#[derive(Clone)]
pub enum CommandTree {
  Terminal {
    name: String,
    help_msg: Option<String>,
    function: Option<Box<(fn() -> Option<String>)>>,
  },
  NonTerminal {
    name: String,
    children: Vec<CommandTree>,
    help_msg: Option<String>,
    function: Option<Box<(fn() -> Option<String>)>>,
  },
  Top(Vec<CommandTree>),
}

impl CommandTree {
  pub fn term(s: &str, help: Option<&str>) -> CommandTree {
    CommandTree::Terminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), function: None }
  }

  pub fn nonterm(s: &str, help: Option<&str>, children: Vec<CommandTree>) -> CommandTree {
    CommandTree::NonTerminal {
      name: s.to_string(),
      help_msg: help.map(|x| x.to_string()),
      children,
      function: None,
    }
  }

  pub fn get_cmd(&self) -> &str {
    match self {
      CommandTree::Terminal { name, .. } => name.as_str(),
      CommandTree::NonTerminal {name, ..} => name.as_str(),
      CommandTree::Top(_) => "",
    }
  }
  pub fn get_help(&self) -> &str {
    match self {
      CommandTree::Terminal { help_msg, ..} => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
      CommandTree::NonTerminal { help_msg, .. } => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
      CommandTree::Top(_) => ""
    }
  }
  pub fn get_children(&self) -> Vec<&str> {
    match self {
      CommandTree::Terminal { .. } => vec![],
      CommandTree::NonTerminal { children, .. } => children.iter().map(|x| x.get_cmd()).collect(),
      CommandTree::Top(children) => children.iter().map(|x| x.get_cmd()).collect(),
    }
  }
}