import {
  html, useState, useEffect, useRef, useMemo, useCallback,
} from './vendor/htm-preact.js';
import { t } from './i18n.js';
import { Icon } from './icon.js';
import { canPreview, downloadEntry } from './file-utils.js';
import {
  HUB, session, cacheGroupIndex, hubFetch, ensureFreshToken, _loadBundleKey,
} from './hub-client.js';
import { FilesPanel, FilePreview } from './files-app.js';
import { VideoApp, bumpMediaMetaGeneration, bumpThumbGeneration } from './video-app.js';
import { MusicApp, bumpMusicMetaGeneration } from './music-app.js';
import { PhotosApp } from './photos-app.js';
import { VideoPlayer } from './video-player.js';
import { transfers } from './transfers.js';

const BATCH_SIZE = 3;
const MAX_POOL_SIZE = 3;
const DEBOUNCE_MS = 200;
const SEARCH_TIMEOUT = 10000;
const SEARCH_VIDEO_ROOT = '__search__';
const SEARCH_AUDIO_ROOT = '__search__';
const SEARCH_PHOTO_ROOTS = ['__search_photos__'];

// -- Connection pool ----------------------------------------------------------

class ConnectionPool {
  constructor(hubBase) {
    this._hubBase = hubBase;
    this._connections = new Map();
    this._connecting = new Map();
  }

  async connect(groupId, token, bundleKey, username, userId) {
    const existing = this._connections.get(groupId);
    if (existing && existing.transport.connected) {
      existing.lastUsed = Date.now();
      return existing;
    }
    if (this._connecting.has(groupId)) return this._connecting.get(groupId);

    const p = this._doConnect(groupId, token, bundleKey, username, userId);
    this._connecting.set(groupId, p);
    try {
      const conn = await p;
      this._connections.set(groupId, conn);
      this._evict();
      return conn;
    } finally {
      this._connecting.delete(groupId);
    }
  }

  async _doConnect(groupId, token, bundleKey, username, userId) {
    const nodesData = await hubFetch(`/v1/groups/${groupId}/nodes`, { token });
    if (!nodesData.nodes || !nodesData.nodes.length) throw new Error('offline');

    const live = (await ensureFreshToken()) || token;
    const transport = new window.MeshBayTransport(this._hubBase, live);
    transport.onNeedToken = async () => (await ensureFreshToken()) || token;

    let timer;
    try {
      await Promise.race([
        transport.connect(
          nodesData.nodes[0].node_id, live, groupId, null, null, bundleKey,
          username, userId, null),
        new Promise((_, reject) => {
          timer = setTimeout(() => reject(new Error('Connection timeout')), SEARCH_TIMEOUT);
        }),
      ]);
      clearTimeout(timer);
    } catch (e) {
      clearTimeout(timer);
      try { transport.close(); } catch {}
      throw e;
    }

    let gek = null;
    if (transport.gekRaw && window.MeshBayCrypto) {
      gek = await window.MeshBayCrypto.importGEK(
        window.MeshBayCrypto.b64encode(transport.gekRaw));
    }
    return { transport, gek, lastUsed: Date.now() };
  }

  _evict() {
    while (this._connections.size > MAX_POOL_SIZE) {
      let oldestId = null, oldestTime = Infinity;
      for (const [id, conn] of this._connections) {
        if (conn.lastUsed < oldestTime) { oldestTime = conn.lastUsed; oldestId = id; }
      }
      if (!oldestId) break;
      const conn = this._connections.get(oldestId);
      try { conn.transport.close(); } catch {}
      this._connections.delete(oldestId);
    }
  }

  closeAll() {
    for (const [, conn] of this._connections) {
      try { conn.transport.close(); } catch {}
    }
    this._connections.clear();
    for (const [, p] of this._connecting) {
      p.then(c => { try { c.transport.close(); } catch {} }).catch(() => {});
    }
    this._connecting.clear();
  }
}

// -- Index fetching -----------------------------------------------------------

async function fetchGroupIndex(groupId, token, bundleKey, username, userId) {
  const nodesData = await hubFetch(`/v1/groups/${groupId}/nodes`, { token });
  if (!nodesData.nodes || !nodesData.nodes.length) return null;

  const live = (await ensureFreshToken()) || token;
  const transport = new window.MeshBayTransport(HUB, live);
  transport.onNeedToken = async () => (await ensureFreshToken()) || token;

  try {
    let timer;
    const ack = await Promise.race([
      transport.connect(
        nodesData.nodes[0].node_id, live, groupId, null, null, bundleKey,
        username, userId, null),
      new Promise((_, reject) => {
        timer = setTimeout(() => reject(new Error('Connection timeout')), SEARCH_TIMEOUT);
      }),
    ]);
    clearTimeout(timer);

    const indexMsg = await transport.fetchIndex();
    const roots = {
      videoRoot: ack.video_root || '',
      audioRoot: ack.audio_root || '',
      photoRoots: ack.photo_roots || [],
    };
    return { entries: indexMsg.entries || [], roots };
  } finally {
    try { transport.close(); } catch {}
  }
}

async function fetchAllIndexes(groups, token, username, userId, onProgress, onBatch) {
  const bundleKey = session.bundleKey || await _loadBundleKey();
  if (bundleKey) session.bundleKey = bundleKey;

  const total = groups.length;
  let done = 0;
  const unreachable = [];
  const results = new Map();

  for (let i = 0; i < groups.length; i += BATCH_SIZE) {
    const batch = groups.slice(i, i + BATCH_SIZE);
    await Promise.all(batch.map(async (g) => {
      try {
        const result = await fetchGroupIndex(g.id, token, bundleKey, username, userId);
        if (result) {
          results.set(g.id, {
            ...result,
            groupName: g.name,
            groupOwner: g.owner_username,
          });
          cacheGroupIndex(g.id, g.name, g.owner_username, result.entries, result.roots);
        } else {
          unreachable.push(g.name || g.id);
        }
      } catch {
        unreachable.push(g.name || g.id);
      }
      done++;
      onProgress({ done, total, unreachable: [...unreachable] });
    }));
    onBatch(new Map(results));
  }
  return { results, unreachable };
}

// -- SearchPage ---------------------------------------------------------------

function underRoot(entry, root) {
  if (!root) return false;
  const p = entry.path || '';
  return p === root || p.startsWith(root + '/');
}

function SearchPage({ token, username, userId, groups, onPlayQueue, userPrefs }) {
  const [indexedGroups, setIndexedGroups] = useState(new Map());
  const [progress, setProgress] = useState({ done: 0, total: 0, unreachable: [] });
  const [fetching, setFetching] = useState(false);
  // Bumped by the Files breadcrumb refresh button — re-runs the all-groups
  // index fetch below, the only "cache" this page has.
  const [refreshTick, setRefreshTick] = useState(0);
  const [query, setQuery] = useState('');
  const [viewMode, setViewMode] = useState('files');
  const [videoEntry, setVideoEntry] = useState(null);
  const [previewEntry, setPreviewEntry] = useState(null);
  const [connecting, setConnecting] = useState(false);
  const poolRef = useRef(null);
  const modalTransportRef = useRef(null);
  const modalGekRef = useRef(null);
  const groupConns = useRef(new Map());
  const [connectionGen, setConnectionGen] = useState(0);
  const debounceRef = useRef(null);
  const [debouncedQuery, setDebouncedQuery] = useState('');

  useEffect(() => {
    poolRef.current = new ConnectionPool(HUB);
    return () => { if (poolRef.current) poolRef.current.closeAll(); };
  }, []);

  useEffect(() => {
    if (debounceRef.current) clearTimeout(debounceRef.current);
    debounceRef.current = setTimeout(() => setDebouncedQuery(query), DEBOUNCE_MS);
    return () => { if (debounceRef.current) clearTimeout(debounceRef.current); };
  }, [query]);

  useEffect(() => {
    if (!groups || !groups.length || !token || !window.MeshBayTransport) return;
    let cancelled = false;

    (async () => {
      setFetching(true);
      setProgress({ done: 0, total: groups.length, unreachable: [] });

      await fetchAllIndexes(
        groups, token, username, userId,
        (p) => { if (!cancelled) setProgress(p); },
        (results) => { if (!cancelled) setIndexedGroups(new Map(results)); },
      );

      if (!cancelled) setFetching(false);
    })();

    return () => { cancelled = true; };
  }, [groups, token, refreshTick]);

  // -- Connection management --

  const connectGroup = useCallback(async (groupId) => {
    if (groupConns.current.has(groupId)) {
      const c = groupConns.current.get(groupId);
      if (c.transport && c.transport.connected) return c;
    }
    if (!poolRef.current) throw new Error('no pool');
    const bundleKey = session.bundleKey || await _loadBundleKey();
    const conn = await poolRef.current.connect(groupId, token, bundleKey, username, userId);
    const entry = {
      transport: conn.transport,
      gek: conn.gek,
      tRef: { current: conn.transport },
      gRef: { current: conn.gek },
    };
    groupConns.current.set(groupId, entry);
    setConnectionGen((g) => g + 1);
    bumpMediaMetaGeneration();
    bumpThumbGeneration();
    bumpMusicMetaGeneration();
    return entry;
  }, [token, username, userId]);

  // Pre-connect to all groups as soon as indexing finishes so thumbnails
  // start loading before the user switches views. The pool evicts old
  // connections but _thumbBlobCache keeps fetched thumbnails across evictions.
  useEffect(() => {
    if (fetching || indexedGroups.size === 0) return;
    let cancelled = false;

    (async () => {
      const groupIds = [...indexedGroups.keys()];
      for (let i = 0; i < groupIds.length; i += BATCH_SIZE) {
        if (cancelled) break;
        const batch = groupIds.slice(i, i + BATCH_SIZE);
        await Promise.all(batch.map(async (gid) => {
          try { await connectGroup(gid); } catch { /* skip */ }
        }));
      }
    })();

    return () => { cancelled = true; };
  }, [fetching, indexedGroups, connectGroup]);

  // -- Entry preparation --

  const q = debouncedQuery.trim().toLowerCase();

  const matchesQuery = useCallback((e) => {
    if (!q) return true;
    return (e.name || '').toLowerCase().includes(q)
        || (e.path || '').toLowerCase().includes(q)
        || (e.display_title || '').toLowerCase().includes(q)
        || (e.artist || '').toLowerCase().includes(q)
        || (e.album || '').toLowerCase().includes(q);
  }, [q]);

  const allEntries = useMemo(() => {
    const result = [];
    for (const [groupId, data] of indexedGroups) {
      for (const e of data.entries) {
        result.push({
          ...e, groupId,
          groupName: data.groupName,
          groupOwner: data.groupOwner,
        });
      }
    }
    return result;
  }, [indexedGroups]);

  // Files view: path-prefixed entries for FilesPanel directory navigation
  const fileEntries = useMemo(() => {
    const result = [];
    for (const [groupId, data] of indexedGroups) {
      for (const e of data.entries) {
        if (q && !matchesQuery(e)) continue;
        const conn = groupConns.current.get(groupId);
        result.push({
          ...e,
          path: data.groupName + (e.path ? '/' + e.path : ''),
          _origPath: e.path,
          groupId,
          groupName: data.groupName,
          groupOwner: data.groupOwner,
          _tRef: conn ? conn.tRef : null,
          _gRef: conn ? conn.gRef : null,
        });
      }
    }
    return result;
  }, [indexedGroups, q, matchesQuery, connectionGen]);

  const fileNodeDirs = useMemo(() => {
    const dirs = [];
    for (const [, data] of indexedGroups) dirs.push(data.groupName);
    return dirs;
  }, [indexedGroups]);

  // Videos view: pre-filtered by videoRoot, path-prefixed
  const videoEntries = useMemo(() => {
    const result = [];
    for (const [groupId, data] of indexedGroups) {
      const root = data.roots.videoRoot;
      if (!root) continue;
      const conn = groupConns.current.get(groupId);
      for (const e of data.entries) {
        if (e.type !== 'video') continue;
        if (!underRoot(e, root)) continue;
        if (q && !matchesQuery(e)) continue;
        result.push({
          ...e,
          path: SEARCH_VIDEO_ROOT + '/' + e.path,
          groupId,
          groupName: data.groupName,
          groupOwner: data.groupOwner,
          _tRef: conn ? conn.tRef : null,
          _gRef: conn ? conn.gRef : null,
        });
      }
    }
    return result;
  }, [indexedGroups, q, matchesQuery, connectionGen]);

  // Music view: pre-filtered by audioRoot, path-prefixed
  const musicEntries = useMemo(() => {
    const result = [];
    for (const [groupId, data] of indexedGroups) {
      const root = data.roots.audioRoot;
      if (!root) continue;
      const conn = groupConns.current.get(groupId);
      for (const e of data.entries) {
        if (e.type !== 'audio') continue;
        if (!underRoot(e, root)) continue;
        if (q && !matchesQuery(e)) continue;
        result.push({
          ...e,
          path: SEARCH_AUDIO_ROOT + '/' + e.path,
          groupId,
          groupName: data.groupName,
          groupOwner: data.groupOwner,
          _tRef: conn ? conn.tRef : null,
          _gRef: conn ? conn.gRef : null,
        });
      }
    }
    return result;
  }, [indexedGroups, q, matchesQuery, connectionGen]);

  // Photos view: pre-filtered by photoRoots, path-prefixed
  const photoEntries = useMemo(() => {
    const result = [];
    for (const [groupId, data] of indexedGroups) {
      const roots = data.roots.photoRoots;
      if (!roots || !roots.length) continue;
      const conn = groupConns.current.get(groupId);
      for (const e of data.entries) {
        if (e.type !== 'image') continue;
        const p = e.path || '';
        if (!roots.some((r) => p === r || p.startsWith(r + '/'))) continue;
        if (q && !matchesQuery(e)) continue;
        result.push({
          ...e,
          path: '__search_photos__/' + e.path,
          groupId,
          groupName: data.groupName,
          groupOwner: data.groupOwner,
          _tRef: conn ? conn.tRef : null,
          _gRef: conn ? conn.gRef : null,
        });
      }
    }
    return result;
  }, [indexedGroups, q, matchesQuery, connectionGen]);

  // -- Callbacks --

  const onPreview = useCallback(async (entry) => {
    const groupId = entry.groupId;
    if (!groupId) return;

    if (entry.type === 'video') {
      setConnecting(true);
      try {
        const conn = await connectGroup(groupId);
        modalTransportRef.current = conn.transport;
        modalGekRef.current = conn.gek;
        setVideoEntry(entry);
      } catch { /* ignore */ }
      setConnecting(false);
      return;
    }

    if (entry.type === 'audio' && onPlayQueue) {
      const origPath = entry._origPath != null ? entry._origPath : entry.path;
      const siblings = allEntries
        .filter((e) => e.type === 'audio' && e.path === origPath && e.groupId === groupId)
        .sort((a, b) =>
          ((a.track_no == null ? 9999 : a.track_no) - (b.track_no == null ? 9999 : b.track_no))
          || (a.name || '').localeCompare(b.name || ''));
      const startIndex = Math.max(0, siblings.findIndex((e) => e.id === entry.id));
      onPlayQueue(siblings, startIndex);
      return;
    }

    if (canPreview(entry)) {
      setConnecting(true);
      try {
        const conn = await connectGroup(groupId);
        modalTransportRef.current = conn.transport;
        modalGekRef.current = conn.gek;
        setPreviewEntry(entry);
      } catch { /* ignore */ }
      setConnecting(false);
    }
  }, [allEntries, onPlayQueue, connectGroup]);

  const handleMusicPlay = useCallback((tracks, startIndex) => {
    setVideoEntry(null);
    if (onPlayQueue) onPlayQueue(tracks, startIndex);
  }, [onPlayQueue]);

  const downloadForModal = useCallback(async (entry) => {
    const transport = modalTransportRef.current;
    if (!transport || !transport.connected) return;
    await downloadEntry(transfers, transport, modalGekRef.current, entry);
  }, []);

  const getTransport = useCallback(async (entry) => {
    const conn = await connectGroup(entry.groupId);
    return { transport: conn.transport, gek: conn.gek };
  }, [connectGroup]);

  // No-op setters for FilesPanel
  const noop = useCallback(() => {}, []);

  // -- Render --

  const totalEntries = allEntries.length;
  const hasResults = totalEntries > 0;
  const defaultTRef = useRef(null);
  const defaultGRef = useRef(null);

  return html`
    <div>
      <div class="search-bar">
        <${Icon} name="search" />
        <input type="text"
          placeholder=${t('search.placeholder')}
          value=${query}
          onInput=${(e) => setQuery(e.target.value)}
          autofocus />
        ${query && html`
          <button class="search-bar-clear" onClick=${() => setQuery('')}>
            <${Icon} name="close" /></button>
        `}
        ${hasResults && html`
          <div class="view-toggle">
            <button class=${viewMode === 'files' ? 'active' : ''}
              onClick=${() => setViewMode('files')}
              title=${t('search.view_files')}>
              <${Icon} name="folder" /></button>
            <button class=${viewMode === 'videos' ? 'active' : ''}
              onClick=${() => setViewMode('videos')}
              title=${t('search.view_videos')}>
              <${Icon} name="video" /></button>
            <button class=${viewMode === 'music' ? 'active' : ''}
              onClick=${() => setViewMode('music')}
              title=${t('search.view_music')}>
              <${Icon} name="music" /></button>
            <button class=${viewMode === 'photos' ? 'active' : ''}
              onClick=${() => setViewMode('photos')}
              title=${t('search.view_photos')}>
              <${Icon} name="image" /></button>
          </div>
        `}
      </div>

      ${fetching && html`
        <div class="search-progress">
          <span class="spinner"></span>
          <span>${t('search.indexing', { done: progress.done, total: progress.total })}</span>
          <div class="search-progress-bar">
            <div class="search-progress-fill"
              style="width:${progress.total ? Math.round(100 * progress.done / progress.total) : 0}%"></div>
          </div>
        </div>
      `}

      ${!fetching && progress.unreachable.length > 0 && html`
        <p class="search-unreachable">
          ${t('search.unreachable', { n: progress.unreachable.length })}
        </p>
      `}

      ${viewMode === 'files' && hasResults && html`
        <${FilesPanel}
          groupId="search"
          transportRef=${defaultTRef}
          gekRef=${defaultGRef}
          status="connected"
          entries=${fileEntries}
          nodeDirs=${fileNodeDirs}
          nodeRoots=${[]}
          setEntries=${noop}
          setNodeDirs=${noop}
          setNodeRoots=${noop}
          applyIndex=${noop}
          isNodeAdmin=${false}
          operatorPaired=${false}
          mayUpload=${false}
          userId=${userId}
          setError=${noop}
          onPreview=${onPreview}
          showGroup=${true}
          readOnly=${true}
          getTransport=${getTransport}
          onRefreshIndex=${() => setRefreshTick((n) => n + 1)} />
      `}

      ${viewMode === 'videos' && hasResults && html`
        <${VideoApp}
          groupId="search"
          transportRef=${defaultTRef}
          gekRef=${defaultGRef}
          status="connected"
          entries=${videoEntries}
          onPreview=${onPreview}
          videoRoot=${SEARCH_VIDEO_ROOT}
          tmdbConfig=${{ enabled: true }}
          isNodeAdmin=${false}
          hideFilter=${true} />
      `}

      ${viewMode === 'music' && hasResults && html`
        <${MusicApp}
          groupId="search"
          transportRef=${defaultTRef}
          gekRef=${defaultGRef}
          status="connected"
          entries=${musicEntries}
          audioRoot=${SEARCH_AUDIO_ROOT}
          musicbrainzConfig=${{ enabled: true }}
          onPlayQueue=${handleMusicPlay}
          hideFilter=${true} />
      `}

      ${viewMode === 'photos' && hasResults && html`
        <${PhotosApp}
          groupId="search"
          transportRef=${defaultTRef}
          gekRef=${defaultGRef}
          status="connected"
          entries=${photoEntries}
          photoRoots=${SEARCH_PHOTO_ROOTS}
          setError=${noop}
          hideFilter=${true}
          readOnly=${true} />
      `}

      ${!hasResults && !fetching && html`
        <p class="page-message">${t('search.hint')}</p>
      `}

      ${connecting && html`
        <div class="video-overlay" style="background:rgba(0,0,0,0.5);display:flex;align-items:center;justify-content:center">
          <span class="spinner"></span>
        </div>
      `}

      ${previewEntry && html`
        <${FilePreview}
          entry=${previewEntry}
          transportRef=${modalTransportRef}
          gekRef=${modalGekRef}
          onClose=${() => setPreviewEntry(null)}
          onDownload=${() => downloadForModal(previewEntry)} />
      `}
      ${videoEntry && html`
        <${VideoPlayer}
          entry=${videoEntry}
          transportRef=${modalTransportRef}
          gekRef=${modalGekRef}
          onClose=${() => setVideoEntry(null)}
          onDownload=${() => downloadForModal(videoEntry)} />
      `}
    </div>
  `;
}

export { SearchPage, ConnectionPool };