Chapter 11 - Chat App/ChatAppFinished/Pods/FirebaseDatabase/Firebase/Database/Core/View/FValueEventRegistration.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 <FirebaseCore/FIRLogger.h>
#import "FValueEventRegistration.h"
#import "FIRDatabaseQuery_Private.h"
#import "FQueryParams.h"
#import "FQuerySpec.h"
#import "FIRDataSnapshot_Private.h"
#import "FCancelEvent.h"
#import "FDataEvent.h"

@interface FValueEventRegistration ()
@property (nonatomic, strong) FRepo* repo;
@property (nonatomic, copy, readwrite) fbt_void_datasnapshot callback;
@property (nonatomic, copy, readwrite) fbt_void_nserror cancelCallback;
@property (nonatomic, readwrite) FIRDatabaseHandle handle;
@end

@implementation FValueEventRegistration

- (id) initWithRepo:(FRepo *)repo
             handle:(FIRDatabaseHandle)fHandle
           callback:(fbt_void_datasnapshot)callbackBlock
     cancelCallback:(fbt_void_nserror)cancelCallbackBlock {
    self = [super init];
    if (self) {
        self.repo = repo;
        self.handle = fHandle;
        self.callback = callbackBlock;
        self.cancelCallback = cancelCallbackBlock;
    }
    return self;
}

- (BOOL) responseTo:(FIRDataEventType)eventType {
    return eventType == FIRDataEventTypeValue;
}

- (FDataEvent *) createEventFrom:(FChange *)change query:(FQuerySpec *)query {
    FIRDatabaseReference *ref = [[FIRDatabaseReference alloc] initWithRepo:self.repo path:query.path];
    FIRDataSnapshot *snapshot = [[FIRDataSnapshot alloc] initWithRef:ref indexedNode:change.indexedNode];
    FDataEvent *eventData = [[FDataEvent alloc] initWithEventType:FIRDataEventTypeValue eventRegistration:self
                                                     dataSnapshot:snapshot];
    return eventData;
}

- (void) fireEvent:(id <FEvent>)event queue:(dispatch_queue_t)queue {
    if ([event isCancelEvent]) {
        FCancelEvent *cancelEvent = event;
        FFLog(@"I-RDB065001", @"Raising cancel value event on %@", event.path);
        NSAssert(self.cancelCallback != nil, @"Raising a cancel event on a listener with no cancel callback");
        dispatch_async(queue, ^{
            self.cancelCallback(cancelEvent.error);
        });
    } else if (self.callback != nil) {
        FDataEvent *dataEvent = event;
        FFLog(@"I-RDB065002", @"Raising value event on %@", dataEvent.snapshot.key);
        dispatch_async(queue, ^{
            self.callback(dataEvent.snapshot);
        });
    }
}

- (FCancelEvent *) createCancelEventFromError:(NSError *)error path:(FPath *)path {
    if (self.cancelCallback != nil) {
        return [[FCancelEvent alloc] initWithEventRegistration:self error:error path:path];
    } else {
        return nil;
    }
}

- (BOOL) matches:(id<FEventRegistration>)other {
    return self.handle == NSNotFound || other.handle == NSNotFound || self.handle == other.handle;
}

@end
