'use client';

import { useState, useEffect, useRef, useCallback } from 'react';
import { motion, AnimatePresence } from 'motion/react';
import { Checkbox } from '@/components/ui/checkbox';
import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover';
import { cn } from '@/lib/utils';
import { useI18n } from '@/lib/hooks/use-i18n';
import { useSettingsStore } from '@/lib/store/settings';
import { useAgentRegistry } from '@/lib/orchestration/registry/store';
import { resolveAgentVoice, getSelectableProvidersWithVoices } from '@/lib/audio/voice-resolver';
import { playBrowserTTSPreview } from '@/lib/audio/browser-tts-preview';
import { useAllVoiceProfiles } from '@/lib/audio/voxcpm-voices';
import { resolveAgentVoiceOptions } from '@/lib/audio/agent-voice';
import { VOXCPM_AUTO_VOICE_ID, VOXCPM_TTS_PROVIDER_ID } from '@/lib/audio/voxcpm';
import {
  Sparkles,
  ChevronDown,
  ChevronUp,
  Shuffle,
  Volume2,
  VolumeX,
  Loader2,
  Search,
} from 'lucide-react';
import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip';
import type { AgentConfig } from '@/lib/orchestration/registry/types';
import type { TTSProviderId } from '@/lib/audio/types';
import type { ProviderWithVoices } from '@/lib/audio/voice-resolver';

function matchesVoiceQuery(value: string | undefined, query: string): boolean {
  return !!value?.toLowerCase().includes(query);
}

function getFilteredModelGroups(
  provider: ProviderWithVoices,
  query: string,
  autoVoiceLabel?: string,
) {
  const normalizedQuery = query.trim().toLowerCase();
  if (!normalizedQuery) return provider.modelGroups;

  return provider.modelGroups
    .map((group) => {
      const groupMatches =
        matchesVoiceQuery(provider.providerName, normalizedQuery) ||
        matchesVoiceQuery(provider.providerId, normalizedQuery) ||
        matchesVoiceQuery(group.modelName, normalizedQuery) ||
        matchesVoiceQuery(group.modelId, normalizedQuery);
      const voices = group.voices.filter(
        (voice) =>
          groupMatches ||
          matchesVoiceQuery(voice.name, normalizedQuery) ||
          matchesVoiceQuery(voice.id, normalizedQuery) ||
          matchesVoiceQuery(voice.language, normalizedQuery) ||
          // Auto Voice is shown by its localized label, not voice.name — match it too.
          (voice.id === VOXCPM_AUTO_VOICE_ID && matchesVoiceQuery(autoVoiceLabel, normalizedQuery)),
      );
      return { ...group, voices };
    })
    .filter((group) => group.voices.length > 0);
}

function isNonPreviewableVoice(providerId: TTSProviderId, voiceId: string): boolean {
  return providerId === VOXCPM_TTS_PROVIDER_ID && voiceId === VOXCPM_AUTO_VOICE_ID;
}

function AgentVoicePill({
  agent,
  agentIndex,
  availableProviders,
  disabled,
}: {
  agent: AgentConfig;
  agentIndex: number;
  availableProviders: ProviderWithVoices[];
  disabled?: boolean;
}) {
  const { t, locale } = useI18n();
  const ttsProvidersConfig = useSettingsStore((s) => s.ttsProvidersConfig);
  const agentVoiceOverrides = useSettingsStore((s) => s.agentVoiceOverrides);
  const setAgentVoiceOverride = useSettingsStore((s) => s.setAgentVoiceOverride);
  const resolved = resolveAgentVoice(agent, agentIndex, availableProviders, agentVoiceOverrides);
  const [popoverOpen, setPopoverOpen] = useState(false);
  const [voiceQuery, setVoiceQuery] = useState('');
  const [previewingId, setPreviewingId] = useState<string | null>(null);
  const previewCancelRef = useRef<(() => void) | null>(null);
  const previewAudioRef = useRef<HTMLAudioElement | null>(null);
  const previewAbortRef = useRef<AbortController | null>(null);
  const visibleProviderGroups = availableProviders
    .map((provider) => ({
      provider,
      groups: getFilteredModelGroups(provider, voiceQuery, t('settings.voxcpmAutoVoice')),
    }))
    .filter(({ groups }) => groups.length > 0);

  const displayName = (() => {
    if (!resolved) return t('agentBar.noVoice');
    for (const p of availableProviders) {
      if (p.providerId === resolved.providerId) {
        const v = p.voices.find((voice) => voice.id === resolved.voiceId);
        if (v) return v.id === VOXCPM_AUTO_VOICE_ID ? t('settings.voxcpmAutoVoice') : v.name;
      }
    }
    return resolved.voiceId;
  })();

  const stopPreview = useCallback(() => {
    previewCancelRef.current?.();
    previewCancelRef.current = null;
    previewAbortRef.current?.abort();
    previewAbortRef.current = null;
    if (previewAudioRef.current) {
      previewAudioRef.current.pause();
      previewAudioRef.current.src = '';
      previewAudioRef.current = null;
    }
    setPreviewingId(null);
  }, []);

  const handlePreview = useCallback(
    async (providerId: TTSProviderId, voiceId: string, modelId?: string) => {
      const key = `${providerId}::${voiceId}`;
      if (previewingId === key) {
        stopPreview();
        return;
      }
      stopPreview();
      setPreviewingId(key);

      const previewText = t('settings.ttsTestTextDefault');

      if (providerId === 'browser-native-tts') {
        const { promise, cancel } = playBrowserTTSPreview({ text: previewText, voice: voiceId });
        previewCancelRef.current = cancel;
        try {
          await promise;
        } catch {
          // ignore abort
        }
        setPreviewingId(null);
        return;
      }

      // Server TTS
      try {
        const controller = new AbortController();
        previewAbortRef.current = controller;
        const providerConfig = ttsProvidersConfig[providerId];
        const providerOptions = await resolveAgentVoiceOptions(agent, {
          providerId,
          providerConfig: { ...providerConfig, modelId: modelId || providerConfig?.modelId },
          voiceId,
          language: locale,
        });
        const res = await fetch('/api/generate/tts', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            text: previewText,
            audioId: 'voice-preview',
            ttsProviderId: providerId,
            ttsModelId: modelId || providerConfig?.modelId,
            ttsVoice: voiceId,
            ttsSpeed: 1,
            ttsApiKey: providerConfig?.apiKey,
            // Managed providers resolve their base URL server-side; only send
            // the client's own base URL (custom providers).
            ttsBaseUrl: providerConfig?.baseUrl || providerConfig?.customDefaultBaseUrl,
            ttsProviderOptions: providerOptions,
          }),
          signal: controller.signal,
        });
        if (!res.ok) throw new Error('TTS error');
        const data = await res.json();
        if (!data.base64) throw new Error('No audio');

        const audio = new Audio(`data:audio/${data.format || 'mp3'};base64,${data.base64}`);
        previewAudioRef.current = audio;
        audio.addEventListener('ended', () => setPreviewingId(null));
        audio.addEventListener('error', () => setPreviewingId(null));
        await audio.play();
      } catch {
        setPreviewingId(null);
      }
    },
    [
      agent.name,
      agent.persona,
      agent.role,
      locale,
      previewingId,
      stopPreview,
      t,
      ttsProvidersConfig,
    ],
  );

  // Cleanup on unmount
  useEffect(() => () => stopPreview(), [stopPreview]);

  // Disabled (TTS off) OR no enabled provider ⇒ render the same muted,
  // non-interactive pill — don't silently hide the control (#665).
  if (disabled) {
    return (
      <div
        onClick={(e) => e.stopPropagation()}
        onPointerDown={(e) => e.stopPropagation()}
        className="flex items-center gap-1.5 h-6 w-[100px] rounded-full bg-muted/40 px-2.5 text-[11px] text-muted-foreground/30 shrink-0 cursor-not-allowed"
      >
        <VolumeX className="size-3 shrink-0" />
        <span className="truncate flex-1 text-left">{displayName}</span>
      </div>
    );
  }

  return (
    <Popover
      open={popoverOpen}
      onOpenChange={(open) => {
        setPopoverOpen(open);
        if (!open) {
          setVoiceQuery('');
          stopPreview();
        }
      }}
    >
      <PopoverTrigger asChild>
        <button
          type="button"
          onClick={(e) => e.stopPropagation()}
          onPointerDown={(e) => e.stopPropagation()}
          className="flex items-center gap-1.5 h-6 w-[100px] rounded-full bg-primary/10 hover:bg-primary/20 dark:bg-primary/25 dark:hover:bg-primary/35 px-2.5 text-[11px] text-primary/80 hover:text-primary dark:text-primary/90 transition-colors shrink-0 cursor-pointer"
        >
          <Volume2 className="size-3 shrink-0" />
          <span className="truncate flex-1 text-left">{displayName}</span>
          <ChevronDown className="size-3 shrink-0 opacity-50" />
        </button>
      </PopoverTrigger>
      <PopoverContent
        side="bottom"
        align="end"
        sideOffset={4}
        className="w-80 p-0 sm:w-96"
        onClick={(e) => e.stopPropagation()}
        onPointerDown={(e) => e.stopPropagation()}
      >
        <div className="border-b border-border/50 p-2">
          <div className="relative">
            <Search className="pointer-events-none absolute left-2.5 top-1/2 size-3.5 -translate-y-1/2 text-muted-foreground/50" />
            <input
              value={voiceQuery}
              onChange={(e) => setVoiceQuery(e.target.value)}
              autoFocus
              aria-label={t('agentBar.searchVoice')}
              placeholder={t('agentBar.searchVoice')}
              className="h-8 w-full rounded-md border border-input bg-background pl-8 pr-3 text-sm outline-none transition-colors placeholder:text-muted-foreground/50 focus:border-primary/50 focus:ring-2 focus:ring-primary/10"
            />
          </div>
        </div>
        <div className="max-h-80 overflow-y-auto p-1">
          {visibleProviderGroups.length === 0 && (
            <div className="px-3 py-6 text-center text-sm text-muted-foreground/60">
              {t('agentBar.noMatchingVoices')}
            </div>
          )}
          {visibleProviderGroups.map(({ provider, groups }) =>
            groups.map((group) => (
              <div key={`${provider.providerId}::${group.modelId}`}>
                <div className="sticky top-0 bg-popover px-2 py-1 text-[11px] font-medium text-muted-foreground/60">
                  {group.modelId
                    ? `${provider.providerName} · ${group.modelName}`
                    : provider.providerName}
                </div>
                {group.voices.map((voice) => {
                  const isActive =
                    resolved?.providerId === provider.providerId &&
                    resolved?.voiceId === voice.id &&
                    (resolved?.modelId || '') === (group.modelId || '');
                  const previewKey = `${provider.providerId}::${voice.id}`;
                  const isPreviewing = previewingId === previewKey;
                  const canPreview = !isNonPreviewableVoice(provider.providerId, voice.id);
                  return (
                    <div
                      key={previewKey}
                      className={cn(
                        'flex items-center gap-1.5 rounded-sm transition-colors',
                        isActive ? 'bg-primary/10' : 'hover:bg-muted',
                      )}
                    >
                      <button
                        type="button"
                        onClick={() => {
                          // Persisted in settings, not on the registry record:
                          // default agent records are reset from code on every
                          // load and would drop the pick.
                          setAgentVoiceOverride(agent.id, {
                            providerId: provider.providerId,
                            modelId: group.modelId || undefined,
                            voiceId: voice.id,
                          });
                          setPopoverOpen(false);
                        }}
                        className={cn(
                          'flex-1 text-left text-[13px] px-2 py-1.5 min-w-0 truncate',
                          isActive ? 'text-primary font-medium' : 'text-foreground',
                        )}
                      >
                        {voice.id === VOXCPM_AUTO_VOICE_ID
                          ? t('settings.voxcpmAutoVoice')
                          : voice.name}
                      </button>
                      {canPreview && (
                        <button
                          type="button"
                          onClick={(e) => {
                            e.stopPropagation();
                            handlePreview(provider.providerId, voice.id, group.modelId);
                          }}
                          className={cn(
                            'flex size-6 shrink-0 items-center justify-center rounded-sm transition-colors',
                            isPreviewing
                              ? 'text-primary'
                              : 'text-muted-foreground/40 hover:text-muted-foreground',
                          )}
                        >
                          {isPreviewing ? (
                            <Loader2 className="size-3.5 animate-spin" />
                          ) : (
                            <Volume2 className="size-3.5" />
                          )}
                        </button>
                      )}
                    </div>
                  );
                })}
              </div>
            )),
          )}
        </div>
      </PopoverContent>
    </Popover>
  );
}

/**
 * Teacher voice pill — reads/writes global ttsProviderId + ttsVoice (single source of truth).
 * This ensures lecture and discussion use the same voice for the teacher.
 */
function TeacherVoicePill({
  availableProviders,
  disabled,
}: {
  availableProviders: ProviderWithVoices[];
  disabled?: boolean;
}) {
  const { t, locale } = useI18n();
  const ttsProviderId = useSettingsStore((s) => s.ttsProviderId);
  const ttsVoice = useSettingsStore((s) => s.ttsVoice);
  const setTTSProvider = useSettingsStore((s) => s.setTTSProvider);
  const setTTSVoice = useSettingsStore((s) => s.setTTSVoice);
  const setTTSProviderConfig = useSettingsStore((s) => s.setTTSProviderConfig);
  const ttsProvidersConfig = useSettingsStore((s) => s.ttsProvidersConfig);
  const [popoverOpen, setPopoverOpen] = useState(false);
  const [voiceQuery, setVoiceQuery] = useState('');
  const [previewingId, setPreviewingId] = useState<string | null>(null);
  const previewCancelRef = useRef<(() => void) | null>(null);
  const previewAudioRef = useRef<HTMLAudioElement | null>(null);
  const previewAbortRef = useRef<AbortController | null>(null);
  const visibleProviderGroups = availableProviders
    .map((provider) => ({
      provider,
      groups: getFilteredModelGroups(provider, voiceQuery, t('settings.voxcpmAutoVoice')),
    }))
    .filter(({ groups }) => groups.length > 0);

  const displayName = (() => {
    // No enabled provider ⇒ no valid voice; show the placeholder, not a stale
    // voice name from a now-disabled provider (#665).
    if (availableProviders.length === 0) return t('agentBar.noVoice');
    for (const p of availableProviders) {
      if (p.providerId === ttsProviderId) {
        const v = p.voices.find((voice) => voice.id === ttsVoice);
        if (v) return v.id === VOXCPM_AUTO_VOICE_ID ? t('settings.voxcpmAutoVoice') : v.name;
      }
    }
    return ttsVoice || 'default';
  })();

  const stopPreview = useCallback(() => {
    previewCancelRef.current?.();
    previewCancelRef.current = null;
    previewAbortRef.current?.abort();
    previewAbortRef.current = null;
    if (previewAudioRef.current) {
      previewAudioRef.current.pause();
      previewAudioRef.current.src = '';
      previewAudioRef.current = null;
    }
    setPreviewingId(null);
  }, []);

  const handlePreview = useCallback(
    async (providerId: TTSProviderId, voiceId: string, modelId?: string) => {
      const key = `${providerId}::${voiceId}`;
      if (previewingId === key) {
        stopPreview();
        return;
      }
      stopPreview();
      setPreviewingId(key);

      const previewText = t('settings.ttsTestTextDefault');

      if (providerId === 'browser-native-tts') {
        const { promise, cancel } = playBrowserTTSPreview({ text: previewText, voice: voiceId });
        previewCancelRef.current = cancel;
        try {
          await promise;
        } catch {
          // ignore abort
        }
        setPreviewingId(null);
        return;
      }

      try {
        const controller = new AbortController();
        previewAbortRef.current = controller;
        const providerConfig = ttsProvidersConfig[providerId];
        const providerOptions = await resolveAgentVoiceOptions(undefined, {
          providerId,
          providerConfig: { ...providerConfig, modelId: modelId || providerConfig?.modelId },
          voiceId,
          language: locale,
        });
        const res = await fetch('/api/generate/tts', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({
            text: previewText,
            audioId: 'voice-preview',
            ttsProviderId: providerId,
            ttsModelId: modelId || providerConfig?.modelId,
            ttsVoice: voiceId,
            ttsSpeed: 1,
            ttsApiKey: providerConfig?.apiKey,
            // Managed providers resolve their base URL server-side; only send
            // the client's own base URL (custom providers).
            ttsBaseUrl: providerConfig?.baseUrl || providerConfig?.customDefaultBaseUrl,
            ttsProviderOptions: providerOptions,
          }),
          signal: controller.signal,
        });
        if (!res.ok) throw new Error('TTS error');
        const data = await res.json();
        if (!data.base64) throw new Error('No audio');
        const audio = new Audio(`data:audio/${data.format || 'mp3'};base64,${data.base64}`);
        previewAudioRef.current = audio;
        audio.addEventListener('ended', () => setPreviewingId(null));
        audio.addEventListener('error', () => setPreviewingId(null));
        await audio.play();
      } catch {
        setPreviewingId(null);
      }
    },
    [locale, previewingId, stopPreview, t, ttsProvidersConfig],
  );

  useEffect(() => () => stopPreview(), [stopPreview]);

  // Disabled (TTS off) OR no enabled provider ⇒ render the same muted,
  // non-interactive pill — don't silently hide the control (#665).
  if (disabled) {
    return (
      <div
        onClick={(e) => e.stopPropagation()}
        onPointerDown={(e) => e.stopPropagation()}
        className="flex items-center gap-1.5 h-6 w-[100px] rounded-full bg-muted/40 px-2.5 text-[11px] text-muted-foreground/30 shrink-0 cursor-not-allowed"
      >
        <VolumeX className="size-3 shrink-0" />
        <span className="truncate flex-1 text-left">{displayName}</span>
      </div>
    );
  }

  return (
    <Popover
      open={popoverOpen}
      onOpenChange={(open) => {
        setPopoverOpen(open);
        if (!open) {
          setVoiceQuery('');
          stopPreview();
        }
      }}
    >
      <PopoverTrigger asChild>
        <button
          type="button"
          onClick={(e) => e.stopPropagation()}
          onPointerDown={(e) => e.stopPropagation()}
          className="flex items-center gap-1.5 h-6 w-[100px] rounded-full bg-primary/10 hover:bg-primary/20 dark:bg-primary/25 dark:hover:bg-primary/35 px-2.5 text-[11px] text-primary/80 hover:text-primary dark:text-primary/90 transition-colors shrink-0 cursor-pointer"
        >
          <Volume2 className="size-3 shrink-0" />
          <span className="truncate flex-1 text-left">{displayName}</span>
          <ChevronDown className="size-3 shrink-0 opacity-50" />
        </button>
      </PopoverTrigger>
      <PopoverContent
        side="bottom"
        align="end"
        sideOffset={4}
        className="w-80 p-0 sm:w-96"
        onClick={(e) => e.stopPropagation()}
        onPointerDown={(e) => e.stopPropagation()}
      >
        <div className="border-b border-border/50 p-2">
          <div className="relative">
            <Search className="pointer-events-none absolute left-2.5 top-1/2 size-3.5 -translate-y-1/2 text-muted-foreground/50" />
            <input
              value={voiceQuery}
              onChange={(e) => setVoiceQuery(e.target.value)}
              autoFocus
              aria-label={t('agentBar.searchVoice')}
              placeholder={t('agentBar.searchVoice')}
              className="h-8 w-full rounded-md border border-input bg-background pl-8 pr-3 text-sm outline-none transition-colors placeholder:text-muted-foreground/50 focus:border-primary/50 focus:ring-2 focus:ring-primary/10"
            />
          </div>
        </div>
        <div className="max-h-80 overflow-y-auto p-1">
          {visibleProviderGroups.length === 0 && (
            <div className="px-3 py-6 text-center text-sm text-muted-foreground/60">
              {t('agentBar.noMatchingVoices')}
            </div>
          )}
          {visibleProviderGroups.map(({ provider, groups }) =>
            groups.map((group) => (
              <div key={`${provider.providerId}::${group.modelId}`}>
                <div className="sticky top-0 bg-popover px-2 py-1 text-[11px] font-medium text-muted-foreground/60">
                  {group.modelId
                    ? `${provider.providerName} · ${group.modelName}`
                    : provider.providerName}
                </div>
                {group.voices.map((voice) => {
                  const currentModelId = ttsProvidersConfig[ttsProviderId]?.modelId || '';
                  const isActive =
                    ttsProviderId === provider.providerId &&
                    ttsVoice === voice.id &&
                    currentModelId === (group.modelId || '');
                  const previewKey = `${provider.providerId}::${voice.id}`;
                  const isPreviewing = previewingId === previewKey;
                  const canPreview = !isNonPreviewableVoice(provider.providerId, voice.id);
                  return (
                    <div
                      key={previewKey}
                      className={cn(
                        'flex items-center gap-1.5 rounded-sm transition-colors',
                        isActive ? 'bg-primary/10' : 'hover:bg-muted',
                      )}
                    >
                      <button
                        type="button"
                        onClick={() => {
                          setTTSProvider(provider.providerId);
                          setTTSVoice(voice.id);
                          if (group.modelId) {
                            setTTSProviderConfig(provider.providerId, { modelId: group.modelId });
                          }
                          setPopoverOpen(false);
                        }}
                        className={cn(
                          'flex-1 text-left text-[13px] px-2 py-1.5 min-w-0 truncate',
                          isActive ? 'text-primary font-medium' : 'text-foreground',
                        )}
                      >
                        {voice.id === VOXCPM_AUTO_VOICE_ID
                          ? t('settings.voxcpmAutoVoice')
                          : voice.name}
                      </button>
                      {canPreview && (
                        <button
                          type="button"
                          onClick={(e) => {
                            e.stopPropagation();
                            handlePreview(provider.providerId, voice.id, group.modelId);
                          }}
                          className={cn(
                            'flex size-6 shrink-0 items-center justify-center rounded-sm transition-colors',
                            isPreviewing
                              ? 'text-primary'
                              : 'text-muted-foreground/40 hover:text-muted-foreground',
                          )}
                        >
                          {isPreviewing ? (
                            <Loader2 className="size-3.5 animate-spin" />
                          ) : (
                            <Volume2 className="size-3.5" />
                          )}
                        </button>
                      )}
                    </div>
                  );
                })}
              </div>
            )),
          )}
        </div>
      </PopoverContent>
    </Popover>
  );
}

export function AgentBar() {
  const { t } = useI18n();
  const { listAgents } = useAgentRegistry();
  const selectedAgentIds = useSettingsStore((s) => s.selectedAgentIds);
  const setSelectedAgentIds = useSettingsStore((s) => s.setSelectedAgentIds);
  const agentMode = useSettingsStore((s) => s.agentMode);
  const setAgentMode = useSettingsStore((s) => s.setAgentMode);
  const setAgentSelectionIsUserSet = useSettingsStore((s) => s.setAgentSelectionIsUserSet);
  const ttsProvidersConfig = useSettingsStore((s) => s.ttsProvidersConfig);
  const ttsEnabled = useSettingsStore((s) => s.ttsEnabled);

  const [open, setOpen] = useState(false);
  const [browserVoices, setBrowserVoices] = useState<SpeechSynthesisVoice[]>([]);
  const { profiles: voiceProfiles } = useAllVoiceProfiles();
  const containerRef = useRef<HTMLDivElement>(null);

  // Load browser native TTS voices
  useEffect(() => {
    if (typeof window === 'undefined' || !window.speechSynthesis) return;
    const loadVoices = () => setBrowserVoices(speechSynthesis.getVoices());
    loadVoices();
    speechSynthesis.addEventListener('voiceschanged', loadVoices);
    return () => speechSynthesis.removeEventListener('voiceschanged', loadVoices);
  }, []);

  const allAgents = listAgents();
  const agents = allAgents.filter((a) => !a.isGenerated);
  const teacherAgent = agents.find((a) => a.role === 'teacher');
  const selectedAgents = agents.filter((a) => selectedAgentIds.includes(a.id));
  const nonTeacherSelected = selectedAgents.filter((a) => a.role !== 'teacher');

  // Single source of truth for selectable provider+voice options (enabled
  // providers + opt-in browser-native), shared with discussion TTS (#665).
  const availableProviders = getSelectableProvidersWithVoices(
    ttsProvidersConfig,
    voiceProfiles,
    browserVoices,
  );

  useEffect(() => {
    if (!open) return;
    const handler = (e: MouseEvent) => {
      const target = e.target as Node;
      if (containerRef.current && containerRef.current.contains(target)) return;
      // Don't close if clicking inside a Radix portal (Popover, Select, etc.)
      if ((target as Element).closest?.('[data-radix-popper-content-wrapper]')) return;
      setOpen(false);
    };
    document.addEventListener('mousedown', handler);
    return () => document.removeEventListener('mousedown', handler);
  }, [open]);

  const handleModeChange = (mode: 'preset' | 'auto') => {
    // Clicking the already-active tab is a visual no-op; it must not convert
    // stage-derived defaults into a "user choice".
    if (mode === agentMode) return;
    // An explicit choice — restoreAgentSelection keeps it across classrooms.
    setAgentSelectionIsUserSet(true);
    setAgentMode(mode);
    if (mode === 'preset') {
      // Remove stale auto-generated agent IDs that may linger from a previous auto classroom
      const presetIds = selectedAgentIds.filter((id) => agents.some((a) => a.id === id));
      const hasTeacher = presetIds.some((id) => {
        const a = agents.find((agent) => agent.id === id);
        return a?.role === 'teacher';
      });
      if (!hasTeacher && teacherAgent) {
        presetIds.unshift(teacherAgent.id);
      }
      setSelectedAgentIds(
        presetIds.length > 0 ? presetIds : ['default-1', 'default-2', 'default-3'],
      );
    } else {
      // Auto mode plays the current classroom's generated agents — leaving the
      // preset ids selected would desync playback from the toggle (UI says
      // Auto, discussion still uses preset agents) and persist an auto
      // selection that can never validate on restore. When no classroom's
      // agents are loaded (fresh home), an empty selection falls back to the
      // stage-derived defaults on the next classroom load.
      setSelectedAgentIds(allAgents.filter((a) => a.isGenerated).map((a) => a.id));
    }
  };

  const toggleAgent = (agentId: string) => {
    const agent = agents.find((a) => a.id === agentId);
    if (agent?.role === 'teacher') return;
    setAgentSelectionIsUserSet(true);
    if (selectedAgentIds.includes(agentId)) {
      setSelectedAgentIds(selectedAgentIds.filter((id) => id !== agentId));
    } else {
      setSelectedAgentIds([...selectedAgentIds, agentId]);
    }
  };

  const getAgentName = (agent: { id: string; name: string }) => {
    const key = `settings.agentNames.${agent.id}`;
    const translated = t(key);
    return translated !== key ? translated : agent.name;
  };

  const getAgentRole = (agent: { role: string }) => {
    const key = `settings.agentRoles.${agent.role}`;
    const translated = t(key);
    return translated !== key ? translated : agent.role;
  };

  const avatarRow = (
    <div className="flex items-center gap-1.5 shrink-0">
      {teacherAgent && (
        <div className="size-8 rounded-full overflow-hidden ring-2 ring-blue-400/40 dark:ring-blue-500/30 shrink-0">
          <img
            src={teacherAgent.avatar}
            alt={getAgentName(teacherAgent)}
            className="size-full object-cover"
          />
        </div>
      )}

      {agentMode === 'auto' ? (
        <>
          <div className="flex -space-x-2">
            {agents.find((a) => a.role === 'assistant') && (
              <div className="size-6 rounded-full overflow-hidden ring-[1.5px] ring-background">
                <img
                  src={agents.find((a) => a.role === 'assistant')!.avatar}
                  alt=""
                  className="size-full object-cover"
                />
              </div>
            )}
          </div>
          <Shuffle className="size-4 text-violet-400 dark:text-violet-500" />
        </>
      ) : (
        <>
          {nonTeacherSelected.length > 0 && (
            <div className="flex -space-x-2">
              {nonTeacherSelected.slice(0, 4).map((agent) => (
                <div
                  key={agent.id}
                  className="size-6 rounded-full overflow-hidden ring-[1.5px] ring-background"
                >
                  <img
                    src={agent.avatar}
                    alt={getAgentName(agent)}
                    className="size-full object-cover"
                  />
                </div>
              ))}
              {nonTeacherSelected.length > 4 && (
                <div className="size-6 rounded-full bg-muted ring-[1.5px] ring-background flex items-center justify-center">
                  <span className="text-[9px] font-bold text-muted-foreground">
                    +{nonTeacherSelected.length - 4}
                  </span>
                </div>
              )}
            </div>
          )}
        </>
      )}
      {ttsEnabled ? (
        <Volume2 className="size-3.5 text-muted-foreground/40 group-hover:text-muted-foreground/60 transition-colors" />
      ) : (
        <VolumeX className="size-3.5 text-muted-foreground/30" />
      )}
    </div>
  );

  const renderAgentRow = (agent: AgentConfig, agentIndex: number, isTeacher: boolean) => {
    const isSelected = isTeacher || selectedAgentIds.includes(agent.id);
    return (
      <div
        key={agent.id}
        onClick={isTeacher ? undefined : () => toggleAgent(agent.id)}
        className={cn(
          'w-full flex items-center gap-2 px-2.5 py-1.5 rounded-lg transition-colors',
          isTeacher ? 'bg-primary/5' : 'cursor-pointer',
          !isTeacher && isSelected && 'bg-primary/5',
          !isTeacher && !isSelected && 'hover:bg-muted/50',
        )}
      >
        <Checkbox
          checked={isSelected}
          disabled={isTeacher}
          className={cn('pointer-events-none', isTeacher && 'opacity-50')}
        />
        <div
          className="size-7 rounded-full overflow-hidden shrink-0 ring-1 ring-border/40"
          style={{ boxShadow: isSelected ? `0 0 0 2px ${agent.color}30` : undefined }}
        >
          <img src={agent.avatar} alt={getAgentName(agent)} className="size-full object-cover" />
        </div>
        <span className="text-[13px] font-medium truncate min-w-0 flex-1">
          {getAgentName(agent)}
        </span>
        <span className="text-[10px] text-muted-foreground/50 shrink-0 w-[52px] text-right">
          {getAgentRole(agent)}
        </span>
        <AgentVoicePill
          agent={agent}
          agentIndex={agentIndex}
          availableProviders={availableProviders}
          disabled={!ttsEnabled || availableProviders.length === 0}
        />
      </div>
    );
  };

  return (
    <div ref={containerRef} className="relative w-96">
      <Tooltip>
        <TooltipTrigger asChild>
          <button
            className={cn(
              'group flex items-center gap-2 cursor-pointer rounded-full px-2.5 py-2 transition-all w-full',
              'border border-border/50 text-muted-foreground/70 hover:text-foreground hover:bg-muted/60',
            )}
            onClick={() => setOpen(!open)}
          >
            <span className="text-xs text-muted-foreground/60 group-hover:text-muted-foreground transition-colors hidden sm:block font-medium flex-1 text-left truncate">
              {open ? t('agentBar.expandedTitle') : t('agentBar.readyToLearn')}
            </span>
            {avatarRow}
            {open ? (
              <ChevronUp className="size-3 text-muted-foreground/40 group-hover:text-muted-foreground/70 transition-colors" />
            ) : (
              <ChevronDown className="size-3 text-muted-foreground/40 group-hover:text-muted-foreground/70 transition-colors" />
            )}
          </button>
        </TooltipTrigger>
        {!open && (
          <TooltipContent side="bottom" sideOffset={4}>
            {t('agentBar.configTooltip')}
          </TooltipContent>
        )}
      </Tooltip>

      <AnimatePresence>
        {open && (
          <motion.div
            initial={{ opacity: 0, y: -4, scale: 0.97 }}
            animate={{ opacity: 1, y: 0, scale: 1 }}
            exit={{ opacity: 0, y: -4, scale: 0.97 }}
            transition={{ duration: 0.2, ease: [0.25, 0.1, 0.25, 1] }}
            className="absolute right-0 top-full mt-1 z-50 w-96"
          >
            <div className="rounded-2xl bg-white/95 dark:bg-slate-800/95 backdrop-blur-sm ring-1 ring-black/[0.04] dark:ring-white/[0.06] shadow-[0_1px_8px_-2px_rgba(0,0,0,0.06)] dark:shadow-[0_1px_8px_-2px_rgba(0,0,0,0.3)] px-2 py-1.5">
              {/* Teacher — always visible */}
              {teacherAgent && (
                <div className="flex items-center gap-2 px-2.5 py-1.5 rounded-lg bg-primary/5 mb-2">
                  <div
                    className="size-7 rounded-full overflow-hidden shrink-0 ring-1 ring-border/40"
                    style={{ boxShadow: `0 0 0 2px ${teacherAgent.color}30` }}
                  >
                    <img
                      src={teacherAgent.avatar}
                      alt={getAgentName(teacherAgent)}
                      className="size-full object-cover"
                    />
                  </div>
                  <span className="text-[13px] font-medium truncate min-w-0 flex-1">
                    {getAgentName(teacherAgent)}
                  </span>
                  <TeacherVoicePill
                    availableProviders={availableProviders}
                    disabled={!ttsEnabled || availableProviders.length === 0}
                  />
                </div>
              )}

              {/* Mode tabs */}
              <div className="flex rounded-lg border bg-muted/30 p-0.5 mb-2">
                <button
                  onClick={() => handleModeChange('preset')}
                  className={cn(
                    'flex-1 py-1.5 text-xs font-medium rounded-md transition-all text-center',
                    agentMode === 'preset'
                      ? 'bg-background shadow-sm text-foreground'
                      : 'text-muted-foreground hover:text-foreground',
                  )}
                >
                  {t('settings.agentModePreset')}
                </button>
                <button
                  onClick={() => handleModeChange('auto')}
                  className={cn(
                    'flex-1 py-1.5 text-xs font-medium rounded-md transition-all text-center flex items-center justify-center gap-1',
                    agentMode === 'auto'
                      ? 'bg-background shadow-sm text-foreground'
                      : 'text-muted-foreground hover:text-foreground',
                  )}
                >
                  <Sparkles className="h-3 w-3" />
                  {t('settings.agentModeAuto')}
                </button>
              </div>

              {agentMode === 'preset' ? (
                <div className="max-h-56 overflow-y-auto -mx-0.5">
                  {agents
                    .filter((a) => a.role !== 'teacher')
                    .map((agent, idx) => renderAgentRow(agent, idx + 1, false))}
                </div>
              ) : (
                <div className="flex flex-col items-center pt-6 pb-3 gap-4">
                  <div className="relative flex items-center justify-center">
                    <div className="absolute size-10 rounded-full bg-violet-400/10 dark:bg-violet-400/15 animate-ping [animation-duration:3s]" />
                    <div className="absolute size-12 rounded-full bg-violet-400/5 dark:bg-violet-400/10 animate-pulse [animation-duration:2.5s]" />
                    <Shuffle className="relative size-5 text-violet-400 dark:text-violet-500" />
                  </div>
                  <div className="flex-1" />
                  <div className="text-center space-y-1">
                    <p className="text-[11px] text-muted-foreground/60">
                      {t('settings.agentModeAutoDesc')}
                    </p>
                    <p className="text-[10px] text-muted-foreground/40">
                      {t('agentBar.voiceAutoAssign')}
                    </p>
                  </div>
                </div>
              )}
            </div>
          </motion.div>
        )}
      </AnimatePresence>
    </div>
  );
}