/*
 * The functions in this file handle redisplay. There are two halves, the
 * ones that update the virtual display screen, and the ones that make the
 * physical display screen the same as the virtual display screen. These
 * functions use hints that are left in the windows by the commands.
 *
 * REVISION HISTORY:
 *
 * ?    Steve Wilhite, 1-Dec-85
 *      - massive cleanup on code.
 */

#include        <stdio.h>
#include        "ed.h"

#define WFDEBUG 0                       /* Window flag debug. */

typedef struct  VIDEO {
        short   v_flag;                 /* Flags */
        char    v_text[1];              /* Screen data. */
}       VIDEO;

#define VFCHG   0x0001                  /* Changed. */

int     sgarbf  = TRUE;                 /* TRUE if screen is garbage */
int     mpresf  = FALSE;                /* TRUE if message in last line */
int     vtrow   = 0;                    /* Row location of SW cursor */
int     vtcol   = 0;                    /* Column location of SW cursor */
int     ttrow   = HUGE;                 /* Row location of HW cursor */
int     ttcol   = HUGE;                 /* Column location of HW cursor */

VIDEO   **vscreen;                      /* Virtual screen. */
VIDEO   **pscreen;                      /* Physical screen. */

/*
 * Initialize the data structures used by the display code. The edge vectors
 * used to access the screens are set up. The operating system's terminal I/O
 * channel is set up. All the other things get initialized at compile time.
 * The original window has "WFCHG" set, so that it will get completely
 * redrawn on the first call to "update".
 */
vtinit()
{
    register int i;
    register VIDEO *vp;

    (*term.t_open)();
    vscreen = (VIDEO **) malloc(term.t_nrow*sizeof(VIDEO *));

    if (vscreen == NULL)
        exit(1);

    pscreen = (VIDEO **) malloc(term.t_nrow*sizeof(VIDEO *));

    if (pscreen == NULL)
        exit(1);

    for (i = 0; i < term.t_nrow; ++i)
        {
        vp = (VIDEO *) malloc(sizeof(VIDEO)+term.t_ncol);

        if (vp == NULL)
            exit(1);

        vscreen[i] = vp;
        vp = (VIDEO *) malloc(sizeof(VIDEO)+term.t_ncol);

        if (vp == NULL)
            exit(1);

        pscreen[i] = vp;
        }
}

/*
 * Clean up the virtual terminal system, in anticipation for a return to the
 * operating system. Move down to the last line and clear it out (the next
 * system prompt will be written in the line). Shut down the channel to the
 * terminal.
 */
vttidy()
{
    movecursor(term.t_nrow, 0);
    (*term.t_eeol)();
    (*term.t_close)();
}

/*
 * Set the virtual cursor to the specified row and column on the virtual
 * screen. There is no checking for nonsense values; this might be a good
 * idea during the early stages.
 */
vtmove(row, col)
{
    vtrow = row;
    vtcol = col;
}

/*
 * Write a character to the virtual screen. The virtual row and column are
 * updated. If the line is too long put a "$" in the last column. This routine
 * only puts printing characters into the virtual terminal buffers. Only
 * column overflow is checked.
 */
vtputc(c)
    int c;
{
    register VIDEO      *vp;

    vp = vscreen[vtrow];

    if (vtcol >= term.t_ncol)
    {
        vp->v_text[term.t_ncol - 1] = '$';
	++vtcol;
    }
    else if (c == '\t')
        {
        do
            {
            vtputc(' ');
            }
        while ((vtcol&0x07) != 0);
        }
    else if (c < 0x20 || c == 0x7F)
        {
        vtputc('^');
        vtputc(c ^ 0x40);
        }
    else
        vp->v_text[vtcol++] = c;                
}

/*
 * Erase from the end of the software cursor to the end of the line on which
 * the software cursor is located.
 */
vteeol()
{
    register VIDEO      *vp;

    vp = vscreen[vtrow];
    while (vtcol < term.t_ncol)
        vp->v_text[vtcol++] = ' ';
}

/*
 * Make sure that the display is right. This is a three part process. First,
 * scan through all of the windows looking for dirty ones. Check the framing,
 * and refresh the screen. Second, make sure that "currow" and "curcol" are
 * correct for the current window. Third, make the virtual and physical
 * screens the same.
 */
update()
{
    register LINE *lp;
    register WINDOW *wp;
    register VIDEO *vp1;
    register VIDEO *vp2;
    register int i;
    register int j;
    register int c;

    wp = wheadp;

    while (wp != NULL)
        {
        /* Look at any window with update flags set on. */

        if (wp->w_flag != 0)
            {
            /* If not force reframe, check the framing. */

            if ((wp->w_flag & WFFORCE) == 0)
                {
                lp = wp->w_linep;

                for (i = 0; i < wp->w_ntrows; ++i)
                    {
                    if (lp == wp->w_dotp)
                        goto out;

                    if (lp == wp->w_bufp->b_linep)
                        break;

                    lp = lforw(lp);
                    }
                }

            /* Not acceptable, better compute a new value for the line at the
             * top of the window. Then set the "WFHARD" flag to force full
             * redraw.
             */
            i = wp->w_force;

            if (i > 0)
                {
                --i;

                if (i >= wp->w_ntrows)
                  i = wp->w_ntrows-1;
                }
            else if (i < 0)
                {
                i += wp->w_ntrows;

                if (i < 0)
                    i = 0;
                }
            else
                i = wp->w_ntrows/2;

            lp = wp->w_dotp;

            while (i != 0 && lback(lp) != wp->w_bufp->b_linep)
                {
                --i;
                lp = lback(lp);
                }

            wp->w_linep = lp;
            wp->w_flag |= WFHARD;       /* Force full. */

out:
            /* Try to use reduced update. Mode line update has its own special
             * flag. The fast update is used if the only thing to do is within
             * the line editing.
             */
            lp = wp->w_linep;
            i = wp->w_toprow;

            if ((wp->w_flag & ~WFMODE) == WFEDIT)
                {
                while (lp != wp->w_dotp)
                    {
                    ++i;
                    lp = lforw(lp);
                    }

                vscreen[i]->v_flag |= VFCHG;
                vtmove(i, 0);

                for (j = 0; j < llength(lp); ++j)
                    vtputc(lgetc(lp, j));

                vteeol();
                }
             else if ((wp->w_flag & (WFEDIT | WFHARD)) != 0)
                {
                while (i < wp->w_toprow+wp->w_ntrows)
                    {
                    vscreen[i]->v_flag |= VFCHG;
                    vtmove(i, 0);

                    if (lp != wp->w_bufp->b_linep)
                        {
                        for (j = 0; j < llength(lp); ++j)
                            vtputc(lgetc(lp, j));

                        lp = lforw(lp);
                        }

                    vteeol();
                    ++i;
                    }
                }
#if ~WFDEBUG
            if ((wp->w_flag&WFMODE) != 0)
                modeline(wp);

            wp->w_flag  = 0;
            wp->w_force = 0;
#endif
            }           
#if WFDEBUG
        modeline(wp);
        wp->w_flag =  0;
        wp->w_force = 0;
#endif
        wp = wp->w_wndp;
        }

    /* Always recompute the row and column number of the hardware cursor. This
     * is the only update for simple moves.
     */
    lp = curwp->w_linep;
    currow = curwp->w_toprow;

    while (lp != curwp->w_dotp)
        {
        ++currow;
        lp = lforw(lp);
        }

    curcol = 0;
    i = 0;

    while (i < curwp->w_doto)
        {
        c = lgetc(lp, i++);

        if (c == '\t')
            curcol |= 0x07;
        else if (c < 0x20 || c == 0x7F)
            ++curcol;

        ++curcol;
        }

    if (curcol >= term.t_ncol)          /* Long line. */
        curcol = term.t_ncol-1;

    /* Special hacking if the screen is garbage. Clear the hardware screen,
     * and update your copy to agree with it. Set all the virtual screen
     * change bits, to force a full update.
     */
    if (sgarbf != FALSE)
        {
        for (i = 0; i < term.t_nrow; ++i)
            {
            vscreen[i]->v_flag |= VFCHG;
            vp1 = pscreen[i];
            for (j = 0; j < term.t_ncol; ++j)
                vp1->v_text[j] = ' ';
            }

        movecursor(0, 0);               /* Erase the screen. */
        (*term.t_eeop)();
        sgarbf = FALSE;                 /* Erase-page clears */
        mpresf = FALSE;                 /* the message area. */
        }

    /* Make sure that the physical and virtual displays agree. Unlike before,
     * the "updateline" code is only called with a line that has been updated
     * for sure.
     */
    for (i = 0; i < term.t_nrow; ++i)
        {
        vp1 = vscreen[i];

        if ((vp1->v_flag&VFCHG) != 0)
            {
            vp1->v_flag &= ~VFCHG;
            vp2 = pscreen[i];
            updateline(i, &vp1->v_text[0], &vp2->v_text[0]);
            }
        }

    /* Finally, update the hardware cursor and flush out buffers. */

    movecursor(currow, curcol);
    (*term.t_flush)();
}

/*
 * Update a single line. This does not know how to use insert or delete
 * character sequences; we are using VT52 functionality. Update the physical
 * row and column variables. It does try an exploit erase to end of line. The
 * RAINBOW version of this routine uses fast video.
 */
updateline(row, vline, pline)
    char vline[];
    char pline[];
{
#if RAINBOW
    register char *cp1;
    register char *cp2;
    register int nch;

    cp1 = &vline[0];                    /* Use fast video. */
    cp2 = &pline[0];
    putline(row+1, 1, cp1);
    nch = term.t_ncol;

    do
        {
        *cp2 = *cp1;
        ++cp2;
        ++cp1;
        }
    while (--nch);
#else
    register char *cp1;
    register char *cp2;
    register char *cp3;
    register char *cp4;
    register char *cp5;
    register int nbflag;

    cp1 = &vline[0];                    /* Compute left match.  */
    cp2 = &pline[0];

    while (cp1!=&vline[term.t_ncol] && cp1[0]==cp2[0])
        {
        ++cp1;
        ++cp2;
        }

    /* This can still happen, even though we only call this routine on changed
     * lines. A hard update is always done when a line splits, a massive
     * change is done, or a buffer is displayed twice. This optimizes out most
     * of the excess updating. A lot of computes are used, but these tend to
     * be hard operations that do a lot of update, so I don't really care.
     */
    if (cp1 == &vline[term.t_ncol])             /* All equal. */
        return;

    nbflag = FALSE;
    cp3 = &vline[term.t_ncol];          /* Compute right match. */
    cp4 = &pline[term.t_ncol];

    while (cp3[-1] == cp4[-1])
        {
        --cp3;
        --cp4;
        if (cp3[0] != ' ')              /* Note if any nonblank */
            nbflag = TRUE;              /* in right match. */
        }

    cp5 = cp3;

    if (nbflag == FALSE)                /* Erase to EOL ? */
        {
        while (cp5!=cp1 && cp5[-1]==' ')
            --cp5;

        if (cp3-cp5 <= 3)               /* Use only if erase is */
            cp5 = cp3;                  /* fewer characters. */
        }

    movecursor(row, cp1-&vline[0]);     /* Go to start of line. */

    while (cp1 != cp5)                  /* Ordinary. */
        {
        (*term.t_putchar)(*cp1);
        ++ttcol;
        *cp2++ = *cp1++;
        }

    if (cp5 != cp3)                     /* Erase. */
        {
        (*term.t_eeol)();
        while (cp1 != cp3)
            *cp2++ = *cp1++;
        }
#endif
}

/*
 * Redisplay the mode line for the window pointed to by the "wp". This is the
 * only routine that has any idea of how the modeline is formatted. You can
 * change the modeline format by hacking at this routine. Called by "update"
 * any time there is a dirty window.
 */
modeline(wp)
    WINDOW *wp;
{
    register char *cp;
    register int c;
    register int n;
    register BUFFER *bp;

    n = wp->w_toprow+wp->w_ntrows;              /* Location. */
    vscreen[n]->v_flag |= VFCHG;                /* Redraw next time. */
    vtmove(n, 0);                               /* Seek to right line. */
    vtputc('-');
    bp = wp->w_bufp;

    if ((bp->b_flag&BFCHG) != 0)                /* "*" if changed. */
        vtputc('*');
    else
        vtputc('-');

    n  = 2;
    cp = " MicroEMACS -- ";                     /* Buffer name. */

    while ((c = *cp++) != 0)
        {
        vtputc(c);
        ++n;
        }

    cp = &bp->b_bname[0];

    while ((c = *cp++) != 0)
        {
        vtputc(c);
        ++n;
        }

    vtputc(' ');
    ++n;

    if (bp->b_fname[0] != 0)            /* File name. */
        {
        cp = "-- File: ";

        while ((c = *cp++) != 0)
            {
            vtputc(c);
            ++n;
            }

        cp = &bp->b_fname[0];

        while ((c = *cp++) != 0)
            {
            vtputc(c);
            ++n;
            }

        vtputc(' ');
        ++n;
        }

#if WFDEBUG
    vtputc('-');
    vtputc((wp->w_flag&WFMODE)!=0  ? 'M' : '-');
    vtputc((wp->w_flag&WFHARD)!=0  ? 'H' : '-');
    vtputc((wp->w_flag&WFEDIT)!=0  ? 'E' : '-');
    vtputc((wp->w_flag&WFMOVE)!=0  ? 'V' : '-');
    vtputc((wp->w_flag&WFFORCE)!=0 ? 'F' : '-');
    n += 6;
#endif

    while (n < term.t_ncol)             /* Pad to full width. */
        {
        vtputc('-');
        ++n;
        }
}

/*
 * Send a command to the terminal to move the hardware cursor to row "row"
 * and column "col". The row and column arguments are origin 0. Optimize out
 * random calls. Update "ttrow" and "ttcol".
 */
movecursor(row, col)
    {
    if (row!=ttrow || col!=ttcol)
        {
        ttrow = row;
        ttcol = col;
        (*term.t_move)(row, col);
        }
    }

/*
 * Erase the message line. This is a special routine because the message line
 * is not considered to be part of the virtual screen. It always works
 * immediately; the terminal buffer is flushed via a call to the flusher.
 */
mlerase()
    {
    movecursor(term.t_nrow, 0);
    (*term.t_eeol)();
    (*term.t_flush)();
    mpresf = FALSE;
    }

/*
 * Ask a yes or no question in the message line. Return either TRUE, FALSE, or
 * ABORT. The ABORT status is returned if the user bumps out of the question
 * with a ^G. Used any time a confirmation is required.
 */
mlyesno(prompt)
    char *prompt;
    {
    register int s;
    char buf[64];

    for (;;)
        {
        strcpy(buf, prompt);
        strcat(buf, " [y/n]? ");
        s = mlreply(buf, buf, sizeof(buf));

        if (s == ABORT)
            return (ABORT);

        if (s != FALSE)
            {
            if (buf[0]=='y' || buf[0]=='Y')
                return (TRUE);

            if (buf[0]=='n' || buf[0]=='N')
                return (FALSE);
            }
        }
    }

/*
 * Write a prompt into the message line, then read back a response. Keep
 * track of the physical position of the cursor. If we are in a keyboard
 * macro throw the prompt away, and return the remembered response. This
 * lets macros run at full speed. The reply is always terminated by a carriage
 * return. Handle erase, kill, and abort keys.
 */
mlreply(prompt, buf, nbuf)
    char *prompt;
    char *buf;
    {
    register int cpos;
    register int i;
    register int c;

    cpos = 0;

    if (kbdmop != NULL)
        {
        while ((c = *kbdmop++) != '\0')
            buf[cpos++] = c;

        buf[cpos] = 0;

        if (buf[0] == 0)
            return (FALSE);

        return (TRUE);
        }

    mlwrite(prompt);

    for (;;)
        {
        c = (*term.t_getchar)();

        switch (c)
            {
            case 0x0D:                  /* Return, end of line */
                buf[cpos++] = 0;

                if (kbdmip != NULL)
                    {
                    if (kbdmip+cpos > &kbdm[NKBDM-3])
                        {
                        ctrlg(FALSE, 0);
                        (*term.t_flush)();
                        return (ABORT);
                        }

                    for (i=0; i<cpos; ++i)
                        *kbdmip++ = buf[i];
                    }

                (*term.t_putchar)('\r');
                ttcol = 0;
                (*term.t_flush)();

                if (buf[0] == 0)
                    return (FALSE);

                return (TRUE);

            case 0x07:                  /* Bell, abort */
                (*term.t_putchar)('^');
                (*term.t_putchar)('G');
                ttcol += 2;
                ctrlg(FALSE, 0);
                (*term.t_flush)();
                return (ABORT);

            case 0x7F:                  /* Rubout, erase */
            case 0x08:                  /* Backspace, erase */
                if (cpos != 0)
                    {
                    (*term.t_putchar)('\b');
                    (*term.t_putchar)(' ');
                    (*term.t_putchar)('\b');
                    --ttcol;

                    if (buf[--cpos] < 0x20)
                        {
                        (*term.t_putchar)('\b');
                        (*term.t_putchar)(' ');
                        (*term.t_putchar)('\b');
                        --ttcol;
                        }

                    (*term.t_flush)();
                    }

                break;

            case 0x15:                  /* C-U, kill */
                while (cpos != 0)
                    {
                    (*term.t_putchar)('\b');
                    (*term.t_putchar)(' ');
                    (*term.t_putchar)('\b');
                    --ttcol;

                    if (buf[--cpos] < 0x20)
                        {
                        (*term.t_putchar)('\b');
                        (*term.t_putchar)(' ');
                        (*term.t_putchar)('\b');
                        --ttcol;
                        }
                    }

                (*term.t_flush)();
                break;

            default:
                if (cpos < nbuf-1)
                    {
                    buf[cpos++] = c;

                    if (c < ' ')
                        {
                        (*term.t_putchar)('^');
                        ++ttcol;
                        c ^= 0x40;
                        }

                    (*term.t_putchar)(c);
                    ++ttcol;
                    (*term.t_flush)();
                    }
            }
        }
    }

/*
 * Write a message into the message line. Keep track of the physical cursor
 * position. A small class of printf like format items is handled. Assumes the
 * stack grows down; this assumption is made by the "++" in the argument scan
 * loop. Set the "message line" flag TRUE.
 */
mlwrite(fmt, arg)
    char *fmt;
    {
    register int c;
    register char *ap;

    movecursor(term.t_nrow, 0);
    ap = (char *) &arg;
    while ((c = *fmt++) != 0) {
        if (c != '%') {
            (*term.t_putchar)(c);
            ++ttcol;
            }
        else
            {
            c = *fmt++;
            switch (c) {
                case 'd':
                    mlputi(*(int *)ap, 10);
                    ap += sizeof(int);
                    break;

                case 'o':
                    mlputi(*(int *)ap,  8);
                    ap += sizeof(int);
                    break;

                case 'x':
                    mlputi(*(int *)ap, 16);
                    ap += sizeof(int);
                    break;

                case 'D':
                    mlputli(*(long *)ap, 10);
                    ap += sizeof(long);
                    break;

                case 's':
                    mlputs(*(char **)ap);
                    ap += sizeof(char *);
                    break;

                default:
                    (*term.t_putchar)(c);
                    ++ttcol;
                }
            }
        }
    (*term.t_eeol)();
    (*term.t_flush)();
    mpresf = TRUE;
    }

/*
 * Write out a string. Update the physical cursor position. This assumes that
 * the characters in the string all have width "1"; if this is not the case
 * things will get screwed up a little.
 */
mlputs(s)
    char *s;
    {
    register int c;

    while ((c = *s++) != 0)
        {
        (*term.t_putchar)(c);
        ++ttcol;
        }
    }

/*
 * Write out an integer, in the specified radix. Update the physical cursor
 * position. This will not handle any negative numbers; maybe it should.
 */
mlputi(i, r)
    {
    register int q;
    static char hexdigits[] = "0123456789ABCDEF";

    if (i < 0)
        {
        i = -i;
        (*term.t_putchar)('-');
        }

    q = i/r;

    if (q != 0)
        mlputi(q, r);

    (*term.t_putchar)(hexdigits[i%r]);
    ++ttcol;
    }

/*
 * do the same except as a long integer.
 */
mlputli(l, r)
    long l;
    {
    register long q;

    if (l < 0)
        {
        l = -l;
        (*term.t_putchar)('-');
        }

    q = l/r;

    if (q != 0)
        mlputli(q, r);

    (*term.t_putchar)((int)(l%r)+'0');
    ++ttcol;
    }

#if RAINBOW

putline(row, col, buf)
    int row, col;
    char buf[];
    {
    int n;

    n = strlen(buf);
    if (col + n - 1 > term.t_ncol)
        n = term.t_ncol - col + 1;
    Put_Data(row, col, n, buf);
    }
#endif