Listen for responses of supervisors

Signed-off-by: Lee Smet <lee.smet@hotmail.com>

src/clients/mycelium_client.rs

@@ -3,6 +3,8 @@ use std::sync::atomic::{AtomicU64, Ordering};
 
 use reqwest::Client as HttpClient;
 
+use base64::Engine;
+use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
 use serde_json::{Value, json};
 use thiserror::Error;
 
@@ -159,6 +161,83 @@ impl MyceliumClient {
             .and_then(|v| v.as_str())
             .map(|s| s.to_string())
     }
+    /// popMessage: retrieve an inbound message if available (optionally filtered by topic).
+    /// - peek: if true, do not remove the message from the queue
+    /// - timeout_secs: seconds to wait for a message (0 returns immediately)
+    /// - topic_plain: optional plain-text topic which will be base64-encoded per Mycelium spec
+    /// Returns:
+    ///   - Ok(Some(result_json)) on success, where result_json matches InboundMessage schema
+    ///   - Ok(None) when there is no message ready (Mycelium returns error code 204)
+    pub async fn pop_message(
+        &self,
+        peek: Option<bool>,
+        timeout_secs: Option<u64>,
+        topic_plain: Option<&str>,
+    ) -> Result<Option<Value>, MyceliumClientError> {
+        // Build params array
+        let mut params_array = vec![];
+        if let Some(p) = peek {
+            params_array.push(serde_json::Value::Bool(p));
+        } else {
+            params_array.push(serde_json::Value::Null)
+        }
+        if let Some(t) = timeout_secs {
+            params_array.push(serde_json::Value::Number(t.into()));
+        } else {
+            params_array.push(serde_json::Value::Null)
+        }
+        if let Some(tp) = topic_plain {
+            let topic_b64 = BASE64_STANDARD.encode(tp.as_bytes());
+            params_array.push(serde_json::Value::String(topic_b64));
+        } else {
+            params_array.push(serde_json::Value::Null)
+        }
+
+        let req = json!({
+            "jsonrpc": "2.0",
+            "id": self.next_id(),
+            "method": "popMessage",
+            "params": serde_json::Value::Array(params_array),
+        });
+
+        tracing::info!(%req, "calling popMessage");
+
+        let resp = self.http.post(&self.base_url).json(&req).send().await?;
+        let status = resp.status();
+        let body: Value = resp.json().await?;
+
+        // Handle JSON-RPC error envelope specially for code 204 (no message ready)
+        if let Some(err) = body.get("error") {
+            let code = err.get("code").and_then(|v| v.as_i64()).unwrap_or(0);
+            let msg = err
+                .get("message")
+                .and_then(|v| v.as_str())
+                .unwrap_or("unknown error");
+
+            if code == 204 {
+                // No message ready
+                return Ok(None);
+            }
+            if code == 408 {
+                // Align with other transport timeout mapping
+                return Err(MyceliumClientError::TransportTimeout);
+            }
+            return Err(MyceliumClientError::RpcError(format!(
+                "code={code} msg={msg}"
+            )));
+        }
+
+        if !status.is_success() {
+            return Err(MyceliumClientError::RpcError(format!(
+                "HTTP {status}, body {body}"
+            )));
+        }
+
+        let result = body.get("result").ok_or_else(|| {
+            MyceliumClientError::InvalidResponse(format!("missing result in response: {body}"))
+        })?;
+        Ok(Some(result.clone()))
+    }
 }
 
 #[cfg(test)]