import React from 'react';
import { Button } from '@/components/ui/button';
import { Link } from 'react-router-dom';
import { Sheet, SheetContent, SheetHeader, SheetTitle, SheetTrigger } from '@/components/ui/sheet';
import AppearanceToggleDropdown from '@/components/appearance-dropdown';
import { Settings, ChevronDown } from 'lucide-react';
import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible';

export default function Header({ title = '' }: { title?: string }) {
  return (
    <div className="sticky top-0 z-20 flex items-center justify-between border-b bg-white/70 px-4 py-2 backdrop-blur dark:bg-black/40">
      <div className="font-semibold">{title}</div>
      <div className="flex items-center gap-2">
        <AppearanceToggleDropdown />
        <SettingsSheet />
      </div>
    </div>
  );
}

function SettingsSheet() {
  return (
    <Sheet>
      <SheetTrigger asChild>
        <Button variant="ghost" size="icon" className="h-9 w-9 rounded-md">
          <Settings className="h-5 w-5" />
          <span className="sr-only">Einstellungen öffnen</span>
        </Button>
      </SheetTrigger>
      <SheetContent side="right" className="w-80 sm:w-96">
        <SheetHeader>
          <SheetTitle>Einstellungen</SheetTitle>
        </SheetHeader>
        <div className="mt-4 space-y-4">
          <Collapsible defaultOpen>
            <div className="flex items-center justify-between">
              <div className="text-sm font-medium">Cache</div>
              <CollapsibleTrigger asChild>
                <Button variant="ghost" size="sm" className="h-7 px-2">
                  <ChevronDown className="h-4 w-4" />
                </Button>
              </CollapsibleTrigger>
            </div>
            <CollapsibleContent>
              <div className="mt-2">
                <ClearCacheButton />
              </div>
            </CollapsibleContent>
          </Collapsible>

          <Collapsible defaultOpen>
            <div className="flex items-center justify-between">
              <div className="text-sm font-medium">Rechtliches</div>
              <CollapsibleTrigger asChild>
                <Button variant="ghost" size="sm" className="h-7 px-2">
                  <ChevronDown className="h-4 w-4" />
                </Button>
              </CollapsibleTrigger>
            </div>
            <CollapsibleContent>
              <ul className="mt-2 list-disc pl-5 text-sm">
                <li><Link to="/legal/impressum" className="underline">Impressum</Link></li>
                <li><Link to="/legal/datenschutz" className="underline">Datenschutz</Link></li>
                <li><Link to="/legal/agb" className="underline">AGB</Link></li>
              </ul>
            </CollapsibleContent>
          </Collapsible>
        </div>
      </SheetContent>
    </Sheet>
  );
}

function ClearCacheButton() {
  const [busy, setBusy] = React.useState(false);
  const [done, setDone] = React.useState(false);

  async function clearAll() {
    setBusy(true); setDone(false);
    try {
      // Clear CacheStorage
      if ('caches' in window) {
        const keys = await caches.keys();
        await Promise.all(keys.map((k) => caches.delete(k)));
      }
      // Clear known IndexedDB dbs (best-effort)
      if ('indexedDB' in window) {
        try { await new Promise((res, rej) => { const r = indexedDB.deleteDatabase('upload-queue'); r.onsuccess=()=>res(null); r.onerror=()=>res(null); }); } catch {}
      }
      setDone(true);
    } finally {
      setBusy(false);
      setTimeout(() => setDone(false), 2500);
    }
  }

  return (
    <div className="mt-2">
      <Button variant="secondary" onClick={clearAll} disabled={busy}>
        {busy ? 'Leere Cache…' : 'Cache leeren'}
      </Button>
      {done && <div className="mt-2 text-xs text-muted-foreground">Cache gelöscht.</div>}
    </div>
  );
}