import 'dart:math';

import 'package:cyberhybridhub_server/spelling/spelling_item_record.dart';
import 'package:cyberhybridhub_server/spelling/spelling_item_selector.dart';
import 'package:cyberhybridhub_server/spelling/spelling_progress_policy.dart';
import 'package:test/test.dart';

void main() {
  test('mastered item is still selectable over many draws', () {
    final SpellingItemSelector selector = SpellingItemSelector(random: Random(99));

    const SpellingItemRecord mastered = SpellingItemRecord(
      id: 'mastered',
      spellingWordId: 'w1',
      canonicalWord: 'separate',
      displayedWord: 'separate',
      isCorrectlySpelled: true,
      correctAnswer: 10,
      familiarityScore: 20,
    );
    const SpellingItemRecord fresh = SpellingItemRecord(
      id: 'fresh',
      spellingWordId: 'w2',
      canonicalWord: 'rhythm',
      displayedWord: 'rythm',
      isCorrectlySpelled: false,
      correctAnswer: -10,
      familiarityScore: 0,
    );

    var masteredHits = 0;
    for (var i = 0; i < 500; i++) {
      final SpellingItemRecord? pick = selector.pickFromCandidates(
        <SpellingItemRecord>[mastered, fresh],
      );
      if (pick!.id == mastered.id) {
        masteredHits++;
      }
    }

    expect(masteredHits, greaterThan(0));
    expect(
      SpellingProgressPolicy.weightForScore(mastered.familiarityScore),
      SpellingProgressPolicy.minWeight,
    );
  });

  test('struggling item is picked more often than mastered peer', () {
    final SpellingItemSelector selector = SpellingItemSelector(random: Random(7));

    const SpellingItemRecord struggling = SpellingItemRecord(
      id: 'struggling',
      spellingWordId: 'w1',
      canonicalWord: 'separate',
      displayedWord: 'seperate',
      isCorrectlySpelled: false,
      correctAnswer: -10,
      familiarityScore: -4,
    );
    const SpellingItemRecord mastered = SpellingItemRecord(
      id: 'mastered',
      spellingWordId: 'w2',
      canonicalWord: 'rhythm',
      displayedWord: 'rhythm',
      isCorrectlySpelled: true,
      correctAnswer: 10,
      familiarityScore: 8,
    );

    var strugglingHits = 0;
    for (var i = 0; i < 300; i++) {
      final SpellingItemRecord? pick = selector.pickFromCandidates(
        <SpellingItemRecord>[struggling, mastered],
      );
      if (pick!.id == struggling.id) {
        strugglingHits++;
      }
    }

    expect(strugglingHits, greaterThan(150));
  });
}