use std::collections::HashMap;

/// Record the shell state
///
/// The [Environment] struct keeps track of various fields, all relating to the
/// shell state. The environment is the first thing setup at the beginning of
/// the shell, and is maintained throughout the lifetime of the process.
///
/// Both [crate::Poem]::read() and [crate::Poem]::recite() rely on this struct
/// for various functions and features.
///
/// # Fields
/// aliases - A table of aliases, set by the user using the built-in 'alias'
/// bins - A lookup table for +x files, constructed from the $PATH
/// cs - Indication of callstack level, helpful for recursively dealing with
///      aliases
///
/// # Examples
/// ```
/// fn main() -> Result<(), io::Error> {
///     let mut env = compose::env();
///     let poem = Poem::read("alias", &mut env)?;
///     poem.recite(&mut env)?;
///     ()
/// }
/// ```
#[derive(Debug, PartialEq, Eq, Clone)]
pub struct Environment {
    pub aliases: HashMap<String, String>,
    pub bins: Vec<String>,
    pub cs: u8,
}

impl Environment {
    /// Initialize an [Environment] struct with the default values
    pub fn new() -> Self {
        Environment {
            aliases: HashMap::new(),
            bins: Vec::new(),
            cs: 0,
        }
    }
}