--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/libmlk-adventure/adventure/action/spawner.c	Fri Oct 01 20:30:00 2021 +0200
@@ -0,0 +1,120 @@
+/*
+ * spawner.c -- spawn battle while moving
+ *
+ * Copyright (c) 2020-2021 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+#include <math.h>
+#include <stdlib.h>
+
+#include <core/alloc.h>
+#include <core/game.h>
+#include <core/util.h>
+
+#include <rpg/battle.h>
+#include <rpg/character.h>
+#include <rpg/map.h>
+
+#include <adventure/molko.h>
+
+#include <adventure/character/black-cat.h>
+
+#include "spawner.h"
+
+static inline unsigned int
+distance(const struct spawner *s)
+{
+	unsigned int gap_x = fmax(s->last_x, s->map->player_x) -
+	                     fmin(s->last_x, s->map->player_x);
+	unsigned int gap_y = fmax(s->last_y, s->map->player_y) -
+			     fmin(s->last_y, s->map->player_y);
+
+	return fmin(s->steps, gap_x + gap_y);
+}
+
+static void
+fight(struct spawner *s)
+{
+	(void)s;
+
+	struct battle *bt;
+
+	bt = alloc_new0(sizeof (*bt));
+
+	bt->enemies[0].ch = alloc_dup(&character_black_cat, sizeof (character_black_cat));
+	bt->enemies[0].x = 400;
+	bt->enemies[0].y = 50;
+	bt->enemies[1].ch = alloc_dup(&character_black_cat, sizeof (character_black_cat));
+	bt->enemies[1].x = 200;
+	bt->enemies[1].y = 100;
+
+	bt->inventory = &molko.inventory;
+
+	for (size_t i = 0; i < TEAM_MEMBER_MAX; ++i) {
+		if (molko.team.members[i]) {
+			bt->team[i].ch = alloc_dup(molko.team.members[i], sizeof (*molko.team.members[i]));
+			character_reset(bt->team[i].ch);
+			bt->team[i].ch->hp = bt->team[i].ch->hpmax;
+			bt->team[i].ch->mp = bt->team[i].ch->mpmax;
+		}
+	}
+
+	molko_fight(bt);
+}
+
+static int
+update(struct action *act, unsigned int ticks)
+{
+	(void)ticks;
+
+	struct spawner *s = act->data;
+
+	if (s->map->player_movement) {
+		s->steps -= distance(s);
+		s->last_x = s->map->player_x;
+		s->last_y = s->map->player_y;
+
+		if (s->steps == 0) {
+			spawner_init(s);
+			fight(s);
+		}
+	}
+
+	return 0;
+}
+
+void
+spawner_init(struct spawner *s)
+{
+	assert(s);
+
+	s->last_x = s->map->player_x;
+	s->last_y = s->map->player_y;
+	s->steps = util_nrand(s->low, s->high);
+}
+
+struct action *
+spawner_action(struct spawner *s)
+{
+	assert(s);
+
+	s->action.data = s;
+	s->action.update = update;
+
+	spawner_init(s);
+
+	return &s->action;
+}