/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2000 Chiharu Shibata
 * 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        <sys/random.h>

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

#define SAVER_NAME       "dragon_saver"

static u_char   *vid;
static int      blanked;

#define VIDEO_MODE      M_VGA_CG320
#define VIDEO_MODE_NAME "M_VGA_CG320"
#define SCRW    320
#define SCRH    200
#define ORDER   13
#define CURVE   3
#define OUT     100

static int      cur_x, cur_y;
static int      curve;
static u_char   dragon_pal[3*256];      /* zero-filled by the compiler */

static __inline int
gpset(int x, int y, int val)
{
        if (x < 0 || y < 0 || SCRW <= x || SCRH <= y) {
                return 0;
        }
        vid[x + y * SCRW] = val;
        return 1;
}

static int
gdraw(int dx, int dy, int val)
{
        int     i;
        int     set = 0;

        if (dx != 0) {
                i = cur_x;
                cur_x += dx;
                if (dx < 0) {
                        i += dx;
                        dx = -dx;
                }
                /* horizontal line */
                for (; dx >= 0; --dx, ++i) {
                        set |= gpset(i, cur_y, val);
                } 
        }
        else {  /* dy != 0 */
                i = cur_y;
                cur_y += dy;
                if (dy < 0) {
                        i += dy;
                        dy = -dy;
                }
                /* vertical line */
                for (; dy >= 0; --dy, ++i) {
                        set |= gpset(cur_x, i, val);
                } 
        }
        return set;
}

static void
dragon_update(video_adapter_t *adp)
{
        static int      i, p, q;
        static int      order, mul, out;
        static int      org_x, org_y;
        static int      dx, dy;
        static unsigned char    fold[1 << (ORDER - 3)];
#define GET_FOLD(x)     (fold[(x) >> 3]  &  (1 << ((x) & 7)))
#define SET_FOLD(x)     (fold[(x) >> 3] |=  (1 << ((x) & 7)))
#define CLR_FOLD(x)     (fold[(x) >> 3] &= ~(1 << ((x) & 7)))
        int     tmp;

        if (curve > CURVE) {
                vidd_clear(adp);

                /* set palette of each curves */
                for (tmp = 0; tmp < 3*CURVE; ++tmp) {
                        dragon_pal[3+tmp] = (u_char)random(); 
                }
                vidd_load_palette(adp, dragon_pal);

                mul = ((random() & 7) + 1) * (SCRW / 320);
                org_x = random() % SCRW; org_y = random() % SCRH;

                curve = 0;
                order = ORDER;
        }

        if (order >= ORDER) {
                ++curve;

                cur_x = org_x; cur_y = org_y;

                switch (curve) {
                case 1:
                        dx = 0; dy = mul;
                        break;
                case 2:
                        dx = mul; dy = 0;
                        break;
                case 3:
                        dx = 0; dy = -mul;
                        break;
                }
                (void)gdraw(dx, dy, curve); out = 0;

                order = 0;
                q = p = 0; i = q + 1;
        }

        if (i > q) {
                SET_FOLD(p); q = p * 2;

                ++order;
                i = p; p = q + 1;
        }

        if (GET_FOLD(q-i) != 0) {
                CLR_FOLD(i);
                tmp = dx; dx =  dy; dy = -tmp;  /* turn right */
        }
        else {
                SET_FOLD(i);
                tmp = dx; dx = -dy; dy =  tmp;  /* turn left */
        }
        if (gdraw(dx, dy, curve)) {
                out = 0;
        }
        else {
                if (++out > OUT) {
                        order = ORDER;  /* force to terminate this curve */
                }
        }
        ++i;
}

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

        if (blank) {
                /* switch to graphics mode */
                if (blanked <= 0) {
                        pl = splhigh();
                        vidd_set_mode(adp, VIDEO_MODE);
                        vid = (u_char *)adp->va_window;
                        curve = CURVE + 1;
                        ++blanked;
                        splx(pl);
                }

                /* update display */
                dragon_update(adp);
        }
        else {
                blanked = 0;
        }
        return 0;
}

static int
dragon_init(video_adapter_t *adp)
{
        video_info_t info;

        /* check that the console is capable of running in 320x200x256 */
        if (vidd_get_info(adp, VIDEO_MODE, &info)) {
                log(LOG_NOTICE,
                    "%s: the console does not support " VIDEO_MODE_NAME "\n",
                    SAVER_NAME);
                return ENODEV;
        }

        blanked = 0;
        return 0;
}

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

static scrn_saver_t dragon_module = {
        SAVER_NAME,
        dragon_init,
        dragon_term,
        dragon_saver,
        NULL,
};

SAVER_MODULE(dragon_saver, dragon_module);