story-kit: merge 322_story_whatsapp_24_hour_messaging_window_and_template_support

server/src/whatsapp.rs

@@ -3,6 +3,7 @@
 //! Provides:
 //! - [`WhatsAppTransport`] — a [`ChatTransport`] that sends messages via the
 //!   Meta Graph API (`graph.facebook.com/v21.0/{phone_number_id}/messages`).
+//! - [`MessagingWindowTracker`] — tracks the 24-hour messaging window per user.
 //! - [`webhook_verify`] / [`webhook_receive`] — Poem handlers for the WhatsApp
 //!   webhook (GET verification handshake + POST incoming messages).
 
@@ -21,45 +22,130 @@ use crate::transport::{ChatTransport, MessageId};
 
 const GRAPH_API_BASE: &str = "https://graph.facebook.com/v21.0";
 
+/// Graph API error code indicating the 24-hour messaging window has elapsed.
+///
+/// When Meta returns this code the caller must fall back to an approved message
+/// template instead of free-form text.
+const ERROR_CODE_OUTSIDE_WINDOW: i64 = 131047;
+
+/// Sentinel error string returned by [`WhatsAppTransport::send_text`] when the
+/// Graph API reports that the 24-hour messaging window has expired.
+const OUTSIDE_WINDOW_ERR: &str = "OUTSIDE_MESSAGING_WINDOW";
+
+// ── Messaging window tracker ─────────────────────────────────────────────
+
+/// Tracks the 24-hour messaging window per WhatsApp phone number.
+///
+/// Meta's Business API only permits free-form text messages within 24 hours of
+/// the last *inbound* message from that user.  After that window expires, only
+/// approved message templates may be sent.
+///
+/// Call [`record_message`] whenever an inbound message is received.  Before
+/// sending a proactive notification, call [`is_within_window`] to choose
+/// between free-form text and a template message.
+pub struct MessagingWindowTracker {
+    last_message: std::sync::Mutex<HashMap<String, std::time::Instant>>,
+    window_duration: std::time::Duration,
+}
+
+impl Default for MessagingWindowTracker {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl MessagingWindowTracker {
+    /// Create a tracker with the standard 24-hour window.
+    pub fn new() -> Self {
+        Self {
+            last_message: std::sync::Mutex::new(HashMap::new()),
+            window_duration: std::time::Duration::from_secs(24 * 60 * 60),
+        }
+    }
+
+    /// Create a tracker with a custom window duration (useful in tests).
+    #[cfg(test)]
+    fn with_duration(window_duration: std::time::Duration) -> Self {
+        Self {
+            last_message: std::sync::Mutex::new(HashMap::new()),
+            window_duration,
+        }
+    }
+
+    /// Record that `phone` sent an inbound message right now.
+    pub fn record_message(&self, phone: &str) {
+        self.last_message
+            .lock()
+            .unwrap()
+            .insert(phone.to_string(), std::time::Instant::now());
+    }
+
+    /// Returns `true` when the last inbound message from `phone` arrived within
+    /// the 24-hour window, meaning free-form replies are still permitted.
+    pub fn is_within_window(&self, phone: &str) -> bool {
+        let map = self.last_message.lock().unwrap();
+        match map.get(phone) {
+            Some(&instant) => instant.elapsed() < self.window_duration,
+            None => false,
+        }
+    }
+}
+
 // ── WhatsApp Transport ──────────────────────────────────────────────────
 
 /// Real WhatsApp Business API transport.
 ///
 /// Sends text messages via `POST {GRAPH_API_BASE}/{phone_number_id}/messages`.
+/// Falls back to approved notification templates when the 24-hour window has
+/// elapsed (Meta error 131047).
 pub struct WhatsAppTransport {
     phone_number_id: String,
     access_token: String,
     client: reqwest::Client,
+    /// Name of the approved Meta message template used for notifications
+    /// outside the 24-hour messaging window.
+    notification_template_name: String,
     /// Optional base URL override for tests.
     api_base: String,
 }
 
 impl WhatsAppTransport {
-    pub fn new(phone_number_id: String, access_token: String) -> Self {
+    pub fn new(
+        phone_number_id: String,
+        access_token: String,
+        notification_template_name: String,
+    ) -> Self {
         Self {
             phone_number_id,
             access_token,
             client: reqwest::Client::new(),
+            notification_template_name,
             api_base: GRAPH_API_BASE.to_string(),
         }
     }
 
     #[cfg(test)]
-    fn with_api_base(phone_number_id: String, access_token: String, api_base: String) -> Self {
+    fn with_api_base(
+        phone_number_id: String,
+        access_token: String,
+        api_base: String,
+    ) -> Self {
         Self {
             phone_number_id,
             access_token,
             client: reqwest::Client::new(),
+            notification_template_name: "pipeline_notification".to_string(),
             api_base,
         }
     }
 
-    /// Send a text message to a WhatsApp user via the Graph API.
+    /// Send a free-form text message to a WhatsApp user via the Graph API.
+    ///
+    /// Returns [`OUTSIDE_WINDOW_ERR`] if the API responds with error code
+    /// 131047 (messaging window expired).  All other errors are returned as
+    /// descriptive strings.
     async fn send_text(&self, to: &str, body: &str) -> Result<String, String> {
-        let url = format!(
-            "{}/{}/messages",
-            self.api_base, self.phone_number_id
-        );
+        let url = format!("{}/{}/messages", self.api_base, self.phone_number_id);
 
         let payload = GraphSendMessage {
             messaging_product: "whatsapp",
@@ -84,9 +170,19 @@ impl WhatsAppTransport {
             .unwrap_or_else(|_| "<no body>".to_string());
 
         if !status.is_success() {
-            return Err(format!(
-                "WhatsApp API returned {status}: {resp_text}"
-            ));
+            // Check for 'outside messaging window' (code 131047).  Return a
+            // distinct sentinel so callers can fall back to a template without
+            // crashing.
+            if let Ok(err_body) = serde_json::from_str::<GraphApiErrorResponse>(&resp_text)
+                && err_body.error.as_ref().and_then(|e| e.code) == Some(ERROR_CODE_OUTSIDE_WINDOW)
+            {
+                slog!(
+                    "[whatsapp] Outside 24-hour messaging window for {to}; \
+                     template required (error 131047)"
+                );
+                return Err(OUTSIDE_WINDOW_ERR.to_string());
+            }
+            return Err(format!("WhatsApp API returned {status}: {resp_text}"));
         }
 
         // Extract the message ID from the response.
@@ -102,6 +198,116 @@ impl WhatsAppTransport {
 
         Ok(msg_id)
     }
+
+    /// Send an approved template notification message.
+    ///
+    /// Used when the 24-hour window has expired and free-form text is not
+    /// permitted.  The template must already be approved in the Meta Business
+    /// Manager under the name configured in `bot.toml`
+    /// (`whatsapp_notification_template`, default `pipeline_notification`).
+    ///
+    /// The template body is expected to accept two positional parameters:
+    /// `{{1}}` = story name, `{{2}}` = pipeline stage.
+    pub async fn send_template_notification(
+        &self,
+        to: &str,
+        story_name: &str,
+        stage: &str,
+    ) -> Result<String, String> {
+        let url = format!("{}/{}/messages", self.api_base, self.phone_number_id);
+
+        let payload = GraphTemplateMessage {
+            messaging_product: "whatsapp",
+            to,
+            r#type: "template",
+            template: GraphTemplate {
+                name: &self.notification_template_name,
+                language: GraphLanguage { code: "en_US" },
+                components: vec![GraphTemplateComponent {
+                    r#type: "body",
+                    parameters: vec![
+                        GraphTemplateParameter {
+                            r#type: "text",
+                            text: story_name.to_string(),
+                        },
+                        GraphTemplateParameter {
+                            r#type: "text",
+                            text: stage.to_string(),
+                        },
+                    ],
+                }],
+            },
+        };
+
+        let resp = self
+            .client
+            .post(&url)
+            .bearer_auth(&self.access_token)
+            .json(&payload)
+            .send()
+            .await
+            .map_err(|e| format!("WhatsApp template API request failed: {e}"))?;
+
+        let status = resp.status();
+        let resp_text = resp
+            .text()
+            .await
+            .unwrap_or_else(|_| "<no body>".to_string());
+
+        if !status.is_success() {
+            return Err(format!(
+                "WhatsApp template API returned {status}: {resp_text}"
+            ));
+        }
+
+        let parsed: GraphSendResponse = serde_json::from_str(&resp_text).map_err(|e| {
+            format!("Failed to parse WhatsApp template API response: {e} — body: {resp_text}")
+        })?;
+
+        let msg_id = parsed
+            .messages
+            .first()
+            .map(|m| m.id.clone())
+            .unwrap_or_default();
+
+        Ok(msg_id)
+    }
+
+    /// Send a pipeline notification, respecting the 24-hour messaging window.
+    ///
+    /// - Within the window: sends a free-form text message.
+    /// - Outside the window (or if the API returns 131047): sends an approved
+    ///   template message instead.
+    ///
+    /// This method never crashes on a messaging-window error — it always
+    /// attempts the template fallback and logs what happened.
+    pub async fn send_notification(
+        &self,
+        to: &str,
+        tracker: &MessagingWindowTracker,
+        story_name: &str,
+        stage: &str,
+    ) -> Result<String, String> {
+        if tracker.is_within_window(to) {
+            let text = format!("Story '{story_name}' has moved to {stage}.");
+            match self.send_text(to, &text).await {
+                Ok(id) => return Ok(id),
+                Err(ref e) if e == OUTSIDE_WINDOW_ERR => {
+                    // Window expired between our check and the API call —
+                    // fall through to the template path.
+                    slog!(
+                        "[whatsapp] Window expired mid-flight for {to}; \
+                         falling back to template"
+                    );
+                }
+                Err(e) => return Err(e),
+            }
+        }
+
+        // Outside window — use the approved template.
+        slog!("[whatsapp] Sending template notification to {to} (outside 24h window)");
+        self.send_template_notification(to, story_name, stage).await
+    }
 }
 
 #[async_trait]
@@ -113,7 +319,24 @@ impl ChatTransport for WhatsAppTransport {
         _html: &str,
     ) -> Result<MessageId, String> {
         slog!("[whatsapp] send_message to {recipient}: {plain:.80}");
-        self.send_text(recipient, plain).await
+        match self.send_text(recipient, plain).await {
+            Ok(id) => Ok(id),
+            Err(ref e) if e == OUTSIDE_WINDOW_ERR => {
+                // Graceful degradation: log and surface a meaningful error
+                // rather than crashing.  Callers sending command responses
+                // should normally be within the window; this handles the edge
+                // case where processing was delayed.
+                slog!(
+                    "[whatsapp] Cannot send to {recipient}: outside 24h window \
+                     (message dropped)"
+                );
+                Err(format!(
+                    "Outside 24-hour messaging window for {recipient}; \
+                     send a message to the bot first to re-open the window"
+                ))
+            }
+            Err(e) => Err(e),
+        }
     }
 
     async fn edit_message(
@@ -160,6 +383,54 @@ struct GraphMessageId {
     id: String,
 }
 
+// ── Graph API error response types ─────────────────────────────────────
+
+#[derive(Deserialize)]
+struct GraphApiErrorResponse {
+    error: Option<GraphApiError>,
+}
+
+#[derive(Deserialize)]
+struct GraphApiError {
+    code: Option<i64>,
+    #[allow(dead_code)]
+    message: Option<String>,
+}
+
+// ── Template message types ──────────────────────────────────────────────
+
+#[derive(Serialize)]
+struct GraphTemplateMessage<'a> {
+    messaging_product: &'a str,
+    to: &'a str,
+    r#type: &'a str,
+    template: GraphTemplate<'a>,
+}
+
+#[derive(Serialize)]
+struct GraphTemplate<'a> {
+    name: &'a str,
+    language: GraphLanguage,
+    components: Vec<GraphTemplateComponent>,
+}
+
+#[derive(Serialize)]
+struct GraphLanguage {
+    code: &'static str,
+}
+
+#[derive(Serialize)]
+struct GraphTemplateComponent {
+    r#type: &'static str,
+    parameters: Vec<GraphTemplateParameter>,
+}
+
+#[derive(Serialize)]
+struct GraphTemplateParameter {
+    r#type: &'static str,
+    text: String,
+}
+
 // ── Webhook types (Meta → us) ───────────────────────────────────────────
 
 /// Top-level webhook payload from Meta.
@@ -355,6 +626,8 @@ pub struct WhatsAppWebhookContext {
     pub history: WhatsAppConversationHistory,
     /// Maximum number of conversation entries to keep per sender.
     pub history_size: usize,
+    /// Tracks the 24-hour messaging window per user phone number.
+    pub window_tracker: Arc<MessagingWindowTracker>,
 }
 
 /// GET /webhook/whatsapp — Meta verification handshake.
@@ -439,6 +712,9 @@ async fn handle_incoming_message(
 ) {
     use crate::matrix::commands::{CommandDispatch, try_handle_command};
 
+    // Record this inbound message to keep the 24-hour window open.
+    ctx.window_tracker.record_message(sender);
+
     let dispatch = CommandDispatch {
         bot_name: &ctx.bot_name,
         bot_user_id: &ctx.bot_user_id,
@@ -668,6 +944,174 @@ async fn handle_llm_message(
 mod tests {
     use super::*;
 
+    // ── MessagingWindowTracker ────────────────────────────────────────
+
+    #[test]
+    fn window_tracker_unknown_user_is_outside_window() {
+        let tracker = MessagingWindowTracker::new();
+        assert!(!tracker.is_within_window("15551234567"));
+    }
+
+    #[test]
+    fn window_tracker_records_within_window() {
+        let tracker = MessagingWindowTracker::new();
+        tracker.record_message("15551234567");
+        assert!(tracker.is_within_window("15551234567"));
+    }
+
+    #[test]
+    fn window_tracker_expired_window_returns_false() {
+        // Use a 1-nanosecond window so it expires immediately.
+        let tracker = MessagingWindowTracker::with_duration(std::time::Duration::from_nanos(1));
+        tracker.record_message("15551234567");
+        // Sleep briefly to ensure the instant has elapsed.
+        std::thread::sleep(std::time::Duration::from_millis(1));
+        assert!(!tracker.is_within_window("15551234567"));
+    }
+
+    #[test]
+    fn window_tracker_tracks_users_independently() {
+        let tracker = MessagingWindowTracker::new();
+        tracker.record_message("111");
+        assert!(tracker.is_within_window("111"));
+        assert!(!tracker.is_within_window("222"));
+    }
+
+    // ── send_text error handling ───────────────────────────────────────
+
+    #[tokio::test]
+    async fn send_text_handles_131047_outside_window_error() {
+        let mut server = mockito::Server::new_async().await;
+        server
+            .mock("POST", "/123456/messages")
+            .with_status(400)
+            .with_body(
+                r#"{"error":{"message":"More than 24 hours have passed","type":"OAuthException","code":131047}}"#,
+            )
+            .create_async()
+            .await;
+
+        let transport = WhatsAppTransport::with_api_base(
+            "123456".to_string(),
+            "test-token".to_string(),
+            server.url(),
+        );
+
+        let result = transport.send_text("15551234567", "hello").await;
+        assert!(result.is_err());
+        assert_eq!(result.unwrap_err(), OUTSIDE_WINDOW_ERR);
+    }
+
+    #[tokio::test]
+    async fn send_message_handles_outside_window_gracefully() {
+        let mut server = mockito::Server::new_async().await;
+        server
+            .mock("POST", "/123456/messages")
+            .with_status(400)
+            .with_body(
+                r#"{"error":{"message":"More than 24 hours have passed","type":"OAuthException","code":131047}}"#,
+            )
+            .create_async()
+            .await;
+
+        let transport = WhatsAppTransport::with_api_base(
+            "123456".to_string(),
+            "test-token".to_string(),
+            server.url(),
+        );
+
+        // send_message must not panic — it returns Err with a human-readable message.
+        let result = transport.send_message("15551234567", "hello", "").await;
+        assert!(result.is_err());
+        let msg = result.unwrap_err();
+        assert!(msg.contains("24-hour messaging window"), "unexpected: {msg}");
+    }
+
+    // ── send_template_notification ────────────────────────────────────
+
+    #[tokio::test]
+    async fn send_template_notification_calls_graph_api() {
+        let mut server = mockito::Server::new_async().await;
+        let mock = server
+            .mock("POST", "/123456/messages")
+            .match_header("authorization", "Bearer test-token")
+            .match_body(mockito::Matcher::PartialJsonString(
+                r#"{"type":"template"}"#.to_string(),
+            ))
+            .with_body(r#"{"messages": [{"id": "wamid.tpl123"}]}"#)
+            .create_async()
+            .await;
+
+        let transport = WhatsAppTransport::with_api_base(
+            "123456".to_string(),
+            "test-token".to_string(),
+            server.url(),
+        );
+
+        let result = transport
+            .send_template_notification("15551234567", "my-story", "done")
+            .await;
+        assert!(result.is_ok(), "unexpected err: {:?}", result.err());
+        assert_eq!(result.unwrap(), "wamid.tpl123");
+        mock.assert_async().await;
+    }
+
+    #[tokio::test]
+    async fn send_notification_uses_text_within_window() {
+        let mut server = mockito::Server::new_async().await;
+        let mock = server
+            .mock("POST", "/123456/messages")
+            .match_body(mockito::Matcher::PartialJsonString(
+                r#"{"type":"text"}"#.to_string(),
+            ))
+            .with_body(r#"{"messages": [{"id": "wamid.txt1"}]}"#)
+            .create_async()
+            .await;
+
+        let transport = WhatsAppTransport::with_api_base(
+            "123456".to_string(),
+            "test-token".to_string(),
+            server.url(),
+        );
+        let tracker = MessagingWindowTracker::new();
+        tracker.record_message("15551234567");
+
+        let result = transport
+            .send_notification("15551234567", &tracker, "my-story", "done")
+            .await;
+        assert!(result.is_ok());
+        mock.assert_async().await;
+    }
+
+    #[tokio::test]
+    async fn send_notification_uses_template_outside_window() {
+        let mut server = mockito::Server::new_async().await;
+        let mock = server
+            .mock("POST", "/123456/messages")
+            .match_body(mockito::Matcher::PartialJsonString(
+                r#"{"type":"template"}"#.to_string(),
+            ))
+            .with_body(r#"{"messages": [{"id": "wamid.tpl2"}]}"#)
+            .create_async()
+            .await;
+
+        let transport = WhatsAppTransport::with_api_base(
+            "123456".to_string(),
+            "test-token".to_string(),
+            server.url(),
+        );
+        // No record_message call — user is outside the window.
+        let tracker = MessagingWindowTracker::new();
+
+        let result = transport
+            .send_notification("15551234567", &tracker, "my-story", "done")
+            .await;
+        assert!(result.is_ok());
+        mock.assert_async().await;
+    }
+
+    // ── Existing webhook / transport tests ────────────────────────────
+
     #[test]
     fn extract_text_messages_parses_valid_payload() {
         let json = r#"{
@@ -790,7 +1234,8 @@ mod tests {
 
     #[tokio::test]
     async fn transport_send_typing_succeeds() {
-        let transport = WhatsAppTransport::new("123".to_string(), "tok".to_string());
+        let transport =
+            WhatsAppTransport::new("123".to_string(), "tok".to_string(), "tpl".to_string());
         assert!(transport.send_typing("room1", true).await.is_ok());
         assert!(transport.send_typing("room1", false).await.is_ok());
     }
@@ -811,9 +1256,7 @@ mod tests {
             server.url(),
         );
 
-        let result = transport
-            .send_message("15551234567", "hello", "")
-            .await;
+        let result = transport.send_message("15551234567", "hello", "").await;
         assert!(result.is_err());
         assert!(result.unwrap_err().contains("401"));
     }