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/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)