use std::convert::Infallible;

use crate::binary_string::BinaryString;
#[cfg(test)]
use crate::test_infra::load_test_file;

use super::FitnessFunction;

pub struct OneMax;
impl OneMax {
    pub fn new() -> Self {
        OneMax
    }
}

impl FitnessFunction for OneMax {
    type In = BinaryString;
    type Out = i32;
    type Err = Infallible;

    fn fit(self: &Self, chromosome: &BinaryString) -> Result<i32, Infallible> {
        Ok(chromosome.into_iter()
           .map(|x| *x as i32)
           .sum())
    }
}

#[test]
fn test_one_max() {
    let data = load_test_file::<i8, i32>("tests/onemax.txt");

    for test in data {
        assert_eq!(
            OneMax::new().fit(&BinaryString::new(test.inp)).unwrap(),
            test.out
        );
    }
}