use std::{
    error,
    fmt,
};

#[derive(Debug)]
pub enum Error
{
    Unknown,
    Message(String),
    MessageStatic(&'static str),
    FileNotFound(std::path::PathBuf),
    BadPath(std::path::PathBuf),
    ExpectedFile(std::path::PathBuf),
}

impl error::Error for Error{}
impl fmt::Display for Error
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
    {
	write!(f, "failed to parse args: ")?;
	match self {
	    Error::Message(message) => write!(f, "{}", message),
	    Error::MessageStatic(message) => write!(f, "{}", message),
	    Error::FileNotFound(file) => write!(f, "file not found: `{:?}`", file),
	    Error::BadPath(file) => write!(f, "bad path: `{:?}`", file),
	    Error::ExpectedFile(file) => write!(f, "expected a file: `{:?}`", file),
	    _ => write!(f, "unknown error"),
	}
    }
}

impl From<String> for Error
{
    fn from(string: String) -> Self
    {
	Self::Message(string)
    }
}

impl From<&'static str> for Error
{
    fn from(string: &'static str) -> Self
    {
	Self::MessageStatic(string)
    }
}

use std::path::PathBuf;
impl From<PathBuf> for Error
{
    fn from(path: PathBuf) -> Self
    {
	
	if !path.exists() {
	    Self::FileNotFound(path)
	} else if path.is_dir() {
	    Self::ExpectedFile(path)
	} else {
	    Self::BadPath(path)
	}
    }
}