use std::error::Error;
use std::fmt;
use std::str::FromStr;

#[derive(Debug, Eq, PartialEq)]
pub struct Position {
    pub x: u8,
    pub y: u8,
}

impl Error for Position {}

impl FromStr for Position {
    type Err = ();

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let string = s.to_string();

        // e.g. "2,5"
        let xy: Vec<&str> = string.split(',').collect();
        let x = xy[0].parse().expect("Bad x coordinate supplied for Position");

        if xy.len() < 2 {
            panic!("Bad position : {}", string);
        }

        let y = xy[1].parse().expect("Bad y coordinate supplied for Position");

        Ok(Position { x, y })
    }
}

impl fmt::Display for Position {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{},{}", self.x, self.y)
    }
}

#[cfg(test)]
mod test {
    use crate::position::Position;
    use std::str::FromStr;

    #[test]
    fn test_position_from_str() {
        assert_eq!(
            Position::from_str(&"4,12").unwrap(),
            Position { x: 4, y: 12 }
        );
    }

    #[test]
    fn test_position_to_string() {
        assert_eq!(Position { x: 4, y: 12 }.to_string(), "4,12".to_string())
    }
}