ImageRecognizer.swift

ImageRecognizer.swift

import Foundation
import Vision

struct ImageRecognizer {
    
  static func get(from image: CGImage, onComplete: @escaping (String) -> Void) {
    // Kick off a new ML Configuration.
    // Here I'm not sure if it's a better idea 
    // to create one configurator for the whole class,
    // or to create a new one every time we want to recognize stuff.
    // Didn't spend enough time with it to care, honestly.
    let configurator = MLModelConfiguration()
    // Kicking off a new classifier for out Suites model
    let classifier = try! Suites(configuration: configurator).model
    // Getting a model 
    // MARK: - TODO, do not force unwrap
    let model = try! VNCoreMLModel(for: classifier)
    // And using it
    handle(VNCoreMLRequest(model: model) { (finished, error) in
      if let error = error {
        // MARK: - TODO, Handle appropriately
        return
      }
      guard let results = finished.results as? [VNClassificationObservation],
            let first = results.first else {
        // MARK: - TODO, Handle appropriately
        return
      }
      onComplete(first.identifier)
    }, for: image)
  }

  // MARK: - Private
  // We have extracted the handler into its own class to clean up the code.
  // Without it we've had a whole bunch of nesting.
  private static func handle(_ request: VNCoreMLRequest, for image: CGImage) {
    do {
      try VNImageRequestHandler(cgImage: image, options: [:]).perform([request])
    } catch {
      fatalError(error.localizedDescription)
    }
  }
}