use nalgebra::DVector;
use rustc_hash::FxHashSet;
use slab::Slab;
use sycamore::prelude::*;

#[derive(Clone, PartialEq)]
pub struct Element {
    pub id: String,
    pub label: String,
    pub color: [f32; 3],
    pub rep: DVector<f64>,
    pub constraints: FxHashSet<usize>
}

#[derive(Clone)]
pub struct Constraint {
    pub args: (usize, usize),
    pub rep: f64
}

// a complete, view-independent description of an assembly
#[derive(Clone)]
pub struct Assembly {
    pub elements: Signal<Slab<Element>>,
    pub constraints: Signal<Slab<Constraint>>
}

impl Assembly {
    pub fn new() -> Assembly {
        Assembly {
            elements: create_signal(Slab::new()),
            constraints: create_signal(Slab::new())
        }
    }
    
    pub fn insert_constraint(&self, constraint: Constraint) {
        let args = constraint.args;
        let key = self.constraints.update(|csts| csts.insert(constraint));
        self.elements.update(|elts| {
            elts[args.0].constraints.insert(key);
            elts[args.1].constraints.insert(key);
        })
    }
}