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 [read()][crate::poem::read] and [recite()][crate::poem::recite]
/// rely on this struct for various functions and features.
///
/// # Examples
/// ```
/// fn main() -> Result<(), io::Error> {
///     let mut env = compose::env();
///     let poem = Poem::read("alias", &mut env)?;
///     poem.recite(&mut env)?;
///     Ok(())
/// }
/// ```
#[derive(Debug, PartialEq, Eq, Clone)]
pub struct Environment {
    /// A table of aliases, set by the user using the built-in 'alias'
    /// command
    pub aliases: HashMap<String, String>,

    /// A lookup table for +x files, constructed from the $PATH (see
    /// [spellcheck()][crate::poem::elements::verse::Verse::spellcheck]
    /// for more details)
    pub bins: Vec<String>,

    /// Indication of callstack level, helpful for recursively dealing
    /// with aliases (see
    /// [add()][crate::poem::elements::verse::Verse::add] for more
    /// details)
    pub cs: u8,

    /// Force the capture of STDOUT (for internal poems)
    pub fc: bool,
}

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