use std::fmt::{Display, Formatter, Result};
use std::ops::{Add, Sub, AddAssign, SubAssign, Div, Mul, DivAssign, MulAssign};

use crate::metric::Unit;
use crate::metric::Primitive;

use crate::declare_unit_basics;

#[derive(Copy, Clone, Debug, PartialOrd, PartialEq)]
pub enum Mass {
    Base(f64, fn(f64) -> f64, &'static str),
    Canonical(f64),
    Kilogram(f64),
    Milligram(f64),
    Gram(f64),
    Tonne(f64),
    Ounce(f64), // international avoirdupois ounce
    Pound(f64), // International avoirdupois pound
}

impl Unit<Mass> for Mass {
    fn to_si_unit(&self) -> Mass {
        match self {
            Mass::Base(_, _, _) => self.clone(),
            Mass::Canonical(value) => Mass::Base(value.clone(), |x| x, "kg"),
            Mass::Kilogram(value) => Mass::Base(value.clone(), |x| x, "kg"),
            Mass::Gram(value) => Mass::Base(value / 1000.0, |x| x * 1000.0, "g"),
            Mass::Milligram(value) => Mass::Base(value / 1_000_000.0, |x| x * 1_000_000.0, "mg"),
            Mass::Tonne(value) => Mass::Base(value * 1000.0, |x| x / 1000.0, "t"),
            Mass::Ounce(value) => Mass::Base(value * 28.349523125 / 1000.0, |x| x / 28.349523125 * 1000.0, "℥"),
            Mass::Pound(value) => Mass::Base(value * 0.45359237, |x| x / 0.45359237, "lb"),
        }
    }
}

declare_unit_basics!(Mass);