// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef IOS_CHROME_APP_APPLICATION_DELEGATE_APP_STATE_H_
#define IOS_CHROME_APP_APPLICATION_DELEGATE_APP_STATE_H_

#import <UIKit/UIKit.h>

#import "ios/chrome/app/application_delegate/app_init_stage.h"
#import "ios/chrome/app/application_delegate/app_state_agent.h"
#import "ios/chrome/app/application_delegate/app_state_observer.h"
#import "ios/chrome/app/background_refresh/background_refresh_app_agent_audience.h"
#import "ios/chrome/app/task_orchestrator.h"
#import "ios/chrome/browser/device_orientation/ui_bundled/portait_orientation_manager.h"
#import "ios/chrome/browser/scoped_ui_blocker/ui_bundled/ui_blocker_manager.h"
#import "ios/chrome/browser/shared/coordinator/scene/scene_state_observer.h"

@class CommandDispatcher;
@class ProfileState;
@class SceneState;
@class DeferredInitializationRunner;
@protocol StartupInformation;

// These values are persisted to logs. Entries should not be renumbered and
// numeric values should never be reused.
enum class PostCrashAction {
  // Restore tabs normally after a clean shutdown.
  kRestoreTabsCleanShutdown = 0,
  // Restore tabs normally after an unclean shutdown.
  kRestoreTabsUncleanShutdown = 1,
  // kStashTabsAndShowNTP is no longer used, but the value 2 cannot be reused
  // as it would break histograms.
  // Restore tabs with `return to previous tab` NTP.
  kShowNTPWithReturnToTab = 3,
  // Show safe mode.
  kShowSafeMode = 4,
  kMaxValue = kShowSafeMode,
};

// Represents the application state and responds to application state changes
// and system events.
@interface AppState : NSObject <BackgroundRefreshAudience,
                                PortraitOrientationManager,
                                SceneStateObserver,
                                UIBlockerManager>

- (instancetype)init NS_UNAVAILABLE;

- (instancetype)initWithStartupInformation:
    (id<StartupInformation>)startupInformation NS_DESIGNATED_INITIALIZER;

// Dispatcher for app-level commands for multiwindow use cases.
// Most features should use the browser-level dispatcher instead.
@property(nonatomic, strong) CommandDispatcher* appCommandDispatcher;

// Container for startup information.
@property(nonatomic, weak) id<StartupInformation> startupInformation;

// YES if the fullscreen sign-in promo has been presented to the user, once.
@property(nonatomic) BOOL fullscreenSigninPromoPresentedOnce;

// Indicates what action, if any, is taken after a crash (stash tabs, show NTP,
// show safe mode).
@property(nonatomic, assign) PostCrashAction postCrashAction;

// YES if the app is resuming from safe mode.
@property(nonatomic) BOOL resumingFromSafeMode;

// The initialization stage the app is currently at.
@property(nonatomic, readonly) AppInitStage initStage;

// YES if the views being presented should only support the portrait
// orientation.
@property(nonatomic, readonly) BOOL portraitOnly;

// All agents that have been attached. Use -addAgent: and -removeAgent: to
// add and remove agents.
@property(nonatomic, readonly) NSArray<id<AppStateAgent>>* connectedAgents;

// Can be used to schedule deferred initialization tasks.
@property(nonatomic, readonly) DeferredInitializationRunner* deferredRunner;

// Can be used to schedule tasks received from the OS.
@property(nonatomic, readonly) TaskOrchestrator* taskOrchestrator;

// Returns the foreground and active scene, if there is one.
- (SceneState*)foregroundActiveScene;

// Returns a list of all connected scenes.
- (NSArray<SceneState*>*)connectedScenes;

// Returns a list of all scenes in the foreground that are not necessarly
// active.
- (NSArray<SceneState*>*)foregroundScenes;

// Returns a list of all known ProfileStates.
- (NSArray<ProfileState*>*)profileStates;

// Adds an observer to this app state. The observers will be notified about
// app state changes per AppStateObserver protocol.
// The observer will be *immediately* notified about the latest init stage
// transition, if any such transitions happened (didTransitionFromInitStage),
// before this method returns.
- (void)addObserver:(id<AppStateObserver>)observer;

// Removes the observer. It's safe to call this at any time, including from
// AppStateObserver callbacks.
- (void)removeObserver:(id<AppStateObserver>)observer;

// Informs the AppState of the connection/disconnection of a SceneState.
- (void)sceneStateConnected:(SceneState*)sceneState;
- (void)sceneStateDisconnected:(SceneState*)sceneState;

// Informs the AppState of the creation/destruction of a ProfileState.
- (void)profileStateCreated:(ProfileState*)profileState;
- (void)profileStateDestroyed:(ProfileState*)profileState;

// Adds a new agent. Agents are owned by the app state.
// This automatically sets the app state on the `agent`.
- (void)addAgent:(id<AppStateAgent>)agent;
// Removes an agent.
- (void)removeAgent:(id<AppStateAgent>)agent;

// Queue the transition to the next app initialization stage. Will stop
// transitioning when the Final stage is reached.
// All observers will be notified about each transition until the next
// transition takes place. If an observer calls this method from a transition
// notification, the method will return, the observers will be notified of the
// prior change, and then transition will take place. Then this method will
// finally return to the runloop. It is an error to queue more than one
// transition at once.
- (void)queueTransitionToNextInitStage;

// Queue the transition (as defined above) to the very first initialization
// stage.
- (void)startInitialization;

@end

#endif  // IOS_CHROME_APP_APPLICATION_DELEGATE_APP_STATE_H_