use crate::core::counter::Counter;
use crate::iterators::{HistogramIterator, PickMetadata, PickyIterator};
use crate::Histogram;

/// An iterator that will yield every bin.
pub struct Iter {
    visited: Option<usize>,
}

impl Iter {
    /// Construct a new full iterator. See `Histogram::iter_all` for details.
    pub fn new<T: Counter>(hist: &Histogram<T>) -> HistogramIterator<T, Iter> {
        HistogramIterator::new(hist, Iter { visited: None })
    }
}

impl<T: Counter> PickyIterator<T> for Iter {
    fn pick(&mut self, index: usize, _: u64, _: T) -> Option<PickMetadata> {
        if self.visited.map(|i| i != index).unwrap_or(true) {
            // haven't visited this index yet
            self.visited = Some(index);
            Some(PickMetadata::new(None, None))
        } else {
            None
        }
    }

    fn more(&mut self, _: usize) -> bool {
        true
    }
}