polyhedron 0.1.0

use std::hash::Hash;

use ordered_float::OrderedFloat;
use priority_queue::PriorityQueue;

/// Max priority queue that can poperly handle floats.
#[derive(Debug)]
pub(crate) struct PQueue<T, W>
where
    T: Eq + Hash,
    W: ordered_float::FloatCore,
{
    queue: PriorityQueue<T, OrderedFloat<W>>,
}

impl<T, W> PQueue<T, W>
where
    T: Eq + Hash,
    W: ordered_float::FloatCore,
{
    pub(crate) fn new() -> Self
    {
        PQueue {
            queue: PriorityQueue::new(),
        }
    }

    pub(crate) fn from_iter<I>(iter: I) -> Self
    where
        I: Iterator<Item = (T, W)>,
    {
        let mut res = PQueue {
            queue: PriorityQueue::new(),
        };

        for (item, weight) in iter
        {
            res.push(item, weight);
        }

        res
    }

    pub(crate) fn push(&mut self, item: T, weight: W) -> Option<OrderedFloat<W>>
    {
        self.queue.push(item, OrderedFloat(weight))
    }

    pub(crate) fn pop(&mut self) -> Option<(T, W)>
    {
        self.queue.pop().map(|item| (item.0, item.1 .0))
    }

    pub(crate) fn remove(&mut self, item: T) -> Option<(T, W)>
    {
        match self.queue.remove(&item)
        {
            None => None,
            Some((i, OrderedFloat(w))) => Some((i, w)),
        }
    }

    pub(crate) fn is_empty(&self) -> bool { self.queue.is_empty() }

    // pub fn len(&self) -> usize { self.queue.len() }

    // pub fn iter(&self) -> impl Iterator<Item = (T, W)> + '_
    // where
    //     T: Clone,
    // {
    //     self.queue
    //         .iter()
    //         .map(|(item, ord_weight)| (item.clone(), ord_weight.0))
    // }
}