit\0"
		    case VT_MOUSE_MIDDLE: 
			SetPosition (w->w_fd, vt->u.mouse.x,
				vt->u.mouse.y);
			switch (DisplayPopUp (w->w_fd, WPOP)) {
			    case 1: /* Next */
			do_next_page: ;
				if (w->w_bottom == w->w_tail)
				    forw = 0;
				refresh = WINgoto (w, w->w_bottom->l_no + 1 - PSLOP);
				break;

			    case 2: /* Prev */
			do_prev_page: ;
				if (w->w_top == w->w_head)
				    forw = 1;
				refresh = WINgoto (w, w->w_top->l_no
					- w->w_height + PSLOP);
				break;

			    case 3: /* Left */
			    case 4: /* Right */
				DisplayStatus (w->w_fd, "not yet");
				clear++;
				break;

			    case 5: /* First */
				forw = 1;
				refresh = WINgoto (w, w->w_head->l_no);
				break;

			    case 6: /* Last */
				forw = 0;
				refresh = WINgoto (w, w->w_tail->l_no
					- w->w_height + 1);
				break;

			    case 7: /* Goto ... */
				snprintf (mylineno, sizeof(mylineno),
					"%d", w->w_top->l_no);
				cancel[0] = 0;
				if (PresentMenu (&mymenu, myanswers)
					|| cancel[0])
				    break;
				if (sscanf (mylineno, "%d", &pos) != 1) {
				    DisplayStatus (w->w_fd, "bad format");
				    clear++;
				    break;
				}
				if (pos < w->w_head->l_no
					|| pos > w->w_tail->l_no) {
				    DisplayStatus (w->w_fd, "no such line");
				    clear++;
				    break;
				}
				refresh = WINgoto (w, pos);
				break;

			    case 8: /* Exit */
				return;

			    default: /* failed or none taken */
				break;
			}
			break;
#undef	WPOP

		    case VT_MOUSE_RIGHT: 
			if (forw) {
			    if (w->w_bottom == w->w_tail)
				return;
			    else
				goto do_next_page;
			}
			else
			    goto do_prev_page;
		}
		break;

	    case VT_EOF: 
		adios (NULL, "end-of-file on window");/* NOTREACHED */

	    default: 
		DisplayStatus (w->w_fd, "unknown VT sequence");
		clear++;
		break;
	}
    }
}


static int
WINgoto (WINDOW *w, int n)
{
    register int i, j;
    register struct line *lp;

    if (n > (i = w->w_tail->l_no - w->w_height + 1))
	n = i;
    if (n < w->w_head->l_no)
	n = w->w_head->l_no;

    if ((i = n - (lp = w->w_head)->l_no)
	    > (j = abs (n - w->w_top->l_no)))
	i = j, lp = w->w_top;

    if (i > (j = abs (w->w_tail->l_no - n)))
	i = j, lp = w->w_tail;

    if (n >= lp->l_no) {
	for (; lp; lp = lp->l_next)
	    if (lp->l_no == n)
		break;
    }
    else {
	for (; lp; lp = lp->l_prev)
	    if (lp->l_no == n)
		break;
	if (!lp)
	    lp = w->w_head;
    }

    if (w->w_top == lp)
	return 0;

    w->w_top = lp;

    return 1;
}


static int
ADJser (int id, short ww, short wh)
{
    register WINDOW *w;

    if (id < 0 || id >= numwins)
	adios (NULL, "ADJser on bogus window (%d)", id);
    w = windows[id];
    if (w->w_fd == NOTOK)
	adios (NULL, "ADJser on closed window (%d)", id);

    w->w_ws.width = w->w_ws.tw = ww;
    w->w_ws.height = w->w_ws.th = wh;

    if (w->w_eb) {
	DeleteElevatorBar (w->w_eb);
	w->w_eb = CreateElevatorBar (w->w_fd, 0, 0, EWIDTH,
			w->w_ws.height, VT_Gray50, 1, EB_VERTICAL,
			EB_ARROWS, w->w_ebloc = 0, w->w_ebsize = EB_MAX,
			VT_White);
	if (w->w_eb == NULL)
	    adios (NULL, "CreateElevatorBar failed");
    }

    Redisplay (w, 1);
}


static int
REFser (int id, short wx, short wy, short ww, short wh)
{
    short cx, cy, cw, ch;
    register WINDOW *w;

    if (id < 0 || id >= numwins)
	adios (NULL, "REFser on bogus window (%d)", id);
    w = windows[id];
    if (w->w_fd == NOTOK)
	adios (NULL, "REFser on closed window (%d)", id);


    if (GetWindowState (w->w_fd, &w->w_ws) == NOTOK)
	adios ("failed", "GetWindowState");

    GetPermanentClipping (w->w_fd, &cx, &cy, &cw, &ch);
    SetPermanentClipping (w->w_fd, wx, wy, ww, wh);
    Redisplay (w, 1);
    SetPermanentClipping (w->w_fd, cx, cy, cw, ch);
}


static void
Redisplay (WINDOW *w, int doeb)
{
    register int y;
    short sx;
    register struct line *lp;

    if (w->w_fd == NOTOK)
	return;

    sx = w->w_eb ? (EWIDTH + ESLOP) : 0;
    w->w_height = w->w_ws.height / w->w_cheight;
    if (w->w_height < 1)
	w->w_height = 1;

    w->w_width = (w->w_ws.width - (w->w_eb ? (EWIDTH + ESLOP) : 0))
	/ w->w_cwidth;
    if (w->w_width < 1)
	w->w_width = 1;

    SetPosition (w->w_fd, sx, 0);
    SetColor (w->w_fd, VT_White);
    PaintRectangleInterior (w->w_fd, w->w_ws.width, w->w_ws.height);

    if (w->w_head) {
	SetColor (w->w_fd, VT_Black);
	for (lp = w->w_top, y = 0;
		lp && y < w->w_height;
		w->w_bottom = lp, lp = lp->l_next, y++) {
	    SetPosition (w->w_fd, sx, y * w->w_cheight + w->w_cbase);
	    PaintString (w->w_fd, VT_STREND, lp->l_buf);
	}
    }

    if (w->w_eb) {
	if ((y = EB_LOC (w)) != w->w_ebloc)
	    MoveElevator (w->w_eb, w->w_ebloc = y);
	if ((y = EB_SIZE (w)) != w->w_ebsize)
	    SizeElevator (w->w_eb, w->w_ebsize = y);
	if (doeb)
	    RefreshElevatorBar (w->w_eb);
    }

    Flush (w->w_fd);
}


static int
EB_SIZE (WINDOW *w)
{
    register int i;

    if (w->w_head == NULL)
	return 0;

    if ((i = w->w_tail->l_no - w->w_head->l_no) <= 0)
	return EB_MAX;

    return (((w->w_bottom->l_no - w->w_top->l_no) * EB_MAX) / i);
}


static int
EB_LOC (WINDOW *w)
{
    register int i;

    if (w->w_head == NULL)
	return 0;

    if ((i = w->w_tail->l_no - w->w_head->l_no) <= 0)
	return EB_MAX;

    return (((w->w_top->l_no - w->w_head->l_no) * EB_MAX) / i);
}

/* SIGNALS */

static void
SIGinit (void)
{
    foreground ();
    if (ioctl (fileno (stdin), TIOCGETP, (char *) &tio) == NOTOK)
	adios ("failed", "ioctl TIOCGETP");
    if (ioctl (fileno (stdin), TIOCGETC, (char *) &tc) == NOTOK)
	adios ("failed", "ioctl TIOCGETC");
    if (ioctl (fileno (stdin), TIOCGLTC, (char *) &ltc) == NOTOK)
	adios ("failed", "ioctl TIOCGLTC");
    sideground ();

    SIGNAL (SIGHUP, SIGser);
    SIGNAL (SIGINT, SIGser);
    SIGNAL (SIGQUIT, SIGser);
}


static void
foreground (void)
{
#ifdef TIOCGPGRP
    int pgrp, tpgrp;
    SIGNAL_HANDLER tstat;

    if ((pgrp = getpgrp (0)) == NOTOK)
	adios ("process group", "unable to determine");
    for (;;) {
	if (ioctl (fileno (stdin), TIOCGPGRP, (char *) &tpgrp) == NOTOK)
	    adios ("tty's process group", "unable to determine");
	if (pgrp == tpgrp)
	    break;

	tstat = SIGNAL (SIGTTIN, SIG_DFL);
	kill (0, SIGTTIN);
	SIGNAL (SIGTTIN, tstat);
    }
    
    SIGNAL (SIGTTIN, SIG_IGN);
    SIGNAL (SIGTTOU, SIG_IGN);
    SIGNAL (SIGTSTP, SIG_IGN);
#endif	TIOCGPGRP
}


static void
sideground (void)
{
#ifdef	TIOCGPGRP
    SIGNAL (SIGTTIN, SIG_DFL);
    SIGNAL (SIGTTOU, SIG_DFL);
    SIGNAL (SIGTSTP, SIG_DFL);
#endif	TIOCGPGRP
}


static int
ALRMser (int sig)
{
     longjmp (PEERctx, DONE);
}


static int
PIPEser (int sig)
{
#ifndef RELIABLE_SIGNALS
    SIGNAL (sig, SIG_IGN);
#endif

    adios (NULL, "lost peer");
}


static int
SIGser (int sig)
{
#ifndef RELIABLE_SIGNALS
    SIGNAL (sig, SIG_IGN);
#endif

    done (1);
}


int
done (int status)
{
    if (dfd != NOTOK)
	RemoveStatus (dfd);

    pFIN ();

    exit (status);
    return 1;  /* dead code to satisfy the compiler */
}


static void
adorn (char *what, char *fmt, ...)
{
    va_list ap
    char *cp;

    cp = invo_name;
    invo_name = NULL;

    va_start(ap, fmt);
    advertise (what, NULL, fmt, ap);
    va_end(ap);

    invo_name = cp;
}


void
advertise (char *what, char *tail, va_list ap)
{
    int eindex = errno;
    char buffer[BUFSIZ], err[BUFSIZ];
    struct iovec iob[20];
    register struct iovec *iov = iob;

    fflush (stdout);
    fflush (stderr);

    if (invo_name) {
	iov->iov_len = strlen (iov->iov_base = invo_name);
	iov++;
	iov->iov_len = strlen (iov->iov_base = ": ");
	iov++;
    }
    
    vsnprintf (buffer, sizeof(buffer), fmt, ap);
    iov->iov_len = strlen (iov->iov_base = buffer);
    iov++;
    if (what) {
	if (*what) {
	    iov->iov_len = strlen (iov->iov_base = " ");
	    iov++;
	    iov->iov_len = strlen (iov->iov_base = what);
	    iov++;
	    iov->iov_len = strlen (iov->iov_base = ": ");
	    iov++;
	}
	if (!(iov->iov_base = strerror (eindex))) {
	    snprintf (err, sizeof(err), "unknown error %d", eindex);
	    iov->iov_base = err;
	}
	iov->iov_len = strlen (iov->iov_base);
	iov++;
    }
    if (tail && *tail) {
	iov->iov_len = strlen (iov->iov_base = ", ");
	iov++;
	iov->iov_len = strlen (iov->iov_base = tail);
	iov++;
    }
    iov->iov_len = strlen (iov->iov_base = "\n");
    iov++;

    if (dfd != NOTOK)
	DisplayVector (iob, iov - iob);
    else
	writev (fileno (stderr), iob, iov - iob);
}


static void
DisplayVector (struct iovec *iov, int n)
{
    register int i;
    register char *cp;
    char buffer[BUFSIZ];

    for (i = 0, cp = NULL; i < n; i++, iov++) {
	snprintf (buffer, sizeof(buffer), "%*.*s", iov->iov_len,
		iov->iov_len, iov->iov_base);
	cp = add (buffer, cp);
    }

    DisplayStatus (dfd, cp);
    free (cp);
    sleep (PAUSE);
    RemoveStatus (dfd);
}