/*
 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "Image.h"
#include <LibGUI/Widget.h>

namespace PixelPaint {

class LayerListWidget final
    : public GUI::Widget
    , ImageClient {
    C_OBJECT(LayerListWidget);

public:
    virtual ~LayerListWidget() override;

    void set_image(Image*);

    void set_selected_layer(Layer*);
    Function<void(Layer*)> on_layer_select;

    void select_bottom_layer();
    void select_top_layer();
    void move_selection(int delta);

private:
    explicit LayerListWidget();

    virtual void paint_event(GUI::PaintEvent&) override;
    virtual void mousedown_event(GUI::MouseEvent&) override;
    virtual void mousemove_event(GUI::MouseEvent&) override;
    virtual void mouseup_event(GUI::MouseEvent&) override;
    virtual void resize_event(GUI::ResizeEvent&) override;

    virtual void image_did_add_layer(size_t) override;
    virtual void image_did_remove_layer(size_t) override;
    virtual void image_did_modify_layer(size_t) override;
    virtual void image_did_modify_layer_stack() override;

    void rebuild_gadgets();
    void relayout_gadgets();

    size_t hole_index_during_move() const;

    struct Gadget {
        size_t layer_index { 0 };
        Gfx::Rect rect;
        Gfx::Rect temporary_rect_during_move;
        bool is_moving { false };
        Gfx::Point movement_delta;
    };

    bool is_moving_gadget() const { return m_moving_gadget_index.has_value(); }

    Optional<size_t> gadget_at(const Gfx::Point&);

    Vector<Gadget> m_gadgets;
    RefPtr<Image> m_image;

    Optional<size_t> m_moving_gadget_index;
    Gfx::Point m_moving_event_origin;
};

}