--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/libmlk-rpg/rpg/selection.c	Fri Oct 01 20:30:00 2021 +0200
@@ -0,0 +1,88 @@
+/*
+ * selection.c -- kind of selection
+ *
+ * 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 <core/util.h>
+
+#include "battle.h"
+#include "character.h"
+#include "selection.h"
+
+static void
+random(struct selection *slt, const struct battle *bt, const struct battle_entity *entities, size_t entitiesz)
+{
+	(void)bt;
+
+	struct {
+		const struct battle_entity *entity;
+		size_t position;
+	} table[BATTLE_ENTITY_MAX] = {0};
+
+	size_t tablesz = 0;
+
+	/*
+	 * Merge the list of valid entities into the table to select a random
+	 * one.
+	 */
+	for (size_t i = 0; i < entitiesz; ++i) {
+		if (battle_entity_ok(&entities[i])) {
+			table[tablesz].entity = &entities[i];
+			table[tablesz++].position = i;
+		}
+	}
+
+	slt->index_character = table[util_nrand(0, tablesz)].position;
+}
+
+static void
+first(struct selection *slt, const struct battle *bt, const struct battle_entity *entities, size_t entitiesz)
+{
+	(void)bt;
+
+	for (size_t i = 0; i < entitiesz; ++i) {
+		if (battle_entity_ok(&entities[i])) {
+			slt->index_character = i;
+			break;
+		}
+	}
+}
+
+void
+selection_first(struct selection *slt, const struct battle *bt)
+{
+	assert(slt);
+	assert(bt);
+
+	if (slt->index_side == 0)
+		first(slt, bt, bt->enemies, BATTLE_ENEMY_MAX);
+	else
+		first(slt, bt, bt->team, BATTLE_TEAM_MAX);
+}
+
+void
+selection_random(struct selection *slt, const struct battle *bt)
+{
+	assert(slt);
+	assert(bt);
+
+	if (slt->index_side == 0)
+		random(slt, bt, bt->enemies, BATTLE_ENEMY_MAX);
+	else
+		random(slt, bt, bt->team, BATTLE_TEAM_MAX);
+}