import 'package:graphql_parser/graphql_parser.dart';
import 'package:test/test.dart';
import 'common.dart';
import 'field_test.dart';
import 'fragment_spread_test.dart';

// TODO: Test inline fragment...
main() {
  test('empty', () {
    expect('{}', isSelectionSet([]));
  });

  test('with commas', () {
    expect(
        '{foo, bar: baz}',
        isSelectionSet([
          isField(fieldName: isFieldName('foo')),
          isField(fieldName: isFieldName('bar', alias: 'baz'))
        ]));
  });

  test('no commas', () {
    expect(
        '{foo bar: baz ...quux}',
        isSelectionSet([
          isField(fieldName: isFieldName('foo')),
          isField(fieldName: isFieldName('bar', alias: 'baz')),
          isFragmentSpread('quux')
        ]));
  });

  test('exceptions', () {
    expect(() => parseSelectionSet('{foo,bar,baz'), throwsSyntaxError);
  });
}

SelectionSetContext parseSelectionSet(String text) =>
    parse(text).parseSelectionSet();

Matcher isSelectionSet(List<Matcher> selections) =>
    new _IsSelectionSet(selections);

class _IsSelectionSet extends Matcher {
  final List<Matcher> selections;

  _IsSelectionSet(this.selections);

  @override
  Description describe(Description description) {
    return description
        .add('is selection set with ${selections.length} selection(s)');
  }

  @override
  bool matches(item, Map matchState) {
    var set = item is SelectionSetContext ? item : parseSelectionSet(item);
    if (set == null) return false;
    if (set.selections.length != selections.length) return false;

    for (int i = 0; i < set.selections.length; i++) {
      var sel = set.selections[i];
      if (!selections[i].matches(
          sel.field ?? sel.fragmentSpread ?? sel.inlineFragment, matchState))
        return false;
    }

    return true;
  }
}