/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/OwnPtr.h>
#include <AK/RefPtr.h>
#include <LibCore/Object.h>
#include <LibGfx/Color.h>
#include <LibGfx/DisjointRectSet.h>
#include <WindowServer/Screen.h>

namespace WindowServer {

class ClientConnection;
class Cursor;
class Window;
class WindowManager;

enum class WallpaperMode {
    Tile,
    Center,
    Stretch,
    Unchecked
};

class Compositor final : public Core::Object {
    C_OBJECT(Compositor)
public:
    static Compositor& the();

    void compose();
    void invalidate_window();
    void invalidate_screen();
    void invalidate_screen(const Gfx::IntRect&);

    void screen_resolution_changed();

    bool set_background_color(const String& background_color);

    bool set_wallpaper_mode(const String& mode);

    bool set_wallpaper(const String& path, Function<void(bool)>&& callback);
    String wallpaper_path() const { return m_wallpaper_path; }

    void invalidate_cursor(bool = false);
    Gfx::IntRect current_cursor_rect() const;
    const Cursor* current_cursor() const { return m_current_cursor; }
    void current_cursor_was_reloaded(const Cursor* new_cursor) { m_current_cursor = new_cursor; }

    void increment_display_link_count(Badge<ClientConnection>);
    void decrement_display_link_count(Badge<ClientConnection>);

    void invalidate_occlusions() { m_occlusions_dirty = true; }

    void did_construct_window_manager(Badge<WindowManager>);

    const Gfx::Bitmap* cursor_bitmap_for_screenshot(Badge<ClientConnection>, Screen&) const;
    const Gfx::Bitmap& front_bitmap_for_screenshot(Badge<ClientConnection>, Screen&) const;

private:
    Compositor();
    void init_bitmaps();
    bool render_animation_frame(Screen&, Gfx::DisjointRectSet&);
    void step_animations();
    void notify_display_links();
    void start_compose_async_timer();
    void recompute_occlusions();
    bool any_opaque_window_above_this_one_contains_rect(const Window&, const Gfx::IntRect&);
    void change_cursor(const Cursor*);
    void draw_geometry_label(Screen&);
    void flush(Screen&);

    RefPtr<Core::Timer> m_compose_timer;
    RefPtr<Core::Timer> m_immediate_compose_timer;
    bool m_flash_flush { false };
    bool m_occlusions_dirty { true };
    bool m_invalidated_any { true };
    bool m_invalidated_window { false };
    bool m_invalidated_cursor { false };

    struct ScreenData {
        RefPtr<Gfx::Bitmap> m_front_bitmap;
        RefPtr<Gfx::Bitmap> m_back_bitmap;
        RefPtr<Gfx::Bitmap> m_temp_bitmap;
        OwnPtr<Gfx::Painter> m_back_painter;
        OwnPtr<Gfx::Painter> m_front_painter;
        OwnPtr<Gfx::Painter> m_temp_painter;
        RefPtr<Gfx::Bitmap> m_cursor_back_bitmap;
        OwnPtr<Gfx::Painter> m_cursor_back_painter;
        Gfx::IntRect m_last_cursor_rect;
        bool m_buffers_are_flipped { false };
        bool m_screen_can_set_buffer { false };
        bool m_cursor_back_is_valid { false };

        Gfx::DisjointRectSet m_flush_rects;
        Gfx::DisjointRectSet m_flush_transparent_rects;
        Gfx::DisjointRectSet m_flush_special_rects;

        void init_bitmaps(Screen&);
        void flip_buffers(Screen&);
        void draw_cursor(Screen&, const Gfx::IntRect&);
        bool restore_cursor_back(Screen&, Gfx::IntRect&);
    };
    friend class ScreenData;
    Vector<ScreenData, default_screen_count> m_screen_data;

    Gfx::DisjointRectSet m_dirty_screen_rects;
    Gfx::DisjointRectSet m_opaque_wallpaper_rects;

    Gfx::IntRect m_last_dnd_rect;
    Gfx::IntRect m_last_geometry_label_damage_rect;

    String m_wallpaper_path { "" };
    WallpaperMode m_wallpaper_mode { WallpaperMode::Unchecked };
    RefPtr<Gfx::Bitmap> m_wallpaper;

    const Cursor* m_current_cursor { nullptr };
    Screen* m_current_cursor_screen { nullptr };
    unsigned m_current_cursor_frame { 0 };
    RefPtr<Core::Timer> m_cursor_timer;

    RefPtr<Core::Timer> m_display_link_notify_timer;
    size_t m_display_link_count { 0 };

    Optional<Gfx::Color> m_custom_background_color;
};

}