treaty -


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use std::{any::TypeId, collections::VecDeque, ops::ControlFlow};
use treaty::{
    any::{any_trait, static_wrapper::OwnedStatic},
    protocol::{
        visitor::{Sequence, SequenceScope, Value},
        Visitor,
    },
    Builder, Walk, Walker,
};

#[test]
fn demo() {
    let a = Data::Sequence(vec![
        Data::Bool(true),
        Data::Sequence(vec![Data::Bool(false), Data::Bool(true)]),
        Data::Bool(false),
    ]);

    let mut builder = JsonLike::default();
    <Data as Walk>::Walker::from(a).walk(builder.as_visitor()).unwrap();
    dbg!(builder.build().unwrap());

    todo!()
}

#[derive(Debug)]
enum Data {
    Bool(bool),
    Sequence(Vec<Data>),
}

const _: () = {
    struct Impl(Data);

    impl From<Data> for Impl {
        fn from(value: Data) -> Self {
            Self(value)
        }
    }

    impl<'ctx> Walk<'ctx> for Data {
        type Walker = Impl;
    }

    impl<'ctx> Walker<'ctx> for Impl {
        type Error = ();

        type Output = ();

        fn walk(self, visitor: Visitor<'_, 'ctx>) -> Result<Self::Output, Self::Error> {
            match self.0 {
                Data::Bool(value) => walk_bool(value, visitor),
                Data::Sequence(value) => walk_vec(value, visitor),
            }
            Ok(())
        }
    }
};

fn walk_bool(value: bool, visitor: Visitor<'_, '_>) {
    visitor
        .upcast_mut::<dyn Value<OwnedStatic<bool>>>()
        .unwrap()
        .visit(OwnedStatic(value));
}

fn walk_vec(value: Vec<Data>, visitor: Visitor<'_, '_>) {
    struct Scope(VecDeque<Data>);

    impl<'ctx> SequenceScope<'ctx> for Scope {
        fn next(
            &mut self,
            visitor: Visitor<'_, 'ctx>,
        ) -> treaty::protocol::ControlFlow<(), treaty::protocol::visitor::Status> {
            if let Some(value) = self.0.pop_front() {
                <<Data as Walk>::Walker>::from(value).walk(visitor).unwrap();

                ControlFlow::Continue(treaty::protocol::visitor::Status::Continue)
            } else {
                ControlFlow::Continue(treaty::protocol::visitor::Status::Done)
            }
        }
    }

    let mut scope = Scope(value.into());

    visitor
        .upcast_mut::<dyn Sequence<'_>>()
        .unwrap()
        .visit(&mut scope);
}

#[derive(Default)]
struct JsonLike(String);

impl<'ctx> Builder<'ctx> for JsonLike {
    type Error = ();

    type Value = String;

    fn as_visitor(&mut self) -> Visitor<'_, 'ctx> {
        self
    }

    fn build(self) -> Result<Self::Value, Self::Error> {
        Ok(self.0)
    }
}

any_trait! {
    impl['a, 'ctx] JsonLike = [
        dyn Value<OwnedStatic<bool>> + 'a,
        dyn Sequence<'ctx> + 'a,
    ];
}

impl Value<OwnedStatic<bool>> for JsonLike {
    fn visit(&mut self, value: OwnedStatic<bool>) -> treaty::protocol::ControlFlow {
        self.0.push_str(&format!("{}", value.0));
        ControlFlow::Continue(())
    }
}

impl<'ctx> Sequence<'ctx> for JsonLike {
    fn visit(&mut self, scope: &mut dyn SequenceScope<'ctx>) -> treaty::protocol::ControlFlow {
        self.0.push_str("[");
        while let ControlFlow::Continue(treaty::protocol::visitor::Status::Continue) =
            scope.next(self)
        {
            self.0.push_str(",");
        }
        self.0.push_str("]");
        ControlFlow::Continue(())
    }
}