--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-rpg/rpg/battle-state-item.c	Fri Jan 08 12:56:10 2021 +0100
@@ -0,0 +1,158 @@
+/*
+ * battle-state-item.c -- battle state (using item)
+ *
+ * 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.
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <core/alloc.h>
+#include <core/panic.h>
+#include <core/window.h>
+
+#include <rpg/inventory.h>
+#include <rpg/item.h>
+
+#include <ui/align.h>
+#include <ui/frame.h>
+#include <ui/label.h>
+
+#include "battle-entity-state.h"
+#include "battle-state.h"
+#include "battle.h"
+
+enum substate {
+	SUBSTATE_ADVANCING,
+	SUBSTATE_MESSAGE,
+	SUBSTATE_RETURNING
+};
+
+struct msg {
+	struct frame frame;
+	struct label label;
+	unsigned int elapsed;
+};
+
+struct self {
+	enum substate substate;
+	struct msg msg;
+	struct battle_entity *source;
+	struct battle_entity *target;
+	struct battle_state state;
+	struct inventory_slot *slot;
+	int origin_x;
+};
+
+static bool
+update(struct battle_state *st, struct battle *bt, unsigned int ticks)
+{
+	struct self *self = st->data;
+
+	switch (self->substate) {
+	case SUBSTATE_ADVANCING:
+		/* Entity is updating from battle, so just inspect its status. */
+		if (battle_entity_update(self->source, 0)) {
+			self->substate = SUBSTATE_MESSAGE;
+			battle_entity_state_normal(self->source);
+		}
+		break;
+	case SUBSTATE_MESSAGE:
+		self->msg.elapsed += ticks;
+
+		if (self->msg.elapsed >= 2000) {
+			self->substate = SUBSTATE_RETURNING;
+			battle_entity_state_moving(self->source, self->origin_x, self->source->y);
+		}
+		break;
+	default:
+		if (battle_entity_update(self->source, 0)) {
+			battle_entity_state_normal(self->source);
+			battle_use(bt, self->slot->item, self->source->ch, self->target->ch);
+		}
+		break;
+	}
+
+	return false;
+}
+
+static void
+draw(const struct battle_state *st, const struct battle *bt)
+{
+	struct self *self = st->data;
+
+	if (self->substate == SUBSTATE_MESSAGE) {
+		frame_draw(&self->msg.frame);
+		label_draw(&self->msg.label);
+	}
+}
+
+static void
+finish(struct battle_state *st, struct battle *bt)
+{
+	(void)bt;
+
+	free(st->data);
+}
+
+void
+battle_state_item(struct battle *bt,
+                  struct character *source,
+                  struct character *target,
+                  struct inventory_slot *slot)
+{
+	assert(bt);
+	assert(source);
+	assert(target);
+	assert(slot);
+
+	struct self *self;
+	unsigned int lw, lh;
+
+	if (!(self = alloc_new0(sizeof (*self))))
+		panic();
+
+	self->source = battle_find(bt, source);
+	self->target = battle_find(bt, target);
+	self->slot = slot;
+	self->origin_x = self->source->x;
+
+	/* Prepare message frame. */
+	self->msg.frame.w = window.w / 3;
+	self->msg.frame.h = window.h / 15;
+	self->msg.frame.theme = bt->theme;
+
+	align(ALIGN_TOP,
+	    &self->msg.frame.x, &self->msg.frame.y, self->msg.frame.w, self->msg.frame.h,
+	    0, 20, window.w, window.h);
+
+	/* Prepare message label box. */
+	self->msg.label.text = slot->item->name;
+	self->msg.label.flags = LABEL_FLAGS_SHADOW;
+	self->msg.label.theme = bt->theme;
+	label_query(&self->msg.label, &lw, &lh);
+
+	align(ALIGN_CENTER,
+	    &self->msg.label.x, &self->msg.label.y, lw, lh,
+	    self->msg.frame.x, self->msg.frame.y, self->msg.frame.w, self->msg.frame.h);
+
+	self->state.data = self;
+	self->state.update = update;
+	self->state.draw = draw;
+	self->state.finish = finish;
+
+	battle_entity_state_moving(self->source, self->origin_x - 100, self->source->y);
+	battle_switch(bt, &self->state);
+}