feat: improve interactive prompts

Enhance Input trait with new methods:
- prompt_text_with_default(): text input with editable default values
- multi_select(): multi-item selection with Space toggle and Enter confirm

Add non-interactive terminal detection:
- Detect non-TTY stdin via std::io::IsTerminal
- Auto-switch to non-interactive mode when piped/redirected
- Debug message when TTY detection triggers mode change

Improve non-interactive error messages:
- Suggest using --help to see available flags
- Clearer messaging about providing values via CLI flags

Ctrl+C handling is already graceful via inquire's error propagation.
Selection filtering and highlighting are native inquire features.

Author: na2axl

src/input/interactive.rs

@@ -5,7 +5,7 @@
 use crate::input::Input;
 use anyhow::Result;
 use inquire::validator::Validation;
-use inquire::{Confirm, Select, Text};
+use inquire::{Confirm, MultiSelect, Select, Text};
 
 #[derive(Debug, Default, Clone, Copy)]
 pub struct InteractiveInput;
@@ -55,4 +55,25 @@ impl Input for InteractiveInput {
 
         Ok(c.prompt()?)
     }
+
+    fn prompt_text_with_default(
+        &self,
+        prompt: &str,
+        default: &str,
+        validator: Option<&dyn Fn(&str) -> Result<Validation, inquire::CustomUserError>>,
+    ) -> Result<String> {
+        let mut t = Text::new(prompt).with_default(default);
+
+        if let Some(v) = validator {
+            t = t.with_validator(v);
+        }
+
+        Ok(t.prompt()?)
+    }
+
+    fn multi_select(&self, prompt: &str, options: &[String]) -> Result<Vec<String>> {
+        let ms = MultiSelect::new(prompt, options.to_vec())
+            .with_help_message("Use Space to toggle, Enter to confirm");
+        Ok(ms.prompt()?)
+    }
 }

src/input/mod.rs

@@ -66,6 +66,22 @@ pub trait Input: Send + Sync {
 
     /// Prompt the user for confirmation (yes/no).
     fn confirm(&self, prompt: &str, default: Option<bool>) -> Result<bool>;
+
+    /// Prompt the user for text input with a default value pre-filled.
+    ///
+    /// The default value is editable by the user. If they press Enter without
+    /// changes, the default is used.
+    fn prompt_text_with_default(
+        &self,
+        prompt: &str,
+        default: &str,
+        validator: Option<&dyn Fn(&str) -> Result<Validation, inquire::CustomUserError>>,
+    ) -> Result<String>;
+
+    /// Prompt the user to select multiple items from a list.
+    ///
+    /// Returns the selected items' labels.
+    fn multi_select(&self, prompt: &str, options: &[String]) -> Result<Vec<String>>;
 }
 
 /// Create an `Input` implementation based on `InputMode`.

src/input/non_interactive.rs

@@ -21,8 +21,9 @@ impl NonInteractiveInput {
 
     fn blocked(&self, kind: &str, prompt: &str) -> anyhow::Error {
         anyhow::anyhow!(
-            "Interactive {} '{}' blocked: non-interactive mode is enabled. \
-             Please provide the required input via command-line arguments instead.",
+            "Interactive {} '{}' blocked: non-interactive mode is active. \
+             Provide the required value via command-line flags instead. \
+             Use --help on the command to see available flags.",
             kind,
             prompt
         )
@@ -47,4 +48,17 @@ impl Input for NonInteractiveInput {
     fn confirm(&self, prompt: &str, _default: Option<bool>) -> Result<bool> {
         Err(self.blocked("confirmation", prompt))
     }
+
+    fn prompt_text_with_default(
+        &self,
+        prompt: &str,
+        _default: &str,
+        _validator: Option<&dyn Fn(&str) -> Result<Validation, inquire::CustomUserError>>,
+    ) -> Result<String> {
+        Err(self.blocked("prompt", prompt))
+    }
+
+    fn multi_select(&self, prompt: &str, _options: &[String]) -> Result<Vec<String>> {
+        Err(self.blocked("multi-select", prompt))
+    }
 }

src/main.rs

@@ -147,8 +147,12 @@ async fn async_main() -> anyhow::Result<()> {
     let output = create_output(output_mode);
 
     // Create input handler based on flags.
-    // Rule: --json implies non-interactive input.
-    let input_mode = if cli.json || cli.non_interactive || cli.quiet {
+    // Rule: --json, --quiet, --non-interactive, or non-TTY stdin all imply non-interactive input.
+    let is_tty = std::io::IsTerminal::is_terminal(&std::io::stdin());
+    let input_mode = if cli.json || cli.non_interactive || cli.quiet || !is_tty {
+        if !is_tty && !cli.json && !cli.non_interactive && !cli.quiet {
+            debug!("stdin is not a terminal — using non-interactive mode. Use --non-interactive to suppress this message.");
+        }
         InputMode::NonInteractive
     } else {
         InputMode::Interactive

tests/feature_template_test.rs

@@ -144,6 +144,25 @@ impl Input for MockInput {
     fn confirm(&self, _prompt: &str, _default: Option<bool>) -> anyhow::Result<bool> {
         Ok(self.confirm_response)
     }
+
+    fn prompt_text_with_default(
+        &self,
+        prompt: &str,
+        _default: &str,
+        _validator: Option<&dyn Fn(&str) -> anyhow::Result<Validation, inquire::CustomUserError>>,
+    ) -> anyhow::Result<String> {
+        Err(anyhow::anyhow!(
+            "MockInput: prompt_text_with_default not implemented for '{}'",
+            prompt
+        ))
+    }
+
+    fn multi_select(&self, prompt: &str, _options: &[String]) -> anyhow::Result<Vec<String>> {
+        Err(anyhow::anyhow!(
+            "MockInput: multi_select not implemented for '{}'",
+            prompt
+        ))
+    }
 }
 
 // Safety: MockInput is only used in single-threaded tests