/// Extract positioned OCR elements from ML Kit structured output.
library;

import 'package:google_mlkit_text_recognition/google_mlkit_text_recognition.dart';

import '../models/ocr_element.dart';

class ReceiptOcr {
  ReceiptOcr._();

  /// Reads blocks → lines → elements. Falls back to line-level boxes when a
  /// line has no element children.
  static OcrDocument fromRecognizedText(
    RecognizedText recognized, {
    required double imageWidth,
    required double imageHeight,
  }) {
    final elements = <OcrElement>[];
    final lines = <OcrLine>[];
    var maxRight = 0.0;
    var maxBottom = 0.0;

    for (final block in recognized.blocks) {
      for (final line in block.lines) {
        final lineElements = <OcrElement>[];
        if (line.elements.isNotEmpty) {
          for (final element in line.elements) {
            final box = element.boundingBox;
            lineElements.add(
              OcrElement(
                text: element.text,
                left: box.left,
                top: box.top,
                right: box.right,
                bottom: box.bottom,
              ),
            );
            if (box.right > maxRight) maxRight = box.right;
            if (box.bottom > maxBottom) maxBottom = box.bottom;
          }
        } else {
          final box = line.boundingBox;
          lineElements.add(
            OcrElement(
              text: line.text,
              left: box.left,
              top: box.top,
              right: box.right,
              bottom: box.bottom,
            ),
          );
          if (box.right > maxRight) maxRight = box.right;
          if (box.bottom > maxBottom) maxBottom = box.bottom;
        }
        elements.addAll(lineElements);
        final box = line.boundingBox;
        lines.add(
          OcrLine(
            text: line.text,
            elements: lineElements,
            left: box.left,
            top: box.top,
            right: box.right,
            bottom: box.bottom,
          ),
        );
      }
    }

    final width = imageWidth > 0 ? imageWidth : maxRight;
    final height = imageHeight > 0 ? imageHeight : maxBottom;

    return OcrDocument(
      elements: elements,
      lines: lines,
      imageWidth: width,
      imageHeight: height,
      flattenedText: recognized.text.trim(),
    );
  }
}