--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-core/core/action.h	Sat Nov 28 22:37:30 2020 +0100
@@ -0,0 +1,239 @@
+/*
+ * action.h -- action states
+ *
+ * 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_CORE_ACTION_H
+#define MOLKO_CORE_ACTION_H
+
+/**
+ * \file action.h
+ * \brief Action states.
+ * \ingroup actions
+ */
+
+#include <stdbool.h>
+
+/**
+ * \brief Maximum number of actions in stack.
+ */
+#define ACTION_STACK_MAX        128
+
+union event;
+
+/**
+ * \brief Action structure.
+ *
+ * Use this structure to create an action that reacts to user events.
+ *
+ * The purpose of actions is to simplify user interaction within a specific
+ * state or a dedicated user routine. With the help of the companion
+ * \ref action_stack it is easy to manage actions in a specific game logic
+ * state.
+ *
+ * All members can be NULL.
+ */
+struct action {
+	/**
+	 * (+&?) Arbitrary user data.
+	 */
+	void *data;
+
+	/**
+	 * (+&?) Handle event.
+	 *
+	 * \param act this action
+	 * \param ev the event
+	 */
+	void (*handle)(struct action *act, const union event *ev);
+
+	/**
+	 * (+?) Update the action.
+	 *
+	 * \param act this action
+	 * \param ticks the number of milliseconds since last frame
+	 * \return true if action has terminated
+	 */
+	bool (*update)(struct action *act, unsigned int ticks);
+
+	/**
+	 * (+?) Draw the action.
+	 *
+	 * \param act this action
+	 */
+	void (*draw)(struct action *act);
+
+	/**
+	 * (+?) Called when the action was completed.
+	 *
+	 * This callback is mostly provided to allow the user doing something
+	 * else once an action is complete. Predefined actions should not use
+	 * this callback by themselves.
+	 *
+	 * \param act this action
+	 */
+	void (*end)(struct action *act);
+
+	/**
+	 * (+?) Destroy internal resources.
+	 *
+	 * Close the action before removal. This function should be used to
+	 * deallocate memory if necessary.
+	 *
+	 * \param act this action
+	 */
+	void (*finish)(struct action *act);
+};
+
+/**
+ * Shortcut for act->handle (if not NULL).
+ *
+ * \pre act != NULL
+ * \pre ev != NULL
+ * \param act the action
+ * \param ev the event
+ */
+void
+action_handle(struct action *act, const union event *ev);
+
+/**
+ * Shortcut for act->update (if not NULL).
+ *
+ * \pre act != NULL
+ * \param act the action
+ * \param ticks the number of milliseconds since last frame
+ * \return Status of act->update or false if act->update is NULL.
+ */
+bool
+action_update(struct action *act, unsigned int ticks);
+
+/**
+ * Shortcut for act->draw (if not NULL).
+ *
+ * \pre act != NULL
+ * \param act the action
+ */
+void
+action_draw(struct action *act);
+
+/**
+ * Shortcut for act->end (if not NULL).
+ *
+ * \pre act != NULL
+ * \param act the action
+ */
+void
+action_end(struct action *act);
+
+/**
+ * Shortcut for act->finish (if not NULL).
+ *
+ * \pre act != NULL
+ * \param act the action
+ */
+void
+action_finish(struct action *act);
+
+/**
+ * \brief Stack of actions.
+ *
+ * The purpose of this structure is to help managing several actions at once.
+ * Actions are automatically removed from the stack if the corresponding update
+ * member function returns true after completion.
+ *
+ * This structure contains pointers to actions that must be kept until the stack
+ * is destroyed. User is responsible of deallocating them if they were allocated
+ * from the heap.
+ */
+struct action_stack {
+	struct action *actions[ACTION_STACK_MAX];        /*!< (+) Actions */
+};
+
+/**
+ * Initalize the action stack.
+ *
+ * It is unnecessary if the object was zero'ed.
+ *
+ * \pre st != NULL
+ * \param st the stack
+ */
+void
+action_stack_init(struct action_stack *st);
+
+/**
+ * Add an action to the stack.
+ *
+ * \pre st != NULL
+ * \pre act != NULL
+ * \param st the stack
+ * \param act the action
+ * \note The pointer must be kept alive.
+ * \return True if the action was added correctly (enough space).
+ */
+bool
+action_stack_add(struct action_stack *st, struct action *act);
+
+/**
+ * Handle an event for all actions.
+ *
+ * \pre st != NULL
+ * \pre ev != NULL
+ * \param st the stack
+ * \param ev the event
+ */
+void
+action_stack_handle(struct action_stack *st, const union event *ev);
+
+/**
+ * Update all actions.
+ *
+ * \pre st != NULL
+ * \param st the stack
+ * \param ticks the number of milliseconds since last frame
+ * \return True if all actions completed.
+ */
+bool
+action_stack_update(struct action_stack *st, unsigned int ticks);
+
+/**
+ * Draw all actions.
+ *
+ * \pre st != NULL
+ * \param st the stack
+ */
+void
+action_stack_draw(const struct action_stack *st);
+
+/**
+ * Tells if there is any pending action in the stack.
+ *
+ * \pre st != NULL
+ * \param st the stack
+ * \return False if there is at least one action in the stack.
+ */
+bool
+action_stack_completed(const struct action_stack *st);
+
+/**
+ * Terminate all actions and clear the stack.
+ *
+ * \pre st != NULL
+ * \param st the stack
+ */
+void
+action_stack_finish(struct action_stack *st);
+
+#endif /* !MOLKO_CORE_ACTION_H */