use crate::*;

use std::error::Error;
use std::fmt;
use std::fmt::{Display, Formatter};
use std::io;
use std::result;

pub type Result<T> = result::Result<T, MyError>;

/// An error that can occur in this crate.
///
/// Generally, this error corresponds to problems with underlying process.
#[derive(Debug)]
pub struct MyError {
    source: io::Error,
    kind: MyErrorKind,
    cmd: ActualCmd,
}

#[derive(Debug)]
#[non_exhaustive]
pub enum MyErrorKind {
    Config,
    PreInstall,
    Install,
    PostInstall,
}

impl MyError {
    pub(crate) fn new(kind: MyErrorKind, source: io::Error, cmd: ActualCmd) -> MyError {
        MyError { source, kind, cmd }
    }

    /// Return the kind of this error.
    pub fn kind(&self) -> &MyErrorKind {
        &self.kind
    }
}

impl Error for MyError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        Some(&self.source)
    }
}

impl Display for MyError {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self.kind {
            MyErrorKind::Config => write!(
                f,
                "Could not read configuration file: {}",
                self.source().unwrap()
            ),
            MyErrorKind::PreInstall => write!(
                f,
                "Could not do the pre_install with command {}: {}",
                self.cmd,
                self.source().unwrap()
            ),
            MyErrorKind::Install => write!(
                f,
                "Could not install with command {}: {}",
                self.cmd,
                self.source().unwrap()
            ),
            MyErrorKind::PostInstall => write!(
                f,
                "Could not do the post_install command {}: {}",
                self.cmd,
                self.source().unwrap()
            ),
        }
    }
}