// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IOS_CHROME_BROWSER_UI_UTIL_KEYBOARD_OBSERVER_HELPER_H_
#define IOS_CHROME_BROWSER_UI_UTIL_KEYBOARD_OBSERVER_HELPER_H_

#import <UIKit/UIKit.h>

@protocol EdgeLayoutGuideProvider;

// Struct to track the current keyboard state.
typedef struct {
  // Is YES if the keyboard is visible or becoming visible.
  BOOL isVisible;
  // Is YES if keyboard is or becoming undocked from bottom of screen.
  BOOL isUndocked;
  // Is YES if keyboard is or becoming split in more than one piece.
  BOOL isSplit;
  // Is YES if a hardware keyboard is in use and only the top part of the
  // software keyboard is showing.
  BOOL isHardware;
  // Is YES if a picker (iPhone only) is currently displayed instead of
  // keyboard.
  BOOL isPicker;
} KeyboardState;

// Delegate informed about the visible/hidden state of the keyboard.
@protocol KeyboardObserverHelperConsumer <NSObject>

// Indicates that |UIKeyboardWillHideNotification| was posted but the keyboard
// was not hidden. For example, this can happen when jumping between fields.
// Deprecated. This is not needed on iOS 13 and will be deleted once support for
// iOS 12 is removed.
- (void)keyboardDidStayOnScreen API_DEPRECATED("Not needed on iOS >12",
                                               ios(11.0, 13.0));

// Indicates that the keyboard state changed, at least on one of the
// |KeyboardState| aspects.
- (void)keyboardWillChangeToState:(KeyboardState)keyboardState;

@end

// Helper to observe the keyboard and report updates.
@interface KeyboardObserverHelper : NSObject

// Keyboard's UIView based on some known, undocumented classes. |nil| if the
// keyboard is not present or found.
// This can break on any iOS update to keyboard architecture.
@property(class, readonly, nonatomic) UIView* keyboardView;

// Best layout guide for the keyboard including the prediction part of it. |nil|
// if the keyboard is not present or found.
// This can break on any iOS update to keyboard architecture.
@property(class, readonly, nonatomic) id<EdgeLayoutGuideProvider>
    keyboardLayoutGuide;

// Flag that indicates if the keyboard is on screen.
// TODO(crbug.com/974226): look into deprecating keyboardOnScreen for
// isKeyboardVisible.
@property(nonatomic, readonly, getter=isKeyboardOnScreen) BOOL keyboardOnScreen;

// The consumer to inform of the keyboard state changes.
@property(nonatomic, weak) id<KeyboardObserverHelperConsumer> consumer;

// Current keyboard state.
@property(nonatomic, readonly, getter=getKeyboardState)
    KeyboardState keyboardState;

@end

#endif  // IOS_CHROME_BROWSER_UI_UTIL_KEYBOARD_OBSERVER_HELPER_H_