first pass of merging in warp (doesn't build)

crates/galaxy_cli/src/local_control/output.rs

@@ -0,0 +1,53 @@
+//! Output rendering helpers for `warpctrl`.
+use std::io::Write as _;
+
+use local_control::protocol::{ControlError, ErrorCode};
+use serde::Serialize;
+
+use crate::agent::OutputFormat;
+
+/// JSON/NDJSON error payload emitted by `warpctrl`.
+#[derive(Serialize)]
+pub(crate) struct ErrorSummary<'a> {
+    pub ok: bool,
+    pub error: &'a ControlError,
+}
+
+pub(super) fn write_control_error(
+    error: &ControlError,
+    output_format: OutputFormat,
+) -> Result<(), ControlError> {
+    match output_format {
+        OutputFormat::Json => write_json(&ErrorSummary { ok: false, error }),
+        OutputFormat::Ndjson => write_json_line(&ErrorSummary { ok: false, error }),
+        OutputFormat::Pretty | OutputFormat::Text => {
+            eprintln!("error: {}: {}", error.code, error.message);
+            if let Some(details) = &error.details {
+                eprintln!("details: {details}");
+            }
+            Ok(())
+        }
+    }
+}
+
+pub(super) fn write_json(value: &impl Serialize) -> Result<(), ControlError> {
+    let stdout = std::io::stdout();
+    let mut lock = stdout.lock();
+    serde_json::to_writer_pretty(&mut lock, value).map_err(write_error)?;
+    writeln!(&mut lock).map_err(write_error)?;
+    Ok(())
+}
+pub(super) fn write_json_line(value: &impl Serialize) -> Result<(), ControlError> {
+    let stdout = std::io::stdout();
+    let mut lock = stdout.lock();
+    serde_json::to_writer(&mut lock, value).map_err(write_error)?;
+    writeln!(&mut lock).map_err(write_error)?;
+    Ok(())
+}
+fn write_error(error: impl std::error::Error) -> ControlError {
+    ControlError::with_details(
+        ErrorCode::Internal,
+        "failed to write local-control output",
+        error.to_string(),
+    )
+}