this_algorithm/spatial-coordinate-systems/src/utm.rs

use crate::{
    common::{parse_direction, parse_f64},
    Error, LatLon,
};
use nom::{
    bytes::complete::take,
    character::complete::{self, space0, space1},
    combinator::{map_opt, map_res, opt},
    sequence::tuple,
    IResult,
};
use std::{fmt, str::FromStr};

#[derive(PartialEq, Debug, Clone)]
pub struct Coordinate {
    zone_num: u8,
    zone_letter: char,
    easting: f64,
    northing: f64,

    latlon: LatLon,
}

impl Coordinate {
    /// ```rust
    /// use spatial_coordinate_systems::utm::Coordinate;
    /// use spatial_coordinate_systems::LatLon;
    ///
    /// assert!(Coordinate::parse("10S 706832mE 4344683mN").is_ok());
    /// assert!(Coordinate::parse("10S 706832mE 4344683N").is_ok());
    /// assert!(Coordinate::parse("10S 706832E 4344683N").is_ok());
    /// assert!(Coordinate::parse("10S706832mE 4344683mN").is_err());
    /// assert!(Coordinate::parse("10S 706832mE 4344683m").is_ok());
    /// assert!(Coordinate::parse("34H 261877.8163738246 6243185.589276327").is_ok());
    /// ```
    pub fn parse(i: &str) -> IResult<&str, Self> {
        map_res(
            tuple((
                complete::u8,
                space0,
                map_opt(take(1_usize), |z: &str| z.chars().next()),
                space1,
                parse_f64,
                // TODO: Can there be spaces around the m here or no?
                opt(complete::char('m')),
                // TODO: Should I allow a direction here or not
                opt(parse_direction),
                space1,
                parse_f64,
                opt(complete::char('m')),
                opt(parse_direction),
            )),
            |(
                zone_num,
                _,
                zone_letter,
                _,
                easting,
                _,
                _easting_direction,
                _,
                northing,
                _,
                _northing_direction,
            )|
             -> Result<_, Error> {
                let latlon = utm::wsg84_utm_to_lat_lon(easting, northing, zone_num, zone_letter)?;

                Ok(Coordinate {
                    easting,
                    northing,
                    zone_num,
                    zone_letter,
                    latlon: LatLon::try_from(latlon)?,
                })
            },
        )(i)
    }
}

impl FromStr for Coordinate {
    type Err = Error;

    fn from_str(i: &str) -> Result<Self, Self::Err> {
        Self::parse(i).map(|(_, ret)| ret).map_err(Into::into)
    }
}

impl fmt::Display for Coordinate {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "{}{} {} {}",
            self.zone_num, self.zone_letter, self.easting, self.northing,
        )
    }
}

impl TryFrom<LatLon> for Coordinate {
    type Error = Error;

    fn try_from(latlon: LatLon) -> Result<Self, Self::Error> {
        // TODO: This does not feel right
        let zone_num = utm::lat_lon_to_zone_number(latlon.get_lat(), latlon.get_lon());
        let zone_letter =
            utm::lat_to_zone_letter(latlon.get_lat()).ok_or(Error::NoUtmZoneLetter)?;
        let (northing, easting, _) =
            utm::to_utm_wgs84(latlon.get_lat(), latlon.get_lon(), zone_num);

        Ok(Self {
            zone_num,
            zone_letter,
            easting,
            northing,
            latlon,
        })
    }
}

impl From<&Coordinate> for LatLon {
    fn from(coordinate: &Coordinate) -> LatLon {
        coordinate.latlon
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_general() {
        macro_rules! p {
            ($tt:tt) => {{
                let cvt = Coordinate::from_str($tt);
                eprintln!("Testing: {} => {:?}", $tt, cvt);
                assert!(cvt.is_ok());
            }};
        }

        dbg!(dbg!(Coordinate::try_from(
            LatLon::new(-33.92487_f64, 18.42406_f64).unwrap()
        ))
        .unwrap()
        .to_string());
        p!("34H 261877.8163738246 6243185.589276327");

        assert_eq!(
            Coordinate::from_str("47N 666962.588 0.000"),
            Ok(Coordinate {
                zone_num: 47,
                zone_letter: 'N',
                easting: 666962.588,
                northing: 0.0,

                // Allow nearby comparisons
                latlon: LatLon::new(1.534972646100779e-9, 100.50027886695585).unwrap()
            })
        );
    }
}