//
// …
//
// Georg Hopp <georg@steffers.org>
//
// Copyright © 2019 Georg Hopp
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

use std::fmt::Debug;
use std::ops::{Add, Div, Sub};

use super::canvas::{Vertex, Vertices};
use super::drawable::Drawable;

#[derive(Debug, Clone)]
pub struct Polyline<T>(pub Vertices<T>);

impl<T> Drawable<T> for Polyline<T>
where T: Add<Output = T> + Sub<Output = T> + Div<Output = T>
       + Debug + Clone + Copy + From<i32> {
    fn plot(&self) -> Vertices<T> {
        let Polyline(cs) = self;

        match cs[..] {
            []     => Vec::<Vertex<T>>::new(),
            [a]    => vec!(a),
            [a, b] => a.line(b),
            _      => {
                let (a, b) = (cs[0], cs[1]);
                let mut r = a.line(b);
                let mut i = b;
                for j in cs[2..].iter() {
                    r.append(&mut i.line(*j)[1..].to_vec());
                    i = *j;
                }
                r
            },
        }
    }
}
/*
impl<T> Display for Polyline<T> where T: Copy {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
        let Polyline(a) = self;
        write!(f, "PLine[{}]", a)
    }
}
*/