use std::collections::BTreeMap;
use std::collections::HashMap;
use std::os::unix::process::ExitStatusExt;
use std::process::{ExitStatus, Output};

/// alias
///
/// The builtin `alias` command. Used to monikers for other verbs, or
/// entire verses.
///
/// # Shell Example
/// ```sh
/// alias vim=nvim
/// ```
pub fn incant(
    clause: &Option<Vec<String>>,
    uout: bool,
    aliases: &mut HashMap<String, String>,
) -> Output {
    let status = 0;
    let mut out: Vec<u8> = Vec::new();
    let err: Vec<u8> = Vec::new();
    match clause {
        Some(clause) => {
            for stanza in clause {
                let (key, val) = match stanza.split_once("=") {
                    Some((key, val)) => (key, val),
                    None => continue,
                };
                aliases.insert(String::from(key), String::from(val));
            }
        }
        None => {
            let mut lines = Vec::new();
            let sorted: BTreeMap<_, _> = aliases.iter().collect();
            for (key, val) in sorted {
                let line = if key.contains(' ') && val.contains(' ') {
                    format!("'{}'='{}'", key, val)
                } else if key.contains(' ') {
                    format!("'{}'={}", key, val)
                } else if val.contains(' ') {
                    format!("{}='{}'", key, val)
                } else if val.is_empty() {
                    format!("{}=''", key)
                } else {
                    format!("{}={}", key, val)
                };
                lines.push(line);
            }

            if uout {
                out.append(&mut format!("{}\n", lines.join("\n")).as_bytes().to_vec());
            } else {
                println!("{}", lines.join("\n"));
            }
        }
    }

    Output {
        status: ExitStatus::from_raw(status),
        stdout: out,
        stderr: err,
    }
}

/// unalias
///
/// The builtin `unalias` command. Used to remove shell monikers, since `alias`
/// may be called with an empty string as the value.
///
/// # Shell Example
/// ```sh
/// unalias vim
/// ```
pub fn unincant(
    clause: &Option<Vec<String>>,
    uerr: bool,
    aliases: &mut HashMap<String, String>,
) -> Output {
    let out: Vec<u8> = Vec::new();
    let mut err: Vec<u8> = Vec::new();

    let status = match clause {
        Some(clause) => {
            for stanza in clause {
                aliases.remove(stanza);
            }
            0
        }
        None => {
            if uerr {
                err.append(&mut "unalias: not enough arguments".as_bytes().to_vec());
            } else {
                eprintln!("unalias: not enough arguments");
            }
            1
        }
    };

    Output {
        status: ExitStatus::from_raw(status),
        stdout: out,
        stderr: err,
    }
}