import 'package:flutter_test/flutter_test.dart';
import 'package:groci/models/ocr_element.dart';
import 'package:groci/services/receipt_parse_config.dart';
import 'package:groci/services/receipt_parser.dart';
import 'package:groci/services/receipt_row_builder.dart';
import 'package:groci/services/receipt_spatial_parser.dart';

/// Synthetic two-column receipt layout (800×1200 image).
const _imageWidth = 800.0;
const _imageHeight = 1200.0;
const _nameLeft = 40.0;
const _priceLeft = 620.0;
const _rowHeight = 24.0;
const _rowGap = 8.0;

OcrElement _word(String text, double row, {bool price = false}) {
  final y = row * (_rowHeight + _rowGap) + 100;
  final left = price ? _priceLeft : _nameLeft;
  final width = text.length * 10.0 + 20;
  return OcrElement(
    text: text,
    left: left,
    top: y,
    right: left + width,
    bottom: y + _rowHeight,
  );
}

OcrLine _line(List<OcrElement> elements) {
  var left = double.infinity;
  var top = double.infinity;
  var right = 0.0;
  var bottom = 0.0;
  for (final e in elements) {
    if (e.left < left) left = e.left;
    if (e.top < top) top = e.top;
    if (e.right > right) right = e.right;
    if (e.bottom > bottom) bottom = e.bottom;
  }
  return OcrLine(
    text: elements.map((e) => e.text).join(' '),
    elements: elements,
    left: left,
    top: top,
    right: right,
    bottom: bottom,
  );
}

OcrDocument _document(
  List<List<OcrElement>> rows, {
  String? flattened,
}) {
  final elements = [for (final row in rows) ...row];
  final lines = [for (final row in rows) _line(row)];
  return OcrDocument(
    elements: elements,
    lines: lines,
    imageWidth: _imageWidth,
    imageHeight: _imageHeight,
    flattenedText: flattened ?? lines.map((l) => l.text).join('\n'),
  );
}

void main() {
  setUpAll(() async {
    await ReceiptParser.loadConfig();
  });

  group('ReceiptRowBuilder', () {
    test('clusters name and price on the same row by Y position', () {
      final rows = ReceiptRowBuilder(receiptParseConfig).buildRows(
        _document([
          [_word('MILK', 0), _word('1,50', 0, price: true)],
        ]),
      );

      expect(rows, hasLength(1));
      expect(rows.single.kind.name, 'item');
      expect(rows.single.nameText, 'MILK');
      expect(rows.single.price, 1.50);
    });

    test('classifies pure quantity row before item logic', () {
      final rows = ReceiptRowBuilder(receiptParseConfig).buildRows(
        _document([
          [_word('2', 1), _word('X', 1), _word('2,99', 1, price: true)],
        ], flattened: '2 X 2,99'),
      );

      expect(rows, hasLength(1));
      expect(rows.single.kind.name, 'quantityModifier');
      expect(rows.single.quantity, 2);
      expect(rows.single.unitPrice, 2.99);
    });

    test('treats row without price-column token as name-only', () {
      final rows = ReceiptRowBuilder(receiptParseConfig).buildRows(
        _document([
          [_word('BROCCOLI', 0)],
        ]),
      );

      expect(rows.single.kind.name, 'nameOnly');
      expect(rows.single.nameText, 'BROCCOLI');
    });

    test('does not merge adjacent ML Kit lines into one row', () {
      final rows = ReceiptRowBuilder(receiptParseConfig).buildRows(
        _document([
          [_word('BIO', 0), _word('VASTKOKEND', 0), _word('AARD', 0)],
          [_word('2', 1), _word('X', 1), _word('1,99', 1, price: true)],
        ]),
      );

      expect(rows, hasLength(2));
      expect(rows[0].nameText, contains('BIO'));
      expect(rows[1].kind.name, 'quantityModifier');
    });
  });

  group('ReceiptSpatialParser lookahead', () {
    test('merges Jumbo-style name row with following quantity modifier', () {
      final result = ReceiptSpatialParser.parse(
        _document([
          [_word('AARDBEIEN', 0)],
          [_word('2', 1), _word('X', 1), _word('3,99', 1, price: true)],
          [_word('Totaal', 2), _word('7,98', 2, price: true)],
        ]),
      );

      expect(result.items, hasLength(1));
      expect(result.items.single.name, 'AARDBEIEN');
      expect(result.items.single.quantity, 2);
      expect(result.items.single.unitPrice, 3.99);
      expect(result.items.single.price, 7.98);
      expect(result.items.single.sourceBounds, isNotNull);
    });

    test('overrides inline price when quantity modifier follows (Kruidvat)', () {
      final result = ReceiptSpatialParser.parse(
        _document([
          [_word('ZEEPTABLET', 0), _word('NEUTRAL', 0), _word('7,98', 0, price: true)],
          [_word('2', 1), _word('X', 1), _word('3,99', 1, price: true)],
        ]),
      );

      expect(result.items, hasLength(1));
      expect(result.items.single.quantity, 2);
      expect(result.items.single.unitPrice, 3.99);
      expect(result.items.single.price, 7.98);
    });

    test('flags name-only row without following modifier for manual review', () {
      final result = ReceiptSpatialParser.parse(
        _document([
          [_word('MILK', 0)],
          [_word('BREAD', 1), _word('2,00', 1, price: true)],
        ]),
      );

      expect(result.items, hasLength(2));
      expect(result.items[0].name, 'MILK');
      expect(result.items[0].needsManualReview, isTrue);
      expect(result.items[1].name, 'BREAD');
      expect(result.items[1].price, 2.00);
    });

    test('parses two side-by-side items without cross-assigning prices', () {
      final result = ReceiptSpatialParser.parse(
        _document([
          [_word('MILK', 0), _word('1,50', 0, price: true)],
          [_word('BREAD', 1), _word('2,00', 1, price: true)],
          [_word('Totaal', 2), _word('3,50', 2, price: true)],
        ]),
      );

      expect(result.items.map((i) => i.name), ['MILK', 'BREAD']);
      expect(result.items.map((i) => i.price), [1.50, 2.00]);
      expect(result.validationPassed, isTrue);
    });

    test('fails validation when printed item count does not match', () {
      final result = ReceiptSpatialParser.parse(
        _document([
          [_word('MILK', 0), _word('1,50', 0, price: true)],
          [_word('Aantal Artikel: 3', 1)],
        ]),
      );

      expect(result.expectedItemCount, 3);
      expect(result.validationPassed, isFalse);
    });
  });
}