step-four_RCTVisionModule.swift

//
//  RCTVisionModule.swift
//  VisionNativeModulePOC
//
//  Created by Tanner West on 6/2/23.
//

import Foundation
import CoreImage
import Vision

@objc(RCTVisionModule)
class RCTVisionModule: NSObject {
  
  func createCIImage(from imageURL: URL) -> CIImage? {
    guard let ciImage = CIImage(contentsOf: imageURL) else {
      // TODO handle error
      return nil
    }
    return ciImage
  }
  
  @objc(detectText:callback:)
  func detectText(_ imgUrl: String, callback: @escaping RCTResponseSenderBlock) {
    
    
    if let imageURL = URL(string: imgUrl) {
      if let ciImage = createCIImage(from: imageURL) {
        let requestHandler = VNImageRequestHandler(ciImage: ciImage)
        let request = VNRecognizeTextRequest(completionHandler: { request, error in
          if let error = error {
            // TODO handle error
          } else if let results = request.results as? [VNRecognizedTextObservation] {
            var result: [String] = []
            for observation in results {
              if let recognizedText = observation.topCandidates(1).first {
                result.append(recognizedText.string)
              }
            }
            callback([result])
          }
        })
        
        do {
          try requestHandler.perform([request])
        } catch {
          // TODO handle error
        }
      }
    }
  }
  
  @objc(detectFaces:callback:)
  func detectFaces(_ imgUrl: String, callback: @escaping RCTResponseSenderBlock) {
    
    if let imageURL = URL(string: imgUrl) {
      if let ciImage = createCIImage(from: imageURL) {
        
        let requestHandler = VNImageRequestHandler(ciImage: ciImage)
        let request = VNDetectFaceRectanglesRequest(completionHandler: { request, error in
          if let error = error {
            // TODO handle error
            print(error)
          } else if let results = request.results as? [VNFaceObservation] {
            var result: [Dictionary<String, CGFloat>] = []
            var resultsLengthString = String(results.count)
            for observation in results {
              let box = observation.boundingBox
              let boxDict = ["width": box.size.width,
                            "height": box.size.height,
                                 "x": box.origin.x,
                                 "y": box.origin.y]
              result.append(boxDict)
            }
            callback([result])
          }
        })
        
        do {
          try requestHandler.perform([request])
        } catch {
          // TODO handle error
          print(error)
        }
      }
    }
  }
}