/*

 Copyright (C) 2014 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 */

@import CloudKit;

#import "AAPLPost.h"

#import "AAPLImage.h"

typedef NS_ENUM(NSInteger, AAPLPostErrorResponse) {

    AAPLPostErrorIgnore,

    AAPLPostErrorRetry,

    AAPLPostErrorSuccess,

};

@implementation AAPLPost

- (instancetype) initWithRecord:(CKRecord *)postRecord

{

    self = [super init];

    if(self)

    {

        _postRecord = postRecord;

    }

    return self;

}

- (void) loadImageWithKeys:(NSArray *)keys completion:(void(^)())updateBlock

{

    // Fetches the imageRecord this post record references in its ImageRefKey. Only fetches the values associated with the keys passed in to the NSArray

    CKReference *imageRecordReference = self.postRecord[AAPLPostImageRefKey];

    CKFetchRecordsOperation *imageOp = [[CKFetchRecordsOperation alloc] initWithRecordIDs:@[imageRecordReference.recordID]];

    imageOp.desiredKeys = keys;

    imageOp.fetchRecordsCompletionBlock = ^(NSDictionary *recordDict, NSError *error) {

        if(error.code == CKErrorPartialFailure) {

            error = error.userInfo[CKPartialErrorsByItemIDKey][[self.postRecord[AAPLPostImageRefKey] recordID]];

        }

        AAPLPostErrorResponse errorResponse = [self handleError:error];

        if(errorResponse == AAPLPostErrorSuccess)

        {

            CKRecord *fetchedImageRecord = recordDict[imageRecordReference.recordID];

            self.imageRecord = [[AAPLImage alloc] initWithRecord:fetchedImageRecord];

            updateBlock();

        }

        else if(errorResponse == AAPLPostErrorRetry)

        {

            NSNumber *seconds = error.userInfo[CKErrorRetryAfterKey] ?: @3;

            NSLog(@"Error: %@. Recoverable, retry after %@ seconds", [error description], seconds);

            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(seconds.integerValue * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

                [self loadImageWithKeys:keys completion:updateBlock];

            });

            self.imageRecord = nil;

        }

        else if(errorResponse == AAPLPostErrorIgnore)

        {

            NSLog(@"Error: %@", [error description]);

            self.imageRecord = nil;

        }

    };

    CKDatabase *publicDB = [[CKContainer defaultContainer] publicCloudDatabase];

    [publicDB addOperation:imageOp];

}

- (AAPLPostErrorResponse) handleError:(NSError *)error

{

    if(error == nil) return AAPLPostErrorSuccess;

    switch ([error code])

    {

        case CKErrorNetworkUnavailable:

        case CKErrorNetworkFailure:

            // A reachability check might be appropriate here so we don't just keep retrying if the user has no service

        case CKErrorServiceUnavailable:

        case CKErrorRequestRateLimited:

            return AAPLPostErrorRetry;

            break;

        case CKErrorBadContainer:

        case CKErrorMissingEntitlement:

        case CKErrorPermissionFailure:

        case CKErrorBadDatabase:

            // This app uses the publicDB with default world readable permissions

        case CKErrorUnknownItem:

        case CKErrorAssetFileNotFound:

            // This shouldn't happen. If an Image record is deleted it should delete all Post records that reference it (CKReferenceActionDeleteSelf)

        case CKErrorIncompatibleVersion:

        case CKErrorQuotaExceeded:

            //App quota will be exceeded, cancelling operation

        case CKErrorOperationCancelled:

            // Nothing to do here, we intentionally cancelled

        case CKErrorNotAuthenticated:

        case CKErrorInvalidArguments:

        case CKErrorResultsTruncated:

        case CKErrorServerRecordChanged:

        case CKErrorAssetFileModified:

        case CKErrorChangeTokenExpired:

        case CKErrorBatchRequestFailed:

        case CKErrorZoneBusy:

        case CKErrorZoneNotFound:

        case CKErrorLimitExceeded:

        case CKErrorUserDeletedZone:

            // These errors are pretty irrelevant here

            // We're fetching only one record by its recordID

            // These errors could be hit fetching multiple records, using zones, saving records, or fetching with predicates

        case CKErrorInternalError:

        case CKErrorServerRejectedRequest:

        case CKErrorConstraintViolation:

            NSLog(@"Nonrecoverable error, will not retry");

        default:

            return AAPLPostErrorIgnore;

            break;

    }

}

@end