.gitignore

@@ -22,3 +22,9 @@ dist/
 CLAUDE.md
 
 data/
+
+# SQLite database
+*.db
+*.db-shm
+*.db-wal
+calendar.db

backend/Cargo.toml

@@ -34,6 +34,10 @@ base64 = "0.21"
 thiserror = "1.0"
 lazy_static = "1.4"
 
+# Database dependencies
+sqlx = { version = "0.7", features = ["runtime-tokio", "sqlite", "uuid", "chrono", "json"] }
+tokio-rusqlite = "0.5"
+
 [dev-dependencies]
 tokio = { version = "1.0", features = ["macros", "rt"] }
 reqwest = { version = "0.11", features = ["json"] }

backend/migrations/001_create_users_table.sql

@@ -0,0 +1,8 @@
+-- Create users table
+CREATE TABLE IF NOT EXISTS users (
+    id TEXT PRIMARY KEY,
+    username TEXT NOT NULL,
+    server_url TEXT NOT NULL,
+    created_at TEXT NOT NULL,
+    UNIQUE(username, server_url)
+);

backend/migrations/002_create_sessions_table.sql

@@ -0,0 +1,16 @@
+-- Create sessions table
+CREATE TABLE IF NOT EXISTS sessions (
+    id TEXT PRIMARY KEY,
+    user_id TEXT NOT NULL,
+    token TEXT NOT NULL UNIQUE,
+    created_at TEXT NOT NULL,
+    expires_at TEXT NOT NULL,
+    last_accessed TEXT NOT NULL,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+
+-- Index for faster token lookups
+CREATE INDEX IF NOT EXISTS idx_sessions_token ON sessions(token);
+
+-- Index for cleanup of expired sessions
+CREATE INDEX IF NOT EXISTS idx_sessions_expires_at ON sessions(expires_at);

backend/migrations/003_create_user_preferences_table.sql

@@ -0,0 +1,11 @@
+-- Create user preferences table
+CREATE TABLE IF NOT EXISTS user_preferences (
+    user_id TEXT PRIMARY KEY,
+    calendar_selected_date TEXT,
+    calendar_time_increment INTEGER,
+    calendar_view_mode TEXT,
+    calendar_theme TEXT,
+    calendar_colors TEXT, -- JSON string for calendar color mappings
+    updated_at TEXT NOT NULL,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);

backend/src/auth.rs

@@ -1,10 +1,12 @@
 use chrono::{Duration, Utc};
 use jsonwebtoken::{decode, encode, Algorithm, DecodingKey, EncodingKey, Header, Validation};
 use serde::{Deserialize, Serialize};
+use uuid::Uuid;
 
 use crate::calendar::CalDAVClient;
 use crate::config::CalDAVConfig;
-use crate::models::{ApiError, AuthResponse, CalDAVLoginRequest};
+use crate::db::{Database, PreferencesRepository, Session, SessionRepository, UserRepository};
+use crate::models::{ApiError, AuthResponse, CalDAVLoginRequest, UserPreferencesResponse};
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Claims {
@@ -17,11 +19,12 @@ pub struct Claims {
 #[derive(Clone)]
 pub struct AuthService {
     jwt_secret: String,
+    db: Database,
 }
 
 impl AuthService {
-    pub fn new(jwt_secret: String) -> Self {
+    pub fn new(jwt_secret: String, db: Database) -> Self {
-        Self { jwt_secret }
+        Self { jwt_secret, db }
     }
 
     /// Authenticate user directly against CalDAV server
@@ -49,13 +52,47 @@ impl AuthService {
                     "✅ Authentication successful! Found {} calendars",
                     calendars.len()
                 );
-                // Authentication successful, generate JWT token
+                
-                let token = self.generate_token(&request.username, &request.server_url)?;
+                // Find or create user in database
+                let user_repo = UserRepository::new(&self.db);
+                let user = user_repo
+                    .find_or_create(&request.username, &request.server_url)
+                    .await
+                    .map_err(|e| ApiError::Database(format!("Failed to create user: {}", e)))?;
+                
+                // Generate JWT token
+                let jwt_token = self.generate_token(&request.username, &request.server_url)?;
+                
+                // Generate session token
+                let session_token = format!("sess_{}", Uuid::new_v4());
+                
+                // Create session in database
+                let session = Session::new(user.id.clone(), session_token.clone(), 24);
+                let session_repo = SessionRepository::new(&self.db);
+                session_repo
+                    .create(&session)
+                    .await
+                    .map_err(|e| ApiError::Database(format!("Failed to create session: {}", e)))?;
+                
+                // Get or create user preferences
+                let prefs_repo = PreferencesRepository::new(&self.db);
+                let preferences = prefs_repo
+                    .get_or_create(&user.id)
+                    .await
+                    .map_err(|e| ApiError::Database(format!("Failed to get preferences: {}", e)))?;
                 
                 Ok(AuthResponse {
-                    token,
+                    token: jwt_token,
+                    session_token,
                     username: request.username,
                     server_url: request.server_url,
+                    preferences: UserPreferencesResponse {
+                        calendar_selected_date: preferences.calendar_selected_date,
+                        calendar_time_increment: preferences.calendar_time_increment,
+                        calendar_view_mode: preferences.calendar_view_mode,
+                        calendar_theme: preferences.calendar_theme,
+                        calendar_colors: preferences.calendar_colors,
+                    },
                 })
             }
             Err(err) => {
@@ -143,4 +180,33 @@ impl AuthService {
 
         Ok(token_data.claims)
     }
+    
+    /// Validate session token
+    pub async fn validate_session(&self, session_token: &str) -> Result<String, ApiError> {
+        let session_repo = SessionRepository::new(&self.db);
+        
+        let session = session_repo
+            .find_by_token(session_token)
+            .await
+            .map_err(|e| ApiError::Database(format!("Failed to find session: {}", e)))?
+            .ok_or_else(|| ApiError::Unauthorized("Invalid session token".to_string()))?;
+        
+        if session.is_expired() {
+            return Err(ApiError::Unauthorized("Session expired".to_string()));
+        }
+        
+        Ok(session.user_id)
+    }
+    
+    /// Logout user by deleting session
+    pub async fn logout(&self, session_token: &str) -> Result<(), ApiError> {
+        let session_repo = SessionRepository::new(&self.db);
+        
+        session_repo
+            .delete(session_token)
+            .await
+            .map_err(|e| ApiError::Database(format!("Failed to delete session: {}", e)))?;
+        
+        Ok(())
+    }
 }

backend/src/db.rs

@@ -0,0 +1,305 @@
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use sqlx::sqlite::{SqlitePool, SqlitePoolOptions};
+use sqlx::{FromRow, Result};
+use std::sync::Arc;
+use uuid::Uuid;
+
+/// Database connection pool wrapper
+#[derive(Clone)]
+pub struct Database {
+    pool: Arc<SqlitePool>,
+}
+
+impl Database {
+    /// Create a new database connection pool
+    pub async fn new(database_url: &str) -> Result<Self> {
+        let pool = SqlitePoolOptions::new()
+            .max_connections(5)
+            .connect(database_url)
+            .await?;
+
+        // Run migrations
+        sqlx::migrate!("./migrations").run(&pool).await?;
+
+        Ok(Self {
+            pool: Arc::new(pool),
+        })
+    }
+
+    /// Get a reference to the connection pool
+    pub fn pool(&self) -> &SqlitePool {
+        &self.pool
+    }
+}
+
+/// User model representing a CalDAV user
+#[derive(Debug, Clone, Serialize, Deserialize, FromRow)]
+pub struct User {
+    pub id: String, // UUID as string for SQLite
+    pub username: String,
+    pub server_url: String,
+    pub created_at: DateTime<Utc>,
+}
+
+impl User {
+    /// Create a new user with generated UUID
+    pub fn new(username: String, server_url: String) -> Self {
+        Self {
+            id: Uuid::new_v4().to_string(),
+            username,
+            server_url,
+            created_at: Utc::now(),
+        }
+    }
+}
+
+/// Session model for user sessions
+#[derive(Debug, Clone, Serialize, Deserialize, FromRow)]
+pub struct Session {
+    pub id: String,      // UUID as string
+    pub user_id: String, // Foreign key to User
+    pub token: String,   // Session token
+    pub created_at: DateTime<Utc>,
+    pub expires_at: DateTime<Utc>,
+    pub last_accessed: DateTime<Utc>,
+}
+
+impl Session {
+    /// Create a new session for a user
+    pub fn new(user_id: String, token: String, expires_in_hours: i64) -> Self {
+        let now = Utc::now();
+        Self {
+            id: Uuid::new_v4().to_string(),
+            user_id,
+            token,
+            created_at: now,
+            expires_at: now + chrono::Duration::hours(expires_in_hours),
+            last_accessed: now,
+        }
+    }
+
+    /// Check if the session has expired
+    pub fn is_expired(&self) -> bool {
+        Utc::now() > self.expires_at
+    }
+}
+
+/// User preferences model
+#[derive(Debug, Clone, Serialize, Deserialize, FromRow)]
+pub struct UserPreferences {
+    pub user_id: String,
+    pub calendar_selected_date: Option<String>,
+    pub calendar_time_increment: Option<i32>,
+    pub calendar_view_mode: Option<String>,
+    pub calendar_theme: Option<String>,
+    pub calendar_colors: Option<String>, // JSON string
+    pub updated_at: DateTime<Utc>,
+}
+
+impl UserPreferences {
+    /// Create default preferences for a new user
+    pub fn default_for_user(user_id: String) -> Self {
+        Self {
+            user_id,
+            calendar_selected_date: None,
+            calendar_time_increment: Some(15),
+            calendar_view_mode: Some("month".to_string()),
+            calendar_theme: Some("light".to_string()),
+            calendar_colors: None,
+            updated_at: Utc::now(),
+        }
+    }
+}
+
+/// Repository for User operations
+pub struct UserRepository<'a> {
+    db: &'a Database,
+}
+
+impl<'a> UserRepository<'a> {
+    pub fn new(db: &'a Database) -> Self {
+        Self { db }
+    }
+
+    /// Find or create a user by username and server URL
+    pub async fn find_or_create(
+        &self,
+        username: &str,
+        server_url: &str,
+    ) -> Result<User> {
+        // Try to find existing user
+        let existing = sqlx::query_as::<_, User>(
+            "SELECT * FROM users WHERE username = ? AND server_url = ?",
+        )
+        .bind(username)
+        .bind(server_url)
+        .fetch_optional(self.db.pool())
+        .await?;
+
+        if let Some(user) = existing {
+            Ok(user)
+        } else {
+            // Create new user
+            let user = User::new(username.to_string(), server_url.to_string());
+            
+            sqlx::query(
+                "INSERT INTO users (id, username, server_url, created_at) VALUES (?, ?, ?, ?)",
+            )
+            .bind(&user.id)
+            .bind(&user.username)
+            .bind(&user.server_url)
+            .bind(&user.created_at)
+            .execute(self.db.pool())
+            .await?;
+
+            Ok(user)
+        }
+    }
+
+    /// Find a user by ID
+    pub async fn find_by_id(&self, user_id: &str) -> Result<Option<User>> {
+        sqlx::query_as::<_, User>("SELECT * FROM users WHERE id = ?")
+            .bind(user_id)
+            .fetch_optional(self.db.pool())
+            .await
+    }
+}
+
+/// Repository for Session operations
+pub struct SessionRepository<'a> {
+    db: &'a Database,
+}
+
+impl<'a> SessionRepository<'a> {
+    pub fn new(db: &'a Database) -> Self {
+        Self { db }
+    }
+
+    /// Create a new session
+    pub async fn create(&self, session: &Session) -> Result<()> {
+        sqlx::query(
+            "INSERT INTO sessions (id, user_id, token, created_at, expires_at, last_accessed) 
+             VALUES (?, ?, ?, ?, ?, ?)",
+        )
+        .bind(&session.id)
+        .bind(&session.user_id)
+        .bind(&session.token)
+        .bind(&session.created_at)
+        .bind(&session.expires_at)
+        .bind(&session.last_accessed)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(())
+    }
+
+    /// Find a session by token and update last_accessed
+    pub async fn find_by_token(&self, token: &str) -> Result<Option<Session>> {
+        let session = sqlx::query_as::<_, Session>("SELECT * FROM sessions WHERE token = ?")
+            .bind(token)
+            .fetch_optional(self.db.pool())
+            .await?;
+
+        if let Some(ref s) = session {
+            if !s.is_expired() {
+                // Update last_accessed time
+                sqlx::query("UPDATE sessions SET last_accessed = ? WHERE id = ?")
+                    .bind(Utc::now())
+                    .bind(&s.id)
+                    .execute(self.db.pool())
+                    .await?;
+            }
+        }
+
+        Ok(session)
+    }
+
+    /// Delete a session (logout)
+    pub async fn delete(&self, token: &str) -> Result<()> {
+        sqlx::query("DELETE FROM sessions WHERE token = ?")
+            .bind(token)
+            .execute(self.db.pool())
+            .await?;
+
+        Ok(())
+    }
+
+    /// Clean up expired sessions
+    pub async fn cleanup_expired(&self) -> Result<u64> {
+        let result = sqlx::query("DELETE FROM sessions WHERE expires_at < ?")
+            .bind(Utc::now())
+            .execute(self.db.pool())
+            .await?;
+
+        Ok(result.rows_affected())
+    }
+}
+
+/// Repository for UserPreferences operations
+pub struct PreferencesRepository<'a> {
+    db: &'a Database,
+}
+
+impl<'a> PreferencesRepository<'a> {
+    pub fn new(db: &'a Database) -> Self {
+        Self { db }
+    }
+
+    /// Get user preferences, creating defaults if not exist
+    pub async fn get_or_create(&self, user_id: &str) -> Result<UserPreferences> {
+        let existing = sqlx::query_as::<_, UserPreferences>(
+            "SELECT * FROM user_preferences WHERE user_id = ?",
+        )
+        .bind(user_id)
+        .fetch_optional(self.db.pool())
+        .await?;
+
+        if let Some(prefs) = existing {
+            Ok(prefs)
+        } else {
+            // Create default preferences
+            let prefs = UserPreferences::default_for_user(user_id.to_string());
+            
+            sqlx::query(
+                "INSERT INTO user_preferences 
+                 (user_id, calendar_selected_date, calendar_time_increment, 
+                  calendar_view_mode, calendar_theme, calendar_colors, updated_at) 
+                 VALUES (?, ?, ?, ?, ?, ?, ?)",
+            )
+            .bind(&prefs.user_id)
+            .bind(&prefs.calendar_selected_date)
+            .bind(&prefs.calendar_time_increment)
+            .bind(&prefs.calendar_view_mode)
+            .bind(&prefs.calendar_theme)
+            .bind(&prefs.calendar_colors)
+            .bind(&prefs.updated_at)
+            .execute(self.db.pool())
+            .await?;
+
+            Ok(prefs)
+        }
+    }
+
+    /// Update user preferences
+    pub async fn update(&self, prefs: &UserPreferences) -> Result<()> {
+        sqlx::query(
+            "UPDATE user_preferences 
+             SET calendar_selected_date = ?, calendar_time_increment = ?, 
+                 calendar_view_mode = ?, calendar_theme = ?, 
+                 calendar_colors = ?, updated_at = ?
+             WHERE user_id = ?",
+        )
+        .bind(&prefs.calendar_selected_date)
+        .bind(&prefs.calendar_time_increment)
+        .bind(&prefs.calendar_view_mode)
+        .bind(&prefs.calendar_theme)
+        .bind(&prefs.calendar_colors)
+        .bind(Utc::now())
+        .bind(&prefs.user_id)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(())
+    }
+}

backend/src/handlers.rs

@@ -2,9 +2,11 @@
 mod auth;
 mod calendar;
 mod events;
+mod preferences;
 mod series;
 
 pub use auth::{get_user_info, login, verify_token};
 pub use calendar::{create_calendar, delete_calendar};
 pub use events::{create_event, delete_event, get_calendar_events, refresh_event, update_event};
+pub use preferences::{get_preferences, logout, update_preferences};
 pub use series::{create_event_series, delete_event_series, update_event_series};

backend/src/handlers/auth.rs

@@ -46,41 +46,12 @@ pub async fn login(
     println!("  Username: {}", request.username);
     println!("  Password length: {}", request.password.len());
 
-    // Basic validation
+    // Use the auth service login method which now handles database, sessions, and preferences
-    if request.username.is_empty() || request.password.is_empty() || request.server_url.is_empty() {
+    let response = state.auth_service.login(request).await?;
-        return Err(ApiError::BadRequest(
-            "Username, password, and server URL are required".to_string(),
-        ));
-    }
 
-    println!("✅ Input validation passed");
+    println!("✅ Login successful with session management");
 
-    // Create a token using the auth service
+    Ok(Json(response))
-    println!("📝 Created CalDAV config");
-
-    // First verify the credentials are valid by attempting to discover calendars
-    let config = CalDAVConfig::new(
-        request.server_url.clone(),
-        request.username.clone(),
-        request.password.clone(),
-    );
-    let client = CalDAVClient::new(config);
-    client
-        .discover_calendars()
-        .await
-        .map_err(|e| ApiError::Unauthorized(format!("Authentication failed: {}", e)))?;
-
-    let token = state
-        .auth_service
-        .generate_token(&request.username, &request.server_url)?;
-
-    println!("🔗 Created CalDAV client, attempting to discover calendars...");
-
-    Ok(Json(AuthResponse {
-        token,
-        username: request.username,
-        server_url: request.server_url,
-    }))
 }
 
 pub async fn verify_token(

backend/src/handlers/preferences.rs

@@ -0,0 +1,123 @@
+use axum::{
+    extract::State,
+    http::{HeaderMap, StatusCode},
+    response::IntoResponse,
+    Json,
+};
+use std::sync::Arc;
+
+use crate::{
+    db::PreferencesRepository,
+    models::{ApiError, UpdatePreferencesRequest, UserPreferencesResponse},
+    AppState,
+};
+
+/// Get user preferences
+pub async fn get_preferences(
+    State(state): State<Arc<AppState>>,
+    headers: HeaderMap,
+) -> Result<impl IntoResponse, ApiError> {
+    // Extract session token from headers
+    let session_token = headers
+        .get("X-Session-Token")
+        .and_then(|h| h.to_str().ok())
+        .ok_or_else(|| ApiError::Unauthorized("Missing session token".to_string()))?;
+
+    // Validate session and get user ID
+    let user_id = state.auth_service.validate_session(session_token).await?;
+
+    // Get preferences from database
+    let prefs_repo = PreferencesRepository::new(&state.db);
+    let preferences = prefs_repo
+        .get_or_create(&user_id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to get preferences: {}", e)))?;
+
+    Ok(Json(UserPreferencesResponse {
+        calendar_selected_date: preferences.calendar_selected_date,
+        calendar_time_increment: preferences.calendar_time_increment,
+        calendar_view_mode: preferences.calendar_view_mode,
+        calendar_theme: preferences.calendar_theme,
+        calendar_colors: preferences.calendar_colors,
+    }))
+}
+
+/// Update user preferences
+pub async fn update_preferences(
+    State(state): State<Arc<AppState>>,
+    headers: HeaderMap,
+    Json(request): Json<UpdatePreferencesRequest>,
+) -> Result<impl IntoResponse, ApiError> {
+    // Extract session token from headers
+    let session_token = headers
+        .get("X-Session-Token")
+        .and_then(|h| h.to_str().ok())
+        .ok_or_else(|| ApiError::Unauthorized("Missing session token".to_string()))?;
+
+    // Validate session and get user ID
+    let user_id = state.auth_service.validate_session(session_token).await?;
+
+    // Update preferences in database
+    let prefs_repo = PreferencesRepository::new(&state.db);
+    
+    let mut preferences = prefs_repo
+        .get_or_create(&user_id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to get preferences: {}", e)))?;
+
+    // Update only provided fields
+    if request.calendar_selected_date.is_some() {
+        preferences.calendar_selected_date = request.calendar_selected_date;
+    }
+    if request.calendar_time_increment.is_some() {
+        preferences.calendar_time_increment = request.calendar_time_increment;
+    }
+    if request.calendar_view_mode.is_some() {
+        preferences.calendar_view_mode = request.calendar_view_mode;
+    }
+    if request.calendar_theme.is_some() {
+        preferences.calendar_theme = request.calendar_theme;
+    }
+    if request.calendar_colors.is_some() {
+        preferences.calendar_colors = request.calendar_colors;
+    }
+
+    prefs_repo
+        .update(&preferences)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to update preferences: {}", e)))?;
+
+    Ok((
+        StatusCode::OK,
+        Json(UserPreferencesResponse {
+            calendar_selected_date: preferences.calendar_selected_date,
+            calendar_time_increment: preferences.calendar_time_increment,
+            calendar_view_mode: preferences.calendar_view_mode,
+            calendar_theme: preferences.calendar_theme,
+            calendar_colors: preferences.calendar_colors,
+        }),
+    ))
+}
+
+/// Logout user
+pub async fn logout(
+    State(state): State<Arc<AppState>>,
+    headers: HeaderMap,
+) -> Result<impl IntoResponse, ApiError> {
+    // Extract session token from headers
+    let session_token = headers
+        .get("X-Session-Token")
+        .and_then(|h| h.to_str().ok())
+        .ok_or_else(|| ApiError::Unauthorized("Missing session token".to_string()))?;
+
+    // Delete session
+    state.auth_service.logout(session_token).await?;
+
+    Ok((
+        StatusCode::OK,
+        Json(serde_json::json!({
+            "success": true,
+            "message": "Logged out successfully"
+        })),
+    ))
+}

backend/src/lib.rs

@@ -9,27 +9,37 @@ use tower_http::cors::{Any, CorsLayer};
 pub mod auth;
 pub mod calendar;
 pub mod config;
+pub mod db;
 pub mod handlers;
 pub mod models;
 
 use auth::AuthService;
+use db::Database;
 
 #[derive(Clone)]
 pub struct AppState {
     pub auth_service: AuthService,
+    pub db: Database,
 }
 
 pub async fn run_server() -> Result<(), Box<dyn std::error::Error>> {
     // Initialize logging
     println!("🚀 Starting Calendar Backend Server");
 
+    // Initialize database
+    let database_url = std::env::var("DATABASE_URL")
+        .unwrap_or_else(|_| "sqlite:calendar.db".to_string());
+    
+    let db = Database::new(&database_url).await?;
+    println!("✅ Database initialized");
+
     // Create auth service
     let jwt_secret = std::env::var("JWT_SECRET")
         .unwrap_or_else(|_| "your-super-secret-jwt-key-change-in-production".to_string());
 
-    let auth_service = AuthService::new(jwt_secret);
+    let auth_service = AuthService::new(jwt_secret, db.clone());
 
-    let app_state = AppState { auth_service };
+    let app_state = AppState { auth_service, db };
 
     // Build our application with routes
     let app = Router::new()
@@ -58,6 +68,10 @@ pub async fn run_server() -> Result<(), Box<dyn std::error::Error>> {
             "/api/calendar/events/series/delete",
             post(handlers::delete_event_series),
         )
+        // User preferences endpoints
+        .route("/api/preferences", get(handlers::get_preferences))
+        .route("/api/preferences", post(handlers::update_preferences))
+        .route("/api/auth/logout", post(handlers::logout))
         .layer(
             CorsLayer::new()
                 .allow_origin(Any)

backend/src/models.rs

@@ -16,8 +16,28 @@ pub struct CalDAVLoginRequest {
 #[derive(Debug, Serialize)]
 pub struct AuthResponse {
     pub token: String,
+    pub session_token: String,
     pub username: String,
     pub server_url: String,
+    pub preferences: UserPreferencesResponse,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone)]
+pub struct UserPreferencesResponse {
+    pub calendar_selected_date: Option<String>,
+    pub calendar_time_increment: Option<i32>,
+    pub calendar_view_mode: Option<String>,
+    pub calendar_theme: Option<String>,
+    pub calendar_colors: Option<String>,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct UpdatePreferencesRequest {
+    pub calendar_selected_date: Option<String>,
+    pub calendar_time_increment: Option<i32>,
+    pub calendar_view_mode: Option<String>,
+    pub calendar_theme: Option<String>,
+    pub calendar_colors: Option<String>,
 }
 
 #[derive(Debug, Serialize)]

frontend/src/auth.rs

@@ -11,11 +11,22 @@ pub struct CalDAVLoginRequest {
     pub password: String,
 }
 
+#[derive(Debug, Serialize, Deserialize, Clone)]
+pub struct UserPreferencesResponse {
+    pub calendar_selected_date: Option<String>,
+    pub calendar_time_increment: Option<i32>,
+    pub calendar_view_mode: Option<String>,
+    pub calendar_theme: Option<String>,
+    pub calendar_colors: Option<String>,
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 pub struct AuthResponse {
     pub token: String,
+    pub session_token: String,
     pub username: String,
     pub server_url: String,
+    pub preferences: UserPreferencesResponse,
 }
 
 #[derive(Debug, Deserialize)]

frontend/src/components/login.rs

@@ -9,12 +9,25 @@ pub struct LoginProps {
 
 #[function_component]
 pub fn Login(props: &LoginProps) -> Html {
-    let server_url = use_state(String::new);
+    // Load remembered values from LocalStorage on mount
-    let username = use_state(String::new);
+    let server_url = use_state(|| {
+        LocalStorage::get::<String>("remembered_server_url").unwrap_or_default()
+    });
+    let username = use_state(|| {
+        LocalStorage::get::<String>("remembered_username").unwrap_or_default()
+    });
     let password = use_state(String::new);
     let error_message = use_state(|| Option::<String>::None);
     let is_loading = use_state(|| false);
     
+    // Remember checkboxes state
+    let remember_server = use_state(|| {
+        LocalStorage::get::<String>("remembered_server_url").is_ok()
+    });
+    let remember_username = use_state(|| {
+        LocalStorage::get::<String>("remembered_username").is_ok()
+    });
+
     let server_url_ref = use_node_ref();
     let username_ref = use_node_ref();
     let password_ref = use_node_ref();
@@ -43,6 +56,38 @@ pub fn Login(props: &LoginProps) -> Html {
         })
     };
     
+    let on_remember_server_change = {
+        let remember_server = remember_server.clone();
+        let server_url = server_url.clone();
+        Callback::from(move |e: Event| {
+            let target = e.target_unchecked_into::<HtmlInputElement>();
+            let checked = target.checked();
+            remember_server.set(checked);
+            
+            if checked {
+                let _ = LocalStorage::set("remembered_server_url", (*server_url).clone());
+            } else {
+                let _ = LocalStorage::delete("remembered_server_url");
+            }
+        })
+    };
+    
+    let on_remember_username_change = {
+        let remember_username = remember_username.clone();
+        let username = username.clone();
+        Callback::from(move |e: Event| {
+            let target = e.target_unchecked_into::<HtmlInputElement>();
+            let checked = target.checked();
+            remember_username.set(checked);
+            
+            if checked {
+                let _ = LocalStorage::set("remembered_username", (*username).clone());
+            } else {
+                let _ = LocalStorage::delete("remembered_username");
+            }
+        })
+    };
+
     let on_submit = {
         let server_url = server_url.clone();
         let username = username.clone();
@@ -73,7 +118,7 @@ pub fn Login(props: &LoginProps) -> Html {
             wasm_bindgen_futures::spawn_local(async move {
                 web_sys::console::log_1(&"🚀 Starting login process...".into());
                 match perform_login(server_url.clone(), username.clone(), password.clone()).await {
-                    Ok((token, credentials)) => {
+                    Ok((token, session_token, credentials, preferences)) => {
                         web_sys::console::log_1(&"✅ Login successful!".into());
                         // Store token and credentials in local storage
                         if let Err(_) = LocalStorage::set("auth_token", &token) {
@@ -82,12 +127,23 @@ pub fn Login(props: &LoginProps) -> Html {
                             is_loading.set(false);
                             return;
                         }
+                        if let Err(_) = LocalStorage::set("session_token", &session_token) {
+                            error_message
+                                .set(Some("Failed to store session token".to_string()));
+                            is_loading.set(false);
+                            return;
+                        }
                         if let Err(_) = LocalStorage::set("caldav_credentials", &credentials) {
                             error_message.set(Some("Failed to store credentials".to_string()));
                             is_loading.set(false);
                             return;
                         }
                         
+                        // Store preferences from database
+                        if let Ok(prefs_json) = serde_json::to_string(&preferences) {
+                            let _ = LocalStorage::set("user_preferences", &prefs_json);
+                        }
+
                         is_loading.set(false);
                         on_login.emit(token);
                     }
@@ -117,6 +173,15 @@ pub fn Login(props: &LoginProps) -> Html {
                             onchange={on_server_url_change}
                             disabled={*is_loading}
                         />
+                        <div class="remember-checkbox">
+                            <input
+                                type="checkbox"
+                                id="remember_server"
+                                checked={*remember_server}
+                                onchange={on_remember_server_change}
+                            />
+                            <label for="remember_server">{"Remember server"}</label>
+                        </div>
                     </div>
 
                     <div class="form-group">
@@ -130,6 +195,15 @@ pub fn Login(props: &LoginProps) -> Html {
                             onchange={on_username_change}
                             disabled={*is_loading}
                         />
+                        <div class="remember-checkbox">
+                            <input
+                                type="checkbox"
+                                id="remember_username"
+                                checked={*remember_username}
+                                onchange={on_remember_username_change}
+                            />
+                            <label for="remember_username">{"Remember username"}</label>
+                        </div>
                     </div>
 
                     <div class="form-group">
@@ -177,7 +251,7 @@ async fn perform_login(
     server_url: String,
     username: String,
     password: String,
-) -> Result<(String, String), String> {
+) -> Result<(String, String, String, serde_json::Value), String> {
     use crate::auth::{AuthService, CalDAVLoginRequest};
     use serde_json;
 
@@ -201,7 +275,17 @@ async fn perform_login(
                 "username": username,
                 "password": password
             });
-            Ok((response.token, credentials.to_string()))
+            
+            // Extract preferences as JSON
+            let preferences = serde_json::json!({
+                "calendar_selected_date": response.preferences.calendar_selected_date,
+                "calendar_time_increment": response.preferences.calendar_time_increment,
+                "calendar_view_mode": response.preferences.calendar_view_mode,
+                "calendar_theme": response.preferences.calendar_theme,
+                "calendar_colors": response.preferences.calendar_colors,
+            });
+            
+            Ok((response.token, response.session_token, credentials.to_string(), preferences))
         }
         Err(err) => {
             web_sys::console::log_1(&format!("❌ Backend error: {}", err).into());

frontend/src/services/mod.rs

@@ -1,3 +1,5 @@
 pub mod calendar_service;
+pub mod preferences;
 
 pub use calendar_service::CalendarService;
+pub use preferences::PreferencesService;

frontend/src/services/preferences.rs

@@ -0,0 +1,177 @@
+use gloo_storage::{LocalStorage, Storage};
+use serde::{Deserialize, Serialize};
+use serde_json;
+use wasm_bindgen::JsCast;
+use wasm_bindgen_futures::JsFuture;
+use web_sys::{Request, RequestInit, RequestMode, Response};
+
+#[derive(Debug, Serialize, Deserialize, Clone)]
+pub struct UserPreferences {
+    pub calendar_selected_date: Option<String>,
+    pub calendar_time_increment: Option<i32>,
+    pub calendar_view_mode: Option<String>,
+    pub calendar_theme: Option<String>,
+    pub calendar_colors: Option<String>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct UpdatePreferencesRequest {
+    pub calendar_selected_date: Option<String>,
+    pub calendar_time_increment: Option<i32>,
+    pub calendar_view_mode: Option<String>,
+    pub calendar_theme: Option<String>,
+    pub calendar_colors: Option<String>,
+}
+
+pub struct PreferencesService {
+    base_url: String,
+}
+
+impl PreferencesService {
+    pub fn new() -> Self {
+        let base_url = option_env!("BACKEND_API_URL")
+            .unwrap_or("http://localhost:3000/api")
+            .to_string();
+        
+        Self { base_url }
+    }
+    
+    /// Load preferences from LocalStorage (cached from login)
+    pub fn load_cached() -> Option<UserPreferences> {
+        if let Ok(prefs_json) = LocalStorage::get::<String>("user_preferences") {
+            serde_json::from_str(&prefs_json).ok()
+        } else {
+            None
+        }
+    }
+    
+    /// Update a single preference field and sync with backend
+    pub async fn update_preference(&self, field: &str, value: serde_json::Value) -> Result<(), String> {
+        // Get session token
+        let session_token = LocalStorage::get::<String>("session_token")
+            .map_err(|_| "No session token found".to_string())?;
+        
+        // Load current preferences
+        let mut preferences = Self::load_cached().unwrap_or(UserPreferences {
+            calendar_selected_date: None,
+            calendar_time_increment: None,
+            calendar_view_mode: None,
+            calendar_theme: None,
+            calendar_colors: None,
+        });
+        
+        // Update the specific field
+        match field {
+            "calendar_selected_date" => {
+                preferences.calendar_selected_date = value.as_str().map(|s| s.to_string());
+            }
+            "calendar_time_increment" => {
+                preferences.calendar_time_increment = value.as_i64().map(|i| i as i32);
+            }
+            "calendar_view_mode" => {
+                preferences.calendar_view_mode = value.as_str().map(|s| s.to_string());
+            }
+            "calendar_theme" => {
+                preferences.calendar_theme = value.as_str().map(|s| s.to_string());
+            }
+            "calendar_colors" => {
+                preferences.calendar_colors = value.as_str().map(|s| s.to_string());
+            }
+            _ => return Err(format!("Unknown preference field: {}", field)),
+        }
+        
+        // Save to LocalStorage cache
+        if let Ok(prefs_json) = serde_json::to_string(&preferences) {
+            let _ = LocalStorage::set("user_preferences", &prefs_json);
+        }
+        
+        // Sync with backend
+        let request = UpdatePreferencesRequest {
+            calendar_selected_date: preferences.calendar_selected_date.clone(),
+            calendar_time_increment: preferences.calendar_time_increment,
+            calendar_view_mode: preferences.calendar_view_mode.clone(),
+            calendar_theme: preferences.calendar_theme.clone(),
+            calendar_colors: preferences.calendar_colors.clone(),
+        };
+        
+        self.sync_preferences(&session_token, &request).await
+    }
+    
+    /// Sync all preferences with backend
+    async fn sync_preferences(
+        &self,
+        session_token: &str,
+        request: &UpdatePreferencesRequest,
+    ) -> Result<(), String> {
+        let window = web_sys::window().ok_or("No global window exists")?;
+        
+        let json_body = serde_json::to_string(request)
+            .map_err(|e| format!("JSON serialization failed: {}", e))?;
+        
+        let opts = RequestInit::new();
+        opts.set_method("POST");
+        opts.set_mode(RequestMode::Cors);
+        opts.set_body(&wasm_bindgen::JsValue::from_str(&json_body));
+        
+        let url = format!("{}/preferences", self.base_url);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+        
+        request
+            .headers()
+            .set("Content-Type", "application/json")
+            .map_err(|e| format!("Header setting failed: {:?}", e))?;
+        
+        request
+            .headers()
+            .set("X-Session-Token", session_token)
+            .map_err(|e| format!("Header setting failed: {:?}", e))?;
+        
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Network request failed: {:?}", e))?;
+        
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response cast failed: {:?}", e))?;
+        
+        if resp.ok() {
+            Ok(())
+        } else {
+            Err(format!("Failed to update preferences: {}", resp.status()))
+        }
+    }
+    
+    /// Migrate preferences from LocalStorage to backend (on first login after update)
+    pub async fn migrate_from_local_storage(&self) -> Result<(), String> {
+        let session_token = LocalStorage::get::<String>("session_token")
+            .map_err(|_| "No session token found".to_string())?;
+        
+        let mut request = UpdatePreferencesRequest {
+            calendar_selected_date: LocalStorage::get::<String>("calendar_selected_date").ok(),
+            calendar_time_increment: LocalStorage::get::<u32>("calendar_time_increment").ok().map(|i| i as i32),
+            calendar_view_mode: LocalStorage::get::<String>("calendar_view_mode").ok(),
+            calendar_theme: LocalStorage::get::<String>("calendar_theme").ok(),
+            calendar_colors: LocalStorage::get::<String>("calendar_colors").ok(),
+        };
+        
+        // Only migrate if we have some preferences to migrate
+        if request.calendar_selected_date.is_some()
+            || request.calendar_time_increment.is_some()
+            || request.calendar_view_mode.is_some()
+            || request.calendar_theme.is_some()
+            || request.calendar_colors.is_some()
+        {
+            self.sync_preferences(&session_token, &request).await?;
+            
+            // Clear old LocalStorage entries after successful migration
+            let _ = LocalStorage::delete("calendar_selected_date");
+            let _ = LocalStorage::delete("calendar_time_increment");
+            let _ = LocalStorage::delete("calendar_view_mode");
+            let _ = LocalStorage::delete("calendar_theme");
+            let _ = LocalStorage::delete("calendar_colors");
+        }
+        
+        Ok(())
+    }
+}

frontend/styles.css

@@ -289,6 +289,27 @@ body {
     cursor: not-allowed;
 }
 
+.remember-checkbox {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    margin-top: 0.5rem;
+}
+
+.remember-checkbox input[type="checkbox"] {
+    width: auto;
+    margin: 0;
+    cursor: pointer;
+}
+
+.remember-checkbox label {
+    margin: 0;
+    font-size: 0.875rem;
+    color: #666;
+    cursor: pointer;
+    user-select: none;
+}
+
 .login-button, .register-button {
     width: 100%;
     padding: 0.75rem;