import React, { useState, useRef, useLayoutEffect, useEffect, useCallback } from 'react';
import { createPortal } from 'react-dom';
import { usePlayerStore } from '../store/playerStore';
import { useOfflineStore } from '../store/offlineStore';
import { useOfflineJobStore } from '../store/offlineJobStore';
import { useAuthStore } from '../store/authStore';
import { useSidebarStore } from '../store/sidebarStore';
import { NavLink } from 'react-router-dom';
import { useTranslation } from 'react-i18next';
import {
  Disc3, Users, Music4, Radio, Settings, Heart, BarChart3, Shuffle,
  PanelLeftClose, PanelLeft, HelpCircle, Dices, AudioLines, HardDriveDownload, Tags, ListMusic, Cast,
  ChevronDown, Check, Music2, TrendingUp, FolderOpen, X,
} from 'lucide-react';
import PsysonicLogo from './PsysonicLogo';
import PSmallLogo from './PSmallLogo';

// All configurable nav items — order and visibility controlled by sidebarStore.
// Exported so Settings can render the same item metadata.
export const ALL_NAV_ITEMS: Record<string, { icon: React.ElementType; labelKey: string; to: string; section: 'library' | 'system' }> = {
  mainstage:    { icon: Disc3,      labelKey: 'sidebar.mainstage',    to: '/',              section: 'library' },
  newReleases:  { icon: Radio,      labelKey: 'sidebar.newReleases',  to: '/new-releases',  section: 'library' },
  allAlbums:    { icon: Music4,     labelKey: 'sidebar.allAlbums',    to: '/albums',        section: 'library' },
  randomAlbums: { icon: Dices,      labelKey: 'sidebar.randomAlbums', to: '/random-albums', section: 'library' },
  artists:      { icon: Users,      labelKey: 'sidebar.artists',      to: '/artists',       section: 'library' },
  genres:       { icon: Tags,       labelKey: 'sidebar.genres',       to: '/genres',        section: 'library' },
  randomMix:    { icon: Shuffle,    labelKey: 'sidebar.randomMix',    to: '/random-mix',    section: 'library' },
  favorites:    { icon: Heart,       labelKey: 'sidebar.favorites',    to: '/favorites',      section: 'library' },
  playlists:    { icon: ListMusic,   labelKey: 'sidebar.playlists',    to: '/playlists',      section: 'library' },
  mostPlayed:   { icon: TrendingUp,  labelKey: 'sidebar.mostPlayed',   to: '/most-played',    section: 'library' },
  radio:        { icon: Cast,        labelKey: 'sidebar.radio',        to: '/radio',          section: 'library' },
  folderBrowser: { icon: FolderOpen,  labelKey: 'sidebar.folderBrowser', to: '/folders',        section: 'library' },
  statistics:   { icon: BarChart3,   labelKey: 'sidebar.statistics',   to: '/statistics',     section: 'system'  },
  help:         { icon: HelpCircle, labelKey: 'sidebar.help',         to: '/help',          section: 'system'  },
};


export default function Sidebar({
  isCollapsed = false,
  toggleCollapse,
}: {
  isCollapsed?: boolean;
  toggleCollapse?: () => void;
}) {
  const { t } = useTranslation();
  const isPlaying   = usePlayerStore(s => s.isPlaying);
  const currentTrack = usePlayerStore(s => s.currentTrack);
  const offlineJobs = useOfflineJobStore(s => s.jobs);
  const cancelAllDownloads = useOfflineJobStore(s => s.cancelAllDownloads);
  const activeJobs = offlineJobs.filter(j => j.status === 'queued' || j.status === 'downloading');
  const offlineAlbums = useOfflineStore(s => s.albums);
  const serverId = useAuthStore(s => s.activeServerId ?? '');
  const isLoggedIn = useAuthStore(s => s.isLoggedIn);
  const musicFolders = useAuthStore(s => s.musicFolders);
  const musicLibraryFilterByServer = useAuthStore(s => s.musicLibraryFilterByServer);
  const setMusicLibraryFilter = useAuthStore(s => s.setMusicLibraryFilter);
  const hasOfflineContent = Object.values(offlineAlbums).some(a => a.serverId === serverId);
  const sidebarItems = useSidebarStore(s => s.items);
  const [libraryDropdownOpen, setLibraryDropdownOpen] = useState(false);
  const [dropdownRect, setDropdownRect] = useState({ top: 0, left: 0, width: 0 });
  const libraryTriggerRef = useRef<HTMLButtonElement>(null);
  const showLibraryPicker = !isCollapsed && isLoggedIn && musicFolders.length > 1;

  const filterId = serverId ? (musicLibraryFilterByServer[serverId] ?? 'all') : 'all';
  const selectedFolderName =
    filterId === 'all' ? null : musicFolders.find(f => f.id === filterId)?.name ?? null;
  const libraryTriggerPlain = filterId === 'all';

  const updateDropdownPosition = useCallback(() => {
    const el = libraryTriggerRef.current;
    if (!el) return;
    const r = el.getBoundingClientRect();
    setDropdownRect({
      top: r.bottom + 4,
      left: r.left,
      width: r.width,
    });
  }, []);

  useLayoutEffect(() => {
    if (!libraryDropdownOpen) return;
    updateDropdownPosition();
    const onWin = () => updateDropdownPosition();
    window.addEventListener('resize', onWin);
    window.addEventListener('scroll', onWin, true);
    return () => {
      window.removeEventListener('resize', onWin);
      window.removeEventListener('scroll', onWin, true);
    };
  }, [libraryDropdownOpen, updateDropdownPosition]);

  useEffect(() => {
    if (!libraryDropdownOpen) return;
    const onDown = (e: MouseEvent) => {
      const t = e.target as Node;
      if (libraryTriggerRef.current?.contains(t)) return;
      const panel = document.querySelector('.nav-library-dropdown-panel');
      if (panel?.contains(t)) return;
      setLibraryDropdownOpen(false);
    };
    const onKey = (e: KeyboardEvent) => {
      if (e.key === 'Escape') setLibraryDropdownOpen(false);
    };
    document.addEventListener('mousedown', onDown);
    document.addEventListener('keydown', onKey);
    return () => {
      document.removeEventListener('mousedown', onDown);
      document.removeEventListener('keydown', onKey);
    };
  }, [libraryDropdownOpen]);

  const pickLibrary = (id: 'all' | string) => {
    setMusicLibraryFilter(id);
    setLibraryDropdownOpen(false);
  };

  // Resolve ordered, visible items per section from store config
  const visibleLibrary = sidebarItems
    .filter(cfg => cfg.visible && ALL_NAV_ITEMS[cfg.id]?.section === 'library')
    .map(cfg => ALL_NAV_ITEMS[cfg.id]);
  const visibleSystem = sidebarItems
    .filter(cfg => cfg.visible && ALL_NAV_ITEMS[cfg.id]?.section === 'system')
    .map(cfg => ALL_NAV_ITEMS[cfg.id]);


  return (
    <aside className={`sidebar animate-slide-in ${isCollapsed ? 'collapsed' : ''}`}>
      <div className="sidebar-brand">
        {isCollapsed
          ? <PSmallLogo style={{ height: '32px', width: 'auto' }} />
          : <PsysonicLogo style={{ height: '28px', width: 'auto' }} />
        }
      </div>

      <button
        className="collapse-btn"
        onClick={toggleCollapse}
        data-tooltip={isCollapsed ? t('sidebar.expand') : t('sidebar.collapse')}
        data-tooltip-pos="right"
      >
        {isCollapsed ? <PanelLeft size={14} /> : <PanelLeftClose size={14} />}
      </button>

      <nav className="sidebar-nav" aria-label="Main navigation">
        {!isCollapsed && (showLibraryPicker ? (
          <>
            <button
              ref={libraryTriggerRef}
              type="button"
              className={`nav-library-scope-trigger ${libraryTriggerPlain ? 'nav-library-scope-trigger--plain' : ''} ${libraryDropdownOpen ? 'nav-library-scope-trigger--open' : ''}`}
              onClick={() => {
                setLibraryDropdownOpen(o => !o);
              }}
              aria-label={t('sidebar.libraryScope')}
              aria-expanded={libraryDropdownOpen}
              aria-haspopup="listbox"
              data-tooltip={libraryDropdownOpen ? undefined : t('sidebar.libraryScope')}
              data-tooltip-pos="bottom"
            >
              {!libraryTriggerPlain ? (
                <Music2 size={16} className="nav-library-scope-icon" strokeWidth={2} aria-hidden />
              ) : null}
              <div className="nav-library-scope-text">
                <span className="nav-library-scope-title">{t('sidebar.library')}</span>
                {selectedFolderName ? (
                  <span className="nav-library-scope-subtitle" data-tooltip={selectedFolderName} data-tooltip-pos="right">
                    {selectedFolderName}
                  </span>
                ) : null}
              </div>
              <ChevronDown size={16} strokeWidth={2.25} className="nav-library-scope-chevron" aria-hidden />
            </button>
            {libraryDropdownOpen &&
              createPortal(
                <div
                  className={`nav-library-dropdown-panel${musicFolders.length > 10 ? ' nav-library-dropdown-panel--many-libraries' : ''}`}
                  role="listbox"
                  aria-label={t('sidebar.libraryScope')}
                  style={{
                    position: 'fixed',
                    top: dropdownRect.top,
                    left: dropdownRect.left,
                    width: dropdownRect.width,
                    minWidth: dropdownRect.width,
                    maxWidth: dropdownRect.width,
                    boxSizing: 'border-box',
                  }}
                >
                  <button
                    type="button"
                    role="option"
                    aria-selected={filterId === 'all'}
                    className={`nav-library-dropdown-item ${filterId === 'all' ? 'nav-library-dropdown-item--selected' : ''}`}
                    onClick={() => pickLibrary('all')}
                  >
                    <span className="nav-library-dropdown-item-label">{t('sidebar.allLibraries')}</span>
                    {filterId === 'all' ? <Check size={16} className="nav-library-dropdown-check" strokeWidth={2.5} /> : <span className="nav-library-dropdown-check-spacer" />}
                  </button>
                  {musicFolders.map(f => (
                    <button
                      key={f.id}
                      type="button"
                      role="option"
                      aria-selected={filterId === f.id}
                      className={`nav-library-dropdown-item ${filterId === f.id ? 'nav-library-dropdown-item--selected' : ''}`}
                      onClick={() => pickLibrary(f.id)}
                    >
                      <span className="nav-library-dropdown-item-label">{f.name}</span>
                      {filterId === f.id ? <Check size={16} className="nav-library-dropdown-check" strokeWidth={2.5} /> : <span className="nav-library-dropdown-check-spacer" />}
                    </button>
                  ))}
                </div>,
                document.body
              )}
          </>
        ) : (
          <span className="nav-section-label">{t('sidebar.library')}</span>
        ))}
        {visibleLibrary.map(item => (
          <NavLink
            key={item.to}
            to={item.to}
            end={item.to === '/'}
            className={({ isActive }) => `nav-link ${isActive ? 'active' : ''}`}
            data-tooltip={isCollapsed ? t(item.labelKey) : undefined}
            data-tooltip-pos="bottom"
          >
            <item.icon size={isCollapsed ? 22 : 18} />
            {!isCollapsed && <span>{t(item.labelKey)}</span>}
          </NavLink>
        ))}

        {/* Now Playing — fixed, always visible */}
        <NavLink
          to="/now-playing"
          className={({ isActive }) => `nav-link nav-link-nowplaying ${isActive ? 'active' : ''}`}
          data-tooltip={isCollapsed ? t('sidebar.nowPlaying') : undefined}
          data-tooltip-pos="bottom"
          style={{ marginTop: 'auto' }}
        >
          <span className="nav-np-icon-wrap">
            <AudioLines size={isCollapsed ? 22 : 18} />
            {isPlaying && currentTrack && <span className="nav-np-dot" />}
          </span>
          {!isCollapsed && <span>{t('sidebar.nowPlaying')}</span>}
        </NavLink>

        {hasOfflineContent && (
          <NavLink
            to="/offline"
            className={({ isActive }) => `nav-link nav-link-offline ${isActive ? 'active' : ''}`}
            data-tooltip={isCollapsed ? t('sidebar.offlineLibrary') : undefined}
            data-tooltip-pos="bottom"
          >
            <HardDriveDownload size={isCollapsed ? 22 : 18} />
            {!isCollapsed && <span>{t('sidebar.offlineLibrary')}</span>}
          </NavLink>
        )}

        {visibleSystem.length > 0 && !isCollapsed && <span className="nav-section-label">{t('sidebar.system')}</span>}
        {visibleSystem.map(item => (
          <NavLink
            key={item.to}
            to={item.to}
            className={({ isActive }) => `nav-link ${isActive ? 'active' : ''}`}
            data-tooltip={isCollapsed ? t(item.labelKey) : undefined}
            data-tooltip-pos="bottom"
          >
            <item.icon size={isCollapsed ? 22 : 18} />
            {!isCollapsed && <span>{t(item.labelKey)}</span>}
          </NavLink>
        ))}
        <NavLink
          to="/settings"
          className={({ isActive }) => `nav-link ${isActive ? 'active' : ''}`}
          data-tooltip={isCollapsed ? t('sidebar.settings') : undefined}
          data-tooltip-pos="bottom"
        >
          <Settings size={isCollapsed ? 22 : 18} />
          {!isCollapsed && <span>{t('sidebar.settings')}</span>}
        </NavLink>

        {activeJobs.length > 0 && (
          <div
            className={`sidebar-offline-queue ${isCollapsed ? 'sidebar-offline-queue--collapsed' : ''}`}
            data-tooltip={isCollapsed ? t('sidebar.downloadingTracks', { n: activeJobs.length }) : undefined}
            data-tooltip-pos="right"
          >
            <HardDriveDownload size={isCollapsed ? 18 : 14} className="spin-slow" />
            {!isCollapsed && (
              <span>{t('sidebar.downloadingTracks', { n: activeJobs.length })}</span>
            )}
            <button
              className="sidebar-offline-cancel"
              onClick={cancelAllDownloads}
              data-tooltip={t('sidebar.cancelDownload')}
              data-tooltip-pos="right"
              aria-label={t('sidebar.cancelDownload')}
            >
              <X size={12} />
            </button>
          </div>
        )}
      </nav>
    </aside>
  );
}