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Add Session Indicators with Customizable Prompt Styles #4

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946b456
feat: Add session indicators with customizable prompt styles
K-NRS Sep 13, 2025
dc4a553
docs: Add visual demo section to README
K-NRS Sep 13, 2025
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71 changes: 70 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ Simple detachable shell sessions with zero configuration. Not a complex multiple
- 🧹 **Auto-Cleanup**: Automatic cleanup of dead sessions
- 🔄 **Session Switching**: Simple attach/detach without complex multiplexing
- 🏷️ **Named Sessions**: Give meaningful names to your sessions
- 👁️ **Session Indicators**: Visual indicators showing you're in an NDS session
- 🐧 **Cross-Platform**: Works on Linux and macOS

## 🎯 Philosophy
Expand Down Expand Up @@ -55,13 +56,40 @@ sudo cp target/release/nds /usr/local/bin/
```


## 🎬 Demo

See NDS in action with key features:

```bash
$ nds new "web-server"
Creating new session 'web-server'...
⬢ user@host:~/project$ # ← Notice session indicator!

$ nds list
Active Sessions:
ID Name Status PID Age
a03fa0b6 web-server running 84405 2m

$ export NDS_PROMPT_STYLE=full
[nds:web-server] user@host:~/project$ # ← Customizable indicators

$ nds # Interactive TUI mode
┌─ NDS Session Manager ─────────────────┐
│ > web-server running 2m │
│ data-proc running 1m │
│ [a]ttach [k]ill [q]uit │
└───────────────────────────────────────┘
```

> 🎥 **Interactive Demo Coming Soon**: Full asciinema recording showcasing all features

## 🚀 Quick Start

```bash
# Create a new session
nds new

# List sessions
# List sessions
nds list

# Attach to a session
Expand Down Expand Up @@ -134,6 +162,42 @@ nds history -s abc123 # History for specific session
- `Ctrl+D` - Detach from current session (when at empty prompt)
- `Enter, ~s` - Switch to another session interactively

### Session Indicators

NDS automatically shows you when you're inside a session with subtle visual indicators:

- **Terminal Title**: Shows `NDS: session-name` in your terminal window title
- **Prompt Indicator**: Adds a visual prefix to your shell prompt

#### Indicator Styles

Control how session indicators appear with the `NDS_PROMPT_STYLE` environment variable:

```bash
# Subtle symbol (default) - shows ⬢ prefix
export NDS_PROMPT_STYLE=subtle
⬢ user@host:~$

# Full session info - shows [nds:session-name] prefix
export NDS_PROMPT_STYLE=full
[nds:my-project] user@host:~$

# Minimal - shows [nds] prefix
export NDS_PROMPT_STYLE=minimal
[nds] user@host:~$

# Disable indicators completely
export NDS_PROMPT_STYLE=none
user@host:~$
```

#### How It Works

- **Automatic**: No configuration files to modify - works out of the box
- **Shell Agnostic**: Works with bash, zsh, and other shells
- **Non-invasive**: Doesn't modify your existing shell configuration
- **User Control**: Can be customized or disabled entirely

## 🏗️ Architecture

NDS uses a simple and robust architecture:
Expand Down Expand Up @@ -212,6 +276,11 @@ export NDS_SHELL=/bin/zsh
NDS_SESSION_ID # Current session ID when attached
NDS_SESSION_NAME # Current session name (if set)

# Session indicator customization
export NDS_PROMPT_STYLE=subtle # Options: subtle, full, minimal, none
NDS_SESSION_DISPLAY # Display name used in indicators (auto-set)
NDS_PROMPT_PREFIX # Computed prefix based on style (auto-set)

# Change detach key binding (coming soon)
export NDS_DETACH_KEY="ctrl-a d"
```
Expand Down
154 changes: 148 additions & 6 deletions src/pty/spawn.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -243,19 +243,23 @@ impl PtyProcess {
std::env::set_var("NDS_SESSION_NAME", session_id);
}

// Set session indicator environment variables
Self::set_session_indicator_env(session_id, &name);

// Set restrictive umask for session isolation
unsafe {
libc::umask(0o077); // Only owner can read/write/execute new files
}

// Get shell
// Get shell and prepare with session indicator
let shell = std::env::var("SHELL").unwrap_or_else(|_| "/bin/sh".to_string());

// Create shell startup command with session indicator setup
let shell_args = Self::prepare_shell_with_indicator(&shell, session_id, &name)?;

// Execute shell
let shell_cstr = std::ffi::CString::new(shell.as_str()).unwrap();
let args = vec![shell_cstr.clone()];

execvp(&shell_cstr, &args)
// Execute shell with prepared arguments
let shell_cstr = std::ffi::CString::new(shell_args.0.as_str()).unwrap();
execvp(&shell_cstr, &shell_args.1)
.map_err(|e| NdsError::ProcessError(format!("execvp failed: {}", e)))?;

// Should never reach here
Expand All @@ -273,6 +277,9 @@ impl PtyProcess {
session.name.as_ref().unwrap_or(&session.id),
);

// Set session indicator environment variables for attach
Self::set_session_indicator_env(&session.id, &session.name);

// Save current terminal state
let stdin_fd = 0;
let original_termios = save_terminal_state(stdin_fd)?;
Expand Down Expand Up @@ -867,6 +874,141 @@ impl PtyProcess {

Ok(())
}

/// Set session indicator environment variables
fn set_session_indicator_env(session_id: &str, name: &Option<String>) {
// Set prompt style (user can override with NDS_PROMPT_STYLE=none to disable)
if std::env::var("NDS_PROMPT_STYLE").is_err() {
std::env::set_var("NDS_PROMPT_STYLE", "subtle");
}

// Set session display name for prompt
let display_name = if let Some(ref session_name) = name {
session_name.clone()
} else {
// Use first 6 chars of session ID for brevity
session_id.chars().take(6).collect::<String>()
};
std::env::set_var("NDS_SESSION_DISPLAY", &display_name);

// Set prompt prefix based on style
let style = std::env::var("NDS_PROMPT_STYLE").unwrap_or_else(|_| "subtle".to_string());
let prefix = match style.as_str() {
"full" => format!("[nds:{}]", display_name),
"minimal" => "[nds]".to_string(),
"symbol" => "⬢".to_string(),
"none" => String::new(),
_ => "⬢".to_string(), // default to subtle symbol
};
std::env::set_var("NDS_PROMPT_PREFIX", &prefix);
}

/// Prepare shell execution with session indicator setup
fn prepare_shell_with_indicator(
shell: &str,
session_id: &str,
name: &Option<String>,
) -> Result<(String, Vec<std::ffi::CString>)> {
let prompt_style = std::env::var("NDS_PROMPT_STYLE").unwrap_or_else(|_| "subtle".to_string());

// If disabled, just return normal shell
if prompt_style == "none" {
let shell_cstr = std::ffi::CString::new(shell).unwrap();
return Ok((shell.to_string(), vec![shell_cstr]));
}

// Create shell initialization script for session indicator
let display_name = if let Some(ref session_name) = name {
session_name.clone()
} else {
session_id.chars().take(6).collect::<String>()
};

// Shell-specific setup for prompt modification
let setup_script = if shell.contains("zsh") {
format!(
r#"
# NDS Session Indicator Setup for Zsh
if [[ -n "$NDS_SESSION_ID" && "$NDS_PROMPT_STYLE" != "none" ]]; then
case "$NDS_PROMPT_STYLE" in
"full") NDS_PREFIX="[nds:{}] " ;;
"minimal") NDS_PREFIX="[nds] " ;;
"symbol") NDS_PREFIX="⬢ " ;;
*) NDS_PREFIX="⬢ " ;;
esac

# Set terminal title
print -Pn "\e]0;NDS: {}\a"

# Modify PS1 if it exists, otherwise create a basic one
if [[ -n "$PS1" ]]; then
export PS1="$NDS_PREFIX$PS1"
else
export PS1="$NDS_PREFIX%n@%m:%~$ "
fi
fi
"#,
display_name, display_name
)
} else if shell.contains("bash") {
format!(
r#"
# NDS Session Indicator Setup for Bash
if [[ -n "$NDS_SESSION_ID" && "$NDS_PROMPT_STYLE" != "none" ]]; then
case "$NDS_PROMPT_STYLE" in
"full") NDS_PREFIX="[nds:{}] " ;;
"minimal") NDS_PREFIX="[nds] " ;;
"symbol") NDS_PREFIX="⬢ " ;;
*) NDS_PREFIX="⬢ " ;;
esac

# Set terminal title
echo -ne "\033]0;NDS: {}\007"

# Modify PS1 if it exists, otherwise create a basic one
if [[ -n "$PS1" ]]; then
export PS1="$NDS_PREFIX$PS1"
else
export PS1="$NDS_PREFIX\u@\h:\w\$ "
fi
fi
"#,
display_name, display_name
)
} else {
// Generic shell setup
format!(
r#"
# NDS Session Indicator Setup (Generic)
if [ -n "$NDS_SESSION_ID" ] && [ "$NDS_PROMPT_STYLE" != "none" ]; then
case "$NDS_PROMPT_STYLE" in
"full") NDS_PREFIX="[nds:{}] " ;;
"minimal") NDS_PREFIX="[nds] " ;;
*) NDS_PREFIX="⬢ " ;;
esac

if [ -n "$PS1" ]; then
export PS1="$NDS_PREFIX$PS1"
else
export PS1="$NDS_PREFIX\$ "
fi
fi
"#,
display_name
)
};

// Execute shell with initialization script
let shell_cstr = std::ffi::CString::new(shell).unwrap();
let init_flag = std::ffi::CString::new("-c").unwrap();
let full_command = format!("{}{}", setup_script, shell);
let command_cstr = std::ffi::CString::new(full_command).unwrap();

Ok((
shell.to_string(),
vec![shell_cstr, init_flag, command_cstr],
))
}
}

impl Drop for PtyProcess {
Expand Down
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