use std::mem::transmute;

use giterated_models::settings::Setting;

use crate::FFIBox;

#[repr(C)]
pub struct NewAnySetting {
    /// 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: SettingVtable,
}

impl NewAnySetting {
    pub fn new<V: IntoSettingVTable>(value: V) -> Self {
        Self {
            inner: FFIBox::from_box(Box::new(value)).untyped(),
            vtable: SettingVtable::new::<V>(),
        }
    }

    pub unsafe fn transmute_owned<T>(self) -> Box<T> {
        Box::from_raw(self.inner.0 as *mut T)
    }

    pub unsafe fn transmute_ref<T>(&self) -> &T {
        let ptr: *const T = transmute(self.inner.0);

        ptr.as_ref().unwrap()
    }
}

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

impl SettingVtable {
    pub fn new<T: IntoSettingVTable>() -> Self {
        Self {
            deserialize: T::deserialize,
            serialize: T::serialize,
        }
    }
}

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

impl<S> IntoSettingVTable for S
where
    S: Setting,
{
    unsafe extern "C" fn deserialize(src: &[u8]) -> Result<(), ()> {
        todo!()
    }

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