import { useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react';
import { ArrowUp, ChevronDown, ChevronRight, Loader2 } from 'lucide-react';
import { useAuthStore } from '@/stores/auth';
import { teacherApi, teacherTopicsPath, teacherConversationsPath, legacyTopicBase, type TeacherCatalogState } from '@/lib/coding-teacher';
import type {
  TeacherDefinition,
  TeacherCatalog,
  TeacherReference,
  TeacherRequest,
  TeacherSend,
  TeacherTopic,
  TeacherTopicList,
} from '../../../shared/coding-teacher';
import { TeacherAvatar } from './TeacherAvatar';
import { TeacherReply } from './TeacherReply';
import { MessageTimestamp } from './MessageTimestamp';
import { ComposerVoiceButton } from './ComposerVoiceButton';
import { useWorksVoiceInput } from '@/hooks/use-works-voice-input';
import { useTeacherModelChoice } from '@/hooks/use-teacher-model-choice';
import { Textarea } from '@/components/ui/textarea';

// Preserve loaded pages and the reading anchor while moving between contacts.
// Durable messages remain Main-owned; this is only the current window's view.
const conversationViews = new Map<string, { topic: TeacherTopic | null; before: string | null; top: number; follow: boolean }>();
const messageOrderKey = (request: TeacherTopic['requests'][number]) => request.origin
  ? [request.origin.projectId, request.origin.topicId, request.origin.requestId].join(':') : request.id;

function restorePendingSend(saved?: TeacherSend, legacyProjectId?: string): TeacherSend | null {
  if (!saved) return null;
  // Keep an interrupted send retryable without restoring retired UI protocol fields.
  const { requestId, text, references, intent, sourceConversationId, projectId, modelId } = saved;
  return { requestId, text, references, intent, sourceConversationId, ...(modelId ? { modelId } : {}), ...(projectId || legacyProjectId ? { projectId: projectId ?? legacyProjectId } : {}) };
}

export function TeacherChatPanel(props: Parameters<typeof ProjectTeacherChatPanel>[0]) {
  const account = useAuthStore(state => state.user?.userId ?? state.user?.username ?? 'signed-out');
  return <ProjectTeacherChatPanel key={`${account}:${props.projectId}:${props.selectedAgent?.teacher_id ?? 'legacy'}:${props.draftRevision ?? ''}`} {...props} />;
}

function ProjectTeacherChatPanel({
  projectId,
  projectName,
  sourceId,
  onBringBack,
  quote,
  onQuoteConsumed,
  draftRevision,
  sampleContext,
  externalTopic,
  onTopicChange,
  onComposingChange,
  selectedAgent,
  catalogState,
  reloadCatalog,
}: {
  projectId: string;
  sourceId: string;
  onBringBack?(text: string): void;
  quote?: TeacherReference;
  onQuoteConsumed?(reference: TeacherReference): void;
  draftRevision?: number;
  sampleContext?: string;
  projectName?: string;
  externalTopic?: TeacherTopic | null;
  onTopicChange?(topic: TeacherTopic): void;
  onComposingChange?(composing: boolean): void;
  selectedAgent?: TeacherCatalog['items'][number];
  catalogState?: TeacherCatalogState;
  reloadCatalog?(): Promise<void>;
}) {
  const continuous = Boolean(selectedAgent && !draftRevision);
  const base = continuous ? teacherConversationsPath(projectId) : teacherTopicsPath(projectId);
  const account = useAuthStore((state) => state.user?.userId ?? state.user?.username ?? 'signed-out');
  const projectDraftKey = `makelore-consultation-draft:${account}:${projectId}:teacher`;
  const draftKey = !draftRevision ? selectedAgent ? `makelore-consultation-draft:${account}:project:${projectId}:agent:${selectedAgent.teacher_id}` : projectDraftKey : null;
  const [cachedView] = useState(() => continuous && draftKey ? conversationViews.get(draftKey) : undefined);
  const [saved] = useState<{ text?: string; references?: TeacherReference[]; pending?: TeacherSend; projectId?: string; sourceId?: string }>(() => {
    try {
      if (!draftKey) return {};
      const current = localStorage.getItem(draftKey);
      if (current) return JSON.parse(current);
      const legacyKey = selectedAgent ? `makelore-consultation-draft:${account}:agent:${selectedAgent.teacher_id}` : projectDraftKey;
      const old = JSON.parse(localStorage.getItem(legacyKey) ?? '{}');
      if ((old.projectId ?? old.pending?.projectId) === projectId) return old;
      // Pre-single-chat versions already had project drafts; retain them as a fallback.
      return selectedAgent ? JSON.parse(localStorage.getItem(`makelore-consultation-draft:${account}:${projectId}:agent:${selectedAgent.teacher_id}`) ?? '{}') : {};
    } catch { return {}; }
  });
  const [referenceScope, setReferenceScope] = useState(quote ? { projectId, sourceId } : { projectId: saved.projectId ?? projectId, sourceId: saved.sourceId ?? sourceId });
  const referenceScopeRef = useRef(referenceScope);
  referenceScopeRef.current = referenceScope;
  const [legacyDraft] = useState<{ text?: string; references?: TeacherReference[] }>(() => {
    try { return draftKey ? JSON.parse(localStorage.getItem(`makelore-consultation-draft:${account}:${projectId}:friend`) ?? '{}') : {}; } catch { return {}; }
  });
  const [unassignedDraft] = useState<{ text?: string; references?: TeacherReference[] }>(() => {
    try { return selectedAgent ? JSON.parse(localStorage.getItem(projectDraftKey) ?? '{}') : {}; } catch { return {}; }
  });
  const persistDraft = useCallback((text: string, references: TeacherReference[], pending?: TeacherSend | null) => {
    if (!draftKey) return;
    try { localStorage.setItem(draftKey, JSON.stringify({ text, references, pending, ...referenceScopeRef.current })); } catch { /* Draft remains in the open panel. */ }
  }, [draftKey]);
  const label = '智能体';
  const [historyOpen, setHistoryOpen] = useState(false);
  const [before, setBefore] = useState<string | null>(cachedView?.before ?? null);
  const [loadingOlder, setLoadingOlder] = useState(false);
  const olderAnchor = useRef<{ height: number; top: number } | null>(null);
  const followBottom = useRef(cachedView?.follow ?? true);
  const restoreTop = useRef(cachedView?.top);
  const scrollPosition = useRef(cachedView?.top ?? 0);
  const [localDefinition, setDefinition] = useState<TeacherDefinition | null>(null);
  const catalogStateRef = useRef(catalogState);
  catalogStateRef.current = catalogState;
  const externalTopicRef = useRef(externalTopic);
  externalTopicRef.current = externalTopic;
  const selectedAgentId = selectedAgent?.teacher_id;
  const selectedAgentRef = useRef(selectedAgent);
  selectedAgentRef.current = selectedAgent;
  const inputRef = useRef<HTMLTextAreaElement>(null);
  const focusedOnce = useRef(false);
  const [topics, setTopics] = useState<TeacherTopicList>({ items: [], lastSelectedTopicId: null });
  const [topic, setTopic] = useState<TeacherTopic | null>(cachedView?.topic ?? null);
  const legacyFriend = topic?.role === 'friend';
  const legacyView = Boolean(continuous && topic && !topic.conversation);
  const viewingLegacy = useRef(false);
  const topicBase = legacyTopicBase(base, legacyFriend);
  const endpointId = continuous ? selectedAgent!.teacher_id : topic?.id ?? '';
  const [text, setText] = useState(saved.text ?? '');
  const [references, setReferences] = useState<TeacherReference[]>(quote ? [quote] : saved.references ?? []);
  useEffect(() => { onComposingChange?.(Boolean(text.trim() || references.length)); }, [text, references.length, onComposingChange]);
  useEffect(() => () => onComposingChange?.(false), [onComposingChange]);
  const draftRef = useRef({ text, references });
  draftRef.current = { text, references };
  const [error, setError] = useState('');
  const [busy, setBusy] = useState(true);
  const [localEnabled, setEnabled] = useState(false);
  const [localLegacyEnabled, setLegacyEnabled] = useState(false);
  const [localTeachers, setTeachers] = useState<TeacherCatalog['items']>([]);
  const [localTeacherVersion, setSelectedTeacherVersion] = useState<number>();
  // Share the current catalog with the topbar without reloading the topic or its draft.
  const teachers = catalogState?.catalog.items ?? localTeachers;
  const selectedTeacher = selectedAgentId ? teachers.find((item) => item.teacher_id === selectedAgentId)
    : teachers.find((item) => item.is_default) ?? teachers[0];
  const enabled = catalogState ? (selectedAgentId ? Boolean(selectedTeacher)
    : teachers.length > 0 || (catalogState.config.enabled && !catalogState.config.definition?.config_id)) : localEnabled;
  const legacyEnabled = catalogState?.config.enabled ?? localLegacyEnabled;
  const selectedTeacherVersion = catalogState ? selectedTeacher?.version : localTeacherVersion;
  const definition = continuous && !legacyView
    ? selectedTeacher?.definition ?? selectedAgent?.definition ?? localDefinition
    : topic?.definition ?? (catalogState
    ? selectedTeacher?.definition ?? selectedAgent?.definition ?? catalogState.config.definition : localDefinition);
  const modelScope = `${account}:${selectedAgentId ?? definition?.config_id ?? definition?.teacher_id ?? 'teacher'}:${draftRevision ?? 'published'}`;
  const modelChoice = useTeacherModelChoice(modelScope);
  const topicEnabled = legacyFriend || legacyView ? false : !topic ? enabled
    : topic.definition.config_id
      ? teachers.some((item) => item.teacher_id === topic.definition.config_id)
      : legacyEnabled;
  const pending = useRef<TeacherSend | null>(restorePendingSend(saved.pending, continuous ? saved.projectId ?? projectId : undefined));
  const sendInFlight = useRef(false);
  useEffect(() => {
    persistDraft(text, references, pending.current);
  }, [text, references, persistDraft]);
  const generation = useRef(0);
  const topicRef = useRef(topic);
  topicRef.current = topic;
  const scrollRef = useRef<HTMLDivElement>(null);
  const beforeRef = useRef(before);
  beforeRef.current = before;
  useEffect(() => () => {
    if (continuous && draftKey && !viewingLegacy.current) conversationViews.set(draftKey, { topic: topicRef.current,
      before: beforeRef.current, top: scrollPosition.current, follow: followBottom.current });
  }, [continuous, draftKey]);
  useLayoutEffect(() => {
    const pane = scrollRef.current;
    if (!pane) return;
    if (restoreTop.current !== undefined) {
      pane.scrollTop = restoreTop.current; restoreTop.current = undefined;
    } else if (olderAnchor.current) {
      pane.scrollTop = olderAnchor.current.top + pane.scrollHeight - olderAnchor.current.height;
      olderAnchor.current = null;
    } else if (followBottom.current) pane.scrollTop = pane.scrollHeight;
  }, [topic?.id, topic?.revision, topic?.requests.length]);
  const consume = useCallback(
    (next: TeacherTopic) => {
      if (next.projectId !== projectId) return;
      if (pending.current && next.requests.some((request) => request.id === pending.current?.requestId)) {
        pending.current = null;
        persistDraft(draftRef.current.text, draftRef.current.references);
      }
      setTopic((current) => {
        const olderSnapshot = current?.id === next.id && current.revision > next.revision;
        if (olderSnapshot && !continuous) return current;
        if (!continuous || current?.id !== next.id) return next;
        const requests = new Map(current.requests.map(request => [request.id, request]));
        next.requests.forEach(request => { if (!olderSnapshot || !requests.has(request.id)) requests.set(request.id, request); });
        return { ...(olderSnapshot ? current : next), requests: [...requests.values()].sort((a, b) => a.createdAt.localeCompare(b.createdAt) || messageOrderKey(a).localeCompare(messageOrderKey(b))) };
      });
    },
    [persistDraft, continuous, projectId]
  );
  useEffect(() => {
    if (!viewingLegacy.current && externalTopic && externalTopic.projectId === projectId
      && (!selectedAgentId || externalTopic.definition.config_id === selectedAgentId)) {
      consume(externalTopic);
      setDefinition(continuous ? selectedAgentRef.current?.definition ?? externalTopic.definition : externalTopic.definition);
    }
  }, [externalTopic, projectId, consume, selectedAgentId, continuous]);
  useEffect(() => { if (topic && !legacyView) onTopicChange?.(topic); }, [topic, onTopicChange, legacyView]);
  useEffect(() => { if (continuous && selectedAgent) setDefinition(selectedAgent.definition); }, [continuous, selectedAgent]);
  useEffect(() => {
    if (!busy && !focusedOnce.current) {
      focusedOnce.current = true;
      inputRef.current?.focus();
    }
  }, [busy]);
  useEffect(() => {
    if (quote) {
      setReferences([quote]);
      setReferenceScope({ projectId, sourceId });
      onQuoteConsumed?.(quote);
    }
  }, [quote, projectId, sourceId, onQuoteConsumed]);
  useEffect(() => {
    let alive = true;
    setBusy(true);
    void (async () => {
      try {
        if (!draftRevision && reloadCatalog) {
          // Opening the panel still checks for updates through the shared loader.
          // A failed background read leaves the last usable catalog in place.
          await reloadCatalog().catch(() => undefined);
        } else if (draftRevision || !catalogStateRef.current) {
          const config = draftRevision
            ? { definition: (await teacherApi.preview(draftRevision)).payload, enabled: true }
            : await teacherApi.config();
          if (alive) {
            setDefinition(config.definition);
            setEnabled(config.enabled);
            setLegacyEnabled(config.enabled);
          }
          if (!draftRevision) {
            const catalog = await teacherApi.catalog();
            if (alive) {
              setTeachers(catalog.items);
              const selected = selectedAgentId
                ? catalog.items.find((item) => item.teacher_id === selectedAgentId)
                : catalog.items.find((item) => item.is_default) ?? catalog.items[0];
              setSelectedTeacherVersion(selected?.version);
              setEnabled(selectedAgentId ? Boolean(selected) : catalog.items.length > 0 || (config.enabled && !config.definition?.config_id));
              const visibleAgent = selected ?? selectedAgentRef.current;
              if (visibleAgent) setDefinition(visibleAgent.definition);
            }
          }
        }
      } catch (e) {
        if (alive) setError(e instanceof Error ? e.message : `${label}配置暂不可用`);
      }
      try {
        if (continuous && selectedAgentId) {
          const view = await teacherApi.conversation(projectId, selectedAgentId);
          if (alive) { if (view.topic) consume(view.topic); if (!cachedView?.topic) setBefore(view.before); }
          return;
        }
        const listed = await teacherApi.list(base);
        if (!alive) return;
        setTopics(listed);
        const previous = listed.items.find((item) => item.id === listed.lastSelectedTopicId
          && (!selectedAgentId || item.teacherId === selectedAgentId))
          ?? (selectedAgentId ? listed.items.find((item) => item.teacherId === selectedAgentId) : undefined);
        if (externalTopicRef.current?.projectId === projectId && (!selectedAgentId || externalTopicRef.current.definition.config_id === selectedAgentId)) {
          consume(externalTopicRef.current);
          setDefinition(externalTopicRef.current.definition);
        } else if (previous) {
          const current = await teacherApi.read(base, previous.id);
          if (alive && (!draftRevision || current.draftRevision === draftRevision)) {
            consume(current);
            setDefinition(current.definition);
          }
        }
      } catch (e) {
        if (alive) setError(e instanceof Error ? e.message : `${label}历史暂不可用`);
      } finally {
        if (alive) setBusy(false);
      }
    })();
    return () => {
      alive = false;
      // This numeric epoch invalidates outstanding requests on unmount; it is not a DOM ref.
      // eslint-disable-next-line react-hooks/exhaustive-deps
      generation.current++;
    };
  }, [base, projectId, draftRevision, label, consume, selectedAgentId, continuous, cachedView, reloadCatalog]);
  const seenPending = useRef<string | undefined>(undefined);
  const markSeen = useCallback(() => {
    const current = topicRef.current;
    const last = current?.requests.at(-1);
    if (!continuous || legacyView || !selectedAgentId || !current || !last || !followBottom.current
      || document.visibilityState === 'hidden' || ['preparing', 'running'].includes(last.status)
      || current.conversation?.seenThrough === last.id || seenPending.current === last.id) return;
    seenPending.current = last.id;
    void teacherApi.seenConversation(projectId, selectedAgentId, last.id).then(consume).catch(() => undefined)
      .finally(() => { seenPending.current = undefined; });
  }, [continuous, legacyView, projectId, selectedAgentId, consume]);
  useEffect(() => { markSeen(); }, [topic?.revision, markSeen]);
  useEffect(() => {
    if (!topic?.id || legacyFriend || legacyView) return;
    const streamTopicId = topic.id;
    let closed = false,
      stream: EventSource | undefined;
    void teacherApi
      .events(topicBase, endpointId)
      .then((source) => {
        if (closed) {
          source.close();
          return;
        }
        stream = source;
        source.addEventListener('snapshot', (event) => {
          if (closed) return;
          const next = JSON.parse((event as MessageEvent).data) as TeacherTopic;
          if (next.id === streamTopicId) consume(next);
        });
        source.onerror = () => {
          if (!closed) setError(`连接暂时中断，正在恢复${label}回复。`);
        };
        source.onopen = () => {
          if (!closed) setError('');
        };
      })
      .catch((e) => {
        if (!closed) setError(e instanceof Error ? e.message : `连接${label}失败`);
      });
    return () => {
      closed = true;
      stream?.close();
    };
  }, [topicBase, topic?.id, endpointId, legacyFriend, legacyView, consume, label]);
  const loadOlder = async () => {
    if (!before || loadingOlder || !selectedAgentId) return;
    const epoch = generation.current;
    setLoadingOlder(true);
    try {
      const page = await teacherApi.conversation(projectId, selectedAgentId, before);
      if (epoch !== generation.current) return;
      const pane = scrollRef.current;
      if (pane) olderAnchor.current = { height: pane.scrollHeight, top: pane.scrollTop };
      followBottom.current = false;
      if (page.topic) consume(page.topic);
      setBefore(page.before);
    } catch (error) { if (epoch === generation.current) setError(error instanceof Error ? error.message : '较早消息加载失败，请重试。'); }
    finally { if (epoch === generation.current) setLoadingOlder(false); }
  };
  const loadLegacy = async () => {
    setHistoryOpen(value => !value);
    try {
      setTopics(await teacherApi.legacyHistory(projectId));
    } catch { setError('旧记录暂时无法读取。'); }
  };
  const returnToConversation = async () => {
    if (!selectedAgentId) return;
    const view = await teacherApi.conversation(projectId, selectedAgentId);
    viewingLegacy.current = false;
    setTopic(view.topic); setBefore(view.before); setDefinition(selectedAgentRef.current?.definition ?? null);
    setHistoryOpen(false);
  };
  const choose = async (id: string) => {
    const version = ++generation.current;
    setBusy(true);
    setError('');
    try {
      const next = continuous ? await teacherApi.legacyRead(projectId, topics.items.find(item => item.id === id)!)
        : await teacherApi.read(legacyTopicBase(base, topics.items.some(item => item.id === id && item.legacyRole === 'friend')), id);
      if (version === generation.current) {
        if (continuous) viewingLegacy.current = true;
        consume(next);
        setDefinition(next.definition);
        pending.current = null;
      }
    } catch (e) {
      if (version === generation.current) setError(e instanceof Error ? e.message : '加载失败');
    } finally {
      if (version === generation.current) setBusy(false);
    }
  };
  const newTopic = async () => {
    const version = ++generation.current;
    setBusy(true);
    setError('');
    try {
      const next = await teacherApi.create(
        base,
        draftRevision,
        sampleContext,
        selectedTeacherVersion
      );
      if (version === generation.current) {
        consume(next);
        setDefinition(next.definition);
        setTopics(await teacherApi.list(base));
        pending.current = null;
      }
    } catch (e) {
      if (version === generation.current)
        setError(e instanceof Error ? e.message : `无法新建${label}话题`);
    } finally {
      if (version === generation.current) setBusy(false);
    }
  };
  const retryScopeMatches = (request: TeacherRequest) => !continuous
    || (request.projectId === projectId && (request.sourceConversationId ?? '') === sourceId);
  const send = async (action?: Pick<TeacherSend, 'text' | 'intent'>, retry?: TeacherRequest) => {
    // A historical retry stays with its original topic and published Agent.
    if (retry && (topicRef.current?.id !== topic?.id || !topic || !retryScopeMatches(retry)
      || (!continuous && topic.projectId !== projectId)
      || (selectedAgentId && topic.definition.config_id !== selectedAgentId)
      || !topic.requests.some((request) => request === retry && request.status === 'completed' && request.replyIncomplete))) return;
    const question = action?.text ?? text;
    const questionReferences = retry?.references ?? (action ? [] : references);
    const questionSourceId = retry
      ? retry.sourceConversationId ?? (continuous || topic?.sourceConversationId === 'project' ? undefined : topic?.sourceConversationId)
      : sourceId;
    if (voiceInput.state !== 'idle' || !question.trim() || busy || sendInFlight.current || !topicEnabled || topicRef.current?.requests.some((request) => ['preparing', 'running'].includes(request.status))) return;
    if (continuous && !retry && questionReferences.length && (referenceScope.projectId !== projectId || referenceScope.sourceId !== sourceId)) {
      setError('引用来自另一个项目或操作对话，请切回来源，或移除引用后再提问。'); return;
    }
    if (continuous && pending.current && !topicRef.current?.requests.some(request => request.id === pending.current?.requestId)
      && (pending.current.text === question || (action?.intent === 'suggestions' && pending.current.intent === 'suggestions'))
      && pending.current.projectId && pending.current.projectId !== projectId) {
      setError('上次提问仍绑定原项目，请切回原项目确认结果后重试。'); return;
    }
    if (continuous && !retry && action?.intent === 'suggestions' && pending.current?.intent === 'suggestions'
      && !topicRef.current?.requests.some(request => request.id === pending.current?.requestId)
      && pending.current.sourceConversationId !== (questionSourceId || undefined)) {
      setError('上次提问仍绑定原操作对话，请切回原操作对话确认结果后重试。'); return;
    }
    const version = generation.current;
    sendInFlight.current = true;
    setBusy(true);
    setError('');
    let current = topicRef.current;
    try {
      if (!current && !continuous) {
        current = await teacherApi.create(
          base,
          draftRevision,
          sampleContext,
          selectedTeacherVersion
        );
        if (version !== generation.current) return;
        consume(current);
        setDefinition(current.definition);
      }
      const previous = pending.current && !current?.requests.some((request) => request.id === pending.current?.requestId)
        ? pending.current
        : null;
      // Copy changes must not create another charge for an uncertain hint request.
      const retrySuggestions = !retry && action?.intent === 'suggestions' && previous?.intent === 'suggestions';
      const input =
        previous && (!continuous || (previous.projectId === projectId
        && previous.sourceConversationId === (questionSourceId || undefined))) && (retrySuggestions || (
          previous.text === question &&
          (previous.intent ?? 'question') === (action?.intent ?? 'question') &&
          JSON.stringify(previous.references) === JSON.stringify(questionReferences) &&
          (!retry || previous.sourceConversationId === (questionSourceId || undefined))
        ))
          ? previous
          : {
            requestId: crypto.randomUUID(), text: question, references: questionReferences,
            ...((retry ? retry.modelId : modelChoice.modelId) ? { modelId: retry ? retry.modelId : modelChoice.modelId } : {}),
            ...(continuous ? { projectId } : {}),
            ...(action?.intent ? { intent: action.intent } : {}),
            ...(questionSourceId ? { sourceConversationId: questionSourceId } : {}),
          };
      pending.current = input;
      persistDraft(text, references, input);
      const next = continuous ? await teacherApi.sendConversation(projectId, selectedAgentId!, input)
        : await teacherApi.send(topicBase, current!.id, input);
      if (version !== generation.current) return;
      consume(next);
      pending.current = null;
      if (action) {
        persistDraft(draftRef.current.text, draftRef.current.references);
      } else {
        setText('');
        setReferences([]);
        persistDraft('', []);
      }
      if (!continuous) setTopics(await teacherApi.list(base));
    } catch (e) {
      if (version === generation.current) {
        const code = (e as { details?: { backendCode?: string } } | null)?.details?.backendCode;
        // These Main validation failures precede acceptance; allow correcting the selection.
        // Uncertain transport failures retain the original request and model to avoid double charging.
        if (code === 'teacher_model_unavailable' || code === 'teacher_model_invalid') {
          pending.current = null;
          persistDraft(draftRef.current.text, draftRef.current.references);
        }
        setError(e instanceof Error ? e.message : '提问失败，请保留问题后重试');
      }
    } finally {
      sendInFlight.current = false;
      if (version === generation.current) setBusy(false);
    }
  };
  const running = topic?.requests.find(
    (request) => request.status === 'preparing' || request.status === 'running'
  );
  const helpUnavailable = busy || !topicEnabled || Boolean(running);
  const askForSuggestions = () => void send({ text: '帮我整体看🧠', intent: 'suggestions' });
  const changeText = (next: string) => { draftRef.current.text = next; setText(next); persistDraft(next, references, pending.current); };
  const voiceInput = useWorksVoiceInput({
    enabled: !busy && topicEnabled && !running,
    scopeKey: `${modelScope}:${projectId}:${sourceId}:${topic?.id ?? 'new'}:${modelChoice.modelId ?? 'default'}`,
    onTranscript: transcript => {
      const current = draftRef.current.text;
      const next = current.trim() ? `${current.trimEnd()}\n${transcript}` : transcript;
      if (next.length > 6000) { setError('文字超过 6000 字，请缩短输入后重新录音。'); return; }
      changeText(next);
    },
  });

  const removeReferences = () => { setReferences([]); persistDraft(text, [], pending.current); };
  const questions = definition?.suggested_questions ?? [];
  return (
    <aside className="consultation-pane flex h-full min-h-0 w-full flex-col"
      data-testid="teacher-chat-panel" aria-label={`${definition?.name ?? label}咨询`}>
      {Boolean(draftRevision) && <p className="px-5 pt-3 text-[11px] text-muted-foreground">运营草稿试聊</p>}
      {continuous && <div className="flex items-center justify-between gap-2 px-5 pt-2 text-[11px] text-muted-foreground">
        <span>本轮项目：{projectName || projectId}{sourceId ? ' · 当前操作对话' : ''}</span>
        <button type="button" onClick={() => void loadLegacy()}>旧记录</button>
      </div>}
      {continuous && historyOpen && <div className="space-y-2 px-5 pt-2 text-xs">
        <p className="text-muted-foreground">升级前的原始记录保留在这里，仅供查看。</p>
        {topics.items.map(item => <button className="block" key={item.id} onClick={() => void choose(item.id)}>{item.title}（只读）</button>)}
        {!topics.items.length && <p>没有待查看的旧记录。</p>}
      </div>}
      {legacyView && <button className="px-5 pt-2 text-left text-xs underline" onClick={() => void returnToConversation().catch(() => setError('暂时无法返回聊天。'))}>返回与智能体的聊天</button>}
      {!continuous && (topics.items.length > 0 || draftRevision) && <div className="px-5 pt-2">
        <button className="text-[11px] text-muted-foreground" onClick={() => setHistoryOpen(!historyOpen)} aria-expanded={historyOpen}>以往讨论 <ChevronDown className="inline h-3 w-3" /></button>
        {(historyOpen || draftRevision) && <div className="mt-2 flex gap-2">
          <select aria-label={`${label}话题`} value={topic?.id ?? ''} disabled={busy} onChange={(e) => void choose(e.target.value)} className="min-w-0 flex-1 rounded-lg border bg-background p-2 text-xs">
            {!topic && <option value="">选择话题</option>}{topics.items.map((item) => <option key={item.id} value={item.id}>{item.title}{item.legacyRole ? '（旧版，仅查看）' : ''}</option>)}
          </select>
          <button type="button" aria-label={`${label}新话题`} disabled={busy || !enabled} onClick={() => void newTopic()}
            className="shrink-0 rounded-lg px-2 text-xs text-muted-foreground hover:bg-white hover:text-foreground disabled:opacity-40">新话题</button>
        </div>}
      </div>}
      <div ref={scrollRef} className="consultation-messages min-h-0 flex-1 overflow-y-auto px-5 py-6"
        onScroll={() => { const pane = scrollRef.current; if (!pane) return;
          scrollPosition.current = pane.scrollTop;
          followBottom.current = pane.scrollHeight - pane.scrollTop - pane.clientHeight < 80;
          markSeen();
          if (continuous && !legacyView && pane.scrollTop < 40) void loadOlder(); }}>
        {continuous && !legacyView && before && <button type="button" disabled={loadingOlder} className="mb-4 w-full text-xs text-muted-foreground" onClick={() => void loadOlder()}>{loadingOlder ? '正在加载…' : '查看更早消息'}</button>}
        {!topic?.requests.length && <div className="flex min-h-full flex-col items-center justify-center pb-5 text-center">
          <TeacherAvatar className="mb-6 h-[68px] w-[68px] rounded-3xl" definition={definition} />
          <h3 className="text-lg font-medium tracking-tight">{definition?.welcome_message || '开始对话'}</h3>
          <div className="mt-6 flex w-full max-w-64 flex-col gap-2">{questions.map((question) => <button key={question} onClick={() => changeText(question)} className="consultation-suggestion flex items-center justify-between gap-2 rounded-lg border bg-white px-3 py-3 text-left text-xs">{question}<ChevronRight className="h-3 w-3 shrink-0 opacity-50" /></button>)}</div>
        </div>}
        {topic?.requests.map((request, index) => <div key={request.id} className="mb-7 space-y-4">
          {continuous && request.projectId && (index === 0 || request.projectId !== topic.requests[index - 1].projectId) && <p className="text-center text-[10px] text-muted-foreground">{request.projectName || '之前的项目'}</p>}
          {request.intent === 'check-in'
            ? <div className="space-y-1"><p className="text-[11px] text-muted-foreground">智能体来看看你的进展</p><MessageTimestamp value={request.createdAt} label="主动检查时间" /></div>
            : <div className="flex flex-col items-end gap-1"><p className="consultation-user max-w-[92%] whitespace-pre-wrap break-words rounded-2xl rounded-br-sm px-4 py-3 text-[13px] leading-7">{request.text}</p><MessageTimestamp value={request.createdAt} label="发送时间" className="text-right" /></div>}
          {request.references.length > 0 && <details className="text-xs text-muted-foreground"><summary>本轮引用 {request.references.length} 项</summary>{request.references.map((ref, index) => <pre className="whitespace-pre-wrap" key={index}>{ref.text}</pre>)}</details>}
          <div className="flex items-center gap-2 text-[11px] text-muted-foreground"><TeacherAvatar definition={definition} className="h-6 w-6 rounded-lg" />{definition?.name ?? label}</div>
          {request.reasoning && <details open={['running', 'preparing'].includes(request.status)} className="min-w-0 text-xs text-muted-foreground" data-testid="teacher-reasoning">
            <summary className="cursor-pointer">思考过程</summary>
            <div className="mt-2 whitespace-pre-wrap break-words border-l-2 pl-3 leading-6 [overflow-wrap:anywhere]" aria-label="智能体思考过程">{request.reasoning}</div>
          </details>}
          {!!request.toolActivity?.length && <details className="text-xs text-muted-foreground">
            <summary className="cursor-pointer">使用了 {request.toolActivity.length} 项工具</summary>
            <ul className="mt-2 space-y-2" aria-label="智能体工具活动">
              {request.toolActivity.map(activity => <li key={activity.id} className="flex items-start justify-between gap-3">
                <span>{activity.name === 'list_project_files' ? '查看项目文件列表' : activity.name === 'read_project_file' ? '读取项目文件' : activity.name === 'read_conversation' ? '读取会话原文' : '使用智能体工具'}</span>
                <span className="shrink-0">{activity.status === 'completed' ? '已完成' : activity.status === 'failed' ? '未完成'
                  : ['running', 'preparing'].includes(request.status) ? '进行中' : '未收到执行结果'}</span>
              </li>)}
            </ul>
          </details>}
          <div className="space-y-1.5">
          {request.status === 'completed' && request.replyIncomplete ? <div className="space-y-3">
            <p role="status" className="text-[13px] leading-7 text-muted-foreground">这次回复未能完整显示</p>
            {request.intent !== 'check-in' && request.text.trim() && <button type="button" disabled={helpUnavailable || !retryScopeMatches(request)} onClick={() => void send({ text: request.text, intent: request.intent }, request)} className="consultation-retry">重新回答</button>}
            {!retryScopeMatches(request) && <p className="text-xs text-muted-foreground">回到原项目和操作对话后，可以重新回答。</p>}
          </div> : request.intent === 'suggestions' ? <>
            {request.response && (request.status === 'completed' || request.presentation === 'reply-v1') && <TeacherReply text={request.response} />}
            {['running', 'preparing'].includes(request.status) && <p role="status" className="flex items-center gap-2 text-[13px] leading-7 text-muted-foreground"><Loader2 className="h-3.5 w-3.5 animate-spin motion-reduce:animate-none" />我看看你最近做到了哪里…</p>}
            {['failed', 'cancelled', 'interrupted'].includes(request.status) && <button type="button" disabled={helpUnavailable || voiceInput.state !== 'idle'} onClick={askForSuggestions} className="consultation-retry">帮我整体看🧠</button>}
          </> : request.response ? <TeacherReply text={request.response} /> : <div className="text-[13px] leading-7">{['running', 'preparing'].includes(request.status) ? <span role="status" className="inline-flex items-center gap-2 text-muted-foreground"><Loader2 className="h-3.5 w-3.5 animate-spin motion-reduce:animate-none" />{label}正在想…</span> : ['cancelled', 'interrupted'].includes(request.status) ? '这次先停在这里。想继续时可以再说说。' : ''}</div>}
          <MessageTimestamp value={request.finishedAt} pending={['running', 'preparing'].includes(request.status)} />
          </div>
          {request.status === 'completed' && !request.replyIncomplete && Boolean(request.suggestedQuestions?.length) && <div className="consultation-follow-ups" aria-label={request.intent === 'suggestions' ? '可以和智能体聊的问题' : '接着聊'}>
            {request.suggestedQuestions?.map((question, index) => <button type="button" key={`${request.id}:${index}`} disabled={helpUnavailable} onClick={() => void send({ text: question })} className="consultation-follow-up"><span className="min-w-0 flex-1">{question}</span><ChevronRight className="h-4 w-4 shrink-0 opacity-70" aria-hidden="true" /></button>)}
          </div>}
          {request.status === 'completed' && !request.replyIncomplete && request.replyParseError && <p role="status" className="text-xs text-muted-foreground">回答正文已保留，部分附加内容未能显示。</p>}
          {request.unparsedResponse && <details className="min-w-0 text-xs text-muted-foreground">
            <summary className="cursor-pointer">查看收到的原始内容</summary>
            <pre className="mt-2 max-h-64 overflow-auto whitespace-pre-wrap break-words rounded-lg border p-3">{request.unparsedResponse}</pre>
          </details>}
          {request.progress && ['running', 'preparing'].includes(request.status) && <p role="status" className="text-xs text-muted-foreground">{request.progress}</p>}
          {(request.truncatedMessages ?? 0) > 0 && <p className="text-xs text-muted-foreground">{draftRevision ? '较长的上下文已节选。' : '较长的上下文已节选，智能体可按需读取原文。'}</p>}
          {request.error && <p className="text-xs text-destructive">{request.error}</p>}
          {onBringBack && request.response && !request.replyIncomplete && request.intent !== 'suggestions' && request.status === 'completed' && <div className="text-[11px] text-muted-foreground">
            <button disabled={continuous && (request.projectId !== projectId || request.sourceConversationId !== sourceId)} onClick={() => onBringBack(request.response)}>
              {continuous && (request.projectId !== projectId || request.sourceConversationId !== sourceId) ? '请打开来源项目和操作对话后带回' : '带回主会话草稿'}</button>
          </div>}
        </div>)}
      </div>
      {error && <p role="alert" className="px-5 py-2 text-xs leading-5 text-destructive">{error}</p>}
      {topic?.unsaved && <div className="px-5 py-2 text-xs text-destructive">回复尚未保存，请复制或重试保存。<button className="ml-2 underline" onClick={() => void teacherApi.save(topicBase, endpointId).then(consume).catch(() => setError('保存失败，请先复制回复。'))}>重试保存</button></div>}
      {!topicEnabled && !error && !busy && <p className="px-5 pb-2 text-xs text-muted-foreground">{legacyFriend ? '这是旧版内置朋友的话题，仅供查看。请选择智能体新建话题。' : `${label}暂未开放，历史仍可查看。`}</p>}
      <form className="shrink-0 px-4 pb-4 pt-2" onSubmit={(e) => { e.preventDefault(); void send(); }}>
        {Boolean(unassignedDraft.text?.trim() || unassignedDraft.references?.length) && <details className="mb-2 text-xs text-muted-foreground">
          <summary>查看之前的项目草稿</summary>
          <div className="max-h-40 overflow-auto whitespace-pre-wrap rounded-lg border p-2">
            {unassignedDraft.text}
            {unassignedDraft.references?.map((ref, index) => <pre className="mt-2 whitespace-pre-wrap" key={index}>{ref.text}</pre>)}
          </div>
        </details>}
        {Boolean(legacyDraft.text?.trim() || legacyDraft.references?.length) && <details className="mb-2 text-xs text-muted-foreground">
          <summary>查看旧版朋友草稿</summary>
          <div className="max-h-40 overflow-auto whitespace-pre-wrap rounded-lg border p-2">
            {legacyDraft.text}
            {legacyDraft.references?.map((ref, index) => <pre className="mt-2 whitespace-pre-wrap" key={index}>{ref.text}</pre>)}
          </div>
        </details>}
        {references.length > 0 && <div className="mb-2 rounded-lg bg-white p-3 text-xs"><p className="line-clamp-3 whitespace-pre-wrap">{references.map((ref) => ref.text).join('\n')}</p><button type="button" className="mt-1 underline" onClick={removeReferences}>移除引用</button></div>}
        {!draftRevision && !text.trim() && (definition?.shortcuts == null || definition.shortcuts.length > 0) &&
          <div className="consultation-shortcuts" role="group" aria-label="快捷提问" data-testid="consultation-shortcuts">
            {definition?.shortcuts == null
              ? <button type="button" disabled={helpUnavailable || voiceInput.state !== 'idle'} onClick={askForSuggestions} className="consultation-hint">帮我整体看🧠</button>
              : definition.shortcuts.map((shortcut, index) => <button
                key={index} type="button" disabled={helpUnavailable || voiceInput.state !== 'idle'}
                onClick={() => void send({ text: shortcut.prompt })}
                className="consultation-hint"
              >{shortcut.label}</button>)}
          </div>}
        <div className="consultation-composer rounded-2xl border bg-white p-3 focus-within:ring-2 focus-within:ring-black/5">
          <Textarea ref={inputRef} aria-label={`向${label}提问`} value={text} disabled={busy} maxLength={6000} onChange={(e) => changeText(e.target.value)} placeholder="和老师聊聊" rows={Math.min(6, text.split('\n').length)}
            onKeyDown={(e) => { if (e.key === 'Enter' && !e.shiftKey && !e.nativeEvent.isComposing) { e.preventDefault(); void send(); } }}
            className="max-h-48 !min-h-[42px] resize-none border-0 bg-transparent px-0 py-1 text-[13px] leading-6 shadow-none placeholder:text-muted-foreground/65 focus-visible:ring-0 focus-visible:ring-offset-0 md:text-[13px] md:leading-5" />
          <div className="flex min-h-8 items-center gap-1" data-testid="consultation-composer-actions">
            <div className="ml-auto flex min-w-0 max-w-full items-center gap-1" data-testid="teacher-composer-runtime-controls">
              <ComposerVoiceButton voiceInput={voiceInput} />
            {running ? <button type="button" className="h-8 rounded-lg border px-3 text-xs" onClick={() => void teacherApi.cancel(topicBase, endpointId, running.id).then(consume).catch(() => setError('暂时无法停止，请稍后重试。'))}>停止回复</button>
            : <button type="submit" aria-label="提问" title={busy ? '正在发送…' : '发送'} disabled={busy || !topicEnabled || !text.trim() || voiceInput.state !== 'idle'} className="consultation-send flex h-8 w-8 shrink-0 items-center justify-center rounded-full text-white disabled:opacity-30"><ArrowUp className="h-4 w-4" /></button>}
            </div>
          </div>
        </div>
      </form>
    </aside>
  );
}