use giterated_models::{object::GiteratedObject, value::GiteratedObjectValue};

use crate::FFIBox;

#[repr(C)]
pub struct NewAnyValue {
    /// A pointer to the plugin-local object type. We are not capable of
    /// knowing what this type is, we use the provided vtable.
    inner: FFIBox<()>,
    vtable: ValueVTable,
}

impl NewAnyValue {
    pub fn new<O, V: IntoValueVTable<O>>(value: V) -> Self {
        NewAnyValue {
            inner: FFIBox::from_box(Box::new(value)).untyped(),
            vtable: ValueVTable::new::<O, V>(),
        }
    }
}

#[derive(Clone, Copy)]
#[repr(C)]
pub struct ValueVTable {
    pub deserialize: unsafe extern "C" fn(&[u8]) -> Result<NewAnyValue, ()>,
    pub serialize: unsafe extern "C" fn(NewAnyValue) -> Result<FFIBox<[u8]>, ()>,
}

impl ValueVTable {
    pub fn new<O, T: IntoValueVTable<O>>() -> Self {
        Self {
            deserialize: T::deserialize,
            serialize: T::serialize,
        }
    }
}

pub trait IntoValueVTable<O> {
    unsafe extern "C" fn deserialize(src: &[u8]) -> Result<NewAnyValue, ()>;
    unsafe extern "C" fn serialize(this: NewAnyValue) -> Result<FFIBox<[u8]>, ()>;
}

impl<O, V> IntoValueVTable<O> for V
where
    O: GiteratedObject,
    V: GiteratedObjectValue<Object = O>,
{
    unsafe extern "C" fn deserialize(src: &[u8]) -> Result<NewAnyValue, ()> {
        let _guard = trace_span!(
            "deserialize value",
            object = O::object_name(),
            value = V::value_name()
        );

        trace!("Deserializing");
        let deserialized: V = serde_json::from_slice(src).unwrap();

        Ok(NewAnyValue {
            inner: FFIBox::from_box(Box::new(deserialized)).untyped(),
            vtable: ValueVTable::new::<O, V>(),
        })
    }

    unsafe extern "C" fn serialize(this: NewAnyValue) -> Result<FFIBox<[u8]>, ()> {
        todo!()
    }
}