use std::marker::PhantomData;
use nalgebra::{allocator::Allocator, DefaultAllocator, Dim, OVector, U1};
use rand::{prelude::SliceRandom, RngCore};
use eoa_lib::initializer::Initializer;
use crate::tsp::NodePermutation;

pub struct TSPRandomInitializer<D>
where
    D: Dim,
    DefaultAllocator: Allocator<D, D>,
{
    _phantom: PhantomData<D>
}

impl<D> TSPRandomInitializer<D>
where
    D: Dim,
    DefaultAllocator: Allocator<D, D>,
{
    pub fn new() -> Self {
        Self { _phantom: PhantomData }
    }
}

impl<D> Initializer<D, NodePermutation<D>> for TSPRandomInitializer<D>
where
    D: Dim,
    DefaultAllocator: Allocator<D, D>,
    DefaultAllocator: Allocator<D>,
{
    fn initialize_single(&self, size: D, rng: &mut dyn RngCore) -> NodePermutation<D> {
        let len = size.value();
        let mut indices = OVector::<usize, D>::from_iterator_generic(size, U1, 0..len);
        indices.as_mut_slice().shuffle(rng);

        NodePermutation { permutation: indices }
    }
}