import { lessonDateLabel } from '../appointment/lesson-display';
import { TeacherTodayReviewService } from '../../core/teacher-today-review.service';
import { lessonStudySources } from '../appointment/lesson-study-sources';
import { DropdownDirective } from '../../shared/dropdown.directive';
import { LearningDraft } from '../../core/learning-draft';
import { ReviewPage, reviewCalendar } from '../../core/review-page';
import { CommonModule } from '@angular/common';
import { ChangeDetectionStrategy, Component, computed, inject, OnDestroy, OnInit, signal } from '@angular/core';
import { ActivatedRoute, Router, RouterLink } from '@angular/router';
import {
  Activity,
  BookOpen,
  BrainCircuit,
  Check,
  CheckCheck,
  ChevronLeft,
  ChevronRight,
  CircleHelp,
  Clock3,
  Flag,
  Headphones,
  Library,
  LucideAngularModule,
  Play,
  RefreshCw,
  RotateCcw,
  Star,
  Trash2,
  Volume2,
  X,
} from 'lucide-angular';
import { catchError, finalize, forkJoin, map, Observable, of, Subscription, switchMap, tap, throwError } from 'rxjs';
import { listeningChoices, shuffledStudy } from '../../core/learning-random';
import { ApiError, ApiService } from '../../core/api.service';
import {
  AntiForgetCalendarDay,
  antiForgetCompleted,
  antiForgetDate,
  antiForgetTasksOnDate,
  buildAntiForgetCalendar,
  buildAntiForgetView,
  mergeAntiForgetItems,
  nearestAntiForgetDate,
} from '../../core/anti-forget';
import { AppUser, PageMeta } from '../../core/models';
import { canStartTeacherLedLearning, isTeacherLedLearningPath } from '../../core/learning-access';
import { isLearningStage, learningReturnUrl } from '../../core/learning-navigation';
import { PlatformService } from '../../core/platform.service';
import { SessionService } from '../../core/session.service';
import { nextReviewWordOrder } from '../../core/review-word-order';

type SourceItem = Record<string, unknown>;

interface Word extends SourceItem {
  id: string;
  wordId: string;
  nodeId: string;
  word: string;
  meaning: string;
  phonetic: string;
  audio: string;
}

interface LetterChoice {
  value: string;
  used: boolean;
}

interface ExamOption {
  text: string;
  value: string | number;
  checked?: boolean;
}

interface ExamQuestion extends SourceItem {
  ID: string | number;
  AskID?: string | number;
  QType?: string | number;
  QContent: string;
  QTitle?: string;
  QOption: ExamOption[];
}

interface ExamAnswer {
  qid: string | number;
  qtype: string | number;
  answer: string | number;
  result: 0 | 1 | 2;
}

interface MemoryStudentOption {
  id: string;
  name: string;
  taskCount: number;
}

const WORD_CATALOG_CATEGORIES = [
  { label: '小学', pid: 8 },
  { label: '初中', pid: 9 },
  { label: '高中', pid: 10 },
  { label: '大学+', pid: 11 },
  { label: '出国', pid: 12 },
] as const;

@Component({
  selector: 'app-learning-page',
  standalone: true,
  imports: [DropdownDirective, CommonModule, LucideAngularModule, RouterLink],
  templateUrl: './learning-page.component.html',
  styleUrl: './learning-page.component.scss',
  changeDetection: ChangeDetectionStrategy.OnPush,
})
export class LearningPageComponent implements OnInit, OnDestroy {
  private static readonly reviewCacheByApi = new WeakMap<ApiService, { identity: string; pages: Map<string, ReviewPage> }>();
  readonly meta = inject(ActivatedRoute).snapshot.data['meta'] as PageMeta;
  readonly nodes = signal<SourceItem[]>([]);
  readonly catalogCategories = WORD_CATALOG_CATEGORIES;
  readonly catalogCategoryIndex = signal(0);
  readonly selectedNodes = signal<Set<string>>(new Set());
  readonly words = signal<Word[]>([]);
  readonly wordPreviewPage = signal(1);
  readonly wordPreviewTotal = signal(0);
  readonly wordPreviewLoading = signal(false);
  private historyPreviewWords: Word[] = [];
  readonly selected = signal<Set<string>>(new Set());
  readonly selectionRevealed = signal<Set<string>>(new Set());
  readonly selectionAssessment = signal<Record<string, 'known' | 'unknown'>>({});
  readonly activeSelectionBucket = signal<'pending' | 'completed'>('pending');
  readonly coursePassTabs = ['未学习', '已学一遍', '已学第二遍', '已学第三遍'];
  readonly coursePass = signal(0);
  readonly coursePassCounts = signal<number[] | null>(null);
  readonly bookPassCounts = signal<number[] | null>(null);
  private readonly courseSelectionCache = signal<Word[]>([]);
  readonly visibleCourseWords = computed(() => {
    const candidates = this.coursePass() === 1 ? [...this.words(), ...this.newlyKnownWords()] : this.words();
    return [...new Map(candidates.map(word => [word.id, word])).values()]
      .filter(word => this.courseWordPass(word) === this.coursePass());
  });
  readonly firstPassProgress = computed(() => {
    const counts = this.bookPassCounts();
    const total = counts?.reduce((sum, n) => sum + n, 0) || 0;
    return total && counts ? Math.round((total - counts[0]) / total * 100) : 0;
  });
  readonly newWordCounts = signal({ pending: 0, completed: 0 });
  private readonly newWordPageSize = 30;
  private readonly newWordSelectionCache = new Map<string, Word>();
  private legacyNewWords: Word[] | null = null;
  readonly currentIndex = signal(0);
  readonly revealed = signal(false);
  readonly completed = signal(false);
  readonly lessonLearnedCount = signal(0);
  readonly historySources = signal<Array<{label: string; count: number}>>([]);
  readonly correct = signal(0);
  readonly unknown = signal<Word[]>([]);
  readonly loading = signal(false);
  readonly calendarLoading = signal(false);
  readonly calendarError = signal('');
  readonly submitting = signal(false);
  readonly selectionTotal=signal(0);readonly selectionPage=signal(1);readonly selectionLoading=signal(false);private selectionRequest?:Subscription;
  readonly error = signal('');
  readonly recordWordless = signal(false);

  readonly studyStep = signal<1 | 2 | 3>(1);
  readonly repetitions = signal<Record<string, number>>({});
  readonly matchLeft = signal<Word[]>([]);
  readonly matchRight = signal<Word[]>([]);
  readonly leftChoice = signal('');
  readonly rightChoice = signal('');
  readonly choicesLoading = signal(false);
  readonly choiceOptions = signal<Word[]>([]);
  readonly letters = signal<LetterChoice[]>([]);
  readonly assembled = signal('');
  readonly spellingCorrect = signal(false);
  readonly reviewState = signal<Record<string, 0 | 1 | 2>>({});
  readonly seen = signal<Set<string>>(new Set());
  readonly recordRevealed = signal<Set<string>>(new Set());
  readonly calendarItems = signal<SourceItem[]>([]);
  readonly memoryStudentId = signal('');
  readonly memoryMonth = signal(new Date(new Date().getFullYear(), new Date().getMonth(), 1, 12));
  readonly memorySelectedDate = signal('');
  readonly reviewScope=signal('');
  readonly reviewCompletion=signal<{amount:number;rewardStatus:string;ineligibleReason?:string;unchanged?:boolean}|null>(null);
  private reviewReturn: {date?:string;studentId?:string;page?:number;scope?:string;scroll?:number}={};
  readonly orderInfo = signal<SourceItem>({});
  readonly learnedRecord = signal<SourceItem>({});
  readonly antiHistory = signal<SourceItem>({});
  readonly myNewWords = signal<SourceItem>({});

  readonly examStarted = signal(false);
  readonly examSubmitted = signal(false);
  readonly askInfo = signal<SourceItem>({});
  readonly examHistory = signal<SourceItem[]>([]);
  readonly examHistoryLoading = signal(false);
  readonly examHistoryError = signal('');
  readonly examHistoryMore = signal(false);
  readonly examCompareIds = signal<string[]>([]);
  readonly comparedExams = computed(() => this.examHistory().filter(r => this.examCompareIds().includes(String(r['GeneralID']))));
  readonly examSaveError = signal('');
  readonly examDateLabel = lessonDateLabel;
  private examHistoryPage = 0;
  private examHistoryRequest?: Subscription;
  private examLoadRequest?: Subscription;
  private examAttemptStamp = '';
  private examLogKey = '';
  private examAnswerId: string | number | null = null;
  readonly previousExam = signal<SourceItem>({});
  readonly questions = signal<ExamQuestion[]>([]);
  readonly answers = signal<ExamAnswer[]>([]);
  readonly timer = signal(10);
  readonly examScore = signal(0);

  readonly icons = {
    Activity,
    BookOpen,
    BrainCircuit,
    Check,
    CheckCheck,
    ChevronLeft,
    ChevronRight,
    CircleHelp,
    Clock3,
    Flag,
    Headphones,
    Library,
    Play,
    RefreshCw,
    RotateCcw,
    Star,
    Trash2,
    Volume2,
    X,
  };
  readonly antiForgetChart = {
    forgettingPath: 'M 26 12 C 38 60 82 88 304 95',
    learningPath: 'M 26 98 C 31 80 35 68 40 61 C 47 50 58 43 68 40 C 81 33 95 29 110 27 C 132 22 156 19 179 19 C 210 18 244 17 276 17 C 286 17 296 17 304 17',
    continuationPath: 'M 276 12 C 284 15 294 16 304 16',
    reviewEvents: [
      { day: 2, x: 40, y: 61, path: 'M 26 12 C 30 30 34 49 40 61' },
      { day: 4, x: 68, y: 40, path: 'M 40 12 C 47 22 57 35 68 40' },
      { day: 7, x: 110, y: 27, path: 'M 68 12 C 79 17 94 24 110 27' },
      { day: 12, x: 179, y: 19, path: 'M 110 12 C 128 15 155 19 179 19' },
      { day: 19, x: 276, y: 17, path: 'M 179 12 C 205 15 244 17 276 17' },
    ],
    days: Array.from({ length: 21 }, (_, index) => ({ day: index + 1, x: 26 + index * 13.9 })),
  };

  readonly current = computed(() => this.words()[this.currentIndex()] ?? null);
  readonly completedSelectionWords = computed(() => this.words().filter((word) => this.selectionWordCompleted(word)));
  readonly pendingSelectionWords = computed(() => this.words().filter((word) => !this.selectionWordCompleted(word)));
  readonly learnedNewWords = computed(() => this.words().filter((word) => this.newWordLearned(word)));
  readonly unlearnedNewWords = computed(() => this.words().filter((word) => !this.newWordLearned(word)));
  readonly visibleNewWords = computed(() => this.activeSelectionBucket() === 'completed' ? this.learnedNewWords() : this.unlearnedNewWords());
  readonly newWordPageCount = computed(() => Math.max(1, Math.ceil(this.selectionTotal() / this.newWordPageSize)));
  readonly allVisibleNewWordsSelected = computed(() => this.visibleNewWords().length > 0 && this.visibleNewWords().every((word) => this.selected().has(word.id)));
  readonly newlyKnownWords = computed(() => (this.isRefineSelectionPage ? this.courseSelectionCache() : this.words()).filter((word) => !this.wordHistoricallyLearned(word) && this.selectionAssessment()[word.id] === 'known'));
  readonly selectionActionLabel = computed(() => {
    const hasLearningWords = this.selected().size > 0;
    const hasKnownWords = this.newlyKnownWords().length > 0;
    if (hasLearningWords && hasKnownWords) return '保存并开始学习';
    if (hasKnownWords) return '保存识词结果';
    return '开始学习';
  });
  readonly currentQuestion = computed(() => this.questions()[this.currentIndex()] ?? null);
  readonly wordPreviewPageCount = computed(() => Math.max(1, Math.ceil(this.wordPreviewTotal() / this.wordPreviewPageSize)));
  readonly wordPreviewPages = computed(() => {
    const pageCount = this.wordPreviewPageCount();
    if (pageCount <= 3) return Array.from({ length: pageCount }, (_, index) => index + 1);
    const start = Math.min(Math.max(1, this.wordPreviewPage() - 1), pageCount - 2);
    return Array.from({ length: 3 }, (_, index) => start + index);
  });
  readonly wordPreviewRangeStart = computed(() => this.wordPreviewTotal()
    ? ((this.wordPreviewPage() - 1) * this.wordPreviewPageSize) + 1
    : 0);
  readonly wordPreviewRangeEnd = computed(() => Math.min(this.wordPreviewPage() * this.wordPreviewPageSize, this.wordPreviewTotal()));
  readonly memoryStudents = computed(() => {
    if(this.reviewPageData()?.students)return this.reviewPageData()!.students!.map(s=>({id:String(s.id),name:s.name,taskCount:s.taskCount}));
    const students = new Map<string, MemoryStudentOption>();
    for (const item of this.calendarItems()) {
      const id = String(item['yhid'] ?? '').trim();
      if (!id) continue;
      const current = students.get(id);
      if (current) current.taskCount += 1;
      else students.set(id, { id, name: this.calendarStudent(item) || `学员 ${id}`, taskCount: 1 });
    }
    return [...students.values()].sort((left, right) => left.name.localeCompare(right.name, 'zh-CN'));
  });
  readonly memorySelectedStudentName = computed(() => this.memoryStudents().find((student) => student.id === this.memoryStudentId())?.name || '全部学员');
  readonly reviewPageData=signal<ReviewPage|null>(null); readonly reviewListPage=signal(1);
  readonly memoryFilteredItems = computed(() => {
    const studentId = this.memoryStudentId();
    return studentId ? this.calendarItems().filter((item) => String(item['yhid'] ?? '') === studentId) : this.calendarItems();
  });
  readonly memoryView = computed(() => buildAntiForgetView(this.memoryFilteredItems()));
  readonly memorySummary = computed(() => this.memoryView().summary);
  readonly memoryCalendar=computed(()=>reviewCalendar(this.reviewPageData()?.dates||[],this.memoryMonth(),this.memorySelectedDate()));
  readonly memorySelectedTasks = computed(() => this.reviewScope() === 'overdue' ? this.memoryFilteredItems() : antiForgetTasksOnDate(this.memoryFilteredItems(), this.memorySelectedDate()));
  readonly memorySelectedLabel = computed(() => {
    const value = this.memorySelectedDate();
    if (!value) return '';
    const [year, month, day] = value.split('-').map(Number);
    return new Intl.DateTimeFormat('zh-CN', { month: 'long', day: 'numeric', weekday: 'short' }).format(new Date(year, month - 1, day, 12));
  });
  readonly memoryTotalCount = computed(() => this.reviewPageData()?.summary.total||0);
  readonly memoryCompletedCount = computed(() => this.reviewPageData()?.summary.completed||0);
  readonly memoryDueCount = computed(() => this.reviewPageData()?.summary.due||0);
  readonly memoryProgress=computed(()=>{const s=this.reviewPageData()?.summary;return s?.total?Math.round(s.completed/s.total*100):0;});
  readonly progress = computed(() => {
    const total = this.isMatchingPage ? this.words().length : this.words().length || this.questions().length;
    if (!total) return 0;
    if (this.isMatchingPage) return Math.round(((total - this.matchLeft().length) / total) * 100);
    return Math.round(((this.currentIndex() + (this.completed() ? 1 : 0)) / total) * 100);
  });

  private readonly route = inject(ActivatedRoute);
  private readonly router = inject(Router);
  private readonly api = inject(ApiService);
  private readonly session = inject(SessionService);
  private readonly todayReviews = inject(TeacherTodayReviewService);
  private readonly platform = inject(PlatformService);
  private readonly wordPreviewPageSize = 30;
  private examTimer: ReturnType<typeof setInterval> | null = null;
  private antiStartedAt = Date.now();
  private calendarRequest?: Subscription;
  private choiceOptionsRequest?: Subscription;
  private choiceOptionsVersion = 0;
  private outsideChoicePool: Word[] | null = null;

  ngOnInit(): void {
    if (isTeacherLedLearningPath(this.meta.path) && !this.isReadOnlyWordView && !this.isReadOnlySelectionPage && !this.canStartPointReading && !this.isNewWordSelfStudyStage) {
      this.platform.toast('点读学习由陪练老师在上课时发起', 'error');
      void this.router.navigateByUrl('/pages/home/cart');
      return;
    }
    if (this.isCatalogPage && Number(this.session.user()?.groupId) === 1) {
      void this.router.navigateByUrl('/pages/home/cart');
      return;
    }
    if(this.isCalendarPage){
      this.reviewScope.set(this.query('scope')==='overdue'?'overdue':'');
      this.memorySelectedDate.set(this.query('date')||this.dateOnly());
      this.memoryStudentId.set(this.query('studentId')||'');
      this.reviewListPage.set(Math.max(1,Number(this.query('page'))||1));
      const [y,m]=this.memorySelectedDate().split('-').map(Number);this.memoryMonth.set(new Date(y,m-1,1,12));
    }
    if(this.isRecordPage)this.reviewReturn=history.state?.reviewReturn||{date:this.query('date')||this.dateOnly()};
    this.load();
  }

  ngOnDestroy(): void {
    this.calendarRequestId++;this.calendarRequest?.unsubscribe();this.selectionRequest?.unsubscribe();
    this.choiceOptionsVersion++;
    this.choiceOptionsRequest?.unsubscribe();
    this.stopExamTimer();
    this.examHistoryRequest?.unsubscribe();this.examLoadRequest?.unsubscribe();
    this.platform.stopAudio();
  }

  get isNodePage(): boolean {
    return ['pages/stu/index', 'pages/stu/stu_list'].includes(this.meta.path);
  }

  get isCatalogPage(): boolean {
    return this.meta.path === 'pages/stu/index';
  }

  get isUnitListPage(): boolean {
    return this.meta.path === 'pages/stu/stu_list';
  }

  get isSelectionPage(): boolean {
    return ['pages/stu/stu_abc', 'pages/his/his_words', 'pages/member/starshop'].includes(this.meta.path);
  }

  get isNewWordSelectionPage(): boolean {
    return this.meta.path === 'pages/member/starshop';
  }

  get isHistoryWordView(): boolean {
    return this.meta.path === 'pages/his/his_words';
  }

  get isRefineSelectionPage(): boolean {
    return this.meta.path === 'pages/stu/stu_abc';
  }

  get isStudyListPage(): boolean {
    return this.meta.path === 'pages/stu/stu_con';
  }

  get isReadOnlySelectionPage(): boolean {
    return !this.canStartPointReading && this.isRefineSelectionPage && this.query('readonly') === '1';
  }

  get canStartPointReading(): boolean {
    return canStartTeacherLedLearning(this.session.groupId());
  }

  get isNewWordSelfStudyStage(): boolean {
    if (Number(this.session.groupId()) !== 1
      || !['pages/stu/stu_con', 'pages/stu/stu3', 'pages/stu/stu4', 'pages/stu/stu5'].includes(this.meta.path)
      || ['nid', 'nids', 'bindingId', 'orderId'].some((key) => this.query(key))) return false;
    return this.storageGet('learn_mode') === 'newword'
      && this.parseArray(this.storageGet('choose_newword_learn')).length > 0;
  }

  get isReadOnlyWordView(): boolean {
    if (this.isHistoryWordView) return true;
    return !this.canStartPointReading && this.isStudyListPage && this.query('readonly') === '1';
  }

  get isMatchingPage(): boolean {
    return this.meta.path === 'pages/stu/stu3';
  }

  get isListeningPage(): boolean {
    return this.meta.path === 'pages/stu/stu4';
  }

  get isSpellingPage(): boolean {
    return ['pages/stu/stu5', 'pages/stu/pl_stu5'].includes(this.meta.path);
  }

  get spellingStageSkipped(): boolean {
    return this.storageGet('skip_spelling_stage') === true;
  }

  get canSkipSpellingStage(): boolean {
    return this.isSpellingPage && (this.canStartPointReading || this.isNewWordSelfStudyStage);
  }

  get hasNextWordBatch(): boolean {
    const currentPage = Number(this.storageGet('_page_current_learn') ?? 1);
    const pages = this.parseArray(this.storageGet('_page_word_orilist'));
    return Number.isInteger(currentPage) && currentPage > 0
      && Array.isArray(pages[currentPage]) && pages[currentPage].length > 0;
  }

  get stageActionLabel(): string {
    if (this.isMatchingPage) return '进入听音识意';
    if (this.isListeningPage && !this.spellingStageSkipped) return '进入组合拼写';
    if (this.hasNextWordBatch) return '学习下一组单词';
    const mode = String(this.storageGet('learn_mode') ?? '');
    if (mode === 'newword' || mode === 'history_word') return '完成学习并返回';
    return this.canStartPointReading && !this.query('orderId') ? '保存并结束学习' : '查看学习结果';
  }

  get canReturnToLearningEntry(): boolean {
    return isLearningStage(this.meta.path, this.route.snapshot.queryParamMap);
  }

  returnToLearningEntry(): void {
    const legacyOrderId = this.meta.path === 'pages/stu/pl_end' ? this.query('id') : '';
    const url = legacyOrderId ? `/pages/shop/get_order?id=${encodeURIComponent(legacyOrderId)}`
      : learningReturnUrl(this.route.snapshot.queryParamMap, history.state?.learningReturnUrl);
    void this.router.navigateByUrl(url, { replaceUrl: true });
  }

  get isReviewPage(): boolean {
    return ['pages/stu/stu6', 'pages/stu/pl_end'].includes(this.meta.path);
  }

  get isCalendarPage(): boolean {
    return this.meta.path === 'pages/stu/stu_calendar';
  }

  get isAntiForgetPage(): boolean {
    return this.meta.path === 'pages/stu/stu7';
  }

  get isRecordPage(): boolean {
    return this.meta.path === 'pages/stu/record';
  }

  get isExamPage(): boolean {
    return this.meta.path === 'pages/his/exam';
  }

  get isReportPage(): boolean {
    return this.meta.path === 'pages/stu/stu_ok';
  }

  get selectionLimit(): number {
    if (this.meta.path === 'pages/stu/stu_abc') return 30;
    if (this.isNewWordSelectionPage) return 100;
    return this.words().length;
  }

  load(): void {
    this.selectionRequest?.unsubscribe();this.selectionPage.set(1);this.selectionTotal.set(0);
    this.resetPageState();
    this.loading.set(true);
    this.error.set('');
    this.recordWordless.set(false);

    if (this.isReportPage) {
      this.loading.set(false);
      return;
    }
    if (this.isNodePage) {
      this.loadNodes();
      return;
    }
    if (this.isSelectionPage) {
      this.loadSelection();
      return;
    }
    if (this.isCalendarPage) {
      this.loadCalendar(true);
      return;
    }
    if (this.isAntiForgetPage) {
      this.loadAntiForget();
      return;
    }
    if (this.isRecordPage) {
      this.loadRecord();
      return;
    }
    if (this.isExamPage) {
      this.loadExam();
      return;
    }
    if (this.meta.path === 'pages/stu/pl_end') {
      this.loadPracticeEnd();
      return;
    }
    if (this.meta.path === 'pages/stu/stu6') {
      this.loadReviewWords();
      return;
    }
    this.loadStageWords();
  }

  openNode(node: SourceItem): void {
    const id = node['NodeID'] ?? node['Nodeid'] ?? node['ID'] ?? node['id'];
    if (this.isCatalogPage) {
      void this.router.navigate(['/pages/stu/stu_list'], { queryParams: { nid: id } });
      return;
    }
    if (this.isUnitListPage && !this.canStartPointReading) {
      void this.router.navigate(['/pages/stu/stu_abc'], {
        queryParams: { nids: id, pnid: this.query('nid'), readonly: 1 },
      });
      return;
    }
    this.toggleNode(node);
  }

  openWordPreviewPage(page: number): void {
    const target = Math.min(Math.max(1, page), this.wordPreviewPageCount());
    if (target === this.wordPreviewPage() || this.wordPreviewLoading()) return;
    const previous = this.wordPreviewPage();
    this.wordPreviewPage.set(target);
    if (this.isHistoryWordView) {
      const start = (target - 1) * this.wordPreviewPageSize;
      this.words.set(this.historyPreviewWords.slice(start, start + this.wordPreviewPageSize));
      setTimeout(() => document.getElementById('readonly-word-title')?.scrollIntoView({ behavior: 'smooth', block: 'start' }));
      return;
    }
    this.wordPreviewLoading.set(true);
    this.loadReadOnlyWords(true, previous);
  }

  selectCatalogCategory(index: number): void {
    if (index === this.catalogCategoryIndex()) return;
    this.catalogCategoryIndex.set(index);
    this.loadNodes();
  }

  toggleNode(node: SourceItem): void {
    const id = this.nodeId(node);
    if (!id) return;
    this.selectedNodes.update((current) => {
      const next = new Set(current);
      if (next.has(id)) next.delete(id); else next.add(id);
      return next;
    });
  }

  startNodeSelection(): void {
    if (!this.selectedNodes().size) {
      this.platform.toast('请选择学习单元', 'error');
      return;
    }
    void this.router.navigate(['/pages/stu/stu_abc'], {
      queryParams: {
        nids: [...this.selectedNodes()].join(','),
        pnid: this.query('nid'),
        bindingId: this.query('bindingId'),
        orderId: this.query('orderId'),
      },
    });
  }

  nodeId(node: SourceItem): string {
    return String(node['NodeID'] ?? node['Nodeid'] ?? node['ID'] ?? node['id'] ?? '');
  }

  nodeTitle(node: SourceItem): string {
    return String(node['NodeName'] ?? node['Title'] ?? node['name'] ?? '词库');
  }

  nodeCount(node: SourceItem): string {
    return String(node['ItemCount'] ?? node['Count'] ?? node['count'] ?? '');
  }

  nodeProgress(node: SourceItem): string {
    const total = this.nodeTotal(node);
    return total > 0 ? `已学 ${this.nodeLearned(node)}/${total} · 进度 ${this.nodeProgressPercent(node)}%` : '';
  }

  nodeLearned(node: SourceItem): number { return Math.max(0, Number(node['yx_word'] ?? 0)); }
  nodeTotal(node: SourceItem): number { return Math.max(0, Number(node['total'] ?? 0)); }
  nodeProgressPercent(node: SourceItem): number {
    const total = this.nodeTotal(node);
    return total ? Math.min(100, Math.round((this.nodeLearned(node) / total) * 100)) : 0;
  }

  toggleWord(word: Word): void {
    if (this.isRefineSelectionPage && !this.canRelearnCourseWord(word)) return;
    const shouldSelect = !this.selected().has(word.id);
    if (!this.setWordSelected(word, shouldSelect) || !this.isRefineSelectionPage) return;
    if (shouldSelect) this.setSelectionAssessment(word, 'unknown');
    else this.clearSelectionAssessment(word);
  }

  selectionWordRevealed(word: Word): boolean {
    return this.selectionRevealed().has(word.id);
  }

  wordHistoricallyLearned(word: Word): boolean {
    return Number(word['w_learned'] ?? 0) > 0;
  }

  newWordLearned(word: Word): boolean {
    return Number(word['xxcs'] ?? 0) >= 2;
  }

  selectionWordCompleted(word: Word): boolean {
    return this.wordHistoricallyLearned(word) || this.selectionAssessment()[word.id] === 'known';
  }

  courseWordPass(word: Word): number {
    return Math.min(3, Math.max(this.selectionAssessment()[word.id] === 'known' ? 1 : 0, Math.floor(Number(word['w_learned']) || 0)));
  }

  coursePassCount(pass: number): number {
    const counts = this.coursePassCounts();
    if (!counts) return 0;
    const known = this.newlyKnownWords().length;
    return Math.max(0, counts[pass] + (pass === 0 ? -known : pass === 1 ? known : 0));
  }

  canRelearnCourseWord(word: Word): boolean {
    const pass = this.courseWordPass(word);
    const counts = this.bookPassCounts();
    return !this.isReadOnlySelectionPage && !!counts && pass < 3
      && (pass === 0 || counts.slice(0, pass).every(count => count === 0));
  }

  get coursePassHint(): string {
    const pass = this.coursePass();
    if (pass === 0) return this.isReadOnlySelectionPage ? '这些单词尚未完成第一遍学习，点击可查看释义。' : '先回忆中文，核对后选择“认识”或“加入学习”。';
    if (pass === 3) return '这些单词已完成三遍学习，可查看和听读音。';
    if (!this.bookPassCounts()) return '正在读取整本学习进度，读取完成后可继续学习。';
    if (this.bookPassCounts()!.slice(0, pass).some(count => count > 0)) return `整本单词完成第${pass === 1 ? '一' : '二'}遍后，可从这里选择单词继续学习。`;
    return this.isReadOnlySelectionPage ? `这些单词已学${pass}遍，可由老师选词继续学习。` : `选择单词开始第${pass === 1 ? '二' : '三'}遍学习。`;
  }

  selectCoursePass(pass: number): void {
    if (pass === this.coursePass() || pass < 0 || pass > 3) return;
    this.selectionRequest?.unsubscribe();
    this.coursePass.set(pass);
    this.selectionPage.set(1);
    this.words.set([]);
    this.selectionTotal.set(0);
    this.loadSelection();
  }

  selectionCompletionLabel(word: Word): string {
    return this.wordHistoricallyLearned(word) ? `已学${this.courseWordPass(word)}遍` : '本次已认识';
  }

  revealSelectionWord(word: Word): void {
    this.selectionRevealed.update((current) => {
      const next = new Set(current);
      if (next.has(word.id)) next.delete(word.id);
      else next.add(word.id);
      return next;
    });
    this.play(word);
  }

  markWordKnown(word: Word): void {
    if (this.isReadOnlySelectionPage || this.wordHistoricallyLearned(word)) return;
    this.setWordSelected(word, false);
    this.setSelectionAssessment(word, 'known');
  }

  markWordUnknown(word: Word): void {
    if (this.isReadOnlySelectionPage || this.wordHistoricallyLearned(word)) return;
    if (this.setWordSelected(word, true)) this.setSelectionAssessment(word, 'unknown');
  }

  toggleAllWords(): void {
    if (this.isNewWordSelectionPage) {
      const visible = this.visibleNewWords();
      const clearVisible = this.allVisibleNewWordsSelected();
      const next = new Set(this.selected());
      for (const word of visible) {
        if (clearVisible) next.delete(word.id);
        else if (next.size < this.selectionLimit) next.add(word.id);
      }
      if (!clearVisible && next.size === this.selectionLimit && visible.some((word) => !next.has(word.id))) {
        this.platform.toast(`本次最多选择 ${this.selectionLimit} 个单词`, 'error');
      }
      this.selected.set(next);
      return;
    }
    if (this.selected().size) {
      this.selected.set(new Set());
      return;
    }
    this.selected.set(new Set(this.words().slice(0, this.selectionLimit).map((word) => word.id)));
  }

  startSelected(): void {
    if (this.submitting() || this.isReadOnlySelectionPage) return;
    const available = this.isNewWordSelectionPage ? [...this.newWordSelectionCache.values()] : this.isRefineSelectionPage ? this.courseSelectionCache().filter(word => this.canRelearnCourseWord(word) && this.selectionAssessment()[word.id] !== 'known') : this.words();
    const chosen = available
      .filter((word) => this.selected().has(word.id));
    const newlyKnown = this.newlyKnownWords();
    if (!chosen.length && !newlyKnown.length) {
      this.platform.toast(this.isRefineSelectionPage ? '请先判断单词是否认识，或选择要学习的单词' : '请先选择要学习的单词', 'error');
      return;
    }

    if (this.meta.path === 'pages/stu/stu_abc') {
      const student = this.session.student() ?? this.session.user();
      if (!student?.userId) {
        this.platform.toast('课程信息错误', 'error');
        return;
      }
      this.submitting.set(true);
      this.persistWordsAsLearned(newlyKnown, student).pipe(finalize(() => this.submitting.set(false))).subscribe({
        next: () => {
          if (newlyKnown.length) this.commitKnownWords(newlyKnown);
          if (chosen.length) {
            this.beginSelectedFlow(chosen, '');
            return;
          }
          this.platform.toast('识词结果已保存', 'success');
        },
        error: (error: ApiError) => this.platform.toast(error.message, 'error'),
      });
      return;
    }

    this.beginSelectedFlow(chosen, this.meta.path === 'pages/member/starshop' ? 'newword' : 'history_word');
  }

  deleteSelectedNewWords(): void {
    const chosen = [...this.newWordSelectionCache.values()].filter((word) => this.selected().has(word.id));
    if (!chosen.length) {
      this.platform.toast('请选择单词', 'error');
      return;
    }
    const owner = Number(this.session.user()?.groupId) === 3 ? this.session.student() : this.session.user();
    this.api.post('e_add_words', {
      uid: owner?.userId,
      wordsId: chosen.map((word) => word.wordId).join(','),
      ifnew: 0,
      kcid: this.query('kcid'),
    }).subscribe({
      next: () => {
        this.platform.toast('已删除', 'success');
        this.load();
      },
      error: (error: ApiError) => this.platform.toast(error.message, 'error'),
    });
  }

  play(word = this.current()): void {
    if (this.isReadOnlySelectionPage || (this.isReadOnlyWordView && !this.isHistoryWordView)) return;
    if (!word?.audio) {
      this.platform.toast('该单词暂无音频', 'error');
      return;
    }
    this.platform.play(this.wordAudioUrl(word.audio));
  }

  toggleRecordAnswer(word: Word): void {
    this.recordRevealed.update((current) => {
      const next = new Set(current);
      if (next.has(word.id)) next.delete(word.id);
      else next.add(word.id);
      return next;
    });
    this.seen.update((current) => new Set(current).add(word.id));
    this.play(word);
  }

  repeatWord(word: Word, index: number): void {
    const count = this.repetitions()[word.id] ?? 0;
    if (this.studyStep() === 1 && index > 0) {
      const previous = this.words()[index - 1];
      if ((this.repetitions()[previous.id] ?? 0) < 3) {
        this.platform.toast('前面还有没读完的单词', 'error');
        return;
      }
    }
    this.play(word);
    if (count < 3) {
      this.repetitions.update((value) => ({ ...value, [word.id]: count + 1 }));
    }
    if (this.words().every((item) => (this.repetitions()[item.id] ?? 0) >= 3)) {
      this.finishStudyRound();
    }
  }

  shuffleStudyWords(): void {
    this.words.set(shuffledStudy(this.words()));
    this.repetitions.set({});
  }

  skipStudyList(): void {
    this.navigateStage('/pages/stu/stu3');
  }

  chooseMatch(side: 'left' | 'right', word: Word): void {
    if (side === 'left') {
      this.leftChoice.set(word.id);
      this.play(word);
    } else {
      this.rightChoice.set(word.id);
    }
    const left = side === 'left' ? word.id : this.leftChoice();
    const right = side === 'right' ? word.id : this.rightChoice();
    if (!left || !right) return;
    if (left !== right) {
      this.platform.toast('答错了，请再试一次', 'error');
      this.leftChoice.set('');
      this.rightChoice.set('');
      return;
    }
    this.platform.playEffect('success');
    this.matchLeft.update((items) => items.filter((item) => item.id !== left));
    this.matchRight.update((items) => items.filter((item) => item.id !== right));
    this.leftChoice.set('');
    this.rightChoice.set('');
    if (this.matchLeft().length === 0) this.completed.set(true);
  }

  chooseMeaning(option: Word): void {
    if (this.choicesLoading() || this.choiceOptions().length !== 4 || this.completed() || !this.choiceOptions().some(w => w.id === option.id)) return;
    const word = this.current();
    if (!word) return;
    if (option.id !== word.id) {
      this.platform.playEffect('error');
      this.platform.toast('答错了，请重新听一遍', 'error');
      this.play(word);
      return;
    }
    this.correct.update((value) => value + 1);
    this.platform.playEffect('success');
    if (this.currentIndex() >= this.words().length - 1) {
      this.completed.set(true);
      return;
    }
    this.currentIndex.update((value) => value + 1);
    this.prepareChoiceOptions();
    setTimeout(() => this.play(), 150);
  }

  spellLetter(index: number): void {
    if (this.spellingCorrect() || this.letters()[index]?.used) return;
    this.letters.update((items) => items.map((item, itemIndex) => itemIndex === index ? { ...item, used: true } : item));
    const next = this.assembled() + this.letters()[index].value;
    this.assembled.set(next);
    const word = this.current();
    if (!word || next.length < word.word.length) return;
    if (next.toLowerCase() === word.word.toLowerCase()) {
      this.spellingCorrect.set(true);
      this.correct.update((value) => value + 1);
      this.platform.playEffect('success');
      this.platform.toast('拼写正确', 'success');
      return;
    }
    this.platform.playEffect('error');
    this.platform.toast('拼写错了，再试一次', 'error');
    this.prepareSpelling();
  }

  resetSpelling(): void {
    this.prepareSpelling();
  }

  nextSpellingWord(): void {
    if (!this.spellingCorrect()) {
      this.platform.toast('请先完成当前单词', 'error');
      return;
    }
    if (this.currentIndex() >= this.words().length - 1) {
      this.completed.set(true);
      return;
    }
    this.currentIndex.update((value) => value + 1);
    this.prepareSpelling();
    this.play();
  }

  skipPracticeStage(): void {
    if ((!this.isMatchingPage && !this.isListeningPage) || this.completed() || this.submitting()) return;
    this.completed.set(true);
    this.continueAfterStage();
  }

  skipSpellingStage(): void {
    if (!this.canSkipSpellingStage || this.completed() || this.submitting()) return;
    this.storageSet('skip_spelling_stage', true);
    this.completed.set(true);
    this.continueAfterStage();
  }

  continueAfterStage(): void {
    if (this.submitting() || !this.completed()) return;
    if (this.isMatchingPage) {
      this.completed.set(false);
      this.navigateStage('/pages/stu/stu4');
    } else if (this.isListeningPage) {
      this.completed.set(false);
      if (this.spellingStageSkipped) this.finishSpellingFlow();
      else this.navigateStage(this.canStartPointReading ? '/pages/stu/pl_stu5' : '/pages/stu/stu5');
    } else if (this.isSpellingPage) {
      this.finishSpellingFlow();
    }
  }

  reviewValue(word: Word): 0 | 1 | 2 {
    return this.reviewState()[word.id] ?? 0;
  }

  markReview(word: Word, state: 1 | 2): void {
    this.reviewState.update((value) => ({ ...value, [word.id]: state }));
    if (this.query('orderId')) this.storageSet('roundReview:' + this.storageGet('batchId'), this.reviewState());
  }

  markAllKnown(): void {
    const allKnown = this.words().every((word) => this.reviewValue(word) === 1);
    const next: Record<string, 0 | 1 | 2> = {};
    for (const word of this.words()) next[word.id] = allKnown ? 0 : 1;
    this.reviewState.set(next);
    if (this.query('orderId')) this.storageSet('roundReview:' + this.storageGet('batchId'), next);
  }

  reviewCount(state: 1 | 2): number {
    return this.words().filter((word) => this.reviewValue(word) === state).length;
  }

  submitReview(continueLearning = false): void {
    if (this.submitting() || !this.words().length) return;
    if (this.words().some((word) => this.reviewValue(word) === 0)) {
      this.platform.toast('请为每个单词选择掌握情况', 'error');
      return;
    }
    if (this.meta.path === 'pages/stu/pl_end') {
      this.submitPracticeEnd(continueLearning);
      return;
    }
    this.saveLearningRecord();
  }

  toggleSeen(word: Word): void {
    this.revealed.set(!this.revealed());
    this.seen.update((current) => new Set(current).add(word.id));
    this.play(word);
    this.updateAntiProgress(word);
    if (this.seen().size === this.words().length) {
      this.platform.toast(`已完成 ${this.words().length} 个单词的复习`, 'success');
    }
  }

  joinAntiWords(): void {
    const chosen = this.words().filter((word) => this.selected().has(word.id));
    if (!chosen.length) {
      this.platform.toast('请选择需要加入生词本的单词', 'error');
      return;
    }
    const existing = this.parseArray(this.myNewWords()['scnr']);
    const combined = new Map<string, SourceItem>();
    for (const item of existing) combined.set(String(item['GeneralID'] ?? ''), item);
    for (const word of chosen) {
      combined.set(word.wordId, { GeneralID: word.wordId, Title: word.word, check: this.reviewValue(word), gldy: word['gldy'] });
    }
    const user = this.session.user();
    const content: SourceItem = {
      ModelID: 55,
      nodeId: 255,
      inputer: user?.honeyName,
      status: 99,
      Hits: combined.size,
      title: user?.honeyName,
    };
    let action = 'content_add';
    if (this.myNewWords()['GeneralID']) {
      content['GeneralID'] = this.myNewWords()['GeneralID'];
      action = 'content_update';
    }
    this.api.post(action, {
      content: JSON.stringify(content),
      addon: JSON.stringify({ UserID: user?.userId, scnr: JSON.stringify([...combined.values()]) }),
    }).subscribe({
      next: () => this.platform.toast('添加成功', 'success'),
      error: (error: ApiError) => this.platform.toast(error.message, 'error'),
    });
  }

  addRecordWords(): void {
    const chosen = this.words().filter((word) => this.selected().has(word.id));
    if (!chosen.length) {
      this.platform.toast('请选择单词', 'error');
      return;
    }
    const owner = Number(this.session.user()?.groupId) === 3 ? this.session.student() : this.session.user();
    this.api.post('e_add_words', {
      uid: owner?.userId,
      wordsId: chosen.map((word) => word.wordId).join(','),
      ifnew: 1,
      kcid: this.query('kcid'),
    }).subscribe({
      next: () => this.platform.toast('添加成功', 'success'),
      error: (error: ApiError) => this.platform.toast(error.message, 'error'),
    });
  }

  endRecord(): void {
    if(this.submitting()||this.reviewCompletion())return;
    this.submitting.set(true);
    this.api.post<{amount:number;rewardStatus:string;ineligibleReason?:string;unchanged?:boolean}>('app_review_complete',{id:this.query('gid')}).pipe(finalize(()=>this.submitting.set(false))).subscribe({
      next:({result})=>{this.reviewCache().clear();if(Number(this.session.groupId())===3)this.todayReviews.markCompleted(this.query('gid'));this.reviewCompletion.set(result);},
      error:(e:ApiError)=>this.platform.toast(e.message,'error'),
    });
  }

  get overdueReview():boolean{return Boolean(this.query('plannedDate')&&this.query('plannedDate')<this.dateOnly());}
  canDeactivate():boolean|Promise<boolean>{
    if(!this.isRecordPage||this.reviewCompletion())return true;
    if(this.submitting())return false;
    return this.seen().size||this.selected().size||this.recordRevealed().size?this.platform.confirm('本次复习尚未提交完成，确定离开？'):true;
  }
  returnToReview(today=false):void{
    const r=today?{date:this.dateOnly()}:this.reviewReturn;
    void this.router.navigate(['/pages/stu/stu_calendar'],{queryParams:{date:r.date,studentId:r.studentId,scope:r.scope,page:r.page},state:{reviewScroll:r.scroll},replaceUrl:true});
  }


  calendarTitle(item: SourceItem): string {
    const title = String(item['kc_title'] ?? item['kctitle'] ?? item['kcmc'] ?? '').trim();
    return title ? title.split('@')[0] : '单词复习';
  }

  calendarStudent(item: SourceItem): string {
    return String(item['honeyName'] ?? item['Title'] ?? '').split('@')[0];
  }

  calendarDate(item: SourceItem): string {
    return antiForgetDate(item);
  }

  calendarFirstLearnedAt(item: SourceItem): string {
    const raw = String(
      item['learned_at']
      ?? item['learnedAt']
      ?? item['firstLearnedAt']
      ?? item['learned_date']
      ?? '',
    ).trim();
    if (!raw) return '首次学习：时间未记录';

    const compactDate = raw.match(/^(\d{4})(\d{2})(\d{2})$/);
    if (compactDate) return `首次学习：${compactDate[1]}-${compactDate[2]}-${compactDate[3]}（时间未记录）`;

    const dateOnly = raw.match(/^(\d{4}-\d{2}-\d{2})$/);
    if (dateOnly) return `首次学习：${dateOnly[1]}（时间未记录）`;

    const normalized = /(?:Z|[+-]\d{2}:?\d{2})$/i.test(raw)
      ? raw
      : `${raw.replace(' ', 'T')}+08:00`;
    const value = new Date(normalized);
    if (Number.isNaN(value.getTime())) return `首次学习：${raw}`;
    const parts = new Intl.DateTimeFormat('zh-CN', {
      timeZone: 'Asia/Shanghai',
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit',
      hourCycle: 'h23',
    }).formatToParts(value);
    const part = (type: Intl.DateTimeFormatPartTypes) => parts.find((itemPart) => itemPart.type === type)?.value ?? '';
    return `首次学习：${part('year')}-${part('month')}-${part('day')} ${part('hour')}:${part('minute')}`;
  }

  calendarReviewNumber(item: SourceItem): number {
    for (const key of ['fxcs', 'fxxh', 'reviewNo', 'reviewIndex', 'review_order']) {
      const value = Number(item[key]);
      if (Number.isFinite(value) && value > 0) return Math.round(value);
    }

    const recordId = String(item['xxjlid'] ?? '').trim();
    if (!recordId) return 1;
    const tasks = this.calendarItems()
      .filter((candidate) => String(candidate['xxjlid'] ?? '').trim() === recordId)
      .sort((left, right) => {
        const dateOrder = antiForgetDate(left).localeCompare(antiForgetDate(right));
        if (dateOrder) return dateOrder;
        return Number(left['GeneralID'] ?? 0) - Number(right['GeneralID'] ?? 0);
      });
    const index = tasks.indexOf(item);
    return index >= 0 ? index + 1 : 1;
  }

  calendarReady(item: SourceItem): boolean {
    const due = String(item['kywsj'] ?? '').slice(0, 10);
    return Boolean(due && Date.parse(due) <= Date.parse(this.dateOnly()) && Number(item['fxzt'] ?? 0) !== 1);
  }

  calendarCompleted(item: SourceItem): boolean {
    return antiForgetCompleted(item);
  }

  selectMemoryDay(day: AntiForgetCalendarDay): void {
    if (day.date === this.memorySelectedDate() && day.inCurrentMonth) return;
    this.reviewScope.set('');this.memorySelectedDate.set(day.date);
    this.reviewListPage.set(1);this.loadCalendar();
    if (!day.inCurrentMonth) {
      const [year, month] = day.date.split('-').map(Number);
      this.memoryMonth.set(new Date(year, month - 1, 1, 12));
    }
  }

  shiftMemoryMonth(amount: number): void {
    const current = this.memoryMonth();
    const next = new Date(current.getFullYear(), current.getMonth() + amount, 1, 12);
    this.memoryMonth.set(next);
    const monthKey = `${next.getFullYear()}-${String(next.getMonth() + 1).padStart(2, '0')}`;
    const firstTask = (this.reviewPageData()?.dates||[]).map(row=>row.date).filter((date) => date.startsWith(monthKey)).sort()[0];
    this.memorySelectedDate.set(firstTask || `${monthKey}-01`);
    this.reviewListPage.set(1);this.loadCalendar();
  }

  showCurrentMemoryMonth(): void {
    const today = this.dateOnly();
    const [year, month] = today.split('-').map(Number);
    this.memoryMonth.set(new Date(year, month - 1, 1, 12));
    this.reviewScope.set('');this.memorySelectedDate.set(today);
    this.reviewListPage.set(1);this.loadCalendar();
  }

  selectMemoryStudent(event: Event): void {
    this.memoryStudentId.set((event.target as HTMLSelectElement).value);this.reviewListPage.set(1);this.loadCalendar();
  }

  memoryTaskStatus(item: SourceItem): string {
    if (this.calendarCompleted(item)) return '已完成';
    return this.calendarReady(item) ? (this.calendarDate(item)<this.dateOnly()?'逾期补做 · 不计薪':'待复习 · 当天完成计薪') : '未到期';
  }

  isWritingRecord(): boolean {
    return String(this.orderInfo()['if_writing'] ?? '') === '1';
  }

  openCalendar(item: SourceItem): void {
    if (!this.calendarReady(item) && !this.calendarCompleted(item)) {
      this.platform.toast('还未到复习时间');
      return;
    }
    const studentId = Number(item['yhid'] ?? 0);
    if (!studentId) {
      this.platform.toast('复习任务缺少关联学员', 'error');
      return;
    }
    this.session.setStudent({
      userId: studentId,
      honeyName: this.calendarStudent(item) || '关联学员',
      groupId: 1,
    });
    void this.router.navigate(['/pages/stu/record'], {
      queryParams: { id: item['xxjlid'], gid: item['GeneralID'], kcid: item['kcid'], plannedDate:this.calendarDate(item),date:this.memorySelectedDate() },
      state:{reviewReturn:{date:this.memorySelectedDate(),studentId:this.memoryStudentId(),page:this.reviewListPage(),scope:this.reviewScope(),scroll:window.scrollY}},
    });
  }

  startExam(): void {
    if (!this.questions().length || this.loading() || this.submitting()) return;
    this.examAttemptStamp=new Date().toISOString();this.examLogKey=crypto.randomUUID();this.examAnswerId=null;this.examSaveError.set('');
    this.answers.set(this.questions().map(q=>({qid:q.ID,qtype:String(q.QType??''),answer:'',result:2})));
    this.examStarted.set(true);
    this.examSubmitted.set(false);
    this.currentIndex.set(0);
    this.startExamTimer();
  }

  answerExam(option: ExamOption, optionIndex: number): void {
    if(this.submitting()||this.examSaveError()||this.examSubmitted())return;
    const question = this.currentQuestion();
    if (!question) return;
    const options = question.QOption.map((item, index) => ({ ...item, checked: index === optionIndex }));
    this.questions.update((items) => items.map((item, index) => index === this.currentIndex() ? { ...item, QOption: options, checked: true } : item));
    const result: 0 | 1 = this.cleanText(option.text) === this.cleanText(question.QContent) ? 1 : 0;
    this.setExamAnswer({ qid: question.ID, qtype: String(question.QType ?? ''), answer: option.value, result });
    this.advanceExam();
  }

  skipExamQuestion(): void {
    if(this.submitting()||this.examSaveError()||this.examSubmitted())return;
    const question = this.currentQuestion();
    if (!question) return;
    this.setExamAnswer({ qid: question.ID, qtype: String(question.QType ?? ''), answer: '', result: 2 });
    this.advanceExam();
  }

  submitExam(): void {
    if(this.submitting()||this.examSubmitted())return;
    this.examSaveError.set('');
    if(this.examAnswerId!==null){this.submitting.set(true);this.saveExamLog(this.examAnswerId);return;}
    this.stopExamTimer();
    const ask = this.askInfo();
    const user = this.session.user();
    const answers = this.answers();
    const mu = {
      AskID: ask['ID'],
      Answer: JSON.stringify(answers),
      Remin: '',
      ZType: 0,
      Zstatus: 0,
      Source: '',
      UserID: user?.userId,
      CDate: this.examAttemptStamp,
    };
    this.submitting.set(true);
    this.api.post<string | number>('vote_add', { mu: JSON.stringify(mu) }).subscribe({
      next: ({ result }) => {this.examAnswerId=result;this.saveExamLog(result);},
      error: (error: ApiError) => {
        this.submitting.set(false);this.examSaveError.set(error.message);
      },
    });
  }

  restart(): void {
    if (this.isExamPage) {
      this.loadExam();
      return;
    }
    this.load();
  }

  leave(): void {
    this.clearLearningStorage();
    void this.router.navigateByUrl('/pages/home/index', { replaceUrl: true });
  }

  private loadNodes(): void {
    this.loading.set(true);
    this.error.set('');
    this.nodes.set([]);
    this.selectedNodes.set(new Set());
    const pid = this.isCatalogPage
      ? WORD_CATALOG_CATEGORIES[this.catalogCategoryIndex()].pid
      : this.query('nid') || this.query('pid');
    const params: Record<string, unknown> = { pid, cpage: 1, psize: 100 };
    if (this.isUnitListPage) {
      const learner = this.canStartPointReading ? this.session.student() : this.session.user();
      if (!learner?.userId) {
        this.loading.set(false);
        this.error.set('未找到当前学员，请返回学习记录重新选择学员');
        return;
      }
      params['ifunit'] = 1;
      params['userId'] = learner.userId;
      params['bindingId'] = this.query('bindingId');
    }
    this.api.get<unknown>('node_list', params).pipe(finalize(() => this.loading.set(false))).subscribe({
      next: (nodes) => {
        const rows = this.findList(nodes.result);
        if (this.isUnitListPage && !this.canStartPointReading && !rows.length && pid) {
          void this.router.navigate(['/pages/stu/stu_abc'], {
            queryParams: { nids: pid, readonly: 1 },
            replaceUrl: true,
          });
          return;
        }
        this.nodes.set(rows);
      },
      error: (error: ApiError) => this.error.set(error.message
        || (this.isCatalogPage ? '词库暂时无法加载，请稍后重试' : '学习单元暂时无法加载，请稍后重试')),
    });
  }

  loadMoreSelection():void{if(!this.selectionLoading()&&this.words().length<this.selectionTotal()){this.selectionPage.update(p=>p+1);this.loadSelection(true);}}
  selectNewWordBucket(bucket: 'pending' | 'completed'): void {
    if (this.activeSelectionBucket() === bucket) return;
    this.selectionRequest?.unsubscribe();
    this.activeSelectionBucket.set(bucket);
    this.selectionPage.set(1);
    this.selectionTotal.set(this.newWordCounts()[bucket]);
    this.words.set([]);
    if (this.legacyNewWords) { this.showLegacyNewWordPage(); return; }
    this.loadSelection();
  }

  goToNewWordPage(page: number): void {
    if (this.selectionLoading() || page < 1 || page > this.newWordPageCount() || page === this.selectionPage()) return;
    this.selectionPage.set(page);
    if (this.legacyNewWords) { this.showLegacyNewWordPage(); return; }
    this.loadSelection();
  }

  private showLegacyNewWordPage(): void {
    const all = this.legacyNewWords ?? [];
    const pending = all.filter((word) => !this.newWordLearned(word));
    const completed = all.filter((word) => this.newWordLearned(word));
    const bucket = this.activeSelectionBucket() === 'completed' ? completed : pending;
    const start = (this.selectionPage() - 1) * this.newWordPageSize;
    this.newWordCounts.set({ pending: pending.length, completed: completed.length });
    this.selectionTotal.set(bucket.length);
    this.words.set(bucket.slice(start, start + this.newWordPageSize));
    for (const word of all) this.newWordSelectionCache.set(word.id, word);
    this.error.set('');
    this.selectionLoading.set(false);
    this.loading.set(false);
  }

  private loadLegacyNewWords(uid: number | undefined, page = 1, collected: Word[] = []): void {
    const size = 500;
    this.selectionRequest = this.api.get<unknown>('e_words_list', { uid, cpage: page, psize: size }).subscribe({
      next: ({ result, page: pageInfo }) => {
        const incoming = this.findList(result).map((item) => this.toNewWord(item)).filter((word) => word.word);
        const all = [...collected, ...incoming];
        const total = Number(pageInfo?.itemCount ?? all.length);
        if (!Number.isFinite(total) || (!incoming.length && all.length < total)) {
          this.error.set('生词本数据未加载完整，请重试');
          this.selectionLoading.set(false);
          this.loading.set(false);
          return;
        }
        if (all.length < total) {
          this.loadLegacyNewWords(uid, page + 1, all);
          return;
        }
        this.legacyNewWords = all;
        this.showLegacyNewWordPage();
      },
      error: (error: ApiError) => {
        this.error.set(error.message || '生词本加载失败，请重试');
        this.selectionLoading.set(false);
        this.loading.set(false);
      },
    });
  }

  private loadSelection(more=false): void {
    const accept=(result:unknown,total:unknown)=>{const incoming=this.findList(result).map(item=>this.meta.path==='pages/member/starshop'?this.toNewWord(item):this.toWord(item)).filter(w=>w.word);this.words.set(more?[...this.words(),...incoming]:incoming);this.selectionTotal.set(Number(total)||this.words().length);};
    const failure=(error:ApiError)=>{if(more){this.selectionPage.update(p=>p-1);this.platform.toast(error.message,'error');}else this.error.set(error.message);};
    if (this.meta.path === 'pages/stu/stu_abc') {
      const student = this.session.student() ?? this.session.user();this.selectionLoading.set(true);
      this.selectionRequest=this.api.get<unknown>('e_ck_list',{checkwords:2,nids:this.query('nids')||this.query('nid'),pnid:this.query('pnid'),learningPass:this.coursePass(),modelId:52,cpage:this.selectionPage(),psize:100,uid:student?.userId}).pipe(finalize(()=>{this.selectionLoading.set(false);this.loading.set(false);})).subscribe({next:({result,page})=>{
        accept(result,page?.itemCount);
        const merged=new Map(this.courseSelectionCache().map(word=>[word.id,word]));
        for(const word of this.words()) merged.set(word.id,word);
        this.courseSelectionCache.set([...merged.values()]);
        const counts=page?.['passCounts'],bookCounts=page?.['bookPassCounts'];
        if(Array.isArray(counts)&&counts.length===4&&Array.isArray(bookCounts)&&bookCounts.length===4){
          this.coursePassCounts.set(counts.map(Number));this.bookPassCounts.set(bookCounts.map(Number));
        }
        this.error.set('');
      },error:failure});return;
    }

    if (this.meta.path === 'pages/his/his_words') {
      this.api.post<unknown>('e_record_detail', { id: this.query('id') }).pipe(finalize(() => this.loading.set(false))).subscribe({
        next: ({ result, addon }) => {
          const words = this.findList(result).map((item) => this.toWord(item)).filter((word) => word.word);
          this.historyPreviewWords = words;
          this.words.set(words.slice(0, this.wordPreviewPageSize));
          this.wordPreviewTotal.set(words.length);
          const sourceAddon = this.findList(addon)[0];
          if (sourceAddon) {
            this.orderInfo.set(sourceAddon);
            if (sourceAddon['GeneralID']) this.api.get<any>('app_lesson_study', {orderId: String(sourceAddon['GeneralID'])}).subscribe({next: ({result}) => this.historySources.set(lessonStudySources(result)), error: () => this.historySources.set([])});
          }
        },
        error: (error: ApiError) => this.error.set(error.message),
      });
      return;
    }

    const owner = Number(this.session.user()?.groupId) === 3 ? this.session.student() : this.session.user();
    this.selectionLoading.set(true);
    this.selectionRequest=this.api.get<unknown>('e_words_list',{uid:owner?.userId,cpage:this.selectionPage(),psize:this.newWordPageSize,learningStatus:this.activeSelectionBucket()}).subscribe({
      next: ({result,page}) => {
        const incoming = this.findList(result).map((item) => this.toNewWord(item)).filter((word) => word.word);
        const pendingCount = Number(page?.['pendingCount']);
        const completedCount = Number(page?.['completedCount']);
        const total = Number(page?.itemCount ?? incoming.length);
        const validCounts = Number.isFinite(pendingCount) && Number.isFinite(completedCount)
          && pendingCount >= 0 && completedCount >= 0 && pendingCount + completedCount >= total
          && (incoming.length > 0 || total === 0 || this.selectionPage() > Math.ceil(total / this.newWordPageSize));
        if (!validCounts) {
          this.loadLegacyNewWords(owner?.userId);
          return;
        }
        this.words.set(incoming);
        for (const word of incoming) this.newWordSelectionCache.set(word.id, word);
        const counts = {pending: pendingCount, completed: completedCount};
        this.newWordCounts.set(counts);
        this.selectionTotal.set(total);
        this.error.set('');
        this.selectionLoading.set(false);
        this.loading.set(false);
      },
      error: (error: ApiError) => {
        failure(error);
        this.selectionLoading.set(false);
        this.loading.set(false);
      },
    });
  }

  private loadStageWords(): void {
    const nid = this.query('nid');
    if (nid && this.isReadOnlyWordView) {
      this.loadReadOnlyWords();
      return;
    }
    if (nid) {
      this.api.get<unknown>('content_list', { nid, modelId: 52, cpage: 1, psize: 300 }).pipe(finalize(() => this.loading.set(false))).subscribe({
        next: ({ result }) => this.initializeStage(this.findList(result).map((item) => this.toWord(item)).filter((word) => word.word)),
        error: (error: ApiError) => this.error.set(error.message),
      });
      return;
    }
    const stored = this.readLearningWords();
    this.loading.set(false);
    if (!stored.length) {
      this.error.set('请先选择本次学习的单词');
      return;
    }
    this.initializeStage(stored);
  }

  private loadReadOnlyWords(pageChange = false, previousPage = 1): void {
    const learner = this.session.student() ?? this.session.user();
    this.api.get<unknown>('e_ck_list', {
      checkwords: 2,
      nids: this.query('nid'),
      modelId: 52,
      cpage: this.wordPreviewPage(),
      psize: this.wordPreviewPageSize,
      uid: learner?.userId,
    }).pipe(finalize(() => {
      if (pageChange) this.wordPreviewLoading.set(false);
      else this.loading.set(false);
    })).subscribe({
      next: ({ result, page }) => {
        const words = this.findList(result).map((item) => this.toWord(item)).filter((word) => word.word);
        this.words.set(words);
        this.wordPreviewTotal.set(Math.max(words.length, Number(page?.itemCount ?? 0)));
        if (pageChange) {
          setTimeout(() => document.getElementById('readonly-word-title')?.scrollIntoView({ behavior: 'smooth', block: 'start' }));
        }
      },
      error: (error: ApiError) => {
        if (pageChange) {
          this.wordPreviewPage.set(previousPage);
          this.platform.toast('该页单词加载失败，请重试', 'error');
          return;
        }
        this.error.set(error.message);
      },
    });
  }

  private initializeStage(source: Word[]): void {
    if (!source.length) {
      this.error.set('本关暂无单词，请返回重新选择学习内容');
      return;
    }
    const words = this.isStudyListPage ? source : this.shuffle(source);
    this.words.set(words);
    if (this.isStudyListPage) {
      this.studyStep.set(1);
      this.repetitions.set({});
    } else if (this.isMatchingPage) {
      this.matchLeft.set(this.shuffle(words));
      this.matchRight.set(this.shuffle(words));
    } else if (this.isListeningPage) {
      this.prepareChoiceOptions();
      setTimeout(() => this.play(), 120);
    } else if (this.isSpellingPage) {
      this.prepareSpelling();
      setTimeout(() => this.play(), 120);
    }
  }

  private finishStudyRound(): void {
    if (this.studyStep() < 3) {
      const next = (this.studyStep() + 1) as 2 | 3;
      this.studyStep.set(next);
      this.words.set(shuffledStudy(this.words()));
      this.repetitions.set({});
      this.platform.toast(next === 2 ? '进入乱序学习' : '进入中文挑战', 'success');
      return;
    }
    this.navigateStage('/pages/stu/stu3');
  }

  retryListeningChoices(): void { this.outsideChoicePool = null; this.prepareChoiceOptions(); }

  private prepareChoiceOptions(): void {
    this.choiceOptionsRequest?.unsubscribe();
    const version = ++this.choiceOptionsVersion;
    const current = this.current();
    if (!current) {
      this.choiceOptions.set([]);
      return;
    }
    const round = [...this.readAllLearningWords(), ...this.words()];
    const apply = (pool: Word[]) => {
      if (version !== this.choiceOptionsVersion || this.current() !== current || this.completed()) return;
      this.choiceOptions.set(listeningChoices(current, round, pool, items => this.shuffle(items)));
      this.choicesLoading.set(false);
    };
    if (this.outsideChoicePool !== null) { apply(this.outsideChoicePool); return; }
    this.choiceOptions.set([]);
    this.choicesLoading.set(true);
    this.choiceOptionsRequest = this.api.get<unknown>('content_list', { modelId: 52, orders: 'NEWID()', cpage: 1, psize: 60, excludeWordIds: [...new Set(round.map(w => w.id))].join(',') }).subscribe({
      next: ({ result }) => {
        if (version !== this.choiceOptionsVersion || this.current() !== current || this.completed()) return;
        this.outsideChoicePool = this.findList(result).map(item => this.toWord(item));
        apply(this.outsideChoicePool);
      },
      error: () => {
        apply([]);
        this.platform.toast('拓展选项暂未加载，本题使用已选词汇', 'info');
      },
    });
  }

  private prepareSpelling(): void {
    const word = this.current();
    this.assembled.set('');
    this.spellingCorrect.set(false);
    this.letters.set(this.shuffle((word?.word ?? '').split('').map((value) => ({ value, used: false }))));
  }

  private finishSpellingFlow(): void {
    const currentPage = Number(this.storageGet('_page_current_learn') ?? 1);
    const mode = String(this.storageGet('learn_mode') ?? '');
    if (mode === 'newword') {
      const learner = this.canStartPointReading ? this.session.student() : this.session.user();
      this.submitting.set(true);
      this.persistWordsAsLearned(this.words(), learner).pipe(finalize(() => this.submitting.set(false))).subscribe({
        next: () => {
          if (this.hasNextWordBatch) {
            this.completed.set(false);
            this.storageSet('_page_current_learn', currentPage + 1);
            this.navigateStage('/pages/stu/stu_con');
            return;
          }
          this.completed.set(false);
          this.clearLearningStorage();
          void this.router.navigateByUrl('/pages/member/starshop', { replaceUrl: true });
        },
        error: (error: ApiError) => {
          this.completed.set(true);
          this.platform.toast(error.message || '学习结果保存失败，请重试', 'error');
        },
      });
      return;
    }
    if (this.hasNextWordBatch) {
      this.completed.set(false);
      this.storageSet('_page_current_learn', currentPage + 1);
      this.navigateStage('/pages/stu/stu_con');
      return;
    }
    if (mode === 'history_word') {
      this.completed.set(false);
      this.clearLearningStorage();
      void this.router.navigateByUrl('/pages/his/his', { replaceUrl: true });
    } else if (this.meta.path === 'pages/stu/pl_stu5' || (this.isListeningPage && this.canStartPointReading && this.storageGet('skip_spelling_stage') === true)) {
      if (this.query('orderId')) {
        this.createPracticeLearningRecord();
      } else {
        this.createStandalonePracticeLearningRecord();
      }
    } else {
      this.navigateStage('/pages/stu/stu6');
    }
  }

  private loadReviewWords(): void {
    const words = this.readAllLearningWords();
    this.words.set(words);
    this.loading.set(false);
    if (!words.length) {
      this.error.set('请先选择本次学习的单词');
      return;
    }
    const user = this.session.user();
    this.api.get<unknown>('content_list', {
      modelId: 56,
      psize: 2,
      myfield2: `UserId=${(this.canStartPointReading ? this.session.student() : user)?.userId}|dqrq=${this.compactDate()}`,
    }).subscribe({
      next: ({ result }) => this.learnedRecord.set(this.findList(result)[0] ?? {}),
      error: (error:ApiError) => this.error.set(error.message),
    });
  }

  private updateUnitRecord(): Observable<unknown> {
    const nids = this.query('nids');
    const bookId = this.query('pnid');
    if (!nids || !bookId) return of(null);
    const wordIds: Record<string, string> = {};
    for (const nodeId of nids.split(',')) {
      wordIds[nodeId] = this.words().filter((word) => word.nodeId === nodeId).map((word) => word.wordId).join(',');
    }
    return this.api.post('unit_record_update', {
      nids,
      userId: (this.canStartPointReading ? this.session.student() : this.session.user())?.userId,
      bookId,
      wordIds: JSON.stringify(wordIds),
    });
  }

  private saveLearningRecord(): void {
    const user = this.session.user();
    const student = Number(user?.groupId) === 3 ? this.session.student() : null;
    const owner = student ?? user;
    const existing = this.learnedRecord();
    const oldItems = this.parseArray(existing['xxqs']);
    const records = new Map<string, SourceItem>();
    for (const item of oldItems) records.set(String(item['GeneralID'] ?? ''), item);
    for (const word of this.words()) {
      records.set(word.wordId, { GeneralID: word.wordId, Title: word.word, check: this.reviewValue(word) });
    }
    const xxqs = [...records.values()];
    const learned = xxqs.length;
    const ygg = xxqs.filter((item) => Number(item['check']) === 1).length;
    const djq = xxqs.filter((item) => Number(item['check']) === 2).length;
    const content: SourceItem = {
      ModelID: 56,
      nodeId: 291,
      inputer: user?.honeyName,
      status: 99,
      Hits: learned,
      title: owner?.honeyName,
    };
    let action = 'content_add_zt';
    if (existing['GeneralID']) {
      content['GeneralID'] = existing['GeneralID'];
      content['UpDateTime'] = this.dateOnly();
      action = 'content_update';
    }
    const addon: SourceItem = {
      con: `完成了${learned}个单词的学习@${this.dateTime()}`,
      dqrq: this.compactDate(),
      pl: student ? user?.userId : 0,
      UserID: owner?.userId,
      learned,
      ygg,
      djq,
      xxqs: JSON.stringify(xxqs),
    };
    if (!existing['xxqs']) addon['fxrl'] = '';
    this.submitting.set(true);
    this.persistWordsAsLearned(this.words(), owner).pipe(
      switchMap(()=>this.updateUnitRecord()),
      switchMap(() => this.api.post(action, { content: JSON.stringify(content), addon: JSON.stringify(addon) })),
      finalize(() => this.submitting.set(false)),
    ).subscribe({
      next: () => {
        this.platform.toast('提交成功', 'success');
        void this.router.navigate(['/pages/member/myorder'], { queryParams: { pnid: this.query('pnid') }, replaceUrl: true });
      },
      error: (error: ApiError) => this.platform.toast(error.message, 'error'),
    });
  }

  private loadPracticeEnd(): void {
    const orderId = this.query('orderId') || this.query('id');
    this.api.get<unknown>('e_order_detail', {id: orderId}).pipe(switchMap(({result}) => {
      const order = this.findList(result)[0] ?? (result as SourceItem);
      const studentId = Number(order?.['szyh']);
      if (!studentId) return throwError(() => new ApiError('预约记录缺少学员信息'));
      this.orderInfo.set(order);
      if (this.session.student()?.userId !== studentId) this.session.setStudent({userId: studentId, groupId: 1, honeyName: String(order['HoneyName'] || '学员')});
      return this.api.get<any>('app_lesson_study', {orderId});
    }), finalize(() => this.loading.set(false))).subscribe({
      next: ({result}) => {
        this.lessonLearnedCount.set(Number(result.record?.learned || 0));
        const batch = result.batches.find((b: any) => b.batchId === (this.query('batchId') || this.storageGet('batchId')))
          || result.batches.find((b: any) => b.status === 'draft' && (!this.query('bindingId') || b.bindingId === this.query('bindingId')));
        if (!batch) { this.error.set('未找到待确认批次，请返回课程查看已保存成果'); return; }
        this.storageSet('batchId', batch.batchId); this.storageSet('batchVersion', batch.version);
        this.orderInfo.update(order => ({...order, learningCourseId: batch.courseId || this.query('pnid') || this.query('kcid') || order['kcid']}));
        const words = batch.words.map((w: SourceItem) => this.toWord(w));
        this.words.set(words);
        const local = (this.storageGet('roundReview:' + batch.batchId) || {}) as Record<string, 0 | 1 | 2>;
        this.reviewState.set(Object.fromEntries(words.map((w: Word) => [w.id, local[w.id] ?? Number(w['check']) ?? 0])));
      }, error: (e: ApiError) => this.error.set(e.message),
    });
  }

  private submitPracticeEnd(continueLearning = false): void {
    this.submitting.set(true);
    this.saveLessonBatch(this.query('mastery') ? 'mastery' : 'confirm', this.words()).pipe(
      switchMap(() => this.query('mastery') ? of(null) : this.persistWordsAsLearned(this.words(), this.session.student())),
      finalize(() => this.submitting.set(false)),
    ).subscribe({next: () => {
      this.clearLearningStorage();
      this.platform.toast(`本轮已保存，本节累计 ${this.lessonLearnedCount()} 个词`, 'success');
      void this.router.navigate(['/pages/shop/get_order'], {queryParams: {id: this.query('orderId') || this.query('id'), ...(continueLearning || this.query('mastery') ? {} : {feedback: '1'})}, replaceUrl: true});
    }, error: (e: ApiError) => this.platform.toast(e.message, 'error')});
  }

  private saveLessonBatch(mode: 'draft' | 'confirm' | 'mastery', words: Word[]): Observable<unknown> {
    const batchId = String(this.storageGet('batchId') || crypto.randomUUID());
    this.storageSet('batchId', batchId);
    const version = Number(this.storageGet('batchVersion') || 0);
    const xxqs = words.map(w => ({GeneralID: w.wordId, Title: w.word, check: mode !== 'draft' ? this.reviewValue(w) : 0}));
    return this.api.post<any>('stu_record_update_v2', {
      orderId: this.query('orderId') || this.query('id'), uid: this.session.student()?.userId,
      batchId, saveMode: mode, expectedVersion: version,
      requestKey: this.draft().command('batch:' + batchId + ':' + version + ':' + mode + ':' + JSON.stringify(xxqs)),
      addon: JSON.stringify({bindingId: this.query('bindingId'), xxqs}),
    }).pipe(tap(({result}) => {
      this.storageSet('batchVersion', result.batchVersion);
      this.lessonLearnedCount.set(Number(result.learned || 0));
    }));
  }

  private createPracticeLearningRecord(): void {
    this.submitting.set(true);
    this.saveLessonBatch('draft', this.readAllLearningWords()).pipe(finalize(() => this.submitting.set(false))).subscribe({
      next: () => this.navigateStage('/pages/stu/pl_end'),
      error: (e: ApiError) => this.platform.toast(e.message, 'error'),
    });
  }

  private createStandalonePracticeLearningRecord(): void {
    const allWords = this.readAllLearningWords();
    const user = this.session.user();
    const student = this.session.student();
    if (Number(user?.groupId) === 3 && !student?.userId) {
      this.platform.toast('请先选择学员', 'error');
      return;
    }
    const owner = Number(user?.groupId) === 3 ? student : user;
    const xxqs = allWords.map((word) => ({ GeneralID: word.wordId, Title: word.word, check: 0 }));
    const content: SourceItem = {
      ModelID: 56,
      nodeId: 291,
      inputer: user?.honeyName,
      status: 99,
      Hits: xxqs.length,
      title: owner?.honeyName,
    };
    const addon: SourceItem = {
      con: `完成了${xxqs.length}个单词的学习@${this.dateTime()}`,
      dqrq: this.compactDate(),
      pl: Number(user?.groupId) === 3 ? user?.userId : 0,
      UserID: owner?.userId,
      learned: xxqs.length,
      ygg: 0,
      djq: 0,
      xxqs: JSON.stringify(xxqs),
      fxrl: '',
      createReviewPlan: false,
      bindingId: this.query('bindingId') || undefined,
    };
    this.submitting.set(true);
    this.persistWordsAsLearned(allWords, owner).pipe(
      switchMap(() => this.api.post('content_add_zt', {
        content: JSON.stringify(content),
        addon: JSON.stringify(addon),
      })),
      finalize(() => this.submitting.set(false)),
    ).subscribe({
      next: () => {
        this.clearLearningStorage();
        this.platform.toast('学习记录已保存', 'success');
        void this.router.navigateByUrl('/pages/his/his', { replaceUrl: true });
      },
      error: (error: ApiError) => this.platform.toast(error.message, 'error'),
    });
  }

  private loadRecord(): void {
    const user = this.session.user();
    const learnerId = Number(user?.groupId) === 3 ? this.session.student()?.userId : user?.userId;
    const recordId = this.query('id');
    const detailParams = { id: recordId, studentId: learnerId };
    const hasWords = (result: unknown) => this.findList(result).some((item) => this.toWord(item).word);
    let originalRecord: SourceItem | undefined;
    this.api.post<unknown>('e_record_detail', detailParams).pipe(
      switchMap((detail) => hasWords(detail.result) ? of(detail) : this.api.get<unknown>('content_get', { id: recordId }).pipe(
        map(({ result }) => {
          originalRecord = this.findList(result)[0];
          return { ...detail, result: this.parseArray(originalRecord?.['xxqs']) };
        }),
        catchError(() => of(detail)),
      )),
      switchMap((detail) => hasWords(detail.result) ? of(detail) : this.api.post<unknown>('app_learning_overview', {
        studentId: learnerId, page: 1, pageSize: 1, refresh: true,
      }).pipe(
        switchMap(() => this.api.post<unknown>('e_record_detail', detailParams)),
        catchError(() => of(detail)),
      )),
      finalize(() => this.loading.set(false)),
    ).subscribe({
      next: ({ result, addon }) => {
        const words = this.findList(result).map((item) => this.toWord(item)).filter((word) => word.word);
        if (!words.length) {
          const wordless = originalRecord && 'xxqs' in originalRecord
            && !this.parseArray(originalRecord['xxqs']).length
            && Number(originalRecord['learned'] ?? 0) === 0;
          this.recordWordless.set(Boolean(wordless));
          const writingRecord = wordless && String(originalRecord?.['con'] ?? '').includes('写作');
          this.error.set(wordless
            ? `${writingRecord ? '这条任务关联的是写作学习记录，原本没有单词' : '这条任务关联的原学习记录没有保存单词'}，无法进行单词复习。任务进度不会被修改。`
            : '这条复习任务暂时没有读取到单词，请点击重新加载；任务进度不会被修改。');
          return;
        }
        this.words.set(words);
        const key = `xiaoshu.review.order.${learnerId}.${this.query('id')}`;
        let previous: string[][] = [];
        try {
          const stored: unknown = JSON.parse(localStorage.getItem(key) ?? '[]');
          if (Array.isArray(stored)) previous = stored.filter((order): order is string[] =>
            Array.isArray(order) && order.every((id) => typeof id === 'string'));
        } catch { /* A damaged or unavailable local cache should not block review. */ }
        try {
          const ordered = nextReviewWordOrder(words, previous, (word) => word.id);
          this.words.set(ordered.words);
          try { localStorage.setItem(key, JSON.stringify(ordered.history)); } catch { /* Review still works without local storage. */ }
        } catch { /* Keep the original words visible if ordering fails. */ }
        this.orderInfo.set(this.findList(addon)[0] ?? {});
      },
      error: (error: ApiError) => this.error.set(error.message),
    });
  }

  turnReviewPage(delta:number):void{this.reviewListPage.update(p=>Math.max(1,Math.min(this.reviewPageData()?.page.pageCount||1,p+delta)));this.loadCalendar();}
  retryCalendar(): void { this.loadCalendar(false, true); }

  private reviewCache(): Map<string, ReviewPage> {
    const identity = `${this.session.token()}|${this.session.user()?.userId ?? ''}|${this.dateOnly()}|${this.api.dataRevision ?? 0}`;
    let cache = LearningPageComponent.reviewCacheByApi.get(this.api);
    if (!cache || cache.identity !== identity) {
      cache = { identity, pages: new Map() };
      LearningPageComponent.reviewCacheByApi.set(this.api, cache);
    }
    return cache.pages;
  }

  private loadCalendar(initial = false, force = false): void {
    const requestId=++this.calendarRequestId;
    this.calendarRequest?.unsubscribe();
    this.calendarError.set('');
    const date = this.memorySelectedDate() || this.dateOnly();
    const key = `${this.memoryStudentId()}|${date}|${this.reviewListPage()}|${this.reviewScope()}`;
    const cache = this.reviewCache();
    const cached = force ? undefined : cache.get(key);
    if (cached) {
      this.reviewPageData.set(cached);this.calendarItems.set(cached.items);this.restoreReviewScroll();
      if(!this.memorySelectedDate())this.memorySelectedDate.set(date);
      this.loading.set(false);this.calendarLoading.set(false);
      return;
    }
    if (initial) this.loading.set(true); else this.calendarLoading.set(true);
    this.calendarRequest = this.api.post<ReviewPage>('app_review_page',{uid:this.session.user()?.userId,studentId:this.memoryStudentId()||undefined,date,scope:this.reviewScope()||undefined,page:this.reviewListPage(),pageSize:20}).pipe(finalize(()=>{
      if(requestId!==this.calendarRequestId)return;
      if(initial)this.loading.set(false);else this.calendarLoading.set(false);
    })).subscribe({next:({result})=>{
      if(requestId!==this.calendarRequestId)return;
      cache.set(key,result);
      this.reviewPageData.set(result);this.calendarItems.set(result.items);this.restoreReviewScroll();
      if(!this.memorySelectedDate())this.memorySelectedDate.set(this.dateOnly());
    },error:(e:ApiError)=>{
      if(requestId!==this.calendarRequestId)return;
      if(initial)this.error.set(e.message);else this.calendarError.set(e.message);
    }});
  }
  private calendarRequestId=0;
  private restoredReviewScroll=false;
  private restoreReviewScroll():void{if(this.restoredReviewScroll)return;this.restoredReviewScroll=true;const top=Number(history.state?.reviewScroll);if(Number.isFinite(top)&&top>0)setTimeout(()=>window.scrollTo({top,behavior:'instant'}));}

  private loadAntiForget(): void {
    const user = this.session.user();
    const date = this.query('date') || this.compactDate();
    this.antiStartedAt = Date.now();
    this.api.get<unknown>('content_list', {
      nid: 76,
      modelId: 54,
      myfield: `fxrl=${date}`,
      myfield2: `UserId=${user?.userId}`,
      cpage: 1,
      psize: 30,
      orders: 'CreateTime=asc',
    }).pipe(finalize(() => this.loading.set(false))).subscribe({
      next: ({ result }) => {
        const words: Word[] = [];
        for (const record of this.findList(result)) {
          for (const item of this.parseArray(record['xxqs'])) words.push(this.toWord({ ...item, recordId: record['GeneralID'] }));
        }
        this.words.set(words.filter((word) => word.word));
      },
      error: (error: ApiError) => this.error.set(error.message),
    });
    if (this.query('hid')) {
      this.api.get<unknown>('content_get', { id: this.query('hid') }).subscribe({
        next: ({ result }) => this.antiHistory.set(this.findList(result)[0] ?? {}),
        error: () => undefined,
      });
    }
    this.api.get<unknown>('content_list', { nid: 255, modelId: 55, cpage: 1, psize: 30, myfield2: `UserId=${user?.userId}`, orders: 'CreateTime=asc' }).subscribe({
      next: ({ result }) => this.myNewWords.set(this.findList(result)[0] ?? {}),
      error: () => undefined,
    });
  }

  private updateAntiProgress(word: Word): void {
    const historyId = this.query('hid');
    if (!historyId) return;
    const seenWords = this.words().filter((item) => this.seen().has(item.id));
    const previousIds = String(this.antiHistory()['xxjlid'] ?? '').split(',').filter(Boolean);
    const recordId = String(word['recordId'] ?? '');
    if (recordId && !previousIds.includes(recordId)) previousIds.push(recordId);
    const scqs = seenWords.map((item) => ({ GeneralID: item.wordId, Title: item.word, gldy: item['gldy'] }));
    const wordIds = `,${scqs.map((item) => item.GeneralID).join(',')},`;
    this.api.post('content_update', {
      content: JSON.stringify({ GeneralID: historyId }),
      addon: JSON.stringify({
        xxjlid: previousIds.join(','),
        scqs: JSON.stringify(scqs),
        yxx: scqs.length,
        scqs2: wordIds,
        times: Math.round((Date.now() - this.antiStartedAt) / 1000),
        num: this.words().length,
      }),
    }).subscribe({ error: () => undefined });
  }

  loadExamHistory(more = false): void {
    if(more && this.examHistoryLoading())return;
    this.examHistoryRequest?.unsubscribe();this.examHistoryLoading.set(true);this.examHistoryError.set('');
    const page=more?this.examHistoryPage+1:1;
    this.examHistoryRequest=this.api.get<{items:SourceItem[];hasMore:boolean}>('app_exam_history',{page}).pipe(finalize(()=>this.examHistoryLoading.set(false))).subscribe({
      next:({result})=>{
        if(!result || !Array.isArray(result.items)){this.examHistoryError.set('测试记录返回异常，请重试');return;}
        this.examHistoryPage=page;this.examHistoryMore.set(result.hasMore);
        this.examHistory.set(more?[...this.examHistory(),...result.items]:result.items);
        if(!more){this.previousExam.set(result.items.find(r=>r['resultAvailable'])||{});this.examCompareIds.set(result.items.filter(r=>r['resultAvailable']).slice(0,2).map(r=>String(r['GeneralID'])));}
      },error:(e:ApiError)=>this.examHistoryError.set(e.message),
    });
  }
  toggleExamComparison(item:SourceItem):void {
    const id=String(item['GeneralID']);if(!item['resultAvailable'])return;
    this.examCompareIds.update(ids=>ids.includes(id)?ids.filter(x=>x!==id):[...ids.slice(-1),id]);
  }
  private loadExam(): void {
    this.stopExamTimer();this.examLoadRequest?.unsubscribe();this.examStarted.set(false);this.examSubmitted.set(false);this.examSaveError.set('');
    this.loading.set(true);this.error.set('');this.questions.set([]);this.turnAskId();
    const askId = Number(this.storageGet('askId') ?? 1);
    this.loadExamHistory();
    this.examLoadRequest=forkJoin({ask:this.api.get<unknown>('vote_ask',{id:askId}),questions:this.api.get<unknown>('vote_question',{askid:askId})}).pipe(finalize(()=>this.loading.set(false))).subscribe({
      next:({ask,questions})=>{this.askInfo.set(this.findList(ask.result)[0]??{});const items=this.shuffle(this.findList(questions.result).map(item=>this.toQuestion(item)));this.questions.set(items);this.answers.set(items.map(q=>({qid:q.ID,qtype:String(q.QType??''),answer:'',result:2})));},
      error:(e:ApiError)=>this.error.set(e.message),
    });
  }

  private turnAskId(): void {
    const current = Number(this.storageGet('askId') ?? 0);
    this.storageSet('askId', current === 1 ? 2 : 1);
  }

  examScoreValue(exam: SourceItem): number {
    return Number(exam['df'] ?? 0);
  }

  examAnalysis(exam: SourceItem): string {
    const score = this.examScoreValue(exam);
    if (score === 0) return '当前处于零基础阶段，可以从最常用的基础词汇开始建立词汇库。';
    if (score <= 2) return '词汇量约为 100-200，处于英语入门或小学一、二年级水平。';
    if (score <= 6) return '词汇量约为 200-400，相当于小学三、四年级水平。';
    if (score <= 12) return '词汇量约为 400-600，相当于小学五、六年级水平。';
    if (score <= 15) return '词汇量约为 600-900，相当于初一水平。';
    if (score <= 18) return '词汇量约为 1000-1500，相当于初二水平。';
    if (score <= 21) return '词汇量约为 1600-1800，相当于初三水平。';
    if (score <= 33) return '词汇量约为 1800-2500，相当于高一水平。';
    if (score <= 39) return '词汇量约为 2500-3000，相当于高二水平。';
    if (score <= 42) return '词汇量约为 3000-3500，相当于高三一般水平。';
    return '词汇量约为 3500-4500，达到高三较高或大学四级水平。';
  }

  examAdvice(exam: SourceItem): string {
    const score = this.examScoreValue(exam);
    if (score <= 6) return '建议先系统学习自然拼读并背诵小学、初中基础词汇，打牢读、认、写基础。';
    if (score <= 12) return '建议重点背诵初中词汇，并通过简单阅读和听力练习持续扩展词汇量。';
    if (score <= 21) return '建议继续背诵初高中核心词汇，配合英文阅读、听力和写作练习巩固运用。';
    if (score <= 39) return '建议学习高二、高三词汇，并通过时文外刊、国家地理和 TED 演讲提升理解与表达。';
    return '建议拓展大学四、六级或雅思托福词汇，通过 BBC、VOA 和英文原著把新词用于真实语境。';
  }

  private setExamAnswer(answer: ExamAnswer): void {
    this.answers.update((items) => items.map((item, index) => index === this.currentIndex() ? answer : item));
  }

  private advanceExam(): void {
    if (this.currentIndex() >= this.questions().length - 1) {
      this.submitExam();
      return;
    }
    this.currentIndex.update((value) => value + 1);
    this.startExamTimer();
  }

  private startExamTimer(): void {
    this.stopExamTimer();
    this.timer.set(10);
    this.examTimer = setInterval(() => {
      if (this.timer() <= 1) {
        this.skipExamQuestion();
      } else {
        this.timer.update((value) => value - 1);
      }
    }, 1000);
  }

  private stopExamTimer(): void {
    if (this.examTimer) clearInterval(this.examTimer);
    this.examTimer = null;
  }

  private saveExamLog(answerId: string | number): void {
    const user = this.session.user();
    const answers = this.answers();
    const score = answers.filter((item) => item.result === 1).length;
    const previous = this.previousExam();
    this.examScore.set(score);
    const content: SourceItem = { ModelID: 61, nodeId: 389, inputer: user?.honeyName, status: 99, Hits: 1, title: user?.honeyName };
    const addon = {
      askid: this.currentQuestion()?.AskID ?? this.askInfo()['ID'],
      prev_score: previous['df'] ?? 0,
      totalScore: answers.length,
      wrong: answers.filter((item) => item.result === 0).length,
      dontKnow: answers.filter((item) => item.result === 2).length,
      answerid: answerId || 0,
      df: score,
      UserID: user?.userId,
    };
    this.api.post('content_add', { requestKey:this.examLogKey,content: JSON.stringify(content), addon: JSON.stringify(addon) }).pipe(finalize(() => this.submitting.set(false))).subscribe({
      next: () => {
        this.examStarted.set(false);
        this.examSubmitted.set(true);
        this.platform.toast('答题结果已保存', 'success');this.loadExamHistory();
      },
      error: (error: ApiError) => this.examSaveError.set(error.message),
    });
  }

  private beginSelectedFlow(chosen: Word[], mode: '' | 'newword' | 'history_word'): void {
    if (this.query('orderId') && !mode) {
      this.submitting.set(true);
      this.api.get<any>('app_lesson_study', {orderId: this.query('orderId')}).pipe(finalize(() => this.submitting.set(false))).subscribe({
        next: ({result}) => {
          const pending = result.batches.find((b: any) => b.status === 'draft' && (!this.query('bindingId') || b.bindingId === this.query('bindingId')));
          if (pending) {
            this.storageSet('batchId', pending.batchId); this.storageSet('batchVersion', pending.version);
            this.platform.toast('还有待确认批次，请先确认掌握状态'); this.navigateStage('/pages/stu/pl_end'); return;
          }
          this.clearLearningStorage(); this.submitting.set(true);
          this.saveLessonBatch('draft', chosen).pipe(finalize(() => this.submitting.set(false))).subscribe({next: () => this.beginSelectedStages(chosen, mode, true),error: (e: ApiError) => this.platform.toast(e.message, 'error')});
        }, error: (e: ApiError) => this.platform.toast(e.message, 'error'),
      }); return;
    }
    this.beginSelectedStages(chosen, mode);
  }

  private beginSelectedStages(chosen: Word[], mode: '' | 'newword' | 'history_word', preserveBatch = false): void {
    if (!preserveBatch) this.clearLearningStorage();
    if (mode) this.storageSet('learn_mode', mode);
    const pages: Word[][] = [];
    for (let index = 0; index < chosen.length; index += 6) pages.push(chosen.slice(index, index + 6));
    const storageKey = mode === 'newword' ? 'choose_newword_learn' : mode === 'history_word' ? 'choose_hisword_learn' : 'choose_word_learn';
    this.storageSet(storageKey, pages[0] ?? chosen);
    this.storageSet('_page_current_learn', 1);
    this.storageSet('_page_total_page', pages.length);
    this.storageSet('_page_word_orilist', pages);
    sessionStorage.setItem(this.learningStorageKey('selectedWords'), JSON.stringify(pages[0] ?? chosen));
    void this.router.navigate(['/pages/stu/stu_con'], {
      replaceUrl: true,
      state: { learningReturnUrl: this.router.url },
      queryParams: {
        nids: this.query('nids') || this.query('nid'),
        pnid: this.query('pnid'),
        bindingId: this.query('bindingId'),
        orderId: this.query('orderId'),
      },
    });
  }

  private navigateStage(path: string): void {
    void this.router.navigate([path], {
      replaceUrl: true,
      state: { learningReturnUrl: history.state?.learningReturnUrl },
      queryParams: {
        nid: this.query('nid'),
        nids: this.query('nids'),
        pnid: this.query('pnid'),
        bindingId: this.query('bindingId'),
        orderId: this.query('orderId') || this.query('id'),
      },
    });
  }

  private readLearningWords(): Word[] {
    const currentPage = Number(this.storageGet('_page_current_learn') ?? 1);
    const pages = this.parseArray(this.storageGet('_page_word_orilist'));
    if (pages.length) {
      const page = pages[currentPage - 1];
      if (Number.isInteger(currentPage) && currentPage > 0 && Array.isArray(page)) {
        const mode = String(this.storageGet('learn_mode') ?? '');
        const key = mode === 'newword' ? 'choose_newword_learn' : mode === 'history_word' ? 'choose_hisword_learn' : 'choose_word_learn';
        this.storageSet(key, page);
        sessionStorage.setItem(this.learningStorageKey('selectedWords'), JSON.stringify(page));
        return page.map((item) => this.toWord(item as SourceItem));
      }
      return [];
    }
    const mode = String(this.storageGet('learn_mode') ?? '');
    const key = mode === 'newword' ? 'choose_newword_learn' : mode === 'history_word' ? 'choose_hisword_learn' : 'choose_word_learn';
    const stored = this.parseArray(this.storageGet(key));
    if (stored.length) return stored.map((item) => this.toWord(item));
    return this.parseArray(sessionStorage.getItem(this.learningStorageKey('selectedWords'))).map((item) => this.toWord(item));
  }

  private readAllLearningWords(): Word[] {
    const pages = this.parseArray(this.storageGet('_page_word_orilist'));
    if (pages.length && pages.every((page) => Array.isArray(page))) {
      return pages.flatMap((page) => (page as SourceItem[]).map((item) => this.toWord(item)));
    }
    return this.readLearningWords();
  }

  private clearLearningStorage(): void { this.draft().clear(); }

  private resetPageState(): void {
    this.outsideChoicePool = null;
    this.choicesLoading.set(false);
    this.choiceOptionsVersion++;
    this.choiceOptionsRequest?.unsubscribe();
    this.stopExamTimer();
    this.nodes.set([]);
    this.selectedNodes.set(new Set());
    this.words.set([]);
    this.historyPreviewWords = [];
    this.historySources.set([]);
    this.wordPreviewPage.set(1);
    this.wordPreviewTotal.set(0);
    this.wordPreviewLoading.set(false);
    this.calendarLoading.set(false);
    this.calendarError.set('');
    this.selected.set(new Set());
    this.newWordSelectionCache.clear();
    this.newWordCounts.set({ pending: 0, completed: 0 });
    this.legacyNewWords = null;
    this.selectionRevealed.set(new Set());
    this.selectionAssessment.set({});
    this.activeSelectionBucket.set('pending');
    this.coursePass.set(0);
    this.coursePassCounts.set(null);
    this.bookPassCounts.set(null);
    this.courseSelectionCache.set([]);
    this.currentIndex.set(0);
    this.revealed.set(false);
    this.completed.set(false);
    this.correct.set(0);
    this.unknown.set([]);
    this.studyStep.set(1);
    this.repetitions.set({});
    this.matchLeft.set([]);
    this.matchRight.set([]);
    this.leftChoice.set('');
    this.rightChoice.set('');
    this.choiceOptions.set([]);
    this.reviewState.set({});
    this.seen.set(new Set());
    this.recordRevealed.set(new Set());
    this.calendarItems.set([]);
    if(!this.isCalendarPage)this.memoryStudentId.set('');
    this.reviewCompletion.set(null);
    this.examStarted.set(false);
    this.examSubmitted.set(false);
  }

  private toWord(item: SourceItem): Word {
    const detailValue = Array.isArray(item['detail']) ? item['detail'][0] : item['detail'];
    const detail = detailValue && typeof detailValue === 'object' ? detailValue as SourceItem : {};
    const source = { ...detail, ...item };
    const id = String(item['GeneralID'] ?? detail['GeneralID'] ?? item['ID'] ?? item['id'] ?? item['gid'] ?? item['Title'] ?? detail['Title'] ?? '');
    const wordId = String(detail['GeneralID'] ?? item['GeneralID'] ?? item['gldy'] ?? id);
    return {
      ...source,
      detail,
      id,
      wordId,
      nodeId: String(item['NodeID'] ?? detail['NodeID'] ?? item['nodeId'] ?? ''),
      word: String(item['Title'] ?? detail['Title'] ?? item['word'] ?? detail['word'] ?? item['Word'] ?? ''),
      meaning: String(item['sy'] ?? detail['sy'] ?? item['jssy'] ?? detail['jssy'] ?? item['Translate'] ?? detail['Translate'] ?? item['Meaning'] ?? ''),
      phonetic: String(item['yb'] ?? detail['yb'] ?? item['Phonetic'] ?? detail['Phonetic'] ?? ''),
      audio: String(item['yp'] ?? detail['yp'] ?? item['dy'] ?? detail['dy'] ?? ''),
    };
  }

  private toNewWord(item: SourceItem): Word {
    const detailValue = Array.isArray(item['detail']) ? item['detail'][0] : item['detail'];
    const detail = detailValue && typeof detailValue === 'object' ? detailValue as SourceItem : {};
    const detailTitle = String(detail['Title'] ?? '').trim();
    const storedTitle = String(item['Title'] ?? '').split('@')[0].trim();
    return this.toWord({ ...item, Title: detailTitle || storedTitle });
  }

  private toQuestion(item: SourceItem): ExamQuestion {
    let options: ExamOption[] = [];
    const raw = item['QOption'];
    if (Array.isArray(raw)) {
      options = raw as ExamOption[];
    } else if (typeof raw === 'string') {
      try { options = JSON.parse(raw) as ExamOption[]; } catch { options = []; }
    }
    return {
      ...item,
      ID: String(item['ID'] ?? item['GeneralID'] ?? ''),
      AskID: String(item['AskID'] ?? ''),
      QType: String(item['QType'] ?? ''),
      QTitle: String(item['QTitle'] ?? ''),
      QContent: this.cleanText(String(item['QContent'] ?? '')),
      QOption: options,
    };
  }

  private wordAudioUrl(path: string): string {
    if (/^(data:|https?:\/\/|\/)/i.test(path)) return this.api.assetUrl(path);
    return this.api.assetUrl(/^UploadFiles\//i.test(path) ? path : `UploadFiles/${path}`);
  }

  private setWordSelected(word: Word, shouldSelect: boolean): boolean {
    const current = this.selected();
    if (shouldSelect && !current.has(word.id) && current.size >= this.selectionLimit) {
      this.platform.toast(`本次最多选择 ${this.selectionLimit} 个单词`, 'error');
      return false;
    }
    const next = new Set(current);
    if (shouldSelect) next.add(word.id);
    else next.delete(word.id);
    this.selected.set(next);
    return true;
  }

  private setSelectionAssessment(word: Word, assessment: 'known' | 'unknown'): void {
    this.selectionAssessment.update((current) => ({ ...current, [word.id]: assessment }));
  }

  private clearSelectionAssessment(word: Word): void {
    this.selectionAssessment.update((current) => Object.fromEntries(Object.entries(current).filter(([id]) => id !== word.id)) as Record<string, 'known' | 'unknown'>);
  }

  private persistWordsAsLearned(words: Word[], owner: AppUser | null | undefined): Observable<unknown> {
    if (!words.length) return of(null);
    return this.api.post('e_add_words', {
      uid: owner?.userId,
      wordsId: words.map((word) => word.wordId).join(','),
      kcid: (this.meta.path === 'pages/stu/pl_end' ? this.orderInfo()['learningCourseId'] : '') || this.query('pnid') || this.query('kcid') || this.orderInfo()['kcid'],
      save: 1,
      requestKey:this.draft().command('learn:'+words.map(w=>w.wordId).sort().join(',')),
    });
  }

  private commitKnownWords(words: Word[]): void {
    const ids = new Set(words.map(word => word.id));
    const update = (current: Word[]) => current.map(word => ids.has(word.id) ? {...word, w_learned: 1} : word);
    this.words.update(update);
    this.courseSelectionCache.update(update);
    const advance = (counts: number[] | null) => counts ? [Math.max(0,counts[0]-ids.size),counts[1]+ids.size,counts[2],counts[3]] : null;
    this.coursePassCounts.update(advance);
    this.bookPassCounts.update(advance);
    this.selectionAssessment.update(current => Object.fromEntries(Object.entries(current).filter(([id]) => !ids.has(id))) as Record<string, 'known' | 'unknown'>);
  }

  private findList(value: unknown): SourceItem[] {
    if (Array.isArray(value)) return value as SourceItem[];
    if (value && typeof value === 'object') {
      for (const nested of Object.values(value)) {
        if (Array.isArray(nested)) return nested as SourceItem[];
        if (nested && typeof nested === 'object') {
          for (const child of Object.values(nested)) if (Array.isArray(child)) return child as SourceItem[];
        }
      }
    }
    return [];
  }

  private parseArray(value: unknown): SourceItem[] {
    if (Array.isArray(value)) return value as SourceItem[];
    if (typeof value !== 'string' || !value) return [];
    try {
      const parsed = JSON.parse(value) as unknown;
      return Array.isArray(parsed) ? parsed as SourceItem[] : [];
    } catch {
      return [];
    }
  }

  private shuffle<T>(items: T[]): T[] {
    const copy = [...items];
    for (let index = copy.length - 1; index > 0; index -= 1) {
      const target = Math.floor(Math.random() * (index + 1));
      [copy[index], copy[target]] = [copy[target], copy[index]];
    }
    return copy;
  }

  private draft():LearningDraft {
    const learner=this.canStartPointReading?this.session.student():this.session.user();
    return new LearningDraft(`xiaoshu.learning.${this.session.user()?.userId}.${learner?.userId}.${this.query('orderId') ? this.query('orderId') + '.' + (this.query('bindingId') || 'unbound') : this.query('bindingId') || 'practice'}`);
  }
  private learningStorageKey(key:string):string{return this.draft().key(key);}
  private storageGet(key:string):unknown{return this.draft().get(key);}
  private storageSet(key:string,value:unknown):void{this.draft().set(key,value);}

  private query(name: string): string {
    return this.route.snapshot.queryParamMap.get(name) ?? '';
  }

  private cleanText(value: string): string {
    return value.replace(/<\/?[^>]*>/g, '').replace(/&nbsp;/gi, '').trim();
  }

  private dateOnly(): string {
    const date = new Date();
    return `${date.getFullYear()}-${this.pad(date.getMonth() + 1)}-${this.pad(date.getDate())}`;
  }

  private compactDate(): string {
    return this.dateOnly().replaceAll('-', '');
  }

  private dateTime(seconds = false): string {
    const date = new Date();
    return `${this.dateOnly()} ${this.pad(date.getHours())}:${this.pad(date.getMinutes())}${seconds ? `:${this.pad(date.getSeconds())}` : ''}`;
  }

  private pad(value: number): string {
    return String(value).padStart(2, '0');
  }
}