import Foundation
import VisionCamera

class RecognizeTextUseCase {
  private let imagePreprocessor: IImagePreprocessor
  private let recognitionService: MLKitTextRecognitionService

  init(
    imagePreprocessor: IImagePreprocessor,
    recognitionService: MLKitTextRecognitionService
  ) {
    self.imagePreprocessor = imagePreprocessor
    self.recognitionService = recognitionService
  }

  func execute(frame: Frame, options: TextRecognitionOptions) throws
    -> TextRecognitionResult
  {
    // autoreleasepool at frame boundary to drain autoreleased Obj-C objects
    // after each frame is processed, preventing buildup across multiple frames
    return try autoreleasepool {
      let preprocessingOptions = ImagePreprocessingOptions(
        invertColors: options.invertColors,
        outputOrientation: options.outputOrientation,
        scaleFactor: options.scaleFactor
      )

      guard
        let processedImage = imagePreprocessor.preprocessFrame(
          frame: frame,
          options: preprocessingOptions
        )
      else {
        throw NSError(
          domain: "RecognizeTextUseCase",
          code: -1,
          userInfo: [NSLocalizedDescriptionKey: "Failed to preprocess image"]
        )
      }

      return try recognitionService.recognize(image: processedImage)
    }
  }

  func execute(
    imageFile: URL,
    imageOptions: ImagePreprocessingOptions,
    textOptions: TextRecognitionOptions
  ) throws -> TextRecognitionResult {
    // autoreleasepool here ensures predictable memory cleanup,
    // especially if this method is called repeatedly or in batches
    return try autoreleasepool {
      guard
        let processedImage = imagePreprocessor.preprocessImage(
          imageFile: imageFile,
          options: imageOptions
        )
      else {
        throw NSError(
          domain: "RecognizeTextUseCase",
          code: -1,
          userInfo: [NSLocalizedDescriptionKey: "Failed to preprocess image"]
        )
      }

      return try recognitionService.recognize(image: processedImage)
    }
  }
}