import Foundation
import MLKitTextRecognition

class MLKitTextAdapter {

  static func toDomain(_ mlkitText: Text?) -> TextRecognitionResult {
    return TextRecognitionResult(
      text: mlkitText?.text,
      blocks: mlkitText?.blocks.map { toTextBlock($0) } ?? []
    )
  }

  private static func toTextBlock(_ block: MLKitTextRecognition.TextBlock)
    -> TextBlock
  {
    return TextBlock(
      text: block.text,
      bounds: toBoundingBox(block.frame),
      corners: block.cornerPoints.map { toCorner($0.cgPointValue) },
      lines: block.lines.map { toTextLine($0) },
      languages: block.recognizedLanguages.map { $0.languageCode ?? "" }
    )
  }

  private static func toTextLine(_ line: MLKitTextRecognition.TextLine)
    -> TextLine
  {
    return TextLine(
      text: line.text,
      bounds: toBoundingBox(line.frame),
      corners: line.cornerPoints.map { toCorner($0.cgPointValue) },
      elements: line.elements.map { toTextElement($0) },
      confidence: nil,
      angle: nil,
      languages: line.recognizedLanguages.map { $0.languageCode ?? "" }
    )
  }

  private static func toTextElement(_ element: MLKitTextRecognition.TextElement)
    -> TextElement
  {
    return TextElement(
      text: element.text,
      bounds: toBoundingBox(element.frame),
      corners: element.cornerPoints.map { toCorner($0.cgPointValue) },
      symbols: [],
      confidence: nil,
      angle: nil,
      languages: element.recognizedLanguages.map { $0.languageCode ?? "" }
    )
  }

  private static func toBoundingBox(_ bounds: CGRect) -> BoundingBox {
    let offsetX = (bounds.midX - ceil(bounds.width)) / 2.0
    let offsetY = (bounds.midY - ceil(bounds.height)) / 2.0

    let x = bounds.maxX + offsetX
    let y = bounds.minY + offsetY

    return BoundingBox(
      x: bounds.midX + (bounds.midX - x),
      y: bounds.midY + (y - bounds.midY),
      centerX: bounds.midX,
      centerY: bounds.midY,
      width: bounds.width,
      height: bounds.height,
      top: bounds.maxY,
      left: bounds.minX,
      bottom: bounds.minY,
      right: bounds.maxX
    )
  }

  private static func toCorner(_ point: CGPoint) -> Corner {
    return Corner(x: Double(point.x), y: Double(point.y))
  }
}