/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1998 Dag-Erling Smørgrav
 * 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
 *    in this position and unchanged.
 * 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 AUTHOR ``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 AUTHOR 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/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/syslog.h>
#include <sys/consio.h>
#include <sys/fbio.h>

#include <dev/fb/fbreg.h>
#include <dev/fb/splashreg.h>
#include <dev/syscons/syscons.h>

#define SAVER_NAME       "warp_saver"
#define SPP              15
#define STARS            (SPP * (1 + 2 + 4 + 8))

#define SET_ORIGIN(adp, o) do {                         \
        int oo = o;                                     \
        if (oo != last_origin)                          \
            vidd_set_win_org(adp, last_origin = oo);            \
        } while (0)

static u_char           *vid;
static int               banksize, scrmode, bpsl, scrw, scrh;
static int               blanked;
static int               star[STARS];
static u_char            warp_pal[768] = {
        0x00, 0x00, 0x00,
        0x66, 0x66, 0x66,
        0x99, 0x99, 0x99,
        0xcc, 0xcc, 0xcc,
        0xff, 0xff, 0xff
        /* the rest is zero-filled by the compiler */
};

static void
warp_update(video_adapter_t *adp)
{
        int i, j, k, n, o, p;
        int last_origin = -1;

        for (i = 1, k = 0, n = SPP*8; i < 5; i++, n /= 2) {
                for (j = 0; j < n; j++, k++) {
                        p = (star[k] / scrw) *  bpsl + (star[k] % scrw);
                        o = 0;
                        while (p > banksize) {
                                p -= banksize;
                                o += banksize;
                        }
                        SET_ORIGIN(adp, o);
                        vid[p] = 0;
                        star[k] += i;
                        if (star[k] > scrw*scrh)
                                star[k] -= scrw*scrh;
                        p = (star[k] / scrw) *  bpsl + (star[k] % scrw);
                        o = 0;
                        while (p > banksize) {
                                p -= banksize;
                                o += banksize;
                        }
                        SET_ORIGIN(adp, o);
                        vid[p] = i;
                }
        }
}

static int
warp_saver(video_adapter_t *adp, int blank)
{
        int pl;

        if (blank) {
                /* switch to graphics mode */
                if (blanked <= 0) {
                        pl = splhigh();
                        vidd_set_mode(adp, scrmode);
                        vidd_load_palette(adp, warp_pal);
                        vidd_set_border(adp, 0);
                        blanked++;
                        vid = (u_char *)adp->va_window;
                        banksize = adp->va_window_size;
                        bpsl = adp->va_line_width;
                        splx(pl);
                        vidd_clear(adp);
                }
                /* update display */
                warp_update(adp);
        } else {
                blanked = 0;
        }
        return (0);
}

static int
warp_init(video_adapter_t *adp)
{
        video_info_t info;
        int i;

        if (!vidd_get_info(adp, M_VGA_CG320, &info)) {
                scrmode = M_VGA_CG320;
        } else {
                log(LOG_NOTICE,
                    "%s: the console does not support M_VGA_CG320\n",
                    SAVER_NAME);
                return (ENODEV);
        }

        scrw = info.vi_width;
        scrh = info.vi_height;

        /* randomize the star field */
        for (i = 0; i < STARS; i++)
                star[i] = random() % (scrw * scrh);

        return (0);
}

static int
warp_term(video_adapter_t *adp)
{
        return (0);
}

static scrn_saver_t warp_module = {
        SAVER_NAME,
        warp_init,
        warp_term,
        warp_saver,
        NULL
};

SAVER_MODULE(warp_saver, warp_module);