ImageLoading.swift

//
//  ImageLoading.swift
//  CloudKitDemo
//
//  Created by Marcus Smith on 2/29/16.
//  Copyright © 2016 FrozenFireStudios. All rights reserved.
//

import UIKit
import CloudKit

enum ImageSize {
    case Thumbnail
    case Medium
    case Fullsize
    
    var recordKey: String {
        switch self {
        case .Thumbnail:
            return "thumbnail"
        case .Medium:
            return "medium"
        case .Fullsize:
            return "fullsize"
        }
    }
}

/// Completion returns the saved image's imageID if successful or an error if unsuccessful
func saveNewImageWithThumbnail(thumbnailImage: UIImage, mediumImage: UIImage, fullsizeImage: UIImage, completion: (imageID: String?, error: ErrorType?) -> Void) {
    let newRecord = CKRecord(recordType: "image")
    do {
        newRecord[ImageSize.Thumbnail.recordKey] = try CKAsset(image: thumbnailImage)
        newRecord[ImageSize.Medium.recordKey] = try CKAsset(image: mediumImage)
        newRecord[ImageSize.Fullsize.recordKey] = try CKAsset(image: fullsizeImage)
        
        CKContainer.defaultContainer().publicCloudDatabase.saveRecord(newRecord, completionHandler: { (record, error) -> Void in
            if let recordID = record?.recordID.recordName {
                completion(imageID: recordID, error: nil)
            }
            else {
                completion(imageID: nil, error: error)
            }
        })
    }
    catch {
        completion(imageID: nil, error: error)
    }
}

/// Completion returns an image if successful or an error if unsuccessful
func fetchImageWithID(imageID: String, imageSize: ImageSize, completion: (image: UIImage?, error: ErrorType?) -> Void) {
    let imageRecordID = CKRecordID(recordName: imageID)
    let fetchOperation = CKFetchRecordsOperation(recordIDs: [imageRecordID])
    fetchOperation.desiredKeys = [imageSize.recordKey]
    fetchOperation.fetchRecordsCompletionBlock = { (records, error) in
        if let imageRecord = records?[imageRecordID], asset = imageRecord[imageSize.recordKey] as? CKAsset, image = asset.image {
            completion(image: image, error: nil)
        }
        else {
            completion(image: nil, error: error)
        }
    }
    CKContainer.defaultContainer().publicCloudDatabase.addOperation(fetchOperation)
}