iCalendar export: domain service + API + MCP tool (#15)

crates/presentation/src/handlers/schedule.rs

@@ -1,6 +1,6 @@
 use axum::Json;
 use axum::extract::{Path, State};
-use axum::http::StatusCode;
+use axum::http::{StatusCode, header};
 use axum::response::IntoResponse;
 use chrono::Utc;
 
@@ -10,6 +10,7 @@ use api_types::{
 use application::schedule::{
     GenerateScheduleCommand, GetCurrentBroadcastQuery, GetEpgQuery, GetSourceQuery,
 };
+use domain::DomainError;
 use domain::value_objects::ChannelId;
 
 use crate::errors::AppError;
@@ -91,3 +92,26 @@ pub async fn list_schedule_history(
             .collect(),
     ))
 }
+
+pub async fn export_ical(
+    State(state): State<AppState>,
+    Path(id): Path<uuid::Uuid>,
+) -> Result<axum::response::Response, AppError> {
+    let channel = state
+        .channel_query
+        .find_by_id(id.into())
+        .await?
+        .ok_or_else(|| AppError(DomainError::NotFound(format!("Channel {id} not found"))))?;
+
+    let ical = domain::generate_ical(channel.name(), channel.timezone(), channel.schedule_config());
+    let disposition = format!("attachment; filename=\"{}.ics\"", channel.name());
+
+    Ok((
+        [
+            (header::CONTENT_TYPE, "text/calendar; charset=utf-8".to_string()),
+            (header::CONTENT_DISPOSITION, disposition),
+        ],
+        ical,
+    )
+        .into_response())
+}