Package portable grid agent operation (#134)

crates/metacrate-grid-agent/src/main.rs

@@ -35,6 +35,7 @@ enum Operation {
     RunOnce,
     Tui,
     TuiClient,
+    PrintPaths,
 }
 
 #[derive(Default)]
@@ -56,10 +57,14 @@ fn options() -> Result<Option<Options>, CliError> {
         }
         if argument == "--help" || argument == "-h" {
             println!(
-                "metacrate-grid-agent [--config PATH] [--check-config | --run-once | --tui | --tui-client]\n\
-                 Configuration precedence: defaults < JSON < secret files < environment."
+                "metacrate-grid-agent [--config PATH] [--check-config | --run-once | --tui | --tui-client | --print-paths]\n\
+                 Configuration precedence: defaults < JSON < secret files < environment.\n\
+                 With no --config, the platform default is used when it exists."
             );
             return Ok(None);
+        } else if argument == "--version" || argument == "-V" {
+            println!("metacrate-grid-agent {}", env!("CARGO_PKG_VERSION"));
+            return Ok(None);
         }
         if argument == "--check-config" {
             set_operation(&mut result, Operation::CheckConfig)?;
@@ -69,6 +74,8 @@ fn options() -> Result<Option<Options>, CliError> {
             set_operation(&mut result, Operation::Tui)?;
         } else if argument == "--tui-client" {
             set_operation(&mut result, Operation::TuiClient)?;
+        } else if argument == "--print-paths" {
+            set_operation(&mut result, Operation::PrintPaths)?;
         } else if argument == "--config" {
             let path = arguments
                 .next()
@@ -99,8 +106,20 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let Some(options) = options()? else {
         return Ok(());
     };
+    let platform_paths = metacrate_grid_agent::PlatformPaths::discover();
+    if options.operation == Operation::PrintPaths {
+        println!("config={}", platform_paths.config_file.display());
+        println!("data={}", platform_paths.data_directory.display());
+        return Ok(());
+    }
     let mut loader = ConfigLoader::new();
-    if let Some(path) = options.config {
+    let config_path = options.config.or_else(|| {
+        platform_paths
+            .config_file
+            .is_file()
+            .then_some(platform_paths.config_file)
+    });
+    if let Some(path) = config_path {
         loader = loader.with_file(path);
     }
     let config = loader.load()?;