use std::rc::Rc;
use sycamore::prelude::*;

use super::test_assembly_chooser::TestAssemblyChooser;
use crate::{
    AppState,
    assembly::{InversiveDistanceRegulator, Point, Sphere},
};

#[component]
pub fn AddRemove() -> View {
    view! {
        div(id="add-remove") {
            button(
                on:click=|_| {
                    let state = use_context::<AppState>();
                    batch(|| {
                        // this call is batched to avoid redundant realizations.
                        // it updates the element list and the regulator list,
                        // which are both tracked by the realization effect
                        /* TO DO */
                        // it would make more to do the batching inside
                        // `insert_element_default`, but that will have to wait
                        // until Sycamore handles nested batches correctly.
                        //
                        //   https://github.com/sycamore-rs/sycamore/issues/802
                        //
                        // the nested batch issue is relevant here because the
                        // assembly loaders in the test assembly chooser use
                        // `insert_element_default` within larger batches
                        state.assembly.insert_element_default::<Sphere>();
                    });
                }
            ) { "Add sphere" }
            button(
                on:click=|_| {
                    let state = use_context::<AppState>();
                    state.assembly.insert_element_default::<Point>();
                }
            ) { "Add point" }
            button(
                class="emoji", /* KLUDGE */ // for convenience, we're using an emoji as a temporary icon for this button
                disabled={
                    let state = use_context::<AppState>();
                    state.selection.with(|sel| sel.len() != 2)
                },
                on:click=|_| {
                    let state = use_context::<AppState>();
                    let subjects: [_; 2] = state.selection.with(
                        // the button is only enabled when two elements are
                        // selected, so we know the cast to a two-element array
                        // will succeed
                        |sel| sel
                            .clone()
                            .into_iter()
                            .collect::<Vec<_>>()
                            .try_into()
                            .unwrap()
                    );
                    state.assembly.insert_regulator(
                        Rc::new(InversiveDistanceRegulator::new(subjects))
                    );
                    state.selection.update(|sel| sel.clear());
                }
            ) { "🔗" }
            TestAssemblyChooser {}
        }
    }
}