use std::any::TypeId;

use common::protocol::{
    hint::{KnownFactory, MockHintWalker},
    value::MockValueVisitor,
};
use effectful::bound::Dynamic;
use effectful::SendSync;
use effectful::blocking::BlockingSpin;
use mockall::predicate::eq;
use treaty::{
    any::{AnyTrait, BorrowedStatic, OwnedStatic, TempBorrowedMutStatic},
    protocol::{
        visitor::{visit_value, Value, ValueKnown, VisitResult},
        walker::hint::Hint,
        DynVisitor,
    },
    Flow,
};

mod common;

/// Tests support for custom type support in the value protocol.
///
/// This is a core feature of treaty so it better work.
#[test]
fn custom_value_type() {
    // The value we want to visit in the value visitor.
    #[derive(PartialEq, Debug, Clone, SendSync)]
    struct MyValue;

    let mut mock = MockValueVisitor::<OwnedStatic<MyValue>, BlockingSpin>::new();

    // Expect the visit method to be called once with the custom type.
    mock.expect_visit()
        .times(2)
        .with(eq(OwnedStatic(MyValue)))
        .return_const(VisitResult::Control(Flow::Done));

    // Cast to a trait object for the value protocol.
    // This shows the visit method is going through the trait.
    let visitor: &mut dyn Value<OwnedStatic<MyValue>, BlockingSpin> = &mut mock;

    // Visit the value.
    let result = visitor.visit(OwnedStatic(MyValue)).into_value();

    // The mock returns that it is done.
    assert_eq!(result, VisitResult::Control(Flow::Done));

    let visitor: &mut dyn AnyTrait<BlockingSpin> = &mut mock;
    assert_eq!(
        visit_value::<_, BlockingSpin>(DynVisitor(visitor), OwnedStatic(MyValue)).into_value(),
        VisitResult::Control(Flow::Done)
    );
}

/// Tests that a value with a lifetime can be given to the value protocol.
///
/// This allows for treaty's zero copy capabilities.
/// Also this is what allows treaty to short circuit things like structs and enums if the visitor
/// supports it.
#[test]
fn borrowed_value() {
    // A value with a lifetime longer than the visitor.
    let context = String::from("test");

    // Scope that doesn't live as long as the context.
    {
        // We borrow the context, this is what we pass to the visitor.
        let value = &context;

        let mut mock = MockValueVisitor::<BorrowedStaticHrt<String>, BlockingSpin>::new();

        // Expect the visit method to be called once with the borrowed value.
        mock.expect_visit()
            .times(2)
            .withf(|BorrowedStatic(value)| *value == "test")
            .return_const(VisitResult::Control(Flow::Done));

        // Cast to a trait object for the value protocol.
        let visitor: &mut dyn Value<BorrowedStaticHrt<String>, BlockingSpin> = &mut mock;

        // Visit the borrowed value.
        assert_eq!(
            visitor.visit(BorrowedStatic(value)).into_value(),
            Flow::Done.into()
        );

        let visitor: &mut dyn AnyTrait<BlockingSpin> = &mut mock;
        assert_eq!(
            visit_value::<_, BlockingSpin>(DynVisitor(visitor), BorrowedStatic(value)).into_value(),
            VisitResult::Control(Flow::Done)
        );
    }

    // Make sure the compiler doesn't do anything funny with the lifetime.
    assert_eq!(context, "test");
}

/// Tests that a value with a temp lifetime can be given to the value protocol.
///
/// This is useful for passing borrows of things inside a walker to a visitor.
/// The visitor can't keep the borrow as the temp lifetime is shorter than the context.
///
/// If you replaced the [`TempBorrowedMutStaticHrt`] with [`BorrowedMutStaticHrt`]
/// this would fail to compile.
#[test]
fn temp_borrowed_value() {
    // A value with a lifetime longer than the visitor.
    let mut context = String::from("test");

    // Scope that doesn't live as long as the context.
    {
        // We borrow the context, this is what we pass to the visitor.
        let value = &mut context;

        let mut mock = MockValueVisitor::<TempBorrowedMutStaticHrt<String>, BlockingSpin>::new();

        // Expect the visit method to be called once with the borrowed value.
        mock.expect_visit()
            .times(2)
            .withf(|TempBorrowedMutStatic(value)| *value == "test")
            .return_const(VisitResult::Control(Flow::Done));

        // Cast to a trait object for the value protocol.
        // We definitly need this for this test so the lifetime is invariant.
        let visitor: &mut dyn Value<TempBorrowedMutStaticHrt<String>, BlockingSpin> = &mut mock;

        // Visit the context to show we can shorten the lifetime.
        // This would also force the lifetime to be to long if this wasn't the Temp form.
        assert_eq!(
            visitor.visit(TempBorrowedMutStatic(value)).into_value(),
            Flow::Done.into()
        );

        // Temporary scope (smaller than the context we set above).
        {
            // A temporary value.
            let mut value = String::from("test");

            // Visit the temp value.
            assert_eq!(
                visitor
                    .visit(TempBorrowedMutStatic(&mut value))
                    .into_value(),
                Flow::Done.into()
            );
        }

        // Force the visitor to outlive the temporary scope.
        let _ = visitor;
    }

    // Make sure the compiler doesn't do anything funny with the lifetime.
    assert_eq!(context, "test");
}

/// Tests for the control flow returns the value protocol visit can return.
#[test]
fn all_visit_results() {
    let mut mock = MockValueVisitor::<OwnedStatic<i32>, BlockingSpin>::new();

    mock.expect_visit()
        .once()
        .with(eq(OwnedStatic(0)))
        .return_const(VisitResult::Control(Flow::Done));

    mock.expect_visit()
        .once()
        .with(eq(OwnedStatic(1)))
        .return_const(VisitResult::Control(Flow::Err));

    mock.expect_visit()
        .once()
        .with(eq(OwnedStatic(2)))
        .return_const(VisitResult::Control(Flow::Continue));

    mock.expect_visit()
        .once()
        .with(eq(OwnedStatic(3)))
        .return_const(VisitResult::Skipped(()));

    let visitor: &mut dyn Value<OwnedStatic<i32>, BlockingSpin> = &mut mock;

    // Visit can return a done.
    assert_eq!(
        visitor.visit(OwnedStatic(0)).into_value(),
        VisitResult::Control(Flow::Done)
    );

    // Visit can return an error signal.
    assert_eq!(
        visitor.visit(OwnedStatic(1)).into_value(),
        VisitResult::Control(Flow::Err)
    );

    // Visit can return a continue.
    assert_eq!(
        visitor.visit(OwnedStatic(2)).into_value(),
        VisitResult::Control(Flow::Continue)
    );

    // A visit can be skipped.
    // This is for runtime visit support checking.
    // The value should be given back, but that's not forced.
    assert_eq!(
        visitor.visit(OwnedStatic(3)).into_value(),
        VisitResult::Skipped(Dynamic(OwnedStatic(3)))
    );
}

/// Tests that the higher ranked name for the value protocol exists.
#[test]
fn value_proto() {
    // The type id of the higher ranked type.
    let id = TypeId::of::<ValueProto<OwnedStatic<i32>, BlockingSpin>>();

    // The type id for the lifetime containing value protocol trait object.
    let name_id = TypeNameId::of_lower::<dyn Value<OwnedStatic<i32>, BlockingSpin>, BlockingSpin>();

    // They should be the same.
    assert_eq!(id, name_id.into_type_id());
}

/// Tests that the value protocol can be given as a hint to a walker.
///
/// The value protocol allows a hint of a preview of the value.
#[test]
fn as_hint() {
    {
        let mut mock = MockHintWalker::<ValueProto<OwnedStatic<i32>, BlockingSpin>>::new();

        mock.expect_known().once().return_const(
            (|_, _hint| {
                Ok(ValueKnown {
                    preview: Some(Dynamic(&OwnedStatic(42))),
                })
            }) as KnownFactory<ValueProto<OwnedStatic<i32>, BlockingSpin>>,
        );

        let walker: &mut dyn Hint<ValueProto<OwnedStatic<i32>, BlockingSpin>> = &mut mock;

        // The value protocol has no hint data, and it has no known data.
        assert_eq!(
            walker.known(&()).into_value(),
            Ok(ValueKnown {
                preview: Some(Dynamic(&OwnedStatic(42)))
            })
        );
    }

    {
        let mut mock = MockHintWalker::<ValueProto<BorrowedStaticHrt<i32>, BlockingSpin>>::new();

        mock.expect_known().once().return_const(
            (|_, _hint| {
                Ok(ValueKnown {
                    preview: Some(Dynamic(&BorrowedStatic(&42))),
                })
            }) as KnownFactory<ValueProto<BorrowedStaticHrt<i32>, BlockingSpin>>,
        );

        let walker: &mut dyn Hint<ValueProto<BorrowedStaticHrt<i32>, BlockingSpin>> = &mut mock;

        // The value protocol has no hint data, and it has no known data.
        assert_eq!(
            walker.known(&()).into_value(),
            Ok(ValueKnown {
                preview: Some(Dynamic(&BorrowedStatic(&42)))
            })
        );
    }

    {
        let mut mock = MockHintWalker::<ValueProto<TempBorrowedMutStaticHrt<i32>, BlockingSpin>>::new();

        mock.expect_known().once().return_const(
            (|_, _hint| Ok(ValueKnown { preview: None }))
                as KnownFactory<ValueProto<TempBorrowedMutStaticHrt<i32>, BlockingSpin>>,
        );

        let walker: &mut dyn Hint<ValueProto<TempBorrowedMutStaticHrt<i32>, BlockingSpin>> = &mut mock;

        // The value protocol has no hint data, and it has no known data.
        assert_eq!(
            walker.known(&()).into_value(),
            Ok(ValueKnown { preview: None })
        );
    }
}