// Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
//
// You are hereby granted a non-exclusive, worldwide, royalty-free license to use,
// copy, modify, and distribute this software in source code or binary form for use
// in connection with the web services and APIs provided by Facebook.
//
// As with any software that integrates with the Facebook platform, your use of
// this software is subject to the Facebook Developer Principles and Policies
// [http://developers.facebook.com/policy/]. This copyright notice shall be
// included in all copies or substantial portions of the software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#import <Foundation/Foundation.h>

#import <FBSDKCoreKit/FBSDKCopying.h>
#import <FBSDKCoreKit/FBSDKGraphRequestConnection.h>
#import <FBSDKCoreKit/FBSDKMacros.h>

/**
  Notification indicating that the `currentAccessToken` has changed.

 the userInfo dictionary of the notification will contain keys
 `FBSDKAccessTokenChangeOldKey` and
 `FBSDKAccessTokenChangeNewKey`.
 */
FBSDK_EXTERN NSString *const FBSDKAccessTokenDidChangeNotification;

/**
  A key in the notification's userInfo that will be set
  if and only if the user ID changed between the old and new tokens.

 Token refreshes can occur automatically with the SDK
  which do not change the user. If you're only interested in user
  changes (such as logging out), you should check for the existence
  of this key. The value is a NSNumber with a boolValue.

  On a fresh start of the app where the SDK reads in the cached value
  of an access token, this key will also exist since the access token
  is moving from a null state (no user) to a non-null state (user).
 */
FBSDK_EXTERN NSString *const FBSDKAccessTokenDidChangeUserID;

/*
  key in notification's userInfo object for getting the old token.

 If there was no old token, the key will not be present.
 */
FBSDK_EXTERN NSString *const FBSDKAccessTokenChangeOldKey;

/*
  key in notification's userInfo object for getting the new token.

 If there is no new token, the key will not be present.
 */
FBSDK_EXTERN NSString *const FBSDKAccessTokenChangeNewKey;

/*
 A key in the notification's userInfo that will be set
 if and only if the token has expired.
 */
FBSDK_EXTERN NSString *const FBSDKAccessTokenDidExpire;


/**
  Represents an immutable access token for using Facebook services.
 */
@interface FBSDKAccessToken : NSObject<FBSDKCopying, NSSecureCoding>

/**
  Returns the app ID.
 */
@property (readonly, copy, nonatomic) NSString *appID;

/**
  Returns the known declined permissions.
 */
@property (readonly, copy, nonatomic) NSSet *declinedPermissions;

/**
  Returns the expiration date.
 */
@property (readonly, copy, nonatomic) NSDate *expirationDate;

/**
  Returns the known granted permissions.
 */
@property (readonly, copy, nonatomic) NSSet *permissions;

/**
  Returns the date the token was last refreshed.
*/
@property (readonly, copy, nonatomic) NSDate *refreshDate;

/**
  Returns the opaque token string.
 */
@property (readonly, copy, nonatomic) NSString *tokenString;

/**
  Returns the user ID.
 */
@property (readonly, copy, nonatomic) NSString *userID;

/**
 Returns whether the access token is expired by checking its expirationDate property
 */
@property (readonly, assign, nonatomic, getter = isExpired) BOOL expired;

- (instancetype)init NS_UNAVAILABLE;
+ (instancetype)new NS_UNAVAILABLE;

/**
  Initializes a new instance.
 - Parameter tokenString: the opaque token string.
 - Parameter permissions: the granted permissions. Note this is converted to NSSet and is only
 an NSArray for the convenience of literal syntax.
 - Parameter declinedPermissions: the declined permissions. Note this is converted to NSSet and is only
 an NSArray for the convenience of literal syntax.
 - Parameter appID: the app ID.
 - Parameter userID: the user ID.
 - Parameter expirationDate: the optional expiration date (defaults to distantFuture).
 - Parameter refreshDate: the optional date the token was last refreshed (defaults to today).

 This initializer should only be used for advanced apps that
 manage tokens explicitly. Typical login flows only need to use `FBSDKLoginManager`
 along with `+currentAccessToken`.
 */
- (instancetype)initWithTokenString:(NSString *)tokenString
                        permissions:(NSArray *)permissions
                declinedPermissions:(NSArray *)declinedPermissions
                              appID:(NSString *)appID
                             userID:(NSString *)userID
                     expirationDate:(NSDate *)expirationDate
                        refreshDate:(NSDate *)refreshDate
NS_DESIGNATED_INITIALIZER;

/**
  Convenience getter to determine if a permission has been granted
 - Parameter permission:  The permission to check.
 */
- (BOOL)hasGranted:(NSString *)permission;

/**
  Compares the receiver to another FBSDKAccessToken
 - Parameter token: The other token
 - Returns: YES if the receiver's values are equal to the other token's values; otherwise NO
 */
- (BOOL)isEqualToAccessToken:(FBSDKAccessToken *)token;

/**
  Returns the "global" access token that represents the currently logged in user.

 The `currentAccessToken` is a convenient representation of the token of the
 current user and is used by other SDK components (like `FBSDKLoginManager`).
 */
+ (FBSDKAccessToken *)currentAccessToken;

/**
 Returns YES if currentAccessToken is not nil AND currentAccessToken is not expired

 */
+ (BOOL)currentAccessTokenIsActive;

/**
  Sets the "global" access token that represents the currently logged in user.
 - Parameter token: The access token to set.

 This will broadcast a notification and save the token to the app keychain.
 */
+ (void)setCurrentAccessToken:(FBSDKAccessToken *)token;

/**
  Refresh the current access token's permission state and extend the token's expiration date,
  if possible.
 - Parameter completionHandler: an optional callback handler that can surface any errors related to permission refreshing.

 On a successful refresh, the currentAccessToken will be updated so you typically only need to
  observe the `FBSDKAccessTokenDidChangeNotification` notification.

 If a token is already expired, it cannot be refreshed.
 */
+ (void)refreshCurrentAccessToken:(FBSDKGraphRequestHandler)completionHandler;

@end
