use sycamore::prelude::*;
use web_sys::{console, wasm_bindgen::JsValue};

use crate::{
    engine,
    AppState,
    assembly::{
        Assembly,
        Constraint,
        ConstraintRole,
        Element
    },
    engine::Q
};

/* DEBUG */
// load an example assembly for testing. this code will be removed once we've
// built a more formal test assembly system
fn load_gen_assemb(assembly: &Assembly) {
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("gemini_a"),
            String::from("Castor"),
            [1.00_f32, 0.25_f32, 0.00_f32],
            engine::sphere(0.5, 0.5, 0.0, 1.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("gemini_b"),
            String::from("Pollux"),
            [0.00_f32, 0.25_f32, 1.00_f32],
            engine::sphere(-0.5, -0.5, 0.0, 1.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("ursa_major"),
            String::from("Ursa major"),
            [0.25_f32, 0.00_f32, 1.00_f32],
            engine::sphere(-0.5, 0.5, 0.0, 0.75)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("ursa_minor"),
            String::from("Ursa minor"),
            [0.25_f32, 1.00_f32, 0.00_f32],
            engine::sphere(0.5, -0.5, 0.0, 0.5)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("moon_deimos"),
            String::from("Deimos"),
            [0.75_f32, 0.75_f32, 0.00_f32],
            engine::sphere(0.0, 0.15, 1.0, 0.25)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("moon_phobos"),
            String::from("Phobos"),
            [0.00_f32, 0.75_f32, 0.50_f32],
            engine::sphere(0.0, -0.15, -1.0, 0.25)
        )
    );
}

/* DEBUG */
// load an example assembly for testing. this code will be removed once we've
// built a more formal test assembly system
fn load_low_curv_assemb(assembly: &Assembly) {
    let a = 0.75_f64.sqrt();
    let _ = assembly.try_insert_element(
        Element::new(
            "central".to_string(),
            "Central".to_string(),
            [0.75_f32, 0.75_f32, 0.75_f32],
            engine::sphere(0.0, 0.0, 0.0, 1.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            "assemb_plane".to_string(),
            "Assembly plane".to_string(),
            [0.75_f32, 0.75_f32, 0.75_f32],
            engine::sphere_with_offset(0.0, 0.0, 1.0, 0.0, 0.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            "side1".to_string(),
            "Side 1".to_string(),
            [1.00_f32, 0.00_f32, 0.25_f32],
            engine::sphere_with_offset(1.0, 0.0, 0.0, 1.0, 0.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            "side2".to_string(),
            "Side 2".to_string(),
            [0.25_f32, 1.00_f32, 0.00_f32],
            engine::sphere_with_offset(-0.5, a, 0.0, 1.0, 0.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            "side3".to_string(),
            "Side 3".to_string(),
            [0.00_f32, 0.25_f32, 1.00_f32],
            engine::sphere_with_offset(-0.5, -a, 0.0, 1.0, 0.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            "corner1".to_string(),
            "Corner 1".to_string(),
            [0.75_f32, 0.75_f32, 0.75_f32],
            engine::sphere(-4.0/3.0, 0.0, 0.0, 1.0/3.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            "corner2".to_string(),
            "Corner 2".to_string(),
            [0.75_f32, 0.75_f32, 0.75_f32],
            engine::sphere(2.0/3.0, -4.0/3.0 * a, 0.0, 1.0/3.0)
        )
    );
    let _ = assembly.try_insert_element(
        Element::new(
            String::from("corner3"),
            String::from("Corner 3"),
            [0.75_f32, 0.75_f32, 0.75_f32],
            engine::sphere(2.0/3.0, 4.0/3.0 * a, 0.0, 1.0/3.0)
        )
    );
}

#[component]
pub fn AddRemove() -> View {
    /* DEBUG */
    let assembly_name = create_signal("general".to_string());
    create_effect(move || {
        // get name of chosen assembly
        let name = assembly_name.get_clone();
        console::log_1(
            &JsValue::from(format!("Showing assembly \"{}\"", name.clone()))
        );
        
        batch(|| {
            let state = use_context::<AppState>();
            let assembly = &state.assembly;
            
            // clear state
            assembly.elements.update(|elts| elts.clear());
            assembly.elements_by_id.update(|elts_by_id| elts_by_id.clear());
            state.selection.update(|sel| sel.clear());
            
            // load assembly
            match name.as_str() {
                "general" => load_gen_assemb(assembly),
                "low-curv" => load_low_curv_assemb(assembly),
                _ => ()
            };
        });
    });
    
    view! {
        div(id="add-remove") {
            button(
                on:click=|_| {
                    let state = use_context::<AppState>();
                    state.assembly.insert_new_element();
                    
                    /* DEBUG */
                    // print updated list of elements by identifier
                    console::log_1(&JsValue::from("elements by identifier:"));
                    for (id, key) in state.assembly.elements_by_id.get_clone().iter() {
                        console::log_3(
                            &JsValue::from(" "),
                            &JsValue::from(id),
                            &JsValue::from(*key)
                        );
                    }
                }
            ) { "+" }
            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 = state.selection.with(
                        |sel| {
                            let subject_vec: Vec<_> = sel.into_iter().collect();
                            (subject_vec[0].clone(), subject_vec[1].clone())
                        }
                    );
                    let measured = state.assembly.elements.map(
                        move |elts| {
                            let reps = (
                                elts[subjects.0].representation.get_clone(),
                                elts[subjects.1].representation.get_clone()
                            );
                            reps.0.dot(&(&*Q * reps.1))
                        }
                    );
                    let desired = create_signal(0.0);
                    let role = create_signal(ConstraintRole::Measure);
                    state.assembly.insert_constraint(Constraint {
                        subjects: subjects,
                        measured: measured,
                        desired: desired,
                        desired_text: create_signal(String::new()),
                        role: role,
                    });
                    state.selection.update(|sel| sel.clear());
                    
                    /* DEBUG */
                    // print updated constraint list
                    console::log_1(&JsValue::from("Constraints:"));
                    state.assembly.constraints.with(|csts| {
                        for (_, cst) in csts.into_iter() {
                            console::log_5(
                                &JsValue::from(" "),
                                &JsValue::from(cst.subjects.0),
                                &JsValue::from(cst.subjects.1),
                                &JsValue::from(":"),
                                &JsValue::from(cst.desired.get_untracked())
                            );
                        }
                    });
                    
                    // update the realization when the observable becomes
                    // constrained, or is edited while constrained
                    create_effect(move || {
                        console::log_1(&JsValue::from(
                            format!("Constraint ({}, {}) updated", subjects.0, subjects.1)
                        ));
                        desired.track();
                        if role.with(|r| matches!(r, ConstraintRole::Constrain)) {
                            state.assembly.realize();
                        }
                    });
                }
            ) { "🔗" }
            select(bind:value=assembly_name) { /* DEBUG */ // example assembly chooser
                option(value="general") { "General" }
                option(value="low-curv") { "Low-curvature" }
                option(value="empty") { "Empty" }
            }
        }
    }
}