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use effectful::{
    bound::{Dynamic, ForceDynamic},
    effective::{Effective, Canonical},
    environment::{Environment},
    DynBind,
    SendSync,
};
use mockall::predicate::eq;
use treaty::{
    any::{BorrowedStatic, OwnedStatic},
    protocol::{
        visitor::{tags, TagConst, VisitResult},
        AsVisitor, DynVisitor,
    },
    walk::walkers::core::r#struct::{StructTypeInfo, StructWalker},
    DefaultMode, Flow, Walker,
};
use effectful::blocking::BlockingSpin;

use crate::common::{
    builder::{EmptyError, MockBuilder},
    protocol::{sequence::MockSequenceVisitor, tag::MockTagVisitor, value::MockValueVisitor},
};

mod common;

#[derive(SendSync)]
struct X {
    a: bool,
    b: i32,
}

struct Info;

// This gives the struct walker enough information to walk the X struct.
impl<'ctx, M, E: Environment> StructTypeInfo<'ctx, M, E> for Info
where
    Dynamic<OwnedStatic<bool>>: DynBind<E>,
    Dynamic<OwnedStatic<i32>>: DynBind<E>,
{
    const NAME: &'static str = "X";

    const FIELDS: &'static [&'static str] = &["a", "b"];

    type FieldError = ();

    type S = StaticType;

    type T = X;

    fn walk_field<'a>(
        index: usize,
        value: &'ctx Self::T,
        mut visitor: DynVisitor<'a, 'ctx, E>,
    ) -> Canonical<'a, Result<Flow, Self::FieldError>, E> {
        E::future(unsafe {
            ForceDynamic::new(async move {
                match index {
                    // A real impl would be expected to tag these values with the field name.
                    0 => {
                        // Basic visit for the field value.
                        let obj = visitor
                            .upcast_mut::<ValueProto<OwnedStatic<bool>, E>>()
                            .unwrap();

                        // Emit the field value.
                        assert_eq!(
                            obj.visit(OwnedStatic(value.a)).into_future().await,
                            Flow::Done.into()
                        );

                        // There are more fields.
                        Ok(Flow::Continue)
                    }
                    1 => {
                        // Basic visit for the field value.
                        let obj = visitor
                            .upcast_mut::<ValueProto<OwnedStatic<i32>, E>>()
                            .unwrap();

                        // Emit the field value.
                        assert_eq!(
                            obj.visit(OwnedStatic(value.b)).into_future().await,
                            Flow::Done.into()
                        );

                        // There are no more fields.
                        Ok(Flow::Done)
                    }
                    _ => Ok(Flow::Done),
                }
            })
        })
        .cast()
    }
}

/// Tests that a struct walker in its most basic form just emits a sequence of field values.
///
/// This makes structs behave like tuples (lists) if the builder doesn't know about any of the
/// extra tags.
#[test]
fn sequence_of_field_values() {
    // The struct value to walk.
    let value = X { a: true, b: 42 };

    // The struct walker using the info we provided about the struct.
    let walker = StructWalker::<Info, _, DefaultMode, BlockingSpin>::new(&value);

    let mut builder = MockBuilder::<(), (), EmptyError, BlockingSpin>::new();

    // Expect a visit on the sequence protocol for the struct fields.
    builder
        .expect_traits_mut()
        .once()
        .with(eq(TypeNameId::of::<SequenceProto<BlockingSpin>, BlockingSpin>()))
        .returning(|_| {
            let mut visitor = MockSequenceVisitor::<BlockingSpin>::new();

            // Expect the sequence visitor to be used.
            visitor.expect_visit().once().returning(|scope| {
                // The struct should have exactly 2 fields.
                assert_eq!(scope.size_hint().into_value(), (2, Some(2)));

                // Get the first field value.
                {
                    let mut visitor = MockBuilder::<(), (), EmptyError, BlockingSpin>::new();

                    // Expect a bool value for the field.
                    visitor
                        .expect_traits_mut()
                        .once()
                        .with(eq(TypeNameId::of::<
                            ValueProto<OwnedStatic<bool>, BlockingSpin>,
                            BlockingSpin,
                        >()))
                        .returning(|_| {
                            let mut visitor =
                                MockValueVisitor::<OwnedStatic<bool>, BlockingSpin>::new();

                            // Expect true.
                            visitor
                                .expect_visit()
                                .once()
                                .with(eq(OwnedStatic(true)))
                                .return_const(Flow::Done);

                            Some(Box::new(DynamicShim(visitor)))
                        });

                    assert_eq!(
                        scope.next(AsVisitor::as_visitor(&mut visitor)).into_value(),
                        Flow::Continue
                    );
                }

                // Get the second field value.
                {
                    let mut visitor = MockBuilder::<(), (), EmptyError, BlockingSpin>::new();

                    // Expect a i32 value.
                    visitor
                        .expect_traits_mut()
                        .once()
                        .with(eq(TypeNameId::of::<
                            ValueProto<OwnedStatic<i32>, BlockingSpin>,
                            BlockingSpin,
                        >()))
                        .returning(|_| {
                            let mut visitor = MockValueVisitor::<OwnedStatic<i32>, BlockingSpin>::new();

                            // Expect a 42.
                            visitor
                                .expect_visit()
                                .once()
                                .with(eq(OwnedStatic(42)))
                                .return_const(Flow::Done);

                            Some(Box::new(DynamicShim(visitor)))
                        });

                    assert_eq!(
                        scope.next(AsVisitor::as_visitor(&mut visitor)).into_value(),
                        Flow::Done
                    );
                }

                // We are done with the sequence of fields.
                VisitResult::Control(Flow::Done)
            });

            Some(Box::new(DynamicShim(visitor)))
        });

    // All other protocols are not used for this test.
    builder.expect_traits_mut().return_var(None);

    // Walk the struct.
    assert_eq!(
        walker
            .walk(AsVisitor::as_visitor(&mut builder))
            .into_value(),
        Ok(())
    );
}

#[test]
fn has_struct_tag() {
    // The struct value to walk.
    let value = X { a: true, b: 42 };

    // The struct walker using the info we provided about the struct.
    let walker = StructWalker::<Info, _, DefaultMode, BlockingSpin>::new(&value);

    let mut builder = MockBuilder::<(), (), EmptyError, BlockingSpin>::new();

    let mut seq = mockall::Sequence::new();

    // Skip the request hint, borrowed value, and type id.
    builder
        .expect_traits_mut()
        .times(4)
        .in_sequence(&mut seq)
        .return_var(None);

    // Expect that the tag for a struct is emmited.
    builder
        .expect_traits_mut()
        .once()
        .in_sequence(&mut seq)
        .with(eq(TypeNameId::of::<
            TagProto<tags::Struct, BlockingSpin>,
            Blocking,
        >()))
        .returning(|_| {
            let mut visitor = MockTagVisitor::<tags::Struct, Blocking>::new();

            visitor.expect_visit().once().returning(|TagConst, walker| {
                let mut visitor = MockBuilder::<(), (), (), Blocking>::new();

                // Walk the noop walker so there isn't an error.
                assert_eq!(
                    walker.walk(DynVisitor(&mut visitor)).into_value(),
                    Flow::Done
                );

                // We are done, the walker should now stop early.
                VisitResult::Control(Flow::Done)
            });

            Some(Box::new(DynamicShim(visitor)))
        });

    // Walk the struct.
    assert_eq!(
        walker
            .walk(AsVisitor::as_visitor(&mut builder))
            .into_value(),
        Ok(())
    );
}

#[test]
fn has_map_backup_tag() {
    // The struct value to walk.
    let value = X { a: true, b: 42 };

    // The struct walker using the info we provided about the struct.
    let walker = StructWalker::<Info, _, DefaultMode, Blocking>::new(&value);

    let mut builder = MockBuilder::<(), (), EmptyError, Blocking>::new();

    let mut seq = mockall::Sequence::new();

    // Skip the request hint, borrowed value type id, and struct tag.
    builder
        .expect_traits_mut()
        .times(6)
        .in_sequence(&mut seq)
        .return_var(None);

    // Expect that the tag for a map is emmited.
    //
    // This only happens if the struct tag isn't supported by the visitor.
    builder
        .expect_traits_mut()
        .once()
        .in_sequence(&mut seq)
        .with(eq(
            TypeNameId::of::<TagProto<tags::Map, Blocking>, Blocking>(),
        ))
        .returning(|_| {
            let mut visitor = MockTagVisitor::<tags::Map, Blocking>::new();

            visitor.expect_visit().once().returning(|TagConst, walker| {
                let mut visitor = MockBuilder::<(), (), (), Blocking>::new();

                // Walk the noop walker so there isn't an error.
                assert_eq!(
                    walker.walk(DynVisitor(&mut visitor)).into_value(),
                    Flow::Done
                );

                // We are done, the walker should now stop early.
                VisitResult::Control(Flow::Done)
            });

            Some(Box::new(DynamicShim(visitor)))
        });

    // Walk the struct.
    assert_eq!(
        walker
            .walk(AsVisitor::as_visitor(&mut builder))
            .into_value(),
        Ok(())
    );
}

#[test]
fn borrowed_value_directly() {
    // The struct value to walk.
    let value = X { a: true, b: 42 };

    // The struct walker using the info we provided about the struct.
    let walker = StructWalker::<Info, _, DefaultMode, Blocking>::new(&value);

    let mut builder = MockBuilder::<(), (), EmptyError, Blocking>::new();

    let mut seq = mockall::Sequence::new();

    // Skip the request hint.
    builder
        .expect_traits_mut()
        .once()
        .in_sequence(&mut seq)
        .return_var(None);

    // Get the struct value directly from the walker.
    builder
        .expect_traits_mut()
        .once()
        .in_sequence(&mut seq)
        .with(eq(TypeNameId::of::<
            ValueProto<BorrowedStaticHrt<X>, Blocking>,
            Blocking,
        >()))
        .returning(|_| {
            let mut visitor = MockValueVisitor::<BorrowedStaticHrt<X>, Blocking>::new();

            // Expect the struct value.
            visitor
                .expect_visit()
                .once()
                .returning(|BorrowedStatic(value)| {
                    // Check the value to be the same.
                    assert!(value.a);
                    assert_eq!(value.b, 42);

                    // We are done, the walker should now stop early.
                    VisitResult::Control(Flow::Done)
                });

            Some(Box::new(DynamicShim(visitor)))
        });

    // Walk the struct.
    assert_eq!(
        walker
            .walk(AsVisitor::as_visitor(&mut builder))
            .into_value(),
        Ok(())
    );
}