use crate::*;

pub fn map_south<O: Output>(
    item_offset: O::Unit,
    item_height: O::Unit,
    item: impl Content<O>
) -> impl Content<O> {
    Push::y(item_offset,
        Align::n(Fixed::y(item_height,
            Fill::x(item))))
}

pub struct Map<'a, A, B, I, F, G>(pub PhantomData<&'a()>, pub F, pub G) where
    I: Iterator<Item = A> + Send + Sync,
    F: Fn() -> I + Send + Sync + 'a,
    G: Fn(A, usize)->B + Send + Sync;

impl<'a, A, B, I, F, G> Map<'a, A, B, I, F, G> where
    I: Iterator<Item = A> + Send + Sync,
    F: Fn() -> I + Send + Sync + 'a,
    G: Fn(A, usize)->B + Send + Sync
{
    pub fn new (f: F, g: G) -> Self {
        Self(Default::default(), f, g)
    }
}

impl<'a, E, A, B, I, F, G> Content<E> for Map<'a, A, B, I, F, G> where
    E: Output,
    B: Render<E>,
    I: Iterator<Item = A> + Send + Sync,
    F: Fn() -> I + Send + Sync + 'a,
    G: Fn(A, usize)->B + Send + Sync
{
    fn layout (&self, area: E::Area) -> E::Area {
        let Self(_, get_iterator, callback) = self;
        let mut index = 0;
        let [mut min_x, mut min_y] = area.center();
        let [mut max_x, mut max_y] = area.center();
        for item in get_iterator() {
            let area = callback(item, index).layout(area).xywh();
            let [x,y,w,h] = area.xywh();
            min_x = min_x.min(x.into());
            min_y = min_y.min(y.into());
            max_x = max_x.max((x + w).into());
            max_y = max_y.max((y + h).into());
            index += 1;
        }
        let w = max_x - min_x;
        let h = max_y - min_y;
        //[min_x.into(), min_y.into(), w.into(), h.into()].into()
        area.center_xy([w.into(), h.into()].into()).into()
    }
    fn render (&self, to: &mut E) {
        let Self(_, get_iterator, callback) = self;
        let mut index = 0;
        //let area = self.layout(to.area());
        for item in get_iterator() {
            let item = callback(item, index);
            //to.place(area.into(), &item);
            to.place(item.layout(to.area()), &item);
            index += 1;
        }
    }
}