Enum hell

injectionExample.playground

//: Playground - noun: a place where people can play

import Foundation
import UIKit

typealias ImagePostProcessingOp = (UIImage) -> Void

enum ImageProcessor {
    case PostProcessOp(ImagePostProcessingOp)
    
    init(postProcessOp : ImagePostProcessingOp?)  {
        if let postProcessOp = postProcessOp {
            self = .PostProcessOp(postProcessOp)
        }
        else {
            self = .PostProcessOp({_ in })
        }
    }
    
    func processImage(original : UIImage) -> UIImage {
        switch self {
        case .PostProcessOp(let op):
            let image = original
            op(image)
            return image
        }
    }
}

enum Cacher {
    case Path(String)
    
    init(path : String)  {
        self = Path(path)
    }

    func saveCachedImage(image : UIImage) {
        switch self {
        case .Path(let path):
            print("Saving image to \(path)")
        }
    }
}

enum Factory {
    case Factory1((ImagePostProcessingOp?) -> ImageProcessor, () -> Cacher)
    case Factory2((ImagePostProcessingOp?) -> ImageProcessor)
    
    init(ipGen : (ImagePostProcessingOp?) -> ImageProcessor, cacherGen : (() -> Cacher)? = nil) {
        if let cacherGen = cacherGen {
            self = .Factory1(ipGen, cacherGen)
        }
        else {
            self = .Factory2(ipGen)
        }
    }
    
    func generate() -> ImageProcessor {
        switch self {
        case .Factory1 (let ipGen, let cacherGen):
            return ipGen(cacherGen().saveCachedImage)
        case .Factory2(let ipGen):
            return ipGen(nil)
        }
    }
}

func validImageProcessor(postProcessingOp: ImagePostProcessingOp?) -> ImageProcessor {
    return ImageProcessor(postProcessOp: postProcessingOp)
}

func defaultCacher() -> Cacher {
    return Cacher(path: NSSearchPathForDirectoriesInDomains(.CachesDirectory, .UserDomainMask, true).first!)
}


Factory(ipGen: validImageProcessor, cacherGen: defaultCacher).generate().processImage(UIImage())
Factory(ipGen: validImageProcessor).generate().processImage(UIImage())