--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-rpg/rpg/battle-entity-state.h	Sat Nov 28 22:37:30 2020 +0100
@@ -0,0 +1,124 @@
+/*
+ * battle-entity-state.h -- abstract battle entity state
+ *
+ * Copyright (c) 2020 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.
+ */
+
+#ifndef MOLKO_RPG_BATTLE_ENTITY_STATE_H
+#define MOLKO_RPG_BATTLE_ENTITY_STATE_H
+
+/**
+ * \file battle-entity-state.h
+ * \brief Abstract battle entity state.
+ *
+ * To animate and update battle entities this structure help splitting the logic
+ * into differents parts.
+ *
+ * In contrast to battle states, battle entity states should not switch
+ * themselves into an other one because battle states may need to wait until the
+ * entity state has finished to continue their own work.
+ *
+ * \note Do not call pointer functions directly but use the functions from this
+ *       file since they may do additional work.
+ */
+
+#include <stdbool.h>
+
+struct battle_entity;
+
+/**
+ * \brief Abstract battle entity state.
+ */
+struct battle_entity_state {
+	/**
+	 * (+&?) Optional state data.
+	 */
+	void *data;
+
+	/**
+	 * (+?) Update the entity.
+	 *
+	 * This function should understand a value of 0 as ticks to just request
+	 * the state's status.
+	 *
+	 * \pre st != NULL
+	 * \pre et != NULL
+	 * \param st this state
+	 * \param et the entity owner
+	 * \param ticks elapsed milliseconds since last frame
+	 * \return True if complete.
+	 */
+	bool (*update)(struct battle_entity_state *st, struct battle_entity *et, unsigned int ticks);
+
+	/**
+	 * (+?) Draw the entity.
+	 *
+	 * If this function is NULL, the default behavior is to draw the entity
+	 * sprite at its current position.
+	 *
+	 * \pre st != NULL
+	 * \pre et != NULL
+	 * \param st this state
+	 * \param et the entity owner
+	 */
+	void (*draw)(const struct battle_entity_state *st, const struct battle_entity *et);
+
+	/**
+	 * (+?) Clear resources.
+	 *
+	 * \pre st != NULL
+	 * \pre et != NULL
+	 * \param st this state
+	 * \param et the entity owner
+	 */
+	void (*finish)(struct battle_entity_state *st, struct battle_entity *et);
+};
+
+/**
+ * Shortcut for st->update (if not NULL).
+ *
+ * \pre st != NULL
+ * \pre et != NULL
+ * \param st this state
+ * \param et the entity owner
+ * \param ticks elapsed milliseconds since last frame
+ * \return True if complete.
+ */
+bool
+battle_entity_state_update(struct battle_entity_state *st, struct battle_entity *et, unsigned int ticks);
+
+/**
+ * Call st->draw or default implementation if NULL.
+ *
+ * \pre st != NULL
+ * \pre et != NULL
+ * \param st this state
+ * \param et the entity owner
+ */
+void
+battle_entity_state_draw(const struct battle_entity_state *st, const struct battle_entity *et);
+
+/**
+ * Shortcut for st->finish (if not NULL).
+ *
+ * \pre st != NULL
+ * \pre et != NULL
+ * \param st this state
+ * \param et the entity owner
+ */
+void
+battle_entity_state_finish(struct battle_entity_state *st, struct battle_entity *et);
+
+#endif /* !MOLKO_RPG_BATTLE_ENTITY_STATE_H */