Chapter 11 - Chat App/ChatAppFinished/Pods/FirebaseDatabase/Firebase/Database/Login/FAuthTokenProvider.m
/*
 * Copyright 2017 Google
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#import "FAuthTokenProvider.h"

#import <FirebaseAuthInterop/FIRAuthInterop.h>
#import <FirebaseCore/FIRAppInternal.h>
#import <FirebaseCore/FIRComponentContainer.h>
#import <FirebaseCore/FIRLogger.h>

#import "FUtilities.h"
#import "FIRDatabaseQuery_Private.h"
#import "FIRNoopAuthTokenProvider.h"

@interface FAuthStateListenerWrapper : NSObject

@property (nonatomic, copy) fbt_void_nsstring listener;
@property (nonatomic, weak) id<FIRAuthInterop> auth;

@end

@implementation FAuthStateListenerWrapper

- (instancetype)initWithListener:(fbt_void_nsstring)listener auth:(id<FIRAuthInterop>)auth {
    self = [super init];
    if (self != nil) {
        self->_listener = listener;
        self->_auth = auth;
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(authStateDidChangeNotification:)
                                                     name:FIRAuthStateDidChangeInternalNotification
                                                   object:nil];
    }
    return self;
}

- (void)authStateDidChangeNotification:(NSNotification *)notification {
    NSDictionary *userInfo = notification.userInfo;
    if (notification.object == self.auth) {
        NSString *token = userInfo[FIRAuthStateDidChangeInternalNotificationTokenKey];
        dispatch_async([FIRDatabaseQuery sharedQueue], ^{
            self.listener(token);
        });
    }
}

- (void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

@end


@interface FIRFirebaseAuthTokenProvider : NSObject <FAuthTokenProvider>

@property (nonatomic, strong) id<FIRAuthInterop> auth;
/** Strong references to the auth listeners as they are only weak in FIRFirebaseApp */
@property (nonatomic, strong) NSMutableArray *authListeners;

- (instancetype) initWithAuth:(id<FIRAuthInterop>)auth;

@end

@implementation FIRFirebaseAuthTokenProvider

- (instancetype)initWithAuth:(id<FIRAuthInterop>)auth {
    self = [super init];
    if (self != nil) {
        self->_auth = auth;
        self->_authListeners = [NSMutableArray array];
    }
    return self;
}

- (void)fetchTokenForcingRefresh:(BOOL)forceRefresh
                     withCallback:(fbt_void_nsstring_nserror)callback {
  if (self.auth == nil) {
    // Signal that Auth is not available by returning nil.
    callback(nil, nil);
  } else {
    [self.auth getTokenForcingRefresh:forceRefresh
                         withCallback:^(NSString * _Nullable token, NSError * _Nullable error) {
        dispatch_async([FIRDatabaseQuery sharedQueue], ^{
            callback(token, error);
        });
    }];
  }
}

- (void)listenForTokenChanges:(_Nonnull fbt_void_nsstring)listener {
    FAuthStateListenerWrapper *wrapper =
        [[FAuthStateListenerWrapper alloc] initWithListener:listener auth:self.auth];
    [self.authListeners addObject:wrapper];
}

@end

@implementation FAuthTokenProvider

+ (id<FAuthTokenProvider>)authTokenProviderWithAuth:(id<FIRAuthInterop>)authInterop {
    return [[FIRFirebaseAuthTokenProvider alloc] initWithAuth:authInterop];
}

@end
