import 'dart:io';

import 'package:collection/collection.dart';
import 'package:jadb/_data_ingestion/kanjivg/objects.dart';
import 'package:xml/xml.dart';

List<KanjiVGItem> parseKanjiVGData(Directory rootDir) {
  final List<KanjiVGItem> items = [];

  for (final file in rootDir.listSync()) {
    if (file is File && file.path.endsWith('.svg')) {
      final String rawSVG = file.readAsStringSync();
      final XmlDocument doc = XmlDocument.parse(rawSVG);

      final strokePathsGroup = doc
          .findAllElements('g')
          .firstWhereOrNull(
            (e) => e.getAttribute('id')?.startsWith('kvg:StrokePaths') ?? false,
          );

      final strokeNumbersGroup = doc
          .findAllElements('g')
          .firstWhereOrNull(
            (e) =>
                e.getAttribute('id')?.startsWith('kvg:StrokeNumbers') ?? false,
          );

      final pathGroups = strokePathsGroup != null
          ? _parsePathGroups(strokePathsGroup)
          : <KanjiPathGroupTreeNode>[];

      final strokeNumbers = strokeNumbersGroup != null
          ? _parseStrokeNumbers(strokeNumbersGroup)
          : <KanjiStrokeNumber>[];

      final paths = strokePathsGroup != null
          ? _parsePaths(strokePathsGroup)
          : <KanjiVGPath>[];

      items.add(
        KanjiVGItem(
          character: file.uri.pathSegments.last.split('.').first,
          paths: paths,
          strokeNumbers: strokeNumbers,
          pathGroups: pathGroups,
        ),
      );
    }
  }

  return items;
}

List<KanjiStrokeNumber> _parseStrokeNumbers(XmlElement group) => group
    .childElements
    .map((e) {
      final num = int.parse(e.innerText);
      final xy = e
          .getAttribute('transform')!
          .split('matrix(1 0 0 1 ')[1]
          .split(')')[0]
          .split(' ')
          .map(double.parse)
          .toList();
      return KanjiStrokeNumber(num, xy[0], xy[1]);
    })
    .toList(growable: false);

List<KanjiPathGroupTreeNode> _parsePathGroups(XmlElement group) => group
    .findElements('g')
    .map((e) {
      return KanjiPathGroupTreeNode(
        // NOTE: the outermost group does not have a number
        id:
            int.tryParse(e.getAttribute('id')!.split('-').last.substring(1)) ??
            0,
        element: e.getAttribute('kvg:element'),
        original: e.getAttribute('kvg:original'),
        variant: e.getAttribute('kvg:variant'),
        position: KanjiPathGroupPosition.fromString(
          e.getAttribute('kvg:position'),
        ),
        radical: KanjiVGRadical.fromString(e.getAttribute('kvg:radical')),
        part: int.tryParse(e.getAttribute('kvg:part') ?? ''),
        radicalForm: e.getAttribute('kvg:radicalForm') == 'true',
        tradForm: e.getAttribute('kvg:tradForm') == 'true',
        partial: e.getAttribute('kvg:partial') == 'true',
        children: _parsePathGroups(e),
      );
    })
    .toList(growable: false);

List<KanjiVGPath> _parsePaths(XmlElement group) => group
    .findAllElements('g')
    .map(
      (g) => g
          .findElements('path')
          .map(
            (e) => KanjiVGPath(
              id: int.parse(e.getAttribute('id')!.split('-').last.substring(1)),
              groupId:
                  int.tryParse(
                    g.getAttribute('id')!.split('-').last.substring(1),
                  ) ??
                  0,
              type: e.getAttribute('kvg:type'),
              svgPath: e.getAttribute('d')!,
            ),
          ),
    )
    .expand((x) => x)
    .toList(growable: false);