///
/// @file Window.h
///
/// @brief The header for the Window class.
///
/// @author
///
/// This file is a part of Ultralight, a next-generation HTML renderer.
///
/// Website: <http://ultralig.ht>
///
/// Copyright (C) 2021 Ultralight, Inc. All rights reserved.
///
#pragma once
#include "Defines.h"
#include <Ultralight/RefPtr.h>
#include <Ultralight/Listener.h>
#include <Ultralight/Bitmap.h>
#include <Ultralight/KeyEvent.h>
#include <Ultralight/MouseEvent.h>
#include <Ultralight/ScrollEvent.h>

namespace ultralight {

class Monitor;
class OverlayManager;
class Surface;
class Window;

///
/// Interface for all Window-related events. @see Window::set_listener
///
class WindowListener {
public:
  virtual ~WindowListener() {}

  ///
  /// Called when the Window is closed.
  ///
  virtual void OnClose(ultralight::Window* window) { }

  ///
  /// Called when the Window is resized.
  ///
  /// @param  width   The new width (in pixels).
  ///
  /// @param  height  The new height (in pixels).
  ///
  virtual void OnResize(ultralight::Window* window, uint32_t width_px, uint32_t height_px) { }

  ///
  /// Called when a keyboard event is fired.
  /// 
  /// @param  evt  Details for the event.
  /// 
  /// @return  Return false to consume the event and prevent it from propagating further.
  /// 
  virtual bool OnKeyEvent(const ultralight::KeyEvent& evt) { return true; }

  ///
  /// Called when a mouse event is fired.
  ///
  /// @param  evt  Details for the event.
  ///
  /// @return  Return false to consume the event and prevent it from propagating further.
  /// 
  virtual bool OnMouseEvent(const ultralight::MouseEvent& evt) { return true; }

  ///
  /// Called when a scroll event is fired.
  ///
  /// @param  evt  Details for the event.
  ///
  /// @return  Return false to consume the event and prevent it from propagating further.
  /// 
  virtual bool OnScrollEvent(const ultralight::ScrollEvent& evt) { return true; }
};

///
/// Window creation flags. @see Window::Create
///
enum WindowFlags : uint8_t {
  kWindowFlags_Borderless  = 1 << 0,
  kWindowFlags_Titled      = 1 << 1,
  kWindowFlags_Resizable   = 1 << 2,
  kWindowFlags_Maximizable = 1 << 3,
  kWindowFlags_Hidden      = 1 << 4,
};

///
/// Window class, represents a platform window.
///
class AExport Window : public RefCounted {
public:
  ///
  /// Create a new Window.
  ///
  /// @param  monitor       The monitor to create the Window on.
  ///
  /// @param  width         The width (in screen coordinates).
  ///
  /// @param  height        The height (in screen coordinates).
  ///
  /// @param  fullscreen    Whether or not the window is fullscreen.
  ///
  /// @param  window_flags  Various window flags.
  /// 
  /// @note  Windows are immediately shown by default unless kWindowFlags_Hidden is set in the
  ///        window_flags parameter. (They can be shown later via Window::Show())
  /// 
  /// @note  Screen coordinates are device-scale-independent and have the following relationship
  ///        to pixel coordinates:   pixel_coordinate = round(screen_coordinate * scale)
  ///
  static RefPtr<Window> Create(Monitor* monitor, uint32_t width, uint32_t height,
    bool fullscreen, unsigned int window_flags);

  ///
  /// Set a WindowListener to receive callbacks for window-related events.
  ///
  /// @note  Ownership remains with the caller.
  ///
  virtual void set_listener(WindowListener* listener) = 0;

  ///
  /// Get the WindowListener, if any.
  ///
  virtual WindowListener* listener() = 0;

  ///
  /// Get the window width (in screen coordinates).
  ///
  virtual uint32_t screen_width() const = 0;

  ///
  /// Get the window width (in pixels).
  ///
  virtual uint32_t width() const = 0;

  ///
  /// Get the window height (in screen coordinates).
  ///
  virtual uint32_t screen_height() const = 0;

  ///
  /// Get the window height (in pixels).
  ///
  virtual uint32_t height() const = 0;

  ///
  /// Move the window to a new position (in screen coordinates) relative to the top-left of the 
  /// monitor area.
  /// 
  virtual void MoveTo(int x, int y) = 0;

  ///
  /// Move the window to the center of the monitor.
  ///
  virtual void MoveToCenter() = 0;

  ///
  /// Get the x-position of the window (in screen coordinates) relative to the top-left of the
  /// monitor area.
  ///
  virtual int x() const = 0;

  ///
  /// Get the y-position of the window (in screen coordinates) relative to the top-left of the
  /// monitor area.
  ///
  virtual int y() const = 0;

  ///
  /// Whether or not the window is fullscreen.
  ///
  virtual bool is_fullscreen() const = 0;

  ///
  /// Whether or not the window is GPU accelerated.
  /// 
  virtual bool is_accelerated() const = 0;

  ///
  /// The render buffer id of the the window's backing texture.
  /// (This will be 0 if the window is not accelerated).
  /// 
  virtual uint32_t render_buffer_id() const = 0;

  ///
  /// The DPI scale of the window.
  ///
  virtual double scale() const = 0;

  ///
  /// Set the window title.
  ///
  virtual void SetTitle(const char* title) = 0;

  ///
  /// Set the cursor.
  ///
  virtual void SetCursor(ultralight::Cursor cursor) = 0;

  ///
  /// Show the window (if it was previously hidden).
  ///
  virtual void Show() = 0;

  ///
  /// Hide the window.
  /// 
  virtual void Hide() = 0;

  ///
  /// Whether or not the window is currently visible (not hidden).
  ///
  virtual bool is_visible() const = 0;

  ///
  /// Close the window.
  ///
  virtual void Close() = 0;

  ///
  /// Convert screen coordinates to pixels using the current DPI scale.
  ///
  virtual int ScreenToPixels(int val) const = 0;

  ///
  /// Convert pixels to screen coordinates using the current DPI scale.
  ///
  virtual int PixelsToScreen(int val) const = 0;

  ///
  /// Draw a surface directly to window, used only by CPU renderer
  ///
  virtual void DrawSurface(int x, int y, Surface* surface) {}

  ///
  /// Get the underlying native window handle.
  ///
  /// @note This is:  - HWND on Windows
  ///                 - NSWindow* on macOS
  ///                 - GLFWwindow* on Linux
  ///
  virtual void* native_handle() const = 0;

protected:
  virtual ~Window();
  virtual OverlayManager* overlay_manager() const = 0;

  friend class OverlayImpl;
};

}  // namespace ultralight