🎨 Palette: Add loading states to authentication buttons

.Jules/palette.md

@@ -0,0 +1,3 @@
+## 2026-06-16 - Reliable Loading States in Vanilla JS Forms
+**Learning:** When implementing async form submissions in vanilla JavaScript, it's safer to use `e.submitter` (wrapped in a null-check) to target the specific button pressed, and to place the UI restoration logic inside a `finally` block. Also, simulated network delays should use awaitable Promises rather than `setTimeout` callbacks so the `finally` block executes deterministically.
+**Action:** Use `try/finally` blocks for UI state restoration and robustly check `e.submitter` when adding loading states to buttons.

web-demo/js/app.js

@@ -65,7 +65,7 @@ class ClimaAI {
 
     setupEventListeners() {
         // Auth
-        document.getElementById('googleSignInBtn').addEventListener('click', () => this.handleGoogleSignIn());
+        document.getElementById('googleSignInBtn').addEventListener('click', (e) => this.handleGoogleSignIn(e));
         document.getElementById('loginForm').addEventListener('submit', (e) => this.handleLogin(e));
         document.getElementById('registerForm').addEventListener('submit', (e) => this.handleRegister(e));
         document.getElementById('showRegister').addEventListener('click', (e) => {
@@ -145,6 +145,14 @@ class ClimaAI {
         const email = document.getElementById('loginEmail').value;
         const password = document.getElementById('loginPassword').value;
 
+        const submitBtn = e.submitter;
+        let originalContent = '';
+        if (submitBtn) {
+            originalContent = submitBtn.innerHTML;
+            submitBtn.innerHTML = 'Loading...';
+            submitBtn.disabled = true;
+        }
+
         try {
             this.showToast('Logging in...', 'info');
             const response = await api.login(email, password);
@@ -155,6 +163,11 @@ class ClimaAI {
             this.checkSubscription();
         } catch (error) {
             this.showToast(error.message || 'Login failed', 'error');
+        } finally {
+            if (submitBtn) {
+                submitBtn.innerHTML = originalContent;
+                submitBtn.disabled = false;
+            }
         }
     }
 
@@ -164,6 +177,14 @@ class ClimaAI {
         const email = document.getElementById('registerEmail').value;
         const password = document.getElementById('registerPassword').value;
 
+        const submitBtn = e.submitter;
+        let originalContent = '';
+        if (submitBtn) {
+            originalContent = submitBtn.innerHTML;
+            submitBtn.innerHTML = 'Loading...';
+            submitBtn.disabled = true;
+        }
+
         try {
             this.showToast('Creating account...', 'info');
             const response = await api.register(email, password, name);
@@ -174,6 +195,11 @@ class ClimaAI {
             this.checkSubscription();
         } catch (error) {
             this.showToast(error.message || 'Registration failed', 'error');
+        } finally {
+            if (submitBtn) {
+                submitBtn.innerHTML = originalContent;
+                submitBtn.disabled = false;
+            }
         }
     }
 
@@ -185,7 +211,15 @@ class ClimaAI {
         this.showToast('Logged out successfully', 'info');
     }
 
-    async handleGoogleSignIn() {
+    async handleGoogleSignIn(e) {
+        const btn = e ? e.currentTarget : document.getElementById('googleSignInBtn');
+        let originalContent = '';
+        if (btn) {
+            originalContent = btn.innerHTML;
+            btn.innerHTML = 'Loading...';
+            btn.disabled = true;
+        }
+
         try {
             this.showToast('🔐 Signing in with Google...', 'info');
 
@@ -197,31 +231,36 @@ class ClimaAI {
             // 5. Backend creates/updates user and returns JWT
 
             // For demo purposes, we'll simulate successful OAuth with demo account
-            setTimeout(async () => {
-                try {
-                    // Auto-login with demo account
-                    const response = await api.login('demo@climaai.com', 'Test1234');
-                    this.user = response.user;
-                    this.showToast('✅ Welcome! Signed in with Google', 'success');
-                    this.showScreen('homeScreen');
-                    this.loadWeatherData();
-                    this.checkSubscription();
-                } catch (error) {
-                    this.showToast('Google Sign-In succeeded! Welcome!', 'success');
-                    // Create a demo user object
-                    this.user = {
-                        email: 'google-user@gmail.com',
-                        full_name: 'Google User',
-                        is_premium: true
-                    };
-                    this.isPremium = true;
-                    this.showScreen('homeScreen');
-                    this.loadWeatherData();
-                }
-            }, 1500); // Simulate OAuth redirect delay
+            await new Promise(resolve => setTimeout(resolve, 1500));
+
+            try {
+                // Auto-login with demo account
+                const response = await api.login('demo@climaai.com', 'Test1234');
+                this.user = response.user;
+                this.showToast('✅ Welcome! Signed in with Google', 'success');
+                this.showScreen('homeScreen');
+                this.loadWeatherData();
+                this.checkSubscription();
+            } catch (error) {
+                this.showToast('Google Sign-In succeeded! Welcome!', 'success');
+                // Create a demo user object
+                this.user = {
+                    email: 'google-user@gmail.com',
+                    full_name: 'Google User',
+                    is_premium: true
+                };
+                this.isPremium = true;
+                this.showScreen('homeScreen');
+                this.loadWeatherData();
+            }
 
         } catch (error) {
             this.showToast(error.message || 'Google Sign-In failed', 'error');
+        } finally {
+            if (btn) {
+                btn.innerHTML = originalContent;
+                btn.disabled = false;
+            }
         }
     }