Fix login flows

public/index.html

@@ -133,8 +133,10 @@
         <p id="cityName">Loading...</p>
     </div>
     
-    <a href="/login" class="auth-button">Login</a>
-    <a href="/city-select" class="auth-button" style="top: 1rem; right: 6rem;">All Cities</a>
+    <div id="authButtons">
+        <a href="/login" class="auth-button" id="loginBtn">Login</a>
+        <a href="/city-select" class="auth-button" style="top: 1rem; right: 6rem;" id="changeCityBtn">All Cities</a>
+    </div>
     
     <div id="map"></div>
     
@@ -163,6 +165,36 @@
         let map;
         let stations = [];
         let currentCity = null;
+        let user = null;
+
+        async function checkAuth() {
+            try {
+                const response = await fetch('/api/user');
+                const data = await response.json();
+                user = data.user;
+                updateAuthButtons();
+            } catch (error) {
+                console.error('Auth check failed:', error);
+                updateAuthButtons();
+            }
+        }
+
+        function updateAuthButtons() {
+            const loginBtn = document.getElementById('loginBtn');
+            const changeCityBtn = document.getElementById('changeCityBtn');
+            
+            if (user) {
+                loginBtn.textContent = 'Dashboard';
+                loginBtn.href = `/city/${currentCity}/dashboard`;
+                changeCityBtn.textContent = 'Change City';
+                changeCityBtn.href = '/city-select';
+            } else {
+                loginBtn.textContent = 'Login';
+                loginBtn.href = `/login?redirect=${encodeURIComponent(window.location.pathname)}`;
+                changeCityBtn.textContent = 'All Cities';
+                changeCityBtn.href = '/city-select';
+            }
+        }
 
         function initMap() {
             // Get city name from URL
@@ -184,6 +216,7 @@
                 attribution: '© OpenStreetMap contributors'
             }).addTo(map);
 
+            checkAuth();
             loadStations();
         }
 
@@ -197,6 +230,7 @@
                     }
                     displayStations();
                     fitMapToStations();
+                    updateAuthButtons();
                 })
                 .catch(error => {
                     console.error('Error loading stations:', error);