import { useEffect, useRef, useState } from 'react';
import { Search, X, Command, ChevronRight, Wifi, WifiOff, Menu } from 'lucide-react';
import { useNavigate, useRouterState } from '@tanstack/react-router';
import { useQuery } from '@tanstack/react-query';
import { fetchHealthStatus } from '../services/healthService';

interface TopBarProps {
  onToggleCommandPalette: () => void;
  onToggleNavigation: () => void;
  navigationOpen: boolean;
}

/** Page title map for breadcrumbs */
const PAGE_TITLES: Record<string, string> = {
  '/': 'Home',
  '/tracks': 'Songs',
  '/albums': 'Albums',
  '/artists': 'Artists',
  '/genres': 'Genres',
  '/vibe': 'Vibe',
  '/discover': 'Discover',
  '/search': 'Search',
  '/settings': 'Settings',
  '/quarantine': 'Quarantine',
  '/jobs': 'Jobs',
};

function Breadcrumbs({ pathname }: { pathname: string }) {
  // Handle detail pages
  const segments = pathname.split('/').filter(Boolean);

  if (segments.length <= 1) {
    const title = PAGE_TITLES[pathname] ?? 'Muzick';
    return (
      <span className="text-sm font-medium text-text truncate">{title}</span>
    );
  }

  // For /albums/$id or /artists/$id
  const parentPath = `/${segments[0]}`;
  const parentTitle = PAGE_TITLES[parentPath] ?? segments[0];
  return (
    <div className="flex items-center gap-1.5 text-sm min-w-0">
      <span className="text-secondary truncate">{parentTitle}</span>
      <ChevronRight size={12} className="text-muted flex-none" />
      <span className="text-text font-medium truncate">Details</span>
    </div>
  );
}

function ConnectionStatus() {
  const { data, isError } = useQuery({
    queryKey: ['health'],
    queryFn: () => fetchHealthStatus(),
    refetchInterval: 30_000,
    staleTime: 10_000,
    retry: 1,
  });

  const healthy = data?.postgres === 'ok';

  return (
    <div
      className={`flex items-center gap-1.5 rounded-md px-2 py-1 text-[11px] font-medium ${
        healthy
          ? 'text-green bg-green/10'
          : isError
            ? 'text-red bg-red/10'
            : 'text-muted bg-surface0'
      }`}
      title={
        healthy
          ? 'All systems healthy'
          : isError
            ? 'Backend unreachable'
            : 'Checking…'
      }
    >
      {healthy ? (
        <Wifi size={12} className="text-green" />
      ) : (
        <WifiOff size={12} className="text-red" />
      )}
      <span className="hidden sm:inline">
        {healthy ? 'Connected' : isError ? 'Offline' : '…'}
      </span>
    </div>
  );
}

export function TopBar({ onToggleCommandPalette, onToggleNavigation, navigationOpen }: TopBarProps) {
  const navigate = useNavigate();
  const inputRef = useRef<HTMLInputElement>(null);
  const { pathname, urlQuery } = useRouterState({
    select: (s) => ({
      pathname: s.location.pathname,
      urlQuery: ((s.location.search as Record<string, unknown>)?.q as string | undefined) ?? '',
    }),
  });
  const onSearchPage = pathname === '/search';
  const [q, setQ] = useState(urlQuery);

  useEffect(() => {
    if (onSearchPage) setQ(urlQuery);
  }, [urlQuery, onSearchPage]);

  // Debounced URL push on search page
  useEffect(() => {
    if (!onSearchPage) return;
    const id = setTimeout(() => {
      const next = q.trim();
      if (next !== urlQuery) {
        void navigate({ to: '/search', search: { q: next || undefined } as any, replace: true });
      }
    }, 250);
    return () => clearTimeout(id);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [q, onSearchPage]);

  // Global "/" shortcut: focus search
  useEffect(() => {
    const onKey = (e: KeyboardEvent) => {
      if (e.key !== '/' || e.metaKey || e.ctrlKey || e.altKey) return;
      const el = document.activeElement;
      const tag = el?.tagName;
      if (tag === 'INPUT' || tag === 'TEXTAREA' || (el as HTMLElement)?.isContentEditable) return;
      e.preventDefault();
      inputRef.current?.focus();
      inputRef.current?.select();
    };
    window.addEventListener('keydown', onKey);
    return () => window.removeEventListener('keydown', onKey);
  }, []);

  const handleSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    if (q.trim()) void navigate({ to: '/search', search: { q: q.trim() } as any });
  };

  return (
    <header className="glass h-12 border-b border-border flex items-center px-2.5 gap-2 sm:px-3 sm:gap-3 shrink-0 z-20">
      <button
        type="button"
        onClick={onToggleNavigation}
        className="rounded-md p-2 text-muted hover:bg-surface0 hover:text-text lg:hidden"
        aria-label={navigationOpen ? 'Close navigation' : 'Open navigation'}
        aria-expanded={navigationOpen}
      >
        {navigationOpen ? <X size={18} /> : <Menu size={18} />}
      </button>
      {/* Breadcrumbs */}
      <div className="hidden sm:flex items-center min-w-0 flex-none max-w-[200px]">
        <Breadcrumbs pathname={pathname} />
      </div>

      {/* Universal search */}
      <form onSubmit={handleSubmit} className="min-w-0 flex-1 max-w-md">
        <div className="relative group">
          <Search size={14} className="absolute left-2.5 top-1/2 -translate-y-1/2 text-muted pointer-events-none transition-colors group-focus-within:text-accent" />
          <input
            ref={inputRef}
            type="text"
            value={q}
            onChange={(e) => setQ(e.target.value)}
            placeholder="Search…"
            /* bg-bg2, not bg-surface0/70: Tailwind cannot alpha-modify these
               var() colors, so that class emitted nothing and the field fell
               back to the UA's white — a white pill in a warm dark room. */
            className="w-full bg-bg2 border border-border rounded-md pl-8 pr-8 py-1.5 text-xs text-text placeholder:text-muted outline-none focus:border-accent focus:bg-surface1 transition-colors"
          />
          {q ? (
            <button
              type="button"
              onClick={() => setQ('')}
              aria-label="Clear search"
              className="absolute right-1 top-1/2 -translate-y-1/2 rounded p-0.5 text-muted hover:text-text hover:bg-surface1 transition-colors"
            >
              <X size={12} />
            </button>
          ) : (
            <kbd className="absolute right-2 top-1/2 -translate-y-1/2 hidden sm:flex items-center rounded border border-border bg-surface1 px-1 py-0.5 text-[10px] font-medium text-muted pointer-events-none">
              /
            </kbd>
          )}
        </div>
      </form>

      {/* Right section */}
      <div className="flex items-center gap-1.5 sm:gap-2 flex-none">
        {/* Connection status */}
        <ConnectionStatus />

        {/* Command palette toggle */}
        <button
          onClick={onToggleCommandPalette}
          className="flex items-center gap-1.5 rounded-md border border-border bg-surface0 px-2 py-1 text-[11px] font-medium text-muted hover:text-text hover:bg-surface1 transition-colors"
          title="Command palette (Ctrl+K)"
        >
          <Command size={12} />
          <span className="hidden sm:inline">Commands</span>
          <kbd className="hidden md:inline rounded border border-border bg-bg2 px-1 text-[10px] text-muted">
            Ctrl+K
          </kbd>
        </button>
      </div>
    </header>
  );
}