/*-
 * 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       "rain_saver"
#ifdef MAX
#undef MAX
#endif
#define MAX              63     /* number of colors (in addition to black) */
#define INCREMENT        4      /* increment between colors */

#define RED(n)           ((n) * 3 + 0)
#define GREEN(n)         ((n) * 3 + 1)
#define BLUE(n)          ((n) * 3 + 2)

#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 u_char            rain_pal[768];
static int               blanked;

static void
rain_update(video_adapter_t *adp)
{
        int i, t;

        t = rain_pal[BLUE(MAX)];
        for (i = MAX; i > 1; i--)
                rain_pal[BLUE(i)] = rain_pal[BLUE(i - 1)];
        rain_pal[BLUE(1)] = t;
        vidd_load_palette(adp, rain_pal);
}

static int
rain_saver(video_adapter_t *adp, int blank)
{
        int i, j, o, p, pl;
        u_char temp;
        int last_origin = -1;

        if (blank) {
                /* switch to graphics mode */
                if (blanked <= 0) {
                        pl = splhigh();
                        vidd_set_mode(adp, scrmode);
                        vidd_load_palette(adp, rain_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);
                        for (i = 0; i < bpsl*scrh; i += banksize) {
                                SET_ORIGIN(adp, i);
                                if ((bpsl * scrh - i) < banksize)
                                        bzero(vid, bpsl * scrh - i);
                                else
                                        bzero(vid, banksize);
                        }
                        SET_ORIGIN(adp, 0);
                        for (i = 0, o = 0, p = 0; i < scrw; i += 2, p += 2) {
                                if (p > banksize) {
                                        p -= banksize;
                                        o += banksize;
                                        SET_ORIGIN(adp, o);
                                }
                                vid[p] = 1 + (random() % MAX);
                        }
                        o = 0; p = 0;
                        for (j = 1; j < scrh; j++)
                          for (i = 0, p = bpsl * (j - 1) - o; i < scrw; i += 2, p+= 2) {
                                while (p > banksize) {
                                        p -= banksize;
                                        o += banksize;
                                }
                                SET_ORIGIN(adp, o);
                                temp = (vid[p] < MAX) ? 1 + vid[p] : 1;
                                if (p + bpsl < banksize) {
                                        vid[p + bpsl] = temp;
                                } else {
                                        SET_ORIGIN(adp, o + banksize);
                                        vid[p + bpsl - banksize] = temp;
                                }
                          }
                }
                
                /* update display */
                rain_update(adp);
        } else {
                blanked = 0;
        }
        return (0);
}

static int
rain_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;

        /* intialize the palette */
        for (i = 1; i < MAX; i++)
                rain_pal[BLUE(i)] = rain_pal[BLUE(i - 1)] + INCREMENT;

        return (0);
}

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

static scrn_saver_t rain_module = {
        SAVER_NAME,
        rain_init,
        rain_term,
        rain_saver,
        NULL
};

SAVER_MODULE(rain_saver, rain_module);