Add external calendars feature: display read-only ICS calendars alongside CalDAV calendars

- Database: Add external_calendars table with user relationships and CRUD operations
- Backend: Implement REST API endpoints for external calendar management and ICS fetching
- Frontend: Add external calendar modal, sidebar section with visibility toggles
- Calendar integration: Merge external events with regular events in unified view
- ICS parsing: Support multiple datetime formats, recurring events, and timezone handling
- Authentication: Integrate with existing JWT token system for user-specific calendars
- UI: Visual distinction with 📅 indicator and separate management section

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/migrations/006_create_external_calendars_table.sql

@@ -0,0 +1,16 @@
+-- Create external_calendars table
+CREATE TABLE external_calendars (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    name TEXT NOT NULL,
+    url TEXT NOT NULL,
+    color TEXT NOT NULL DEFAULT '#4285f4',
+    is_visible BOOLEAN NOT NULL DEFAULT 1,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    last_fetched DATETIME,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+
+-- Create index for performance
+CREATE INDEX idx_external_calendars_user_id ON external_calendars(user_id);

backend/src/auth.rs

@@ -112,6 +112,17 @@ impl AuthService {
         self.decode_token(token)
     }
 
+    /// Get user from token
+    pub async fn get_user_from_token(&self, token: &str) -> Result<crate::db::User, ApiError> {
+        let claims = self.verify_token(token)?;
+        
+        let user_repo = UserRepository::new(&self.db);
+        user_repo
+            .find_or_create(&claims.username, &claims.server_url)
+            .await
+            .map_err(|e| ApiError::Database(format!("Failed to get user: {}", e)))
+    }
+
     /// Create CalDAV config from token
     pub fn caldav_config_from_token(
         &self,

backend/src/db.rs

@@ -99,6 +99,38 @@ pub struct UserPreferences {
     pub updated_at: DateTime<Utc>,
 }
 
+/// External calendar model
+#[derive(Debug, Clone, Serialize, Deserialize, FromRow)]
+pub struct ExternalCalendar {
+    pub id: i32,
+    pub user_id: String,
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+    pub created_at: DateTime<Utc>,
+    pub updated_at: DateTime<Utc>,
+    pub last_fetched: Option<DateTime<Utc>>,
+}
+
+impl ExternalCalendar {
+    /// Create a new external calendar
+    pub fn new(user_id: String, name: String, url: String, color: String) -> Self {
+        let now = Utc::now();
+        Self {
+            id: 0, // Will be set by database
+            user_id,
+            name,
+            url,
+            color,
+            is_visible: true,
+            created_at: now,
+            updated_at: now,
+            last_fetched: None,
+        }
+    }
+}
+
 impl UserPreferences {
     /// Create default preferences for a new user
     pub fn default_for_user(user_id: String) -> Self {
@@ -308,6 +340,91 @@ impl<'a> PreferencesRepository<'a> {
         .execute(self.db.pool())
         .await?;
 
+        Ok(())
+    }
+}
+
+/// Repository for ExternalCalendar operations
+pub struct ExternalCalendarRepository<'a> {
+    db: &'a Database,
+}
+
+impl<'a> ExternalCalendarRepository<'a> {
+    pub fn new(db: &'a Database) -> Self {
+        Self { db }
+    }
+
+    /// Get all external calendars for a user
+    pub async fn get_by_user(&self, user_id: &str) -> Result<Vec<ExternalCalendar>> {
+        sqlx::query_as::<_, ExternalCalendar>(
+            "SELECT * FROM external_calendars WHERE user_id = ? ORDER BY created_at ASC",
+        )
+        .bind(user_id)
+        .fetch_all(self.db.pool())
+        .await
+    }
+
+    /// Create a new external calendar
+    pub async fn create(&self, calendar: &ExternalCalendar) -> Result<i32> {
+        let result = sqlx::query(
+            "INSERT INTO external_calendars (user_id, name, url, color, is_visible, created_at, updated_at) 
+             VALUES (?, ?, ?, ?, ?, ?, ?)",
+        )
+        .bind(&calendar.user_id)
+        .bind(&calendar.name)
+        .bind(&calendar.url)
+        .bind(&calendar.color)
+        .bind(&calendar.is_visible)
+        .bind(&calendar.created_at)
+        .bind(&calendar.updated_at)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(result.last_insert_rowid() as i32)
+    }
+
+    /// Update an external calendar
+    pub async fn update(&self, id: i32, calendar: &ExternalCalendar) -> Result<()> {
+        sqlx::query(
+            "UPDATE external_calendars 
+             SET name = ?, url = ?, color = ?, is_visible = ?, updated_at = ?
+             WHERE id = ? AND user_id = ?",
+        )
+        .bind(&calendar.name)
+        .bind(&calendar.url)
+        .bind(&calendar.color)
+        .bind(&calendar.is_visible)
+        .bind(Utc::now())
+        .bind(id)
+        .bind(&calendar.user_id)
+        .execute(self.db.pool())
+        .await?;
+
+        Ok(())
+    }
+
+    /// Delete an external calendar
+    pub async fn delete(&self, id: i32, user_id: &str) -> Result<()> {
+        sqlx::query("DELETE FROM external_calendars WHERE id = ? AND user_id = ?")
+            .bind(id)
+            .bind(user_id)
+            .execute(self.db.pool())
+            .await?;
+
+        Ok(())
+    }
+
+    /// Update last_fetched timestamp
+    pub async fn update_last_fetched(&self, id: i32, user_id: &str) -> Result<()> {
+        sqlx::query(
+            "UPDATE external_calendars SET last_fetched = ? WHERE id = ? AND user_id = ?",
+        )
+        .bind(Utc::now())
+        .bind(id)
+        .bind(user_id)
+        .execute(self.db.pool())
+        .await?;
+
         Ok(())
     }
 }

backend/src/handlers.rs

@@ -1,12 +0,0 @@
-// Re-export all handlers from the modular structure
-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/external_calendars.rs

@@ -0,0 +1,142 @@
+use axum::{
+    extract::{Path, State},
+    response::Json,
+};
+use serde::{Deserialize, Serialize};
+use std::sync::Arc;
+
+use crate::{
+    db::{ExternalCalendar, ExternalCalendarRepository},
+    models::ApiError,
+    AppState,
+};
+
+use super::auth::{extract_bearer_token};
+
+#[derive(Debug, Deserialize)]
+pub struct CreateExternalCalendarRequest {
+    pub name: String,
+    pub url: String,
+    pub color: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct UpdateExternalCalendarRequest {
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+}
+
+#[derive(Debug, Serialize)]
+pub struct ExternalCalendarResponse {
+    pub id: i32,
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+    pub created_at: chrono::DateTime<chrono::Utc>,
+    pub updated_at: chrono::DateTime<chrono::Utc>,
+    pub last_fetched: Option<chrono::DateTime<chrono::Utc>>,
+}
+
+impl From<ExternalCalendar> for ExternalCalendarResponse {
+    fn from(calendar: ExternalCalendar) -> Self {
+        Self {
+            id: calendar.id,
+            name: calendar.name,
+            url: calendar.url,
+            color: calendar.color,
+            is_visible: calendar.is_visible,
+            created_at: calendar.created_at,
+            updated_at: calendar.updated_at,
+            last_fetched: calendar.last_fetched,
+        }
+    }
+}
+
+pub async fn get_external_calendars(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+) -> Result<Json<Vec<ExternalCalendarResponse>>, ApiError> {
+    // Extract and verify token, get user
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    let calendars = repo
+        .get_by_user(&user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to get external calendars: {}", e)))?;
+
+    let response: Vec<ExternalCalendarResponse> = calendars.into_iter().map(Into::into).collect();
+    Ok(Json(response))
+}
+
+pub async fn create_external_calendar(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Json(request): Json<CreateExternalCalendarRequest>,
+) -> Result<Json<ExternalCalendarResponse>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let calendar = ExternalCalendar::new(
+        user.id,
+        request.name,
+        request.url,
+        request.color,
+    );
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    let id = repo
+        .create(&calendar)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to create external calendar: {}", e)))?;
+
+    let mut created_calendar = calendar;
+    created_calendar.id = id;
+
+    Ok(Json(created_calendar.into()))
+}
+
+pub async fn update_external_calendar(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Path(id): Path<i32>,
+    Json(request): Json<UpdateExternalCalendarRequest>,
+) -> Result<Json<()>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let mut calendar = ExternalCalendar::new(
+        user.id,
+        request.name,
+        request.url,
+        request.color,
+    );
+    calendar.is_visible = request.is_visible;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    repo.update(id, &calendar)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to update external calendar: {}", e)))?;
+
+    Ok(Json(()))
+}
+
+pub async fn delete_external_calendar(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Path(id): Path<i32>,
+) -> Result<Json<()>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    repo.delete(id, &user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to delete external calendar: {}", e)))?;
+
+    Ok(Json(()))
+}

backend/src/handlers/ics_fetcher.rs

@@ -0,0 +1,238 @@
+use axum::{
+    extract::{Path, State},
+    response::Json,
+};
+use chrono::{DateTime, Utc};
+use ical::parser::ical::component::IcalEvent;
+use reqwest::Client;
+use serde::Serialize;
+use std::sync::Arc;
+
+use crate::{
+    db::ExternalCalendarRepository,
+    models::ApiError,
+    AppState,
+};
+
+// Import VEvent from calendar-models shared crate
+use calendar_models::VEvent;
+
+use super::auth::{extract_bearer_token};
+
+#[derive(Debug, Serialize)]
+pub struct ExternalCalendarEventsResponse {
+    pub events: Vec<VEvent>,
+    pub last_fetched: DateTime<Utc>,
+}
+
+pub async fn fetch_external_calendar_events(
+    headers: axum::http::HeaderMap,
+    State(app_state): State<Arc<AppState>>,
+    Path(id): Path<i32>,
+) -> Result<Json<ExternalCalendarEventsResponse>, ApiError> {
+    let token = extract_bearer_token(&headers)?;
+    let user = app_state.auth_service.get_user_from_token(&token).await?;
+
+    let repo = ExternalCalendarRepository::new(&app_state.db);
+    
+    // Get user's external calendars to verify ownership and get URL
+    let calendars = repo
+        .get_by_user(&user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to get external calendars: {}", e)))?;
+
+    let calendar = calendars
+        .into_iter()
+        .find(|c| c.id == id)
+        .ok_or_else(|| ApiError::NotFound("External calendar not found".to_string()))?;
+
+    if !calendar.is_visible {
+        return Ok(Json(ExternalCalendarEventsResponse {
+            events: vec![],
+            last_fetched: Utc::now(),
+        }));
+    }
+
+    // Fetch ICS content from URL
+    let client = Client::new();
+    let response = client
+        .get(&calendar.url)
+        .send()
+        .await
+        .map_err(|e| ApiError::Internal(format!("Failed to fetch calendar: {}", e)))?;
+
+    if !response.status().is_success() {
+        return Err(ApiError::Internal(format!("Calendar server returned: {}", response.status())));
+    }
+
+    let ics_content = response
+        .text()
+        .await
+        .map_err(|e| ApiError::Internal(format!("Failed to read calendar content: {}", e)))?;
+
+    // Parse ICS content
+    let events = parse_ics_content(&ics_content)
+        .map_err(|e| ApiError::BadRequest(format!("Failed to parse calendar: {}", e)))?;
+
+    // Update last_fetched timestamp
+    repo.update_last_fetched(id, &user.id)
+        .await
+        .map_err(|e| ApiError::Database(format!("Failed to update last_fetched: {}", e)))?;
+
+    Ok(Json(ExternalCalendarEventsResponse {
+        events,
+        last_fetched: Utc::now(),
+    }))
+}
+
+fn parse_ics_content(ics_content: &str) -> Result<Vec<VEvent>, Box<dyn std::error::Error>> {
+    let reader = ical::IcalParser::new(ics_content.as_bytes());
+    let mut events = Vec::new();
+
+    for calendar in reader {
+        let calendar = calendar?;
+        for component in calendar.events {
+            if let Ok(vevent) = convert_ical_to_vevent(component) {
+                events.push(vevent);
+            }
+        }
+    }
+
+    Ok(events)
+}
+
+fn convert_ical_to_vevent(ical_event: IcalEvent) -> Result<VEvent, Box<dyn std::error::Error>> {
+    use uuid::Uuid;
+
+    let mut summary = None;
+    let mut description = None;
+    let mut location = None;
+    let mut dtstart = None;
+    let mut dtend = None;
+    let mut uid = None;
+    let mut all_day = false;
+    let mut rrule = None;
+
+    // Extract properties
+    for property in ical_event.properties {
+        match property.name.as_str() {
+            "SUMMARY" => {
+                summary = property.value;
+            }
+            "DESCRIPTION" => {
+                description = property.value;
+            }
+            "LOCATION" => {
+                location = property.value;
+            }
+            "DTSTART" => {
+                if let Some(value) = property.value {
+                    // Check if it's a date-only value (all-day event)
+                    if value.len() == 8 && !value.contains('T') {
+                        all_day = true;
+                        // Parse YYYYMMDD format
+                        if let Ok(date) = chrono::NaiveDate::parse_from_str(&value, "%Y%m%d") {
+                            dtstart = Some(chrono::TimeZone::from_utc_datetime(&Utc, &date.and_hms_opt(12, 0, 0).unwrap()));
+                        }
+                    } else {
+                        // Parse datetime - could be various formats
+                        if let Some(dt) = parse_datetime(&value) {
+                            dtstart = Some(dt);
+                        }
+                    }
+                }
+            }
+            "DTEND" => {
+                if let Some(value) = property.value {
+                    if all_day && value.len() == 8 && !value.contains('T') {
+                        // For all-day events, DTEND is exclusive so use the date as-is at noon
+                        if let Ok(date) = chrono::NaiveDate::parse_from_str(&value, "%Y%m%d") {
+                            dtend = Some(chrono::TimeZone::from_utc_datetime(&Utc, &date.and_hms_opt(12, 0, 0).unwrap()));
+                        }
+                    } else {
+                        if let Some(dt) = parse_datetime(&value) {
+                            dtend = Some(dt);
+                        }
+                    }
+                }
+            }
+            "UID" => {
+                uid = property.value;
+            }
+            "RRULE" => {
+                rrule = property.value;
+            }
+            _ => {} // Ignore other properties for now
+        }
+    }
+
+    let vevent = VEvent {
+        uid: uid.unwrap_or_else(|| Uuid::new_v4().to_string()),
+        dtstart: dtstart.ok_or("Missing DTSTART")?,
+        dtend,
+        summary,
+        description,
+        location,
+        all_day,
+        rrule,
+        exdate: Vec::new(), // External calendars don't need exception handling
+        recurrence_id: None,
+        created: None,
+        last_modified: None,
+        dtstamp: Utc::now(),
+        sequence: Some(0),
+        status: None,
+        transp: None,
+        organizer: None,
+        attendees: Vec::new(),
+        url: None,
+        attachments: Vec::new(),
+        categories: Vec::new(),
+        priority: None,
+        resources: Vec::new(),
+        related_to: None,
+        geo: None,
+        duration: None,
+        class: None,
+        contact: None,
+        comment: None,
+        rdate: Vec::new(),
+        alarms: Vec::new(),
+        etag: None,
+        href: None,
+        calendar_path: None,
+    };
+
+    Ok(vevent)
+}
+
+fn parse_datetime(datetime_str: &str) -> Option<DateTime<Utc>> {
+    // Try various datetime formats commonly found in ICS files
+    
+    // Format: 20231201T103000Z (UTC)
+    if let Ok(dt) = DateTime::parse_from_str(datetime_str, "%Y%m%dT%H%M%SZ") {
+        return Some(dt.with_timezone(&Utc));
+    }
+    
+    // Format: 20231201T103000 (floating time - assume UTC)
+    if let Ok(dt) = chrono::NaiveDateTime::parse_from_str(datetime_str, "%Y%m%dT%H%M%S") {
+        return Some(chrono::TimeZone::from_utc_datetime(&Utc, &dt));
+    }
+
+    // Format: 20231201T103000-0500 (with timezone offset)
+    if let Ok(dt) = DateTime::parse_from_str(datetime_str, "%Y%m%dT%H%M%S%z") {
+        return Some(dt.with_timezone(&Utc));
+    }
+
+    // Format: 2023-12-01T10:30:00Z (ISO format)
+    if let Ok(dt) = DateTime::parse_from_str(datetime_str, "%Y-%m-%dT%H:%M:%SZ") {
+        return Some(dt.with_timezone(&Utc));
+    }
+
+    // Format: 2023-12-01T10:30:00 (ISO without timezone)
+    if let Ok(dt) = chrono::NaiveDateTime::parse_from_str(datetime_str, "%Y-%m-%dT%H:%M:%S") {
+        return Some(chrono::TimeZone::from_utc_datetime(&Utc, &dt));
+    }
+
+    None
+}

backend/src/handlers/mod.rs

@@ -0,0 +1,15 @@
+pub mod auth;
+pub mod calendar;
+pub mod events;
+pub mod external_calendars;
+pub mod ics_fetcher;
+pub mod preferences;
+pub mod series;
+
+pub use auth::*;
+pub use calendar::*;
+pub use events::*;
+pub use external_calendars::*;
+pub use ics_fetcher::*;
+pub use preferences::*;
+pub use series::*;

backend/src/lib.rs

@@ -1,6 +1,6 @@
 use axum::{
     response::Json,
-    routing::{get, post},
+    routing::{delete, get, post},
     Router,
 };
 use std::sync::Arc;
@@ -72,6 +72,12 @@ pub async fn run_server() -> Result<(), Box<dyn std::error::Error>> {
         .route("/api/preferences", get(handlers::get_preferences))
         .route("/api/preferences", post(handlers::update_preferences))
         .route("/api/auth/logout", post(handlers::logout))
+        // External calendars endpoints
+        .route("/api/external-calendars", get(handlers::get_external_calendars))
+        .route("/api/external-calendars", post(handlers::create_external_calendar))
+        .route("/api/external-calendars/:id", post(handlers::update_external_calendar))
+        .route("/api/external-calendars/:id", delete(handlers::delete_external_calendar))
+        .route("/api/external-calendars/:id/events", get(handlers::fetch_external_calendar_events))
         .layer(
             CorsLayer::new()
                 .allow_origin(Any)

frontend/Cargo.toml

@@ -37,6 +37,7 @@ reqwest = { version = "0.11", features = ["json"] }
 ical = "0.7"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+serde-wasm-bindgen = "0.6"
 
 # Date and time handling
 chrono = { version = "0.4", features = ["serde", "wasm-bindgen"] }

frontend/src/app.rs

@@ -1,10 +1,11 @@
 use crate::components::{
     CalendarContextMenu, ContextMenu, CreateCalendarModal, CreateEventModal, DeleteAction,
-    EditAction, EventContextMenu, EventCreationData, RouteHandler, Sidebar, Theme, ViewMode,
+    EditAction, EventContextMenu, EventCreationData, ExternalCalendarModal, RouteHandler, 
+    Sidebar, Theme, ViewMode,
 };
 use crate::components::sidebar::{Style};
 use crate::models::ical::VEvent;
-use crate::services::{calendar_service::UserInfo, CalendarService};
+use crate::services::{calendar_service::{UserInfo, ExternalCalendar}, CalendarService};
 use chrono::NaiveDate;
 use gloo_storage::{LocalStorage, Storage};
 use wasm_bindgen::JsCast;
@@ -73,6 +74,11 @@ pub fn App() -> Html {
     let _recurring_edit_modal_open = use_state(|| false);
     let _recurring_edit_event = use_state(|| -> Option<VEvent> { None });
     let _recurring_edit_data = use_state(|| -> Option<EventCreationData> { None });
+    
+    // External calendar state
+    let external_calendars = use_state(|| -> Vec<ExternalCalendar> { Vec::new() });
+    let external_calendar_events = use_state(|| -> Vec<VEvent> { Vec::new() });
+    let external_calendar_modal_open = use_state(|| false);
 
     // Calendar view state - load from localStorage if available
     let current_view = use_state(|| {
@@ -301,6 +307,50 @@ pub fn App() -> Html {
         });
     }
 
+    // Load external calendars when auth token is available
+    {
+        let auth_token = auth_token.clone();
+        let external_calendars = external_calendars.clone();
+        let external_calendar_events = external_calendar_events.clone();
+
+        use_effect_with((*auth_token).clone(), move |token| {
+            if token.is_some() {
+                let external_calendars = external_calendars.clone();
+                let external_calendar_events = external_calendar_events.clone();
+
+                wasm_bindgen_futures::spawn_local(async move {
+                    // Load external calendars
+                    match CalendarService::get_external_calendars().await {
+                        Ok(calendars) => {
+                            external_calendars.set(calendars.clone());
+                            
+                            // Load events for visible external calendars
+                            let mut all_events = Vec::new();
+                            for calendar in calendars {
+                                if calendar.is_visible {
+                                    if let Ok(events) = CalendarService::fetch_external_calendar_events(calendar.id).await {
+                                        all_events.extend(events);
+                                    }
+                                }
+                            }
+                            external_calendar_events.set(all_events);
+                        }
+                        Err(err) => {
+                            web_sys::console::log_1(
+                                &format!("Failed to load external calendars: {}", err).into(),
+                            );
+                        }
+                    }
+                });
+            } else {
+                external_calendars.set(Vec::new());
+                external_calendar_events.set(Vec::new());
+            }
+
+            || ()
+        });
+    }
+
     let on_outside_click = {
         let color_picker_open = color_picker_open.clone();
         let context_menu_open = context_menu_open.clone();
@@ -924,6 +974,53 @@ pub fn App() -> Html {
                                         let create_modal_open = create_modal_open.clone();
                                         move |_| create_modal_open.set(true)
                                     })}
+                                    on_create_external_calendar={Callback::from({
+                                        let external_calendar_modal_open = external_calendar_modal_open.clone();
+                                        move |_| external_calendar_modal_open.set(true)
+                                    })}
+                                    external_calendars={(*external_calendars).clone()}
+                                    on_external_calendar_toggle={Callback::from({
+                                        let external_calendars = external_calendars.clone();
+                                        let external_calendar_events = external_calendar_events.clone();
+                                        move |id: i32| {
+                                            let external_calendars = external_calendars.clone();
+                                            let external_calendar_events = external_calendar_events.clone();
+                                            wasm_bindgen_futures::spawn_local(async move {
+                                                // Find the calendar and toggle its visibility
+                                                let mut calendars = (*external_calendars).clone();
+                                                if let Some(calendar) = calendars.iter_mut().find(|c| c.id == id) {
+                                                    calendar.is_visible = !calendar.is_visible;
+                                                    
+                                                    // Update on server
+                                                    if let Err(err) = CalendarService::update_external_calendar(
+                                                        calendar.id,
+                                                        &calendar.name,
+                                                        &calendar.url,
+                                                        &calendar.color,
+                                                        calendar.is_visible,
+                                                    ).await {
+                                                        web_sys::console::log_1(
+                                                            &format!("Failed to update external calendar: {}", err).into(),
+                                                        );
+                                                        return;
+                                                    }
+                                                    
+                                                    external_calendars.set(calendars.clone());
+                                                    
+                                                    // Reload events for all visible external calendars
+                                                    let mut all_events = Vec::new();
+                                                    for cal in calendars {
+                                                        if cal.is_visible {
+                                                            if let Ok(events) = CalendarService::fetch_external_calendar_events(cal.id).await {
+                                                                all_events.extend(events);
+                                                            }
+                                                        }
+                                                    }
+                                                    external_calendar_events.set(all_events);
+                                                }
+                                            });
+                                        }
+                                    })}
                                     color_picker_open={(*color_picker_open).clone()}
                                     on_color_change={on_color_change}
                                     on_color_picker_toggle={on_color_picker_toggle}
@@ -941,6 +1038,7 @@ pub fn App() -> Html {
                                         auth_token={(*auth_token).clone()}
                                         user_info={(*user_info).clone()}
                                         on_login={on_login.clone()}
+                                        external_calendar_events={(*external_calendar_events).clone()}
                                         on_event_context_menu={Some(on_event_context_menu.clone())}
                                         on_calendar_context_menu={Some(on_calendar_date_context_menu.clone())}
                                         view={(*current_view).clone()}
@@ -1193,6 +1291,46 @@ pub fn App() -> Html {
                     on_create={on_event_create}
                     available_calendars={user_info.as_ref().map(|ui| ui.calendars.clone()).unwrap_or_default()}
                 />
+
+                <ExternalCalendarModal
+                    is_open={*external_calendar_modal_open}
+                    on_close={Callback::from({
+                        let external_calendar_modal_open = external_calendar_modal_open.clone();
+                        move |_| external_calendar_modal_open.set(false)
+                    })}
+                    on_success={Callback::from({
+                        let external_calendars = external_calendars.clone();
+                        let external_calendar_events = external_calendar_events.clone();
+                        move |_| {
+                            // Reload external calendars
+                            let external_calendars = external_calendars.clone();
+                            let external_calendar_events = external_calendar_events.clone();
+                            wasm_bindgen_futures::spawn_local(async move {
+                                match CalendarService::get_external_calendars().await {
+                                    Ok(calendars) => {
+                                        external_calendars.set(calendars.clone());
+                                        
+                                        // Load events for visible external calendars
+                                        let mut all_events = Vec::new();
+                                        for calendar in calendars {
+                                            if calendar.is_visible {
+                                                if let Ok(events) = CalendarService::fetch_external_calendar_events(calendar.id).await {
+                                                    all_events.extend(events);
+                                                }
+                                            }
+                                        }
+                                        external_calendar_events.set(all_events);
+                                    }
+                                    Err(err) => {
+                                        web_sys::console::log_1(
+                                            &format!("Failed to reload external calendars: {}", err).into(),
+                                        );
+                                    }
+                                }
+                            });
+                        }
+                    })}
+                />
             </div>
         </BrowserRouter>
     }

frontend/src/components/calendar.rs

@@ -14,6 +14,8 @@ pub struct CalendarProps {
     #[prop_or_default]
     pub user_info: Option<UserInfo>,
     #[prop_or_default]
+    pub external_calendar_events: Vec<VEvent>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, NaiveDate)>>,
@@ -101,10 +103,13 @@ pub fn Calendar(props: &CalendarProps) -> Html {
         let loading = loading.clone();
         let error = error.clone();
         let current_date = current_date.clone();
+        let external_events = props.external_calendar_events.clone(); // Clone before the effect
+        let view = props.view.clone(); // Clone before the effect
         
-        use_effect_with((*current_date, props.view.clone()), move |(date, _view)| {
+        use_effect_with((*current_date, view.clone(), external_events.len()), move |(date, _view, _external_len)| {
             let auth_token: Option<String> = LocalStorage::get("auth_token").ok();
             let date = *date; // Clone the date to avoid lifetime issues
+            let external_events = external_events.clone(); // Clone external events to avoid lifetime issues
             
             if let Some(token) = auth_token {
                 let events = events.clone();
@@ -141,7 +146,11 @@ pub fn Calendar(props: &CalendarProps) -> Html {
                         .await
                     {
                         Ok(vevents) => {
-                            let grouped_events = CalendarService::group_events_by_date(vevents);
+                            // Combine regular events with external calendar events
+                            let mut all_events = vevents;
+                            all_events.extend(external_events);
+                            
+                            let grouped_events = CalendarService::group_events_by_date(all_events);
                             events.set(grouped_events);
                             loading.set(false);
                         }

frontend/src/components/external_calendar_modal.rs

@@ -0,0 +1,193 @@
+use web_sys::HtmlInputElement;
+use yew::prelude::*;
+
+use crate::services::calendar_service::CalendarService;
+
+#[derive(Properties, PartialEq)]
+pub struct ExternalCalendarModalProps {
+    pub is_open: bool,
+    pub on_close: Callback<()>,
+    pub on_success: Callback<()>,
+}
+
+#[function_component(ExternalCalendarModal)]
+pub fn external_calendar_modal(props: &ExternalCalendarModalProps) -> Html {
+    let name_ref = use_node_ref();
+    let url_ref = use_node_ref();
+    let color_ref = use_node_ref();
+    let is_loading = use_state(|| false);
+    let error_message = use_state(|| None::<String>);
+
+    let on_submit = {
+        let name_ref = name_ref.clone();
+        let url_ref = url_ref.clone();
+        let color_ref = color_ref.clone();
+        let is_loading = is_loading.clone();
+        let error_message = error_message.clone();
+        let on_close = props.on_close.clone();
+        let on_success = props.on_success.clone();
+
+        Callback::from(move |e: SubmitEvent| {
+            e.prevent_default();
+            
+            let name = name_ref
+                .cast::<HtmlInputElement>()
+                .map(|input| input.value())
+                .unwrap_or_default()
+                .trim()
+                .to_string();
+            
+            let url = url_ref
+                .cast::<HtmlInputElement>()
+                .map(|input| input.value())
+                .unwrap_or_default()
+                .trim()
+                .to_string();
+                
+            let color = color_ref
+                .cast::<HtmlInputElement>()
+                .map(|input| input.value())
+                .unwrap_or_else(|| "#4285f4".to_string());
+
+            if name.is_empty() {
+                error_message.set(Some("Calendar name is required".to_string()));
+                return;
+            }
+
+            if url.is_empty() {
+                error_message.set(Some("Calendar URL is required".to_string()));
+                return;
+            }
+
+            // Basic URL validation
+            if !url.starts_with("http://") && !url.starts_with("https://") {
+                error_message.set(Some("Please enter a valid HTTP or HTTPS URL".to_string()));
+                return;
+            }
+
+            error_message.set(None);
+            is_loading.set(true);
+
+            let is_loading = is_loading.clone();
+            let error_message = error_message.clone();
+            let on_close = on_close.clone();
+            let on_success = on_success.clone();
+
+            wasm_bindgen_futures::spawn_local(async move {
+                match CalendarService::create_external_calendar(&name, &url, &color).await {
+                    Ok(_) => {
+                        is_loading.set(false);
+                        on_success.emit(());
+                        on_close.emit(());
+                    }
+                    Err(e) => {
+                        is_loading.set(false);
+                        error_message.set(Some(format!("Failed to add calendar: {}", e)));
+                    }
+                }
+            });
+        })
+    };
+
+    let on_cancel = {
+        let on_close = props.on_close.clone();
+        Callback::from(move |_| {
+            on_close.emit(());
+        })
+    };
+    
+    let on_cancel_clone = on_cancel.clone();
+
+    if !props.is_open {
+        return html! {};
+    }
+
+    html! {
+        <div class="modal-overlay" onclick={on_cancel_clone}>
+            <div class="modal-content" onclick={Callback::from(|e: MouseEvent| e.stop_propagation())}>
+                <div class="modal-header">
+                    <h3>{"Add External Calendar"}</h3>
+                    <button class="modal-close" onclick={on_cancel.clone()}>{"×"}</button>
+                </div>
+                
+                <form onsubmit={on_submit}>
+                    <div class="modal-body">
+                        {
+                            if let Some(error) = (*error_message).as_ref() {
+                                html! {
+                                    <div class="error-message">
+                                        {error}
+                                    </div>
+                                }
+                            } else {
+                                html! {}
+                            }
+                        }
+                        
+                        <div class="form-group">
+                            <label for="external-calendar-name">{"Calendar Name"}</label>
+                            <input
+                                ref={name_ref}
+                                id="external-calendar-name"
+                                type="text"
+                                placeholder="My External Calendar"
+                                disabled={*is_loading}
+                                required={true}
+                            />
+                        </div>
+
+                        <div class="form-group">
+                            <label for="external-calendar-url">{"ICS URL"}</label>
+                            <input
+                                ref={url_ref}
+                                id="external-calendar-url"
+                                type="url"
+                                placeholder="https://example.com/calendar.ics"
+                                disabled={*is_loading}
+                                required={true}
+                            />
+                            <small class="form-help">
+                                {"Enter the public ICS URL for the calendar you want to add"}
+                            </small>
+                        </div>
+
+                        <div class="form-group">
+                            <label for="external-calendar-color">{"Color"}</label>
+                            <input
+                                ref={color_ref}
+                                id="external-calendar-color"
+                                type="color"
+                                value="#4285f4"
+                                disabled={*is_loading}
+                            />
+                        </div>
+                    </div>
+
+                    <div class="modal-actions">
+                        <button
+                            type="button"
+                            class="btn btn-secondary"
+                            onclick={on_cancel}
+                            disabled={*is_loading}
+                        >
+                            {"Cancel"}
+                        </button>
+                        <button
+                            type="submit"
+                            class="btn btn-primary"
+                            disabled={*is_loading}
+                        >
+                            {
+                                if *is_loading {
+                                    "Adding..."
+                                } else {
+                                    "Add Calendar"
+                                }
+                            }
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+    }
+}

frontend/src/components/mod.rs

@@ -8,6 +8,7 @@ pub mod create_event_modal;
 pub mod event_context_menu;
 pub mod event_form;
 pub mod event_modal;
+pub mod external_calendar_modal;
 pub mod login;
 pub mod month_view;
 pub mod recurring_edit_modal;
@@ -26,6 +27,7 @@ pub use create_event_modal::CreateEventModal;
 pub use event_form::EventCreationData;
 pub use event_context_menu::{DeleteAction, EditAction, EventContextMenu};
 pub use event_modal::EventModal;
+pub use external_calendar_modal::ExternalCalendarModal;
 pub use login::Login;
 pub use month_view::MonthView;
 pub use recurring_edit_modal::{RecurringEditAction, RecurringEditModal};

frontend/src/components/route_handler.rs

@@ -20,6 +20,8 @@ pub struct RouteHandlerProps {
     pub user_info: Option<UserInfo>,
     pub on_login: Callback<String>,
     #[prop_or_default]
+    pub external_calendar_events: Vec<VEvent>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, chrono::NaiveDate)>>,
@@ -48,6 +50,7 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
     let auth_token = props.auth_token.clone();
     let user_info = props.user_info.clone();
     let on_login = props.on_login.clone();
+    let external_calendar_events = props.external_calendar_events.clone();
     let on_event_context_menu = props.on_event_context_menu.clone();
     let on_calendar_context_menu = props.on_calendar_context_menu.clone();
     let view = props.view.clone();
@@ -60,6 +63,7 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
             let auth_token = auth_token.clone();
             let user_info = user_info.clone();
             let on_login = on_login.clone();
+            let external_calendar_events = external_calendar_events.clone();
             let on_event_context_menu = on_event_context_menu.clone();
             let on_calendar_context_menu = on_calendar_context_menu.clone();
             let view = view.clone();
@@ -87,6 +91,7 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
                         html! {
                             <CalendarView
                                 user_info={user_info}
+                                external_calendar_events={external_calendar_events}
                                 on_event_context_menu={on_event_context_menu}
                                 on_calendar_context_menu={on_calendar_context_menu}
                                 view={view}
@@ -108,6 +113,8 @@ pub fn route_handler(props: &RouteHandlerProps) -> Html {
 pub struct CalendarViewProps {
     pub user_info: Option<UserInfo>,
     #[prop_or_default]
+    pub external_calendar_events: Vec<VEvent>,
+    #[prop_or_default]
     pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
     #[prop_or_default]
     pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, chrono::NaiveDate)>>,
@@ -139,6 +146,7 @@ pub fn calendar_view(props: &CalendarViewProps) -> Html {
         <div class="calendar-view">
             <Calendar
                 user_info={props.user_info.clone()}
+                external_calendar_events={props.external_calendar_events.clone()}
                 on_event_context_menu={props.on_event_context_menu.clone()}
                 on_calendar_context_menu={props.on_calendar_context_menu.clone()}
                 view={props.view.clone()}

frontend/src/components/sidebar.rs

@@ -1,5 +1,5 @@
 use crate::components::CalendarListItem;
-use crate::services::calendar_service::UserInfo;
+use crate::services::calendar_service::{UserInfo, ExternalCalendar};
 use web_sys::HtmlSelectElement;
 use yew::prelude::*;
 use yew_router::prelude::*;
@@ -101,6 +101,9 @@ pub struct SidebarProps {
     pub user_info: Option<UserInfo>,
     pub on_logout: Callback<()>,
     pub on_create_calendar: Callback<()>,
+    pub on_create_external_calendar: Callback<()>,
+    pub external_calendars: Vec<ExternalCalendar>,
+    pub on_external_calendar_toggle: Callback<i32>,
     pub color_picker_open: Option<String>,
     pub on_color_change: Callback<(String, String)>,
     pub on_color_picker_toggle: Callback<String>,
@@ -206,10 +209,59 @@ pub fn sidebar(props: &SidebarProps) -> Html {
                     html! {}
                 }
             }
+            
+            // External calendars section
+            <div class="external-calendar-list">
+                <h3>{"External Calendars"}</h3>
+                {
+                    if !props.external_calendars.is_empty() {
+                        html! {
+                            <ul class="external-calendar-items">
+                                {
+                                    props.external_calendars.iter().map(|cal| {
+                                        let on_toggle = {
+                                            let on_external_calendar_toggle = props.on_external_calendar_toggle.clone();
+                                            let cal_id = cal.id;
+                                            Callback::from(move |_| {
+                                                on_external_calendar_toggle.emit(cal_id);
+                                            })
+                                        };
+                                        
+                                        html! {
+                                            <li class="external-calendar-item">
+                                                <div class="external-calendar-info">
+                                                    <input
+                                                        type="checkbox"
+                                                        checked={cal.is_visible}
+                                                        onchange={on_toggle}
+                                                    />
+                                                    <span 
+                                                        class="external-calendar-color" 
+                                                        style={format!("background-color: {}", cal.color)}
+                                                    />
+                                                    <span class="external-calendar-name">{&cal.name}</span>
+                                                    <span class="external-calendar-indicator">{"📅"}</span>
+                                                </div>
+                                            </li>
+                                        }
+                                    }).collect::<Html>()
+                                }
+                            </ul>
+                        }
+                    } else {
+                        html! {}
+                    }
+                }
+            </div>
+            
             <div class="sidebar-footer">
                 <button onclick={props.on_create_calendar.reform(|_| ())} class="create-calendar-button">
                     {"+ Create Calendar"}
                 </button>
+                
+                <button onclick={props.on_create_external_calendar.reform(|_| ())} class="create-external-calendar-button">
+                    {"+ Add External Calendar"}
+                </button>
 
                 <div class="view-selector">
                     <select class="view-selector-dropdown" onchange={on_view_change}>

frontend/src/services/calendar_service.rs

@@ -1,4 +1,5 @@
 use chrono::{DateTime, Datelike, Duration, NaiveDate, TimeZone, Utc, Weekday};
+use gloo_storage::{LocalStorage, Storage};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use wasm_bindgen::JsCast;
@@ -1854,4 +1855,256 @@ impl CalendarService {
 
         None
     }
+
+    // ==================== EXTERNAL CALENDAR METHODS ====================
+
+    pub async fn get_external_calendars() -> Result<Vec<ExternalCalendar>, String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("GET");
+        opts.set_mode(RequestMode::Cors);
+
+        let service = Self::new();
+        let url = format!("{}/external-calendars", service.base_url);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        let json = JsFuture::from(resp.json().unwrap())
+            .await
+            .map_err(|e| format!("JSON parsing failed: {:?}", e))?;
+
+        let external_calendars: Vec<ExternalCalendar> = serde_wasm_bindgen::from_value(json)
+            .map_err(|e| format!("Deserialization failed: {:?}", e))?;
+
+        Ok(external_calendars)
+    }
+
+    pub async fn create_external_calendar(name: &str, url: &str, color: &str) -> Result<ExternalCalendar, String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("POST");
+        opts.set_mode(RequestMode::Cors);
+
+        let body = serde_json::json!({
+            "name": name,
+            "url": url,
+            "color": color
+        });
+
+        let service = Self::new();
+        let body_string = serde_json::to_string(&body)
+            .map_err(|e| format!("JSON serialization failed: {}", e))?;
+        opts.set_body(&body_string.into());
+
+        let url = format!("{}/external-calendars", service.base_url);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Content-Type", "application/json")
+            .map_err(|e| format!("Content-Type header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        let json = JsFuture::from(resp.json().unwrap())
+            .await
+            .map_err(|e| format!("JSON parsing failed: {:?}", e))?;
+
+        let external_calendar: ExternalCalendar = serde_wasm_bindgen::from_value(json)
+            .map_err(|e| format!("Deserialization failed: {:?}", e))?;
+
+        Ok(external_calendar)
+    }
+
+    pub async fn update_external_calendar(
+        id: i32,
+        name: &str,
+        url: &str,
+        color: &str,
+        is_visible: bool,
+    ) -> Result<(), String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("POST");
+        opts.set_mode(RequestMode::Cors);
+
+        let body = serde_json::json!({
+            "name": name,
+            "url": url,
+            "color": color,
+            "is_visible": is_visible
+        });
+
+        let service = Self::new();
+        let body_string = serde_json::to_string(&body)
+            .map_err(|e| format!("JSON serialization failed: {}", e))?;
+        opts.set_body(&body_string.into());
+
+        let url = format!("{}/external-calendars/{}", service.base_url, id);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Content-Type", "application/json")
+            .map_err(|e| format!("Content-Type header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        Ok(())
+    }
+
+    pub async fn delete_external_calendar(id: i32) -> Result<(), String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("DELETE");
+        opts.set_mode(RequestMode::Cors);
+
+        let service = Self::new();
+        let url = format!("{}/external-calendars/{}", service.base_url, id);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        Ok(())
+    }
+
+    pub async fn fetch_external_calendar_events(id: i32) -> Result<Vec<VEvent>, String> {
+        let token = LocalStorage::get::<String>("auth_token")
+            .map_err(|_| "No authentication token found".to_string())?;
+
+        let window = web_sys::window().ok_or("No global window exists")?;
+
+        let opts = RequestInit::new();
+        opts.set_method("GET");
+        opts.set_mode(RequestMode::Cors);
+
+        let service = Self::new();
+        let url = format!("{}/external-calendars/{}/events", service.base_url, id);
+        let request = Request::new_with_str_and_init(&url, &opts)
+            .map_err(|e| format!("Request creation failed: {:?}", e))?;
+
+        request
+            .headers()
+            .set("Authorization", &format!("Bearer {}", token))
+            .map_err(|e| format!("Authorization header setting failed: {:?}", e))?;
+
+        let resp_value = JsFuture::from(window.fetch_with_request(&request))
+            .await
+            .map_err(|e| format!("Request failed: {:?}", e))?;
+
+        let resp: Response = resp_value
+            .dyn_into()
+            .map_err(|e| format!("Response casting failed: {:?}", e))?;
+
+        if !resp.ok() {
+            return Err(format!("HTTP error: {}", resp.status()));
+        }
+
+        let json = JsFuture::from(resp.json().unwrap())
+            .await
+            .map_err(|e| format!("JSON parsing failed: {:?}", e))?;
+
+        #[derive(Deserialize)]
+        struct ExternalCalendarEventsResponse {
+            events: Vec<VEvent>,
+        }
+
+        let response: ExternalCalendarEventsResponse = serde_wasm_bindgen::from_value(json)
+            .map_err(|e| format!("Deserialization failed: {:?}", e))?;
+
+        Ok(response.events)
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct ExternalCalendar {
+    pub id: i32,
+    pub name: String,
+    pub url: String,
+    pub color: String,
+    pub is_visible: bool,
+    pub created_at: chrono::DateTime<chrono::Utc>,
+    pub updated_at: chrono::DateTime<chrono::Utc>,
+    pub last_fetched: Option<chrono::DateTime<chrono::Utc>>,
 }