/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1999 Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp>
 * Copyright (c) 1992-1998 Søren Schmidt
 * 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,
 *    without modification, immediately at the beginning of the file.
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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 <sys/cdefs.h>
#include "opt_syscons.h"

#ifndef SC_NO_HISTORY

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/consio.h>
#include <sys/tty.h>
#include <sys/kernel.h>
#include <sys/malloc.h>

#if defined(__arm__) || defined(__powerpc__)
#include <machine/sc_machdep.h>
#else
#include <machine/pc/display.h>
#endif

#include <dev/syscons/syscons.h>

/*
 * XXX Placeholder.
 * This calculations should be dynamically scaled by number of separate sc
 * devices.  A base value of 'extra_history_size' should be defined for
 * each syscons unit, and added and subtracted from the dynamic
 * 'extra_history_size' as units are added and removed.  This way, each time
 * a new syscons unit goes online, extra_history_size is automatically bumped.
 */
#define MAXSC   1

#if !defined(SC_MAX_HISTORY_SIZE)
#define SC_MAX_HISTORY_SIZE     (1000 * MAXCONS * MAXSC)
#endif

#if !defined(SC_HISTORY_SIZE)
#define SC_HISTORY_SIZE         (ROW * 4)
#endif

#if (SC_HISTORY_SIZE * MAXCONS * MAXSC) > SC_MAX_HISTORY_SIZE
#undef SC_MAX_HISTORY_SIZE
#define SC_MAX_HISTORY_SIZE     (SC_HISTORY_SIZE * MAXCONS * MAXSC)
#endif

/* local variables */
static int              extra_history_size
                                = SC_MAX_HISTORY_SIZE - SC_HISTORY_SIZE*MAXCONS;

/* local functions */
static void copy_history(sc_vtb_t *from, sc_vtb_t *to);
static void history_to_screen(scr_stat *scp);

/* allocate a history buffer */
int
sc_alloc_history_buffer(scr_stat *scp, int lines, int prev_ysize, int wait)
{
        /*
         * syscons unconditionally allocates buffers up to 
         * SC_HISTORY_SIZE lines or scp->ysize lines, whichever 
         * is larger. A value greater than that is allowed, 
         * subject to extra_history_size.
         */
        sc_vtb_t *history;
        sc_vtb_t *prev_history;
        int cur_lines;                          /* current buffer size */
        int min_lines;                          /* guaranteed buffer size */
        int delta;                              /* lines to put back */

        if (lines <= 0)
                lines = SC_HISTORY_SIZE;        /* use the default value */

        /* make it at least as large as the screen size */
        lines = imax(lines, scp->ysize);

        /* remove the history buffer while we update it */
        history = prev_history = scp->history;
        scp->history = NULL;

        /* calculate the amount of lines to put back to extra_history_size */
        delta = 0;
        if (prev_history) {
                cur_lines = sc_vtb_rows(history);
                min_lines = imax(SC_HISTORY_SIZE, prev_ysize);
                if (cur_lines > min_lines)
                        delta = cur_lines - min_lines;
        }

        /* lines up to min_lines are always allowed. */
        min_lines = imax(SC_HISTORY_SIZE, scp->ysize);
        if (lines > min_lines) {
                if (lines - min_lines > extra_history_size + delta) {
                        /* too many lines are requested */
                        scp->history = prev_history;
                        return EINVAL;
                }
        }

        /* allocate a new buffer */
        history = (sc_vtb_t *)malloc(sizeof(*history),
                                     M_DEVBUF,
                                     (wait) ? M_WAITOK : M_NOWAIT);
        if (history != NULL) {
                if (lines > min_lines)
                        extra_history_size -= lines - min_lines;
                /* XXX error check? */
                sc_vtb_init(history, VTB_RINGBUFFER, scp->xsize, lines,
                            NULL, wait);
                /* FIXME: XXX no good? */
                sc_vtb_clear(history, scp->sc->scr_map[0x20],
                             SC_NORM_ATTR << 8);
                if (prev_history != NULL)
                        copy_history(prev_history, history);
                scp->history_pos = sc_vtb_tail(history);
        } else {
                scp->history_pos = 0;
        }

        /* destroy the previous buffer */
        if (prev_history != NULL) {
                extra_history_size += delta;
                sc_vtb_destroy(prev_history);
                free(prev_history, M_DEVBUF);
        }

        scp->history = history;

        return 0;
}

static void
copy_history(sc_vtb_t *from, sc_vtb_t *to)
{
        int lines;
        int cols;
        int cols1;
        int cols2;
        int pos;
        int i;

        lines = sc_vtb_rows(from);
        cols1 = sc_vtb_cols(from);
        cols2 = sc_vtb_cols(to);
        cols = imin(cols1, cols2);
        pos = sc_vtb_tail(from);
        for (i = 0; i < lines; ++i) {
                sc_vtb_append(from, pos, to, cols);
                if (cols < cols2)
                        sc_vtb_seek(to, sc_vtb_pos(to, 
                                                   sc_vtb_tail(to), 
                                                   cols2 - cols));
                pos = sc_vtb_pos(from, pos, cols1);
        }
}

void
sc_free_history_buffer(scr_stat *scp, int prev_ysize)
{
        sc_vtb_t *history;
        int cur_lines;                          /* current buffer size */
        int min_lines;                          /* guaranteed buffer size */

        history = scp->history;
        scp->history = NULL;
        if (history == NULL)
                return;

        cur_lines = sc_vtb_rows(history);
        min_lines = imax(SC_HISTORY_SIZE, prev_ysize);
        extra_history_size += (cur_lines > min_lines) ? 
                                  cur_lines - min_lines : 0;

        sc_vtb_destroy(history);
        free(history, M_DEVBUF);
}

/* copy entire screen into the top of the history buffer */
void
sc_hist_save(scr_stat *scp)
{
        sc_vtb_append(&scp->vtb, 0, scp->history, scp->xsize*scp->ysize);
        scp->history_pos = sc_vtb_tail(scp->history);
}

/* restore the screen by copying from the history buffer */
int
sc_hist_restore(scr_stat *scp)
{
        int ret;

        if (scp->history_pos != sc_vtb_tail(scp->history)) {
                scp->history_pos = sc_vtb_tail(scp->history);
                history_to_screen(scp);
                ret =  0;
        } else {
                ret = 1;
        }
        sc_vtb_seek(scp->history, sc_vtb_pos(scp->history, 
                                             sc_vtb_tail(scp->history),
                                             -scp->xsize*scp->ysize));
        return ret;
}

/* copy screen-full of saved lines */
static void
history_to_screen(scr_stat *scp)
{
        int pos;
        int i;

        pos = scp->history_pos;
        for (i = 1; i <= scp->ysize; ++i) {
                pos = sc_vtb_pos(scp->history, pos, -scp->xsize);
                sc_vtb_copy(scp->history, pos,
                            &scp->vtb, scp->xsize*(scp->ysize - i),
                            scp->xsize);
        }
        mark_all(scp);
}

/* go to the tail of the history buffer */
void
sc_hist_home(scr_stat *scp)
{
        scp->history_pos = sc_vtb_tail(scp->history);
        history_to_screen(scp);
}

/* go to the top of the history buffer */
void
sc_hist_end(scr_stat *scp)
{
        scp->history_pos = sc_vtb_pos(scp->history, sc_vtb_tail(scp->history),
                                      scp->xsize*scp->ysize);
        history_to_screen(scp);
}

/* move one line up */
int
sc_hist_up_line(scr_stat *scp)
{
        if (sc_vtb_pos(scp->history, scp->history_pos, -(scp->xsize*scp->ysize))
            == sc_vtb_tail(scp->history))
                return -1;
        scp->history_pos = sc_vtb_pos(scp->history, scp->history_pos,
                                      -scp->xsize);
        history_to_screen(scp);
        return 0;
}

/* move one line down */
int
sc_hist_down_line(scr_stat *scp)
{
        if (scp->history_pos == sc_vtb_tail(scp->history))
                return -1;
        scp->history_pos = sc_vtb_pos(scp->history, scp->history_pos,
                                      scp->xsize);
        history_to_screen(scp);
        return 0;
}

int
sc_hist_ioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
{
        scr_stat *scp;
        int error;

        switch (cmd) {
        case CONS_HISTORY:      /* set history size */
                scp = SC_STAT(tp);
                if (*(int *)data <= 0)
                        return EINVAL;
                if (scp->status & BUFFER_SAVED)
                        return EBUSY;
                DPRINTF(5, ("lines:%d, ysize:%d, pool:%d\n",
                            *(int *)data, scp->ysize, extra_history_size));
                error = sc_alloc_history_buffer(scp, 
                                               imax(*(int *)data, scp->ysize),
                                               scp->ysize, TRUE);
                DPRINTF(5, ("error:%d, rows:%d, pool:%d\n", error,
                            sc_vtb_rows(scp->history), extra_history_size));
                return error;

        case CONS_CLRHIST:
                scp = SC_STAT(tp);
                sc_vtb_clear(scp->history, scp->sc->scr_map[0x20],
                    SC_NORM_ATTR << 8);
                return 0;
        }

        return ENOIOCTL;
}

#endif /* SC_NO_HISTORY */