use core::cell::RefCell;
use neon::prelude::*;
use sixtyfps_compilerlib::typeregister::Type;
use sixtyfps_corelib::abi::datastructures::Resource;
use sixtyfps_corelib::ComponentRefPin;

use std::rc::Rc;

mod persistent_context;

struct WrappedComponentType(Option<Rc<sixtyfps_interpreter::ComponentDescription>>);
struct WrappedComponentBox(Option<Rc<sixtyfps_interpreter::ComponentBox>>);

/// We need to do some gymnastic with closures to pass the ExecuteContext with the right lifetime
type GlobalContextCallback =
    dyn for<'b> Fn(&mut ExecuteContext<'b>, &persistent_context::PersistentContext<'b>);
scoped_tls_hkt::scoped_thread_local!(static GLOBAL_CONTEXT:
    for <'a> &'a dyn Fn(&GlobalContextCallback));

/// Load a .60 files.
///
/// The first argument of this finction is a string to the .60 file
///
/// The return value is a SixtyFpsComponentType
fn load(mut cx: FunctionContext) -> JsResult<JsValue> {
    let path = cx.argument::<JsString>(0)?.value();
    let path = std::path::Path::new(path.as_str());
    let source = std::fs::read_to_string(&path).or_else(|e| cx.throw_error(e.to_string()))?;
    let c = match sixtyfps_interpreter::load(source.as_str(), &path) {
        Ok(c) => c,
        Err(diag) => {
            diag.print(source);
            return cx.throw_error("Compilation error");
        }
    };

    let mut obj = SixtyFpsComponentType::new::<_, JsValue, _>(&mut cx, std::iter::empty())?;
    cx.borrow_mut(&mut obj, |mut obj| obj.0 = Some(c));
    Ok(obj.as_value(&mut cx))
}

fn create<'cx>(
    cx: &mut CallContext<'cx, impl neon::object::This>,
    component_type: Rc<sixtyfps_interpreter::ComponentDescription>,
) -> JsResult<'cx, JsValue> {
    let mut component = component_type.clone().create();
    let persistent_context = persistent_context::PersistentContext::new(cx);

    if let Some(args) = cx.argument_opt(0).and_then(|arg| arg.downcast::<JsObject>().ok()) {
        let properties = component_type.properties();
        for x in args.get_own_property_names(cx)?.to_vec(cx)? {
            let prop_name = x.to_string(cx)?.value();
            let value = args.get(cx, x)?;
            let ty = properties
                .get(&prop_name)
                .ok_or(())
                .or_else(|()| {
                    cx.throw_error(format!("Property {} not found in the component", prop_name))
                })?
                .clone();
            if ty == Type::Signal {
                let _fun = value.downcast_or_throw::<JsFunction, _>(cx)?;
                let fun_idx = persistent_context.allocate(cx, value);
                component_type
                    .set_signal_handler(
                        component.borrow_mut(),
                        prop_name.as_str(),
                        Box::new(move |()| {
                            GLOBAL_CONTEXT.with(|cx_fn| {
                                cx_fn(&move |cx, presistent_context| {
                                    presistent_context
                                        .get(cx, fun_idx)
                                        .unwrap()
                                        .downcast::<JsFunction>()
                                        .unwrap()
                                        .call::<_, _, JsValue, _>(
                                            cx,
                                            JsUndefined::new(),
                                            std::iter::empty(),
                                        )
                                        .unwrap();
                                })
                            })
                        }),
                    )
                    .or_else(|_| cx.throw_error(format!("Cannot set signal")))?;
            } else {
                let value = to_eval_value(value, ty, cx)?;
                component_type
                    .set_property(component.borrow(), prop_name.as_str(), value)
                    .or_else(|_| cx.throw_error(format!("Cannot assign property")))?;
            }
        }
    }

    let mut obj = SixtyFpsComponent::new::<_, JsValue, _>(cx, std::iter::empty())?;
    persistent_context.save_to_object(cx, obj.downcast().unwrap());
    cx.borrow_mut(&mut obj, |mut obj| obj.0 = Some(Rc::new(component)));
    Ok(obj.as_value(cx))
}

fn to_eval_value<'cx>(
    val: Handle<JsValue>,
    ty: sixtyfps_compilerlib::typeregister::Type,
    cx: &mut impl Context<'cx>,
) -> NeonResult<sixtyfps_interpreter::Value> {
    use sixtyfps_interpreter::Value;
    match ty {
        Type::Invalid
        | Type::Component(_)
        | Type::Builtin(_)
        | Type::Model
        | Type::Signal
        | Type::PathElements => cx.throw_error("Cannot convert to a Sixtyfps property value"),
        Type::Float32 | Type::Int32 => {
            Ok(Value::Number(val.downcast_or_throw::<JsNumber, _>(cx)?.value()))
        }
        Type::String => Ok(Value::String(val.to_string(cx)?.value().as_str().into())),
        Type::Color | Type::Array(_) | Type::Object(_) => todo!(),
        Type::Resource => Ok(Value::String(val.to_string(cx)?.value().as_str().into())),
        Type::Bool => Ok(Value::Bool(val.downcast_or_throw::<JsBoolean, _>(cx)?.value())),
    }
}

fn to_js_value<'cx>(
    val: sixtyfps_interpreter::Value,
    cx: &mut impl Context<'cx>,
) -> NeonResult<Handle<'cx, JsValue>> {
    use sixtyfps_interpreter::Value;
    Ok(match val {
        Value::Void => JsUndefined::new().as_value(cx),
        Value::Number(n) => JsNumber::new(cx, n).as_value(cx),
        Value::String(s) => JsString::new(cx, s.as_str()).as_value(cx),
        Value::Bool(b) => JsBoolean::new(cx, b).as_value(cx),
        Value::Resource(r) => match r {
            Resource::None => JsUndefined::new().as_value(cx),
            Resource::AbsoluteFilePath(path) => JsString::new(cx, path.as_str()).as_value(cx),
            Resource::EmbeddedData { .. } => JsNull::new().as_value(cx), // TODO: maybe pass around node buffers?
        },
        Value::Array(a) => {
            let js_array = JsArray::new(cx, a.len() as _);
            for (i, e) in a.into_iter().enumerate() {
                let v = to_js_value(e, cx)?;
                js_array.set(cx, i as u32, v)?;
            }
            js_array.as_value(cx)
        }
        Value::Object(o) => {
            let js_object = JsObject::new(cx);
            for (k, e) in o.into_iter() {
                let v = to_js_value(e, cx)?;
                js_object.set(cx, k.as_str(), v)?;
            }
            js_object.as_value(cx)
        }
        Value::Color(c) => JsNumber::new(cx, c.as_argb_encoded()).as_value(cx),
        Value::PathElements(_) => todo!(),
    })
}

fn show<'cx>(
    cx: &mut CallContext<'cx, impl neon::object::This>,
    component: ComponentRefPin,
    presistent_context: persistent_context::PersistentContext<'cx>,
) -> JsResult<'cx, JsUndefined> {
    cx.execute_scoped(|cx| {
        let cx = RefCell::new(cx);
        let cx_fn = move |callback: &GlobalContextCallback| {
            callback(&mut *cx.borrow_mut(), &presistent_context)
        };
        GLOBAL_CONTEXT.set(&&cx_fn, || {
            let window = sixtyfps_rendering_backend_gl::create_gl_window();
            window.run(component);
        })
    });

    Ok(JsUndefined::new())
}

declare_types! {
    class SixtyFpsComponentType for WrappedComponentType {
        init(_) {
            Ok(WrappedComponentType(None))
        }
        method create(mut cx) {
            let this = cx.this();
            let ct = cx.borrow(&this, |x| x.0.clone());
            let ct = ct.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            create(&mut cx, ct)
        }
        method name(mut cx) {
            let this = cx.this();
            let ct = cx.borrow(&this, |x| x.0.clone());
            let ct = ct.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            Ok(cx.string(ct.id()).as_value(&mut cx))
        }
        method properties(mut cx) {
            let this = cx.this();
            let ct = cx.borrow(&this, |x| x.0.clone());
            let ct = ct.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            let properties = ct.properties();
            let array = JsArray::new(&mut cx, properties.len() as u32);
            let mut len: u32 = 0;
            for (p, _) in properties.iter().filter(|(_, prop_type)| prop_type.is_property_type()) {
                let prop_name = JsString::new(&mut cx, p);
                array.set(&mut cx, len, prop_name)?;
                len = len + 1;
            }
            Ok(array.as_value(&mut cx))
        }
        method signals(mut cx) {
            let this = cx.this();
            let ct = cx.borrow(&this, |x| x.0.clone());
            let ct = ct.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            let properties = ct.properties();
            let array = JsArray::new(&mut cx, properties.len() as u32);
            let mut len: u32 = 0;
            for (p, _) in properties.iter().filter(|(_, prop_type)| **prop_type == Type::Signal) {
                let prop_name = JsString::new(&mut cx, p);
                array.set(&mut cx, len, prop_name)?;
                len = len + 1;
            }
            Ok(array.as_value(&mut cx))
        }
    }

    class SixtyFpsComponent for WrappedComponentBox {
        init(_) {
            Ok(WrappedComponentBox(None))
        }
        method show(mut cx) {
            let mut this = cx.this();
            let component = cx.borrow(&mut this, |x| x.0.clone());
            let component = component.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            let persistent_context = persistent_context::PersistentContext::from_object(&mut cx, this.downcast().unwrap())?;
            show(&mut cx, component.borrow(), persistent_context)?;
            Ok(JsUndefined::new().as_value(&mut cx))
        }
        method get_property(mut cx) {
            let prop_name = cx.argument::<JsString>(0)?.value();
            let this = cx.this();
            let lock = cx.lock();
            let x = this.borrow(&lock).0.clone();
            let component = x.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            let value = component.description()
                .get_property(component.borrow(), prop_name.as_str())
                .or_else(|_| cx.throw_error(format!("Cannot read property")))?;
            to_js_value(value, &mut cx)
        }
        method set_property(mut cx) {
            let prop_name = cx.argument::<JsString>(0)?.value();
            let this = cx.this();
            let lock = cx.lock();
            let x = this.borrow(&lock).0.clone();
            let component  = x.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            let ty = component.description().properties()
                .get(&prop_name)
                .ok_or(())
                .or_else(|()| {
                    cx.throw_error(format!("Property {} not found in the component", prop_name))
                })?
                .clone();

            let value = to_eval_value(cx.argument::<JsValue>(1)?, ty, &mut cx)?;
            component.description()
                .set_property(component.borrow(), prop_name.as_str(), value)
                .or_else(|_| cx.throw_error(format!("Cannot assign property")))?;

            Ok(JsUndefined::new().as_value(&mut cx))
        }
        method emit_signal(mut cx) {
            let signal_name = cx.argument::<JsString>(0)?.value();
            let this = cx.this();
            let lock = cx.lock();
            let x = this.borrow(&lock).0.clone();
            let component = x.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
            component.description()
                .emit_signal(component.borrow(), signal_name.as_str())
                .or_else(|_| cx.throw_error(format!("Cannot emit signal")))?;

            Ok(JsUndefined::new().as_value(&mut cx))
        }
    }
}

register_module!(mut m, {
    m.export_function("load", load)?;
    Ok(())
});