/* ============================================================
   BAN YARO — Gassi-Treffen
   Treffen entdecken, erstellen, beitreten
   ============================================================ */

window.Page_walks = (() => {

  // ----------------------------------------------------------
  // OFFLINE-CACHE
  // ----------------------------------------------------------
  const _CACHE_KEY   = 'by_walks_cache';
  const _PENDING_KEY = 'by_walks_pending';

  function _getPending() {
    try { return JSON.parse(localStorage.getItem(_PENDING_KEY) || '[]'); } catch { return []; }
  }
  function _setPending(list) {
    try { localStorage.setItem(_PENDING_KEY, JSON.stringify(list)); } catch {}
  }
  function _addPending(data) {
    const list = _getPending();
    const entry = { ...data, id: `pending_${Date.now()}`, _isPending: true,
                    created_at: new Date().toISOString(),
                    teilnehmer_count: 1, max_teilnehmer: data.max_teilnehmer || 10,
                    status: 'open' };
    list.push(entry);
    _setPending(list);
    return entry;
  }
  async function _syncPending() {
    if (!navigator.onLine) return;
    const list = _getPending();
    if (!list.length) return;
    let ok = 0;
    for (const item of [...list]) {
      try {
        const { id: _pid, _isPending, created_at: _ca, teilnehmer_count: _tc, status: _st, ...payload } = item;
        await API.walks.create(payload);
        _setPending(_getPending().filter(x => x.id !== item.id));
        ok++;
      } catch {}
    }
    if (ok > 0) { UI.toast.success(`${ok} Treffen synchronisiert.`); _loadData(); }
  }
  window.addEventListener('online', _syncPending);

  let _container     = null;
  let _appState      = null;
  let _data          = [];
  let _view          = 'liste';     // 'liste' | 'karte'
  let _tab           = 'treffen';   // 'treffen' | 'challenge' | 'stamm'
  let _map           = null;
  let _markers       = [];
  let _userPos       = null;
  let _challengeData = null;
  let _gassiZeiten   = [];

  // _esc ersetzt durch UI.escape()

  // Datum deutsch formatieren: "2026-04-20" → "Sonntag, 20. April 2026"
  // Hinweis: UI.time.format() liefert kein weekday — daher lokale Funktion beibehalten
  function _fmtDate(iso) {
    if (!iso) return '—';
    const d = new Date(iso + 'T12:00:00');
    return d.toLocaleDateString('de-DE', { weekday: 'long', day: 'numeric', month: 'long', year: 'numeric' });
  }

  // Datum kurz: "So, 20.04." — UI.time.formatShort() gibt "20. Apr." ohne Wochentag
  // Hinweis: Format nicht äquivalent zu UI.time.formatShort() — daher lokal beibehalten
  function _fmtDateShort(iso) {
    if (!iso) return '—';
    const d = new Date(iso + 'T12:00:00');
    return d.toLocaleDateString('de-DE', { weekday: 'short', day: '2-digit', month: '2-digit' });
  }

  function _isToday(iso) {
    return iso === new Date().toISOString().slice(0, 10);
  }

  function _isPast(iso) {
    return iso < new Date().toISOString().slice(0, 10);
  }

  function _sourceIcon(source) {
    if (source === 'places') return 'star';
    if (source === 'osm')    return 'map-pin';
    return 'map-trifold';
  }

  // ----------------------------------------------------------
  // INIT
  // ----------------------------------------------------------
  async function init(container, appState) {
    _container = container;
    _appState  = appState;
    _render();
    // Desktop: Leaflet sofort laden damit Karte bereit ist wenn Daten kommen
    if (window.innerWidth >= 1024) UI.loadLeaflet();
    try { _userPos = await API.getLocation(); } catch {}
    _loadData();
  }

  function refresh() {
    _loadData();
    if (_tab === 'challenge') _loadChallenge();
    if (_tab === 'stamm')     _loadGassiZeiten();
  }
  function onDogChange() {}
  function openNew() {
    if (_tab === 'challenge') { _showSubmitForm(); return; }
    if (_tab === 'stamm')     { _showGassiZeitForm(); return; }
    _showCreateForm();
  }

  // ----------------------------------------------------------
  // RENDER — Grundstruktur
  // ----------------------------------------------------------
  function _render() {
    _container.innerHTML = `
      <div class="walks-layout">

        <!-- Tab-Bar -->
        <div class="by-tabs" id="walks-tab-bar" style="padding:var(--space-3) var(--space-4) 0">
          <button class="by-tab active" data-tab="treffen">${UI.icon('paw-print')} Treffen</button>
          <button class="by-tab" data-tab="challenge">${UI.icon('camera')} Challenge</button>
          <button class="by-tab" data-tab="stamm">${UI.icon('clock')} Stamm-Gassis</button>
        </div>

        <!-- Tab: Treffen -->
        <div id="walks-tab-treffen" class="walks-tab-panel">
          <!-- Toolbar -->
          <div class="by-toolbar">
            <div class="walks-view-toggle" id="walks-view-toggle">
              <button class="walks-view-btn active" data-view="liste">${UI.icon('list')} Liste</button>
              <button class="walks-view-btn" data-view="karte">${UI.icon('map-trifold')} Karte</button>
            </div>
            <button class="btn btn-primary btn-sm" id="walks-create-btn">${UI.icon('plus')} Treffen planen</button>
          </div>
          <!-- Liste -->
          <div id="walks-list-view" class="walks-content">
            <div id="walks-list">
              <p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Lädt…</p>
            </div>
          </div>
          <!-- Karte (auf Desktop immer sichtbar via CSS) -->
          <div id="walks-map-view" class="walks-content"
               style="${window.innerWidth >= 1024 ? '' : 'display:none'}">
            <div id="walks-map" class="walks-map"></div>
          </div>
        </div>

        <!-- Tab: Challenge -->
        <div id="walks-tab-challenge" class="walks-tab-panel hidden">
          <div id="challenge-content">
            <p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Lädt…</p>
          </div>
        </div>

        <!-- Tab: Stamm-Gassis -->
        <div id="walks-tab-stamm" class="walks-tab-panel hidden">
          <div class="by-toolbar">
            <span style="font-weight:600;color:var(--c-text)">${UI.icon('clock')} Stamm-Gassi-Zeiten</span>
            <button class="btn btn-primary btn-sm" id="gassi-zeit-add-btn">${UI.icon('plus')} Meine Zeit eintragen</button>
          </div>
          <div id="gassi-zeiten-content">
            <p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Lädt…</p>
          </div>
        </div>

      </div>
    `;

    // Tab-Bar Events
    document.getElementById('walks-tab-bar').addEventListener('click', e => {
      const btn = e.target.closest('.by-tab');
      if (!btn) return;
      _switchTab(btn.dataset.tab);
    });

    document.getElementById('walks-view-toggle').addEventListener('click', e => {
      const btn = e.target.closest('.walks-view-btn');
      if (!btn) return;
      _switchView(btn.dataset.view);
    });

    document.getElementById('walks-create-btn').addEventListener('click', () => {
      if (!_appState.user) {
        UI.toast.warning('Bitte zuerst anmelden.');
        App.navigate('settings');
        return;
      }
      _showCreateForm();
    });

    document.getElementById('gassi-zeit-add-btn').addEventListener('click', () => {
      if (!_appState.user) { UI.toast.warning('Bitte zuerst anmelden.'); App.navigate('settings'); return; }
      _showGassiZeitForm();
    });
  }

  function _switchTab(tab) {
    _tab = tab;
    document.querySelectorAll('.by-tab').forEach(b =>
      b.classList.toggle('active', b.dataset.tab === tab));
    document.querySelectorAll('.walks-tab-panel').forEach(p => p.style.display = 'none');
    const panel = document.getElementById(`walks-tab-${tab}`);
    if (panel) panel.style.display = '';

    if (tab === 'challenge' && !_challengeData) _loadChallenge();
    if (tab === 'stamm'     && !_gassiZeiten.length) _loadGassiZeiten();
  }

  function _switchView(view) {
    _view = view;
    document.querySelectorAll('.walks-view-btn').forEach(b =>
      b.classList.toggle('active', b.dataset.view === view));

    // Desktop: beide Panels bleiben via CSS sichtbar
    if (window.innerWidth >= 1024) return;

    document.getElementById('walks-list-view').style.display = view === 'liste' ? '' : 'none';
    document.getElementById('walks-map-view').style.display  = view === 'karte' ? '' : 'none';

    if (view === 'karte') {
      _initMap().then(() => {
        setTimeout(() => _map?.invalidateSize(), 150);
        setTimeout(() => _map?.invalidateSize(), 400);
      });
    }
  }

  // ----------------------------------------------------------
  // Daten laden
  // ----------------------------------------------------------
  async function _loadData() {
    const pending = _getPending();
    try {
      const fetched = await API.walks.list(
        _userPos?.lat ?? null,
        _userPos?.lon ?? null
      );
      try { localStorage.setItem(_CACHE_KEY, JSON.stringify({ ts: Date.now(), data: fetched })); } catch {}
      _data = [...pending, ...fetched];
      _renderList();
      _renderMarkers();
      if (window.innerWidth >= 1024) {
        _initMap().then(() => {
          setTimeout(() => _map?.invalidateSize(), 150);
          setTimeout(() => _map?.invalidateSize(), 400);
        });
      }
    } catch {
      try {
        const raw = localStorage.getItem(_CACHE_KEY);
        if (raw) {
          _data = [...pending, ...(JSON.parse(raw).data || [])];
          _renderList();
          _renderMarkers();
          UI.toast.info('Offline — zeige zuletzt geladene Treffen.');
          return;
        }
      } catch {}
      _data = pending;
      if (pending.length) { _renderList(); _renderMarkers(); return; }
      UI.toast.error('Treffen konnten nicht geladen werden.');
    }
  }

  // ----------------------------------------------------------
  // Liste rendern
  // ----------------------------------------------------------
  function _renderList() {
    const el = document.getElementById('walks-list');
    if (!el) return;

    if (!_data.length) {
      el.innerHTML = `
        <div style="text-align:center;padding:var(--space-10) var(--space-4)">
          <div style="font-size:3rem;margin-bottom:var(--space-3)">${UI.icon('dog')}</div>
          <p class="text-secondary">Noch keine Treffen in deiner Nähe.</p>
          <button class="btn btn-primary mt-4" id="walks-first-btn">
            Erstes Treffen planen
          </button>
        </div>`;
      document.getElementById('walks-first-btn')?.addEventListener('click', _showCreateForm);
      return;
    }

    // Heute + zukünftige Treffen
    const heute    = _data.filter(w => _isToday(w.datum));
    const upcoming = _data.filter(w => !_isToday(w.datum) && !_isPast(w.datum));

    let html = '';

    if (heute.length) {
      html += `<div class="by-section-label">${UI.icon('star')} Heute</div>`;
      html += heute.map(w => _walkCardHTML(w)).join('');
    }

    if (upcoming.length) {
      html += `<div class="by-section-label">${UI.icon('calendar-dots')} Demnächst</div>`;
      html += upcoming.map(w => _walkCardHTML(w)).join('');
    }

    el.innerHTML = `<div class="walks-list-inner">${html}</div>`;

    el.querySelectorAll('.walks-card').forEach(card => {
      card.addEventListener('click', () => _openDetail(parseInt(card.dataset.id)));
    });

    el.querySelectorAll('.wk-note-btn').forEach(btn => {
      btn.addEventListener('click', e => {
        e.stopPropagation();
        UI.noteModal(
          'walk',
          parseInt(btn.dataset.wkNoteId),
          btn.dataset.wkNoteLabel,
          btn.dataset.wkNoteOrt || null
        );
      });
    });
  }

  function _walkCardHTML(w) {
    const isOwn    = _appState.user?.id === w.user_id;
    const isFull   = w.status === 'voll' || w.teilnehmer_count >= w.max_teilnehmer;
    const today    = _isToday(w.datum);
    const spots    = w.max_teilnehmer - w.teilnehmer_count;

    return `
      <div class="walks-card ${today ? 'walks-card--today' : ''}" data-id="${w.id}">
        <div class="walks-card-date">
          <div class="walks-card-day">${_fmtDateShort(w.datum)}</div>
          <div class="walks-card-time">${w.uhrzeit}</div>
        </div>
        <div class="walks-card-body">
          <div class="walks-card-title">${UI.escape(w.titel)}</div>
          ${w.ort_name ? `<div class="walks-card-ort">${UI.icon('map-pin')} ${UI.escape(w.ort_name)}</div>` : ''}
          <div class="walks-card-meta">
            <span class="walks-badge ${isFull ? 'walks-badge--full' : 'walks-badge--open'}">
              ${isFull ? '🔴 Voll' : `🟢 ${spots} Platz${spots !== 1 ? 'e' : ''} frei`}
            </span>
            <span class="walks-badge">${UI.icon('paw-print')} ${w.teilnehmer_count}/${w.max_teilnehmer}</span>
            ${isOwn ? '<span class="walks-badge walks-badge--own">Mein Treffen</span>' : ''}
            ${w._isPending ? `<span style="font-size:10px;color:var(--c-warning,#d97706);font-weight:600">⏳ Sync ausstehend</span>` : ''}
          </div>
        </div>
        <div style="display:flex;flex-direction:column;align-items:flex-end;gap:var(--space-1)">
          <div class="walks-card-arrow">›</div>
          ${_appState.user ? `<button class="btn-icon wk-note-btn"
                                data-wk-note-id="${w.id}"
                                data-wk-note-label="${UI.escape(w.titel + ' ' + w.datum)}"
                                data-wk-note-ort="${UI.escape(w.ort_name || '')}"
                                title="Notiz" style="color:var(--c-text-muted);font-size:var(--text-xs)">
                                ${UI.icon('note-pencil')}</button>` : ''}
        </div>
      </div>`;
  }

  // ----------------------------------------------------------
  // Leaflet + Karte
  // ----------------------------------------------------------
  async function _initMap() {
    const el = document.getElementById('walks-map');
    if (!el || _map) return;
    const center = _userPos ? [_userPos.lat, _userPos.lon] : [51.1657, 10.4515];
    _map = await UI.map.create('walks-map', { center, zoom: _userPos ? 12 : 6 });
    _renderMarkers();
  }

  function _renderMarkers() {
    if (!_map || !window.L) return;
    _markers.forEach(m => m.remove());
    _markers = [];
    _data.forEach(w => {
      if (!w.lat || !w.lon) return;
      const isFull = w.status === 'voll' || w.teilnehmer_count >= w.max_teilnehmer;
      const color  = _isToday(w.datum) ? 'var(--c-primary)' : (isFull ? '#6B7280' : '#22C55E');
      const m = UI.leafletMarker({ lat: w.lat, lon: w.lon, color, icon: UI.icon('dog') })
        .addTo(_map)
        .bindTooltip(`${w.titel} · ${_fmtDateShort(w.datum)} ${w.uhrzeit}`, { direction: 'top', offset: [0,-16] })
        .on('click', () => _openDetail(w.id));
      _markers.push(m);
    });
    // Karte auf alle Marker zoomen damit alle Treffen sichtbar sind
    if (_markers.length === 1) {
      _map.setView(_markers[0].getLatLng(), 13);
    } else if (_markers.length > 1) {
      const group = L.featureGroup(_markers);
      _map.fitBounds(group.getBounds().pad(0.2));
    }
  }

  // ----------------------------------------------------------
  // RSVP-Status → Label + Farbe
  // ----------------------------------------------------------
  function _rsvpBadge(status) {
    if (status === 'yes')     return `<span class="walks-rsvp-badge walks-rsvp--yes">Zusage</span>`;
    if (status === 'maybe')   return `<span class="walks-rsvp-badge walks-rsvp--maybe">Vielleicht</span>`;
    if (status === 'no')      return `<span class="walks-rsvp-badge walks-rsvp--no">Absage</span>`;
    return `<span class="walks-rsvp-badge walks-rsvp--invited">Eingeladen</span>`;
  }

  function _avatarInitials(name) {
    const parts = (name || '?').trim().split(/\s+/);
    const initials = parts.length >= 2
      ? parts[0][0] + parts[parts.length - 1][0]
      : parts[0].slice(0, 2);
    return initials.toUpperCase();
  }

  function _invitationRowHTML(inv) {
    return `
      <div class="walks-invitation-row">
        <div class="walks-inv-avatar">${_avatarInitials(inv.user_name)}</div>
        <div class="walks-inv-info">
          <div class="walks-inv-name">${UI.escape(inv.user_name)}</div>
          ${inv.hunde ? `<div class="walks-inv-hunde">${UI.icon('dog')} ${UI.escape(inv.hunde)}</div>` : ''}
        </div>
        <div class="walks-inv-badge">${_rsvpBadge(inv.status)}</div>
      </div>`;
  }

  // ----------------------------------------------------------
  // Detail-Modal
  // ----------------------------------------------------------
  async function _openDetail(walkId) {
    let walk, participantData;
    try {
      walk = await API.walks.get(walkId);
      if (_appState.user) {
        try { participantData = await API.walks.participants(walkId); } catch {}
      }
    } catch (err) {
      UI.toast.error(err.message);
      return;
    }

    const isOwn      = _appState.user?.id === walk.user_id;
    const isJoined   = walk.teilnehmer?.some(t => t.user_id === _appState.user?.id);
    const isFull     = walk.status === 'voll' || walk.teilnehmer_count >= walk.max_teilnehmer;
    const isPast     = _isPast(walk.datum);
    const spots      = walk.max_teilnehmer - walk.teilnehmer_count;
    const myRsvp     = participantData?.my_rsvp ?? null;
    const isInvited  = !!myRsvp;
    const invitations = participantData?.invitations ?? [];

    // Teilnehmerliste mit Hundefotos
    const teilnehmerHTML = walk.teilnehmer?.length
      ? walk.teilnehmer.map(t => {
          const dogsHTML = (t.hunde_liste || []).map(d => {
            const av = d.foto_url
              ? `<img src="${UI.escape(d.foto_url)}" alt="${UI.escape(d.name)}"
                      style="width:28px;height:28px;border-radius:50%;object-fit:cover;flex-shrink:0;border:1.5px solid var(--c-border)">`
              : `<div style="width:28px;height:28px;border-radius:50%;background:var(--c-surface-2);
                             display:flex;align-items:center;justify-content:center;flex-shrink:0;border:1.5px solid var(--c-border)">
                   <svg class="ph-icon" style="width:14px;height:14px;color:var(--c-text-muted)" aria-hidden="true"><use href="/icons/phosphor.svg#dog"></use></svg>
                 </div>`;
            return `<div style="display:flex;align-items:center;gap:4px">
              ${av}
              <span class="text-xs-secondary">${UI.escape(d.name)}${d.rasse ? ` · ${UI.escape(d.rasse)}` : ''}</span>
            </div>`;
          }).join('');
          return `
            <div class="walks-participant">
              <div class="walks-inv-avatar walks-inv-avatar--sm">${_avatarInitials(t.user_name)}</div>
              <div class="flex-1-min">
                <div class="walks-participant-name">${UI.escape(t.user_name)}</div>
                ${dogsHTML ? `<div style="display:flex;flex-wrap:wrap;gap:var(--space-1);margin-top:4px">${dogsHTML}</div>` : ''}
              </div>
            </div>`;
        }).join('')
      : '';

    // Einladungsliste
    const invListHTML = invitations.length
      ? invitations.map(inv => _invitationRowHTML(inv)).join('')
      : `<p class="text-sm-muted">Noch keine Einladungen.</p>`;

    // RSVP-Section für eingeladene Nutzer
    const rsvpSectionHTML = (isInvited && !isOwn) ? `
      <div class="walks-rsvp-section" id="wd-rsvp-section">
        <div class="walks-detail-section-label">${UI.icon('check-circle')} Deine Antwort</div>
        <div class="walks-rsvp-buttons">
          <button type="button" class="walks-rsvp-btn ${myRsvp === 'yes' ? 'active' : ''}" data-rsvp="yes">
            ${UI.icon('check')} Zusagen
          </button>
          <button type="button" class="walks-rsvp-btn ${myRsvp === 'maybe' ? 'active' : ''}" data-rsvp="maybe">
            ${UI.icon('question')} Vielleicht
          </button>
          <button type="button" class="walks-rsvp-btn ${myRsvp === 'no' ? 'active' : ''}" data-rsvp="no">
            ${UI.icon('x')} Absagen
          </button>
        </div>
      </div>
    ` : '';

    const body = `
      <div class="walks-detail-header">
        <div class="walks-detail-date">
          ${_fmtDate(walk.datum)}<br>
          <strong>um ${walk.uhrzeit} Uhr</strong>
        </div>
        ${walk.ort_name ? `<div style="margin-top:var(--space-2);color:var(--c-text-secondary)">${UI.icon('map-pin')} ${UI.escape(walk.ort_name)}</div>` : ''}
        <div style="margin-top:var(--space-2);display:flex;gap:var(--space-2);flex-wrap:wrap">
          <span class="walks-badge ${isFull ? 'walks-badge--full' : 'walks-badge--open'}">
            ${isFull ? '🔴 Voll' : `🟢 ${spots} Platz${spots !== 1 ? 'e' : ''} frei`}
          </span>
          <span class="walks-badge">${UI.icon('paw-print')} ${walk.teilnehmer_count}/${walk.max_teilnehmer} Teilnehmer</span>
          ${isOwn ? '<span class="walks-badge walks-badge--own">Dein Treffen</span>' : ''}
        </div>
      </div>

      ${walk.beschreibung ? `
        <p style="margin:var(--space-4) 0;color:var(--c-text-secondary)">${UI.escape(walk.beschreibung)}</p>
      ` : ''}

      ${rsvpSectionHTML}

      <div class="walks-detail-section">
        <div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:var(--space-2)">
          <div class="walks-detail-section-label" style="margin-bottom:0">${UI.icon('users')} Einladungen</div>
          ${isOwn && !isPast ? `<button type="button" class="btn btn-secondary btn-sm" id="wd-invite-btn">${UI.icon('user-plus')} Einladen</button>` : ''}
        </div>
        <div id="wd-inv-list">${invListHTML}</div>
      </div>

      ${walk.teilnehmer?.length ? `
        <div class="walks-detail-section">
          <div class="walks-detail-section-label">${UI.icon('check-circle')} Beigetreten (${walk.teilnehmer_count}/${walk.max_teilnehmer})</div>
          ${teilnehmerHTML}
        </div>
      ` : ''}

      <div class="walks-detail-section">
        <div class="walks-detail-section-label">${UI.icon('star')} Bewertung</div>
        <div id="wd-rating-${walk.id}"></div>
      </div>

      <!-- Fotos nach dem Treffen -->
      <div class="walks-detail-section" id="wd-photos-section">
        <div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:var(--space-2)">
          <div class="walks-detail-section-label" style="margin-bottom:0">${UI.icon('images')} Fotos</div>
          ${(isPast || _isToday(walk.datum)) && (isJoined || isOwn) ? `
            <label style="cursor:pointer">
              <input type="file" id="wd-photo-input" accept="image/*" class="hidden">
              <span class="btn btn-secondary btn-sm">${UI.icon('camera')} Foto hinzufügen</span>
            </label>` : ''}
        </div>
        <div id="wd-photos-grid" style="display:grid;grid-template-columns:repeat(3,1fr);gap:4px;margin-top:var(--space-2)">
          ${(walk.photos || []).length === 0
            ? `<p style="grid-column:1/-1;color:var(--c-text-muted);font-size:var(--text-sm)">Noch keine Fotos.</p>`
            : (walk.photos || []).map(p => `
                <div style="position:relative;aspect-ratio:1">
                  <img src="${UI.escape(p.url)}" style="width:100%;height:100%;object-fit:cover;border-radius:var(--radius-sm);cursor:pointer"
                       data-lightbox-url="${UI.escape(p.url)}">
                  ${p.user_id === _appState.user?.id || isOwn ? `
                    <button type="button" class="wd-photo-del" data-photo-id="${p.id}"
                            style="position:absolute;top:3px;right:3px;background:rgba(0,0,0,.6);color:#fff;border:none;border-radius:50%;width:20px;height:20px;cursor:pointer;font-size:11px;display:flex;align-items:center;justify-content:center;padding:0">✕</button>
                  ` : ''}
                </div>`).join('')}
        </div>
      </div>

      <p style="color:var(--c-text-muted);font-size:0.8rem;margin-top:var(--space-4)">
        Veranstaltet von ${UI.escape(walk.veranstalter_name || 'Unbekannt')}
      </p>

      ${isOwn && !isPast ? `
        <div id="wd-cancel-wrap" class="mt-3">
          <button type="button" class="btn btn-ghost btn-sm" id="wd-cancel-walk"
                  style="color:var(--c-danger);width:100%">
            ${UI.icon('x-circle')} Treffen stornieren
          </button>
        </div>` : ''}

      ${isJoined && !isOwn ? `
        <div id="wd-leave-wrap" class="mt-3">
          <button type="button" class="btn btn-ghost btn-sm" id="wd-leave"
                  style="color:var(--c-danger);width:100%">
            ${UI.icon('sign-out')} Nicht mehr teilnehmen
          </button>
        </div>` : ''}
    `;

    let footer;
    if (isOwn) {
      footer = `
        <button type="button" class="btn btn-secondary flex-1" id="wd-edit">${UI.icon('pencil-simple')} Bearbeiten</button>
        <button type="button" class="btn btn-primary flex-1" id="wd-close">Schließen</button>
      `;
    } else if (!_appState.user) {
      footer = `
        <button type="button" class="btn btn-secondary flex-1" id="wd-close">Schließen</button>
        <button type="button" class="btn btn-primary flex-1" id="wd-login">Anmelden zum Beitreten</button>
      `;
    } else if (isJoined) {
      footer = `
        <button type="button" class="btn btn-primary flex-1" id="wd-close">Schließen</button>
      `;
    } else if (isPast || isFull) {
      footer = `<button type="button" class="btn btn-primary flex-1" id="wd-close">Schließen</button>`;
    } else {
      footer = `
        <button type="button" class="btn btn-secondary flex-1" id="wd-close">Schließen</button>
        <button type="button" class="btn btn-primary flex-1" id="wd-join">${UI.icon('dog')} Mitmachen</button>
      `;
    }

    UI.modal.open({ title: `${UI.icon('dog')} ${walk.titel}`, body, footer });

    // Bewertungskomponente initialisieren (nur nach abgelaufenem Treffen sinnvoll, aber immer anzeigen)
    UI.ratingStars({
      containerId: `wd-rating-${walk.id}`,
      targetType:  'walk',
      targetId:    walk.id,
      isLoggedIn:  !!_appState.user,
    });

    document.getElementById('wd-close')?.addEventListener('click', UI.modal.close);

    // Foto-Upload
    document.getElementById('wd-photo-input')?.addEventListener('change', async function() {
      if (!this.files.length) return;
      const file = this.files[0];
      // Client-Side-Kompression vor Upload (HEIC bleibt unverändert)
      const toUpload = await API.compressImage(file);
      const formData = new FormData();
      formData.append('file', toUpload);
      try {
        const photo = await API.walks.uploadPhoto(walk.id, formData);
        const grid = document.getElementById('wd-photos-grid');
        if (grid) {
          grid.querySelector('p')?.remove();
          const div = document.createElement('div');
          div.style.cssText = 'position:relative;aspect-ratio:1';
          div.innerHTML = `
            <img src="${UI.escape(photo.url)}" style="width:100%;height:100%;object-fit:cover;border-radius:var(--radius-sm);cursor:pointer"
                 data-lightbox-url="${UI.escape(photo.url)}">
            <button type="button" class="wd-photo-del" data-photo-id="${photo.id}"
                    style="position:absolute;top:3px;right:3px;background:rgba(0,0,0,.6);color:#fff;border:none;border-radius:50%;width:20px;height:20px;cursor:pointer;font-size:11px;display:flex;align-items:center;justify-content:center;padding:0">✕</button>`;
          grid.appendChild(div);
          _bindPhotoDel(walk.id, div);
          UI.toast.success('Foto hochgeladen.');
        }
      } catch (err) {
        UI.toast.error(err.message || 'Fehler beim Hochladen.');
      }
      this.value = '';
    });

    // Foto löschen — alle bestehenden Buttons
    function _bindPhotoDel(walkId, container) {
      container.querySelectorAll('.wd-photo-del').forEach(btn => {
        btn.addEventListener('click', async () => {
          if (!window.confirm('Foto löschen?')) return;
          try {
            await API.walks.deletePhoto(walkId, parseInt(btn.dataset.photoId));
            btn.closest('[style*="aspect-ratio"]')?.remove();
            UI.toast.success('Foto gelöscht.');
          } catch (err) { UI.toast.error(err.message || 'Fehler.'); }
        });
      });
    }
    _bindPhotoDel(walk.id, document);

    document.getElementById('wd-login')?.addEventListener('click', () => {
      UI.modal.close();
      App.navigate('settings');
    });

    document.getElementById('wd-edit')?.addEventListener('click', () => {
      UI.modal.close();
      _showEditForm(walk);
    });

    // Einladen-Button
    document.getElementById('wd-invite-btn')?.addEventListener('click', () => {
      UI.modal.close();
      _showInviteModal(walk);
    });

    // RSVP-Buttons
    document.querySelectorAll('.walks-rsvp-btn').forEach(btn => {
      btn.addEventListener('click', async () => {
        const status = btn.dataset.rsvp;
        try {
          await API.walks.rsvp(walk.id, status);
          // Buttons aktualisieren
          document.querySelectorAll('.walks-rsvp-btn').forEach(b => {
            b.classList.toggle('active', b.dataset.rsvp === status);
          });
          UI.toast.success(
            status === 'yes' ? 'Zugesagt!' :
            status === 'maybe' ? 'Antwort: Vielleicht.' :
            'Abgesagt.'
          );
        } catch (err) { UI.toast.error(err.message); }
      });
    });

    // Stornieren: Zwei-Klick-Pattern (kein UI.modal.confirm im Modal)
    let _cancelPending = false;
    document.getElementById('wd-cancel-walk')?.addEventListener('click', async () => {
      const btn = document.getElementById('wd-cancel-walk');
      if (!_cancelPending) {
        _cancelPending = true;
        btn.textContent = 'Wirklich stornieren? (nochmal tippen)';
        btn.style.fontWeight = 'var(--weight-semibold)';
        setTimeout(() => {
          _cancelPending = false;
          if (btn) {
            btn.innerHTML = `${UI.icon('x-circle')} Treffen stornieren`;
            btn.style.fontWeight = '';
          }
        }, 3000);
        return;
      }
      _cancelPending = false;
      try {
        await API.walks.cancel(walk.id);
        _data = _data.filter(w => w.id !== walk.id);
        UI.modal.close();
        _renderList();
        _renderMarkers();
        UI.toast.success('Treffen storniert.');
      } catch (err) { UI.toast.error(err.message); }
    });

    document.getElementById('wd-join')?.addEventListener('click', () => {
      UI.modal.close();
      _showJoinForm(walk);
    });

    // Austreten: Zwei-Klick-Pattern
    let _leavePending = false;
    document.getElementById('wd-leave')?.addEventListener('click', async () => {
      const btn = document.getElementById('wd-leave');
      if (!_leavePending) {
        _leavePending = true;
        btn.textContent = 'Wirklich austreten? (nochmal tippen)';
        btn.style.fontWeight = 'var(--weight-semibold)';
        setTimeout(() => {
          _leavePending = false;
          if (btn) {
            btn.innerHTML = `${UI.icon('sign-out')} Nicht mehr teilnehmen`;
            btn.style.fontWeight = '';
          }
        }, 3000);
        return;
      }
      _leavePending = false;
      try {
        const res = await API.walks.leave(walk.id);
        const idx = _data.findIndex(w => w.id === walk.id);
        if (idx !== -1) _data[idx].teilnehmer_count = res.teilnehmer_count;
        UI.modal.close();
        _renderList();
        UI.toast.success('Du nimmst nicht mehr teil.');
      } catch (err) { UI.toast.error(err.message); }
    });
  }

  // ----------------------------------------------------------
  // Freunde einladen
  // ----------------------------------------------------------
  async function _showInviteModal(walk) {
    let candidates;
    try {
      candidates = await API.walks.inviteCandidates(walk.id);
    } catch (err) {
      UI.toast.error(err.message);
      return;
    }

    const listHTML = candidates.length
      ? candidates.map(f => `
          <div class="walks-invite-row" data-friend-id="${f.friend_id}" data-friend-name="${UI.escape(f.friend_name)}">
            <div class="walks-inv-avatar">${_avatarInitials(f.friend_name)}</div>
            <div class="walks-inv-name flex-1">${UI.escape(f.friend_name)}</div>
            <button type="button" class="btn btn-primary btn-sm walks-invite-send">
              ${UI.icon('paper-plane-tilt')} Einladen
            </button>
          </div>`).join('')
      : `<p class="text-muted">Alle Freunde wurden bereits eingeladen.</p>`;

    const body = `
      <p style="color:var(--c-text-secondary);margin-bottom:var(--space-3)">
        ${_fmtDate(walk.datum)} · ${walk.uhrzeit} Uhr
        ${walk.ort_name ? `· ${UI.escape(walk.ort_name)}` : ''}
      </p>
      <div id="invite-list">${listHTML}</div>
    `;

    const footer = `
      <button type="button" class="btn btn-secondary flex-1" id="invite-back">Zurück</button>
    `;

    UI.modal.open({ title: `${UI.icon('user-plus')} Freunde einladen`, body, footer });

    document.getElementById('invite-back')?.addEventListener('click', () => {
      UI.modal.close();
      _openDetail(walk.id);
    });

    document.querySelectorAll('.walks-invite-send').forEach(btn => {
      btn.addEventListener('click', async () => {
        const row      = btn.closest('.walks-invite-row');
        const friendId = parseInt(row.dataset.friendId);
        const name     = row.dataset.friendName;
        await UI.asyncButton(btn, async () => {
          await API.walks.invite(walk.id, friendId);
          row.innerHTML = `
            <div class="walks-inv-avatar">${_avatarInitials(name)}</div>
            <div class="walks-inv-name flex-1">${UI.escape(name)}</div>
            <span class="walks-rsvp-badge walks-rsvp--invited">Eingeladen</span>
          `;
          UI.toast.success(`${name} eingeladen.`);
        });
      });
    });
  }

  // ----------------------------------------------------------
  // Beitreten-Formular (Hunde wählen)
  // ----------------------------------------------------------
  function _showJoinForm(walk) {
    const dogs = _appState.dogs || [];
    const dogsHtml = dogs.length
      ? dogs.map(d => `
          <label style="display:flex;align-items:center;gap:var(--space-2);cursor:pointer;
                         padding:var(--space-2) 0">
            <input type="checkbox" name="dog" value="${d.id}" checked>
            ${UI.icon('dog')} ${UI.escape(d.name)}
          </label>`).join('')
      : `<p class="text-muted">Keine Hunde im Profil — du kannst trotzdem mitmachen.</p>`;

    const body = `
      <p style="color:var(--c-text-secondary);margin-bottom:var(--space-4)">
        ${_fmtDate(walk.datum)} um ${walk.uhrzeit} Uhr<br>
        ${walk.ort_name ? `${UI.icon('map-pin')} ${UI.escape(walk.ort_name)}` : ''}
      </p>
      <form id="join-form" autocomplete="off">
        <div class="form-group">
          <label class="form-label">Mit welchen Hunden?</label>
          ${dogsHtml}
        </div>
      </form>
    `;

    const footer = `
      <button type="button" class="btn btn-secondary flex-1" id="join-cancel">Abbrechen</button>
      <button type="submit" form="join-form" class="btn btn-primary flex-1" id="join-confirm">${UI.icon('dog')} Mitmachen</button>
    `;

    UI.modal.open({ title: `Treffen beitreten`, body, footer });

    document.getElementById('join-cancel')?.addEventListener('click', UI.modal.close);

    document.getElementById('join-form')?.addEventListener('submit', async e => {
      e.preventDefault();
      const btn     = document.getElementById('join-confirm');
      const checked = [...document.querySelectorAll('[name="dog"]:checked')];
      const dogIds  = checked.map(cb => parseInt(cb.value));

      await UI.asyncButton(btn, async () => {
        const res = await API.walks.join(walk.id, dogIds);
        const idx = _data.findIndex(w => w.id === walk.id);
        if (idx !== -1) _data[idx].teilnehmer_count = res.teilnehmer_count;
        UI.modal.close();
        _renderList();
        _renderMarkers();
        UI.toast.success(`Du nimmst teil! 🎉`);
      });
    });
  }

  // ----------------------------------------------------------
  // Treffen erstellen / bearbeiten — Formular
  // ----------------------------------------------------------
  function _showCreateForm(prefill = {}) {
    const today = new Date().toISOString().slice(0, 10);
    _showWalkForm(null, { datum: today, uhrzeit: '10:00', ...prefill });
  }

  function _showEditForm(walk) {
    _showWalkForm(walk);
  }

  function _showWalkForm(walk, defaults = {}) {
    const isEdit = !!walk;
    const v = walk || defaults;

    // Location-State (verwaltet außerhalb des DOM)
    let _locLat  = v.lat  != null ? parseFloat(v.lat)  : null;
    let _locLon  = v.lon  != null ? parseFloat(v.lon)  : null;
    let _locName = v.ort_name || null;

    const body = `
      <form id="walk-form" autocomplete="off">

        <div class="form-group">
          <label class="form-label">Titel *</label>
          <input class="form-control" type="text" name="titel"
                 value="${UI.escape(v.titel || '')}"
                 placeholder="z. B. Sonntagsspaziergang im Stadtpark" required>
        </div>

        <div class="grid-2">
          <div class="form-group">
            <label class="form-label">Datum *</label>
            <input class="form-control" type="date" name="datum"
                   value="${UI.escape(v.datum || '')}" required>
          </div>
          <div class="form-group">
            <label class="form-label">Uhrzeit *</label>
            <input class="form-control" type="time" name="uhrzeit"
                   value="${UI.escape(v.uhrzeit || '10:00')}" required>
          </div>
        </div>

        <div class="form-group" id="wf-location-group">
          <label class="form-label">Treffpunkt</label>
          <div id="wf-location-picker"></div>
        </div>

        <div class="form-group">
          <label class="form-label">Max. Teilnehmer</label>
          <input class="form-control" type="number" name="max_teilnehmer"
                 value="${v.max_teilnehmer || 10}" min="2" max="50">
        </div>

        <div class="form-group">
          <label class="form-label">Beschreibung <span class="text-secondary">(optional)</span></label>
          <textarea class="form-control" name="beschreibung" rows="3"
                    placeholder="Treffpunkt-Details, Streckenlänge, Hundefreundlichkeit…">${UI.escape(v.beschreibung || '')}</textarea>
        </div>

      </form>
    `;

    const footer = `
      <div style="display:flex;flex-direction:column;gap:var(--space-2);width:100%">
        <button type="submit" form="walk-form" class="btn btn-primary w-full">
          ${isEdit ? `${UI.icon('floppy-disk')} Speichern` : `${UI.icon('calendar-dots')} Treffen planen`}
        </button>
        <button type="button" class="btn btn-secondary" id="wf-cancel">Abbrechen</button>
      </div>
    `;

    UI.modal.open({ title: isEdit ? `${UI.icon('pencil-simple')} Treffen bearbeiten` : `${UI.icon('dog')} Treffen planen`, body, footer });

    document.getElementById('wf-cancel')?.addEventListener('click', UI.modal.close);

    // Location Picker
    let _wfPicker = null;
    setTimeout(() => {
      _wfPicker = UI.locationPicker({
        containerId: 'wf-location-picker',
        onSelect: (lat, lon, name) => { _locLat = lat; _locLon = lon; _locName = name; },
      });
      if (_locLat != null) _wfPicker.setValue(_locLat, _locLon, _locName);
    }, 50);


    // Formular absenden
    document.getElementById('walk-form')?.addEventListener('submit', async e => {
      e.preventDefault();
      const btn = document.querySelector('[form="walk-form"][type="submit"]') || e.target.querySelector('[type="submit"]');
      const fd  = UI.formData(e.target);

      // Koordinaten aus State lesen (nicht aus fd, da hidden)
      const lat = _locLat;
      const lon = _locLon;

      if (!lat || !lon) {
        UI.toast.warning('Bitte einen Treffpunkt auf der Karte wählen oder GPS nutzen.');
        return;
      }

      await UI.asyncButton(btn, async () => {
        const payload = {
          titel:          fd.titel?.trim(),
          datum:          fd.datum,
          uhrzeit:        fd.uhrzeit,
          lat:            parseFloat(lat),
          lon:            parseFloat(lon),
          ort_name:       _locName || null,
          max_teilnehmer: parseInt(fd.max_teilnehmer) || 10,
          beschreibung:   fd.beschreibung || null,
        };

        if (isEdit) {
          const updated = await API.walks.update(walk.id, payload);
          const idx = _data.findIndex(w => w.id === walk.id);
          if (idx !== -1) _data[idx] = { ..._data[idx], ...updated };
          UI.toast.success('Treffen aktualisiert.');
          UI.modal.close();
          _renderList();
          _renderMarkers();
        } else {
          let created;
          try {
            created = await API.walks.create(payload);
          } catch (netErr) {
            if (netErr instanceof TypeError || !navigator.onLine) {
              _addPending(payload);
              UI.modal.close();
              UI.toast.success('Offline gespeichert — wird synchronisiert sobald Verbindung besteht.');
              _loadData();
              return;
            }
            throw netErr;
          }
          if (created?._queued) { UI.modal.close(); _loadData(); return; }
          _data.unshift({ ...created, teilnehmer_count: 0 });
          UI.toast.success('Treffen geplant! 🎉');
          UI.modal.close();
          _renderList();
          _renderMarkers();
        }
      });
    });
  }

  // ----------------------------------------------------------
  // Notiz-Modal (Custom DOM — kein UI.modal um Konflikte zu vermeiden)
  // ----------------------------------------------------------

  // ==============================================================
  // FEATURE 1: Foto-Challenge der Woche
  // ==============================================================

  async function _loadChallenge() {
    const el = document.getElementById('challenge-content');
    if (!el) return;
    try {
      _challengeData = await API.get('challenges/current');
      _renderChallenge();
    } catch (e) {
      el.innerHTML = `<p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Konnte Challenge nicht laden.</p>`;
    }
  }

  function _renderChallenge() {
    const el = document.getElementById('challenge-content');
    if (!el || !_challengeData) return;
    const { challenge, submissions, my_submission_id, days_left } = _challengeData;

    const canSubmit = _appState.user && !my_submission_id;
    const dayLabel  = days_left === 1 ? '1 Tag' : `${days_left} Tage`;

    el.innerHTML = `
      <div class="challenge-banner">
        <div class="challenge-banner-inner">
          <div class="challenge-thema">${UI.escape(challenge.thema)}</div>
          <div class="challenge-meta">
            ${UI.icon('calendar')} ${_fmtDate(challenge.start_date)} – ${_fmtDate(challenge.end_date)}
            &nbsp;·&nbsp; ${UI.icon('timer')} Noch ${dayLabel}
          </div>
          ${canSubmit ? `<button class="btn btn-primary btn-sm" id="challenge-submit-btn" class="mt-3">${UI.icon('camera')} Foto einreichen</button>` : ''}
          ${my_submission_id ? `<span class="badge badge-success mt-2">${UI.icon('check')} Du hast bereits teilgenommen</span>` : ''}
        </div>
      </div>

      <div class="challenge-winners" id="challenge-winners-section">
        <h4 style="padding:var(--space-3) var(--space-4);margin:0;color:var(--c-text-secondary);font-size:var(--text-xs);text-transform:uppercase;letter-spacing:.05em">Letzte Gewinner</h4>
        <div id="challenge-winners-list"><p style="color:var(--c-text-secondary);padding:0 var(--space-4);font-size:var(--text-sm)">Lädt…</p></div>
      </div>

      <div style="padding:var(--space-4) var(--space-4) var(--space-2)">
        <h4 style="margin:0;font-size:var(--text-sm);font-weight:600;color:var(--c-text)">
          ${UI.icon('images')} Einreichungen dieser Woche (${submissions.length})
        </h4>
      </div>
      <div class="challenge-gallery" id="challenge-gallery">
        ${submissions.length === 0
          ? `<p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8);grid-column:1/-1">Noch keine Fotos — sei der Erste! 📸</p>`
          : submissions.map(s => _challengeSubmissionCard(s)).join('')}
      </div>
    `;

    // Submit-Button
    const submitBtn = document.getElementById('challenge-submit-btn');
    if (submitBtn) submitBtn.addEventListener('click', _showSubmitForm);

    // Vote-Buttons
    el.querySelectorAll('.challenge-vote-btn').forEach(btn => {
      btn.addEventListener('click', async () => {
        if (!_appState.user) { UI.toast.warning('Bitte anmelden.'); return; }
        const subId = parseInt(btn.dataset.id);
        try {
          const res = await API.post(`challenges/submissions/${subId}/vote`, {});
          btn.querySelector('.vote-count').textContent = res.votes;
          btn.classList.toggle('voted', res.voted);
        } catch (e) { UI.toast.error(e.message || 'Fehler beim Abstimmen.'); }
      });
    });

    // Gewinner laden
    _loadChallengeWinners();
  }

  function _challengeSubmissionCard(s) {
    const voted = s.i_voted;
    return `
      <div class="challenge-sub-card">
        <img src="${UI.escape(s.foto_url)}" alt="Challenge-Foto" loading="lazy"
             data-fb-src="/icons/icon-192.png"
             data-lightbox-url="${UI.escape(s.foto_url)}">
        <div class="challenge-sub-info">
          <div class="challenge-sub-user">${UI.icon('user')} ${UI.escape(s.user_name || 'Anonym')}
            ${s.dog_name ? ` · 🐕 ${UI.escape(s.dog_name)}` : ''}</div>
          ${s.caption ? `<div class="challenge-sub-caption">${UI.escape(s.caption)}</div>` : ''}
          <button class="challenge-vote-btn ${voted ? 'voted' : ''}" data-id="${s.id}">
            ${UI.icon(voted ? 'heart-fill' : 'heart')} <span class="vote-count">${s.votes}</span>
          </button>
        </div>
      </div>
    `;
  }

  async function _loadChallengeWinners() {
    const el = document.getElementById('challenge-winners-list');
    if (!el) return;
    try {
      const winners = await API.get('challenges/winners');
      if (!winners.length) { el.innerHTML = '<p style="color:var(--c-text-secondary);padding:0 var(--space-4);font-size:var(--text-sm)">Noch keine vergangenen Challenges.</p>'; return; }
      el.innerHTML = `<div class="challenge-winners-row">` +
        winners.map(w => {
          if (!w.winner) return `<div class="challenge-winner-chip"><span>${UI.escape(w.challenge.thema)}</span><small>Kein Gewinner</small></div>`;
          return `<div class="challenge-winner-chip">
            <img src="${UI.escape(w.winner.foto_url)}" alt="Gewinner" data-fb-src="/icons/icon-192.png">
            <div>
              <div style="font-weight:600;font-size:var(--text-xs)">${UI.escape(w.challenge.thema)}</div>
              <div class="text-xs-secondary">${UI.escape(w.winner.user_name)} · ${w.winner.votes} ❤️</div>
            </div>
          </div>`;
        }).join('') +
      `</div>`;
    } catch {}
  }

  async function _showSubmitForm() {
    if (!_challengeData) return;
    const dogs = _appState.dogs || [];
    const dogOptions = dogs.map(d => `<option value="${d.id}">${UI.escape(d.name)}</option>`).join('');

    UI.modal.open({
      title: `📸 ${UI.escape(_challengeData.challenge.thema)}`,
      body: `
        <form id="challenge-submit-form" class="flex-col-gap-3">
          <div class="form-group">
            <label>Foto *</label>
            <input type="file" id="challenge-foto-input" accept="image/*" required class="w-full">
          </div>
          ${dogs.length ? `<div class="form-group">
            <label>Hund</label>
            <select id="challenge-dog-select" class="w-full">
              <option value="">Kein Hund</option>
              ${dogOptions}
            </select>
          </div>` : ''}
          <div class="form-group">
            <label>Bildunterschrift</label>
            <input type="text" id="challenge-caption" placeholder="z.B. Mein Bello beim besten Schnüffeln…" maxlength="200" class="w-full">
          </div>
        </form>
      `,
      footer: `
        <button class="btn btn-secondary" data-modal-close>Abbrechen</button>
        <button class="btn btn-primary" id="challenge-submit-ok">Einreichen</button>
      `,
    });

    document.getElementById('challenge-submit-ok').addEventListener('click', async () => {
      const fotoInput = document.getElementById('challenge-foto-input');
      if (!fotoInput.files.length) { UI.toast.warning('Bitte ein Foto auswählen.'); return; }
      const caption   = document.getElementById('challenge-caption')?.value?.trim() || '';
      const dogSelect = document.getElementById('challenge-dog-select');
      const dogId     = dogSelect ? (parseInt(dogSelect.value) || '') : '';

      const fd = new FormData();
      fd.append('foto', fotoInput.files[0]);
      if (caption) fd.append('caption', caption);
      if (dogId)   fd.append('dog_id', dogId);

      try {
        await API.upload(`challenges/${_challengeData.challenge.id}/submit`, fd);
        UI.toast.success('Foto eingereicht! Viel Erfolg 🎉');
        UI.modal.close();
        _challengeData = null;
        _loadChallenge();
      } catch (e) { UI.toast.error(e.message || 'Fehler beim Einreichen.'); }
    });
  }


  // ==============================================================
  // FEATURE 2: Gassi-Zeiten-Pool (Stamm-Gassis)
  // ==============================================================

  const _WOCHENTAGE = [
    { key: 'mo', label: 'Mo' }, { key: 'di', label: 'Di' }, { key: 'mi', label: 'Mi' },
    { key: 'do', label: 'Do' }, { key: 'fr', label: 'Fr' }, { key: 'sa', label: 'Sa' },
    { key: 'so', label: 'So' },
  ];

  async function _loadGassiZeiten() {
    const el = document.getElementById('gassi-zeiten-content');
    if (!el) return;
    try {
      const params = _userPos ? `?lat=${_userPos.lat}&lon=${_userPos.lon}&radius=10000` : '';
      _gassiZeiten = await API.get(`gassi-zeiten${params}`);
      _renderGassiZeiten();
    } catch (e) {
      el.innerHTML = `<p style="color:var(--c-text-secondary);text-align:center;padding:var(--space-8)">Konnte Gassi-Zeiten nicht laden.</p>`;
    }
  }

  function _renderGassiZeiten() {
    const el = document.getElementById('gassi-zeiten-content');
    if (!el) return;

    if (!_gassiZeiten.length) {
      el.innerHTML = `
        <div style="text-align:center;padding:var(--space-8);color:var(--c-text-secondary)">
          ${UI.icon('clock')}
          <p>Noch keine Stamm-Gassi-Zeiten in deiner Nähe.</p>
          <p class="text-sm">Trag deine regelmäßigen Zeiten ein — andere finden dich dann!</p>
        </div>`;
      return;
    }

    const myZeiten  = _gassiZeiten.filter(z => z.is_mine);
    const andereZeiten = _gassiZeiten.filter(z => !z.is_mine);

    let html = '';

    if (myZeiten.length) {
      html += `<div style="padding:var(--space-3) var(--space-4) var(--space-1);font-weight:600;font-size:var(--text-xs);color:var(--c-text-secondary);text-transform:uppercase;letter-spacing:.05em">Meine Zeiten</div>`;
      html += myZeiten.map(z => _gassiZeitCard(z)).join('');
    }

    if (andereZeiten.length) {
      html += `<div style="padding:var(--space-3) var(--space-4) var(--space-1);font-weight:600;font-size:var(--text-xs);color:var(--c-text-secondary);text-transform:uppercase;letter-spacing:.05em">In deiner Nähe</div>`;
      html += andereZeiten.map(z => _gassiZeitCard(z)).join('');
    }

    el.innerHTML = html;

    // Events
    el.querySelectorAll('.gz-delete-btn').forEach(btn => {
      btn.addEventListener('click', async () => {
        if (!confirm('Gassi-Zeit löschen?')) return;
        try {
          await API.del(`gassi-zeiten/${btn.dataset.id}`);
          _gassiZeiten = _gassiZeiten.filter(z => z.id !== parseInt(btn.dataset.id));
          _renderGassiZeiten();
          UI.toast.success('Gelöscht.');
        } catch (e) { UI.toast.error(e.message || 'Fehler.'); }
      });
    });

    el.querySelectorAll('.gz-toggle-btn').forEach(btn => {
      btn.addEventListener('click', async () => {
        const gz = _gassiZeiten.find(z => z.id === parseInt(btn.dataset.id));
        if (!gz) return;
        try {
          const updated = await API.patch(`gassi-zeiten/${gz.id}`, { aktiv: gz.aktiv ? 0 : 1 });
          const idx = _gassiZeiten.findIndex(z => z.id === gz.id);
          if (idx !== -1) _gassiZeiten[idx] = { ..._gassiZeiten[idx], aktiv: updated.aktiv };
          _renderGassiZeiten();
        } catch (e) { UI.toast.error(e.message || 'Fehler.'); }
      });
    });

    el.querySelectorAll('.gz-chat-btn').forEach(btn => {
      btn.addEventListener('click', () => {
        const userId = parseInt(btn.dataset.userId);
        App.navigate('chat', { user_id: userId });
      });
    });
  }

  function _gassiZeitCard(z) {
    const wochentageLabel = (z.wochentage || []).join(', ').toUpperCase();
    const distLabel = z.distance_m != null
      ? `<span style="color:var(--c-text-secondary);font-size:var(--text-xs)">${z.distance_m < 1000 ? z.distance_m + ' m' : (z.distance_m/1000).toFixed(1) + ' km'}</span>`
      : '';
    const pausedStyle = z.aktiv ? '' : 'opacity:.5';

    return `
      <div class="gassi-zeit-card" style="${pausedStyle}">
        <div class="gz-avatar">
          ${z.dog_foto_url
            ? `<img src="${UI.escape(z.dog_foto_url)}" alt="${UI.escape(z.dog_name || '')}">`
            : `<div class="gz-avatar-placeholder">${UI.icon('paw-print')}</div>`}
        </div>
        <div class="gz-body">
          <div class="gz-name">${UI.escape(z.dog_name || z.user_name || '?')}
            ${z.dog_rasse ? `<span class="badge text-xs">${UI.escape(z.dog_rasse)}</span>` : ''}
            ${!z.aktiv ? `<span class="badge badge-warning">Pausiert</span>` : ''}
          </div>
          <div class="gz-meta">
            ${UI.icon('clock')} ${UI.escape(z.uhrzeit)}
            &nbsp;·&nbsp; ${wochentageLabel}
            ${z.ort_name ? `&nbsp;·&nbsp; ${UI.icon('map-pin')} ${UI.escape(z.ort_name)}` : ''}
            ${distLabel}
          </div>
          ${z.notiz ? `<div class="gz-notiz">${UI.escape(z.notiz)}</div>` : ''}
        </div>
        <div class="gz-actions">
          ${z.is_mine ? `
            <button class="btn btn-outline btn-xs gz-toggle-btn" data-id="${z.id}" title="${z.aktiv ? 'Pausieren' : 'Aktivieren'}">
              ${UI.icon(z.aktiv ? 'pause' : 'play')}
            </button>
            <button class="btn btn-outline btn-xs gz-delete-btn" data-id="${z.id}" title="Löschen">
              ${UI.icon('trash')}
            </button>
          ` : `
            <button class="btn btn-primary btn-xs gz-chat-btn" data-user-id="${z.user_id}" title="Chat öffnen">
              ${UI.icon('chat-circle')} Mitmachen
            </button>
          `}
        </div>
      </div>
    `;
  }

  async function _showGassiZeitForm() {
    const dogs = _appState.dogs || [];
    const dogOptions = dogs.map(d => `<option value="${d.id}">${UI.escape(d.name)}</option>`).join('');
    const wdBtns = _WOCHENTAGE.map(w =>
      `<label class="wd-btn"><input type="checkbox" value="${w.key}"> ${w.label}</label>`
    ).join('');

    UI.modal.open({
      title: `${UI.icon('clock')} Stamm-Gassi-Zeit eintragen`,
      body: `
        <form id="gassi-zeit-form" class="flex-col-gap-3">
          ${dogs.length ? `<div class="form-group">
            <label>Hund</label>
            <select id="gz-dog-select" class="w-full">
              <option value="">Kein Hund</option>
              ${dogOptions}
            </select>
          </div>` : ''}
          <div class="form-group">
            <label>Uhrzeit *</label>
            <input type="time" id="gz-uhrzeit" required class="w-full">
          </div>
          <div class="form-group">
            <label>Wochentage *</label>
            <div class="wd-selector">${wdBtns}</div>
          </div>
          <div class="form-group">
            <label>Ort (optional)</label>
            <input type="text" id="gz-ort-name" placeholder="z.B. Stadtpark Ebersberg" class="w-full">
          </div>
          <div class="form-group">
            <label>Notiz (optional)</label>
            <input type="text" id="gz-notiz" placeholder="z.B. Wir sind eine ruhige Gruppe…" maxlength="200" class="w-full">
          </div>
        </form>
      `,
      footer: `
        <button class="btn btn-secondary" data-modal-close>Abbrechen</button>
        <button class="btn btn-primary" id="gz-save-btn">Speichern</button>
      `,
    });

    document.getElementById('gz-save-btn').addEventListener('click', async () => {
      const uhrzeit = document.getElementById('gz-uhrzeit')?.value;
      if (!uhrzeit) { UI.toast.warning('Bitte Uhrzeit angeben.'); return; }

      const wochentage = Array.from(document.querySelectorAll('.wd-btn input:checked')).map(cb => cb.value);
      if (!wochentage.length) { UI.toast.warning('Bitte mindestens einen Wochentag wählen.'); return; }

      const dogId   = parseInt(document.getElementById('gz-dog-select')?.value) || null;
      const ortName = document.getElementById('gz-ort-name')?.value?.trim() || null;
      const notiz   = document.getElementById('gz-notiz')?.value?.trim() || null;

      const payload = { wochentage, uhrzeit, ort_name: ortName, notiz };
      if (dogId) payload.dog_id = dogId;
      if (_userPos) { payload.lat = _userPos.lat; payload.lon = _userPos.lon; }

      try {
        const created = await API.post('gassi-zeiten', payload);
        _gassiZeiten.unshift({ ...created });
        _renderGassiZeiten();
        UI.toast.success('Gassi-Zeit eingetragen! 🐾');
        UI.modal.close();
      } catch (e) { UI.toast.error(e.message || 'Fehler beim Speichern.'); }
    });
  }


  return { init, refresh, onDogChange, openNew, openDetail: _openDetail };

})();