use core::fmt;
use serde::Deserialize;

pub type MLE<T> = Result<T, MLError>;

#[derive(Debug, Deserialize)]
pub struct MLError {
    etype: ErrorType,
    message: String,
}

#[derive(Debug, Deserialize)]
pub enum ErrorType {
    ArgumentError,
    ConfigError,
    LibToml,
    IoError,
}

impl std::error::Error for MLError {
    fn description(&self) -> &str {
        &self.message
    }
}

impl fmt::Display for MLError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self.etype {
            ErrorType::ArgumentError => write!(f, "ARGS"),
            ErrorType::ConfigError => write!(f, "CONFIG"),
            ErrorType::LibToml => write!(f, "TOML"),
            ErrorType::IoError => write!(f, "IO")
        }
    }
}

impl From<toml::de::Error> for MLError {
    fn from(error: toml::de::Error) -> Self {
        Self { etype: ErrorType::LibToml, message: error.to_string() }
    }
}

impl From<toml::ser::Error> for MLError {
    fn from(error: toml::ser::Error) -> Self {
        Self { etype: ErrorType::LibToml, message: error.to_string() }
    }
}

impl From<std::io::Error> for MLError {
    fn from(error: std::io::Error) -> Self {
        Self { etype: ErrorType::IoError, message: error.to_string() }
    }
}

impl MLError {
    pub fn new(etype: ErrorType, message: &str) -> Self {
        Self { etype, message: String::from(message) }
    }
}