#include <AK/StringView.h>
#include <AK/TypeCasts.h>
#include <AK/Variant.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/AsyncIteratorPrototype.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/Promise.h>
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/VM.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Runtime/ValueInlines.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Bindings/QueuingStrategy.h>
#include <LibWeb/Bindings/ReadableStream.h>
#include <LibWeb/DOM/AbortSignal.h>
#include <LibWeb/Streams/ReadableStream.h>
#include <LibWeb/Streams/ReadableStreamAsyncIterator.h>
#include <LibWeb/Streams/ReadableStreamBYOBReader.h>
#include <LibWeb/Streams/ReadableStreamDefaultReader.h>
#include <LibWeb/Streams/WritableStream.h>
#include <LibWeb/WebIDL/AsyncIterator.h>
#include <LibWeb/WebIDL/Promise.h>
#include <LibWeb/WebIDL/Tracing.h>

namespace Web::Bindings {

void ReadableStreamConstructor::initialize(JS::Realm& realm, JS::NativeFunction& object)
{
    auto& vm = realm.vm();
    [[maybe_unused]] u8 default_attributes = JS::Attribute::Enumerable;

    
    object.define_direct_property(vm.names.length, JS::Value(0), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.name, JS::PrimitiveString::create(vm, "ReadableStream"_utf16), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.prototype, &ensure_web_prototype<ReadableStreamPrototype>(realm, "ReadableStream"_fly_string), 0);
    object.define_native_function(realm, "from"_utf16_fly_string, from, 1, JS::Attribute::Enumerable | JS::Attribute::Configurable | JS::Attribute::Writable);

}

JS::ThrowCompletionOr<GC::Ref<JS::Object>> ReadableStreamConstructor::construct([[maybe_unused]] InterfaceConstructor& constructor, [[maybe_unused]] JS::FunctionObject& new_target)
{
    WebIDL::log_trace(constructor.vm(), "ReadableStreamConstructor::construct");
    auto& vm = constructor.vm();
    [[maybe_unused]] auto& realm = *vm.current_realm();

    // To internally create a new object implementing the interface ReadableStream:

    // 3.2. Let prototype be ? Get(newTarget, "prototype").
    auto prototype = TRY(new_target.get(vm.names.prototype));

    // 3.3. If Type(prototype) is not Object, then:
    if (!prototype.is_object()) {
        // 1. Let targetRealm be ? GetFunctionRealm(newTarget).
        auto* target_realm = TRY(JS::get_function_realm(vm, new_target));

        // 2. Set prototype to the interface prototype object for interface in targetRealm.
        VERIFY(target_realm);
        prototype = &Bindings::ensure_web_prototype<ReadableStreamPrototype>(*target_realm, "ReadableStream"_fly_string);
    }

    auto arg0 = vm.argument(0);
    GC::Ptr<JS::Object> underlying_source {};
    if (!arg0.is_undefined())
        underlying_source = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::Ref<JS::Object>> {
        if (!arg0.is_object())
            return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObject, arg0);
        return GC::Ref { arg0.as_object() };
    }(); }));

    auto arg1 = vm.argument(1);
    QueuingStrategy strategy = QueuingStrategy {};
    if (!arg1.is_undefined())
        strategy = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_queuing_strategy(vm, arg1); }));

    auto impl = TRY(throw_dom_exception_if_needed(vm, [&] { return Streams::ReadableStream::construct_impl(realm, underlying_source, strategy); }));

    // 7. Set instance.[[Prototype]] to prototype.
    VERIFY(prototype.is_object());
    impl->set_prototype(&prototype.as_object());

    // FIXME: Steps 8...11. of the "internally create a new object implementing the interface ReadableStream" algorithm
    // (https://webidl.spec.whatwg.org/#js-platform-objects) are currently not handled, or are handled within Streams::ReadableStream::construct_impl().

    return *impl;
}

GC_DEFINE_ALLOCATOR(ReadableStreamPrototype);

ReadableStreamPrototype::ReadableStreamPrototype([[maybe_unused]] JS::Realm& realm)
    : Object(ConstructWithPrototypeTag::Tag, realm.intrinsics().object_prototype())
{
}

ReadableStreamPrototype::~ReadableStreamPrototype()
{
}


void ReadableStreamPrototype::initialize(JS::Realm& realm)
{
    auto& object = *this;
    [[maybe_unused]] auto& vm = realm.vm();
    [[maybe_unused]] u8 default_attributes = JS::Attribute::Enumerable | JS::Attribute::Configurable | JS::Attribute::Writable;

    object.set_prototype(realm.intrinsics().object_prototype());

    auto locked_id = "locked"_utf16_fly_string;
    auto native_locked_getter = JS::NativeFunction::create(realm, locked_getter, 0, locked_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_locked_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto locked_attributes = default_attributes;

    // 5. Let desc be the PropertyDescriptor{[[Get]]: getter, [[Set]]: setter, [[Enumerable]]: true, [[Configurable]]: configurable}.

    // 7. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_accessor(locked_id, native_locked_getter, native_locked_setter, locked_attributes);

    // 8. FIXME: If attr’s type is an observable array type with type argument T, then set target’s backing observable array exotic object for attr to the result of creating an observable array exotic object in realm, given T, attr’s set an indexed value algorithm, and attr’s delete an indexed value algorithm.
    object.define_native_function(realm, "cancel"_utf16_fly_string, cancel, 0, default_attributes);

    object.define_native_function(realm, "getReader"_utf16_fly_string, get_reader, 0, default_attributes);

    object.define_native_function(realm, "pipeThrough"_utf16_fly_string, pipe_through, 1, default_attributes);

    object.define_native_function(realm, "pipeTo"_utf16_fly_string, pipe_to, 1, default_attributes);

    object.define_native_function(realm, "tee"_utf16_fly_string, tee, 0, default_attributes);

    object.define_native_function(realm, vm.names.values, values, 0, default_attributes);
    object.define_direct_property(vm.well_known_symbol_async_iterator(), object.get_without_side_effects(vm.names.values), JS::Attribute::Configurable | JS::Attribute::Writable);

    object.define_direct_property(vm.well_known_symbol_to_string_tag(), JS::PrimitiveString::create(vm, "ReadableStream"_utf16), JS::Attribute::Configurable);
    Base::initialize(realm);
}

void ReadableStreamPrototype::define_unforgeable_attributes(JS::Realm& realm, [[maybe_unused]] JS::Object& object)
{
    [[maybe_unused]] auto& vm = realm.vm();
    [[maybe_unused]] u8 default_attributes = JS::Attribute::Enumerable;
}

[[maybe_unused]] static JS::ThrowCompletionOr<Streams::ReadableStream*> impl_from(JS::VM& vm, JS::Value js_value)
{

    if (auto impl = js_value.as_if<Streams::ReadableStream>())
        return impl.ptr();
    return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "ReadableStream");
}

[[maybe_unused]] static JS::ThrowCompletionOr<Streams::ReadableStream*> impl_from(JS::VM& vm)
{
    auto this_value = vm.this_value();
    if (this_value.is_nullish())
        this_value = &vm.current_realm()->global_object();
    return impl_from(vm, this_value);
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamConstructor::from)
{
    WebIDL::log_trace(vm, "ReadableStreamConstructor::from");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    if (vm.argument_count() < 1)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountOne, "from");

    auto arg0 = vm.argument(0);
    auto async_iterable = TRY(throw_dom_exception_if_needed(vm, [&] { return arg0; }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return Streams::ReadableStream::from(vm, async_iterable); }));
    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::locked_getter)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::locked_getter");
    [[maybe_unused]] auto& realm = *vm.current_realm();

    auto* idl_object = TRY(impl_from(vm));


    auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->locked(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::cancel)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::cancel");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    auto steps = [&realm, &vm]() -> JS::ThrowCompletionOr<GC::Ref<WebIDL::Promise>> {
        (void)realm;
    [[maybe_unused]] Streams::ReadableStream* idl_object = TRY(impl_from(vm));

    auto arg0 = vm.argument(0);
    Optional<JS::Value> reason {};
    if (!arg0.is_undefined())
        reason = TRY(throw_dom_exception_if_needed(vm, [&] { return arg0; }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->cancel(reason); }));
        return R;
    };

    auto maybe_R = steps();

    // And then, if an exception E was thrown:
    // 1. If op has a return type that is a promise type, then return ! Call(%Promise.reject%, %Promise%, «E»).
    // 2. Otherwise, end these steps and allow the exception to propagate.
    if (maybe_R.is_throw_completion())
        return WebIDL::create_rejected_promise(realm, maybe_R.error_value())->promise();

    return GC::Ref { as<JS::Promise>(*maybe_R.release_value()->promise()) };
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::get_reader)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::get_reader");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] Streams::ReadableStream* idl_object = TRY(impl_from(vm));

    auto arg0 = vm.argument(0);
    ReadableStreamGetReaderOptions options = ReadableStreamGetReaderOptions {};
    if (!arg0.is_undefined())
        options = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_readable_stream_get_reader_options(vm, arg0); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->get_reader(options); }));
    return R.visit(
        [&](GC::Ref<Streams::ReadableStreamDefaultReader> const& visited_union_value0) -> JS::Value
        {
            return JS::Value(visited_union_value0);
        },
        [&](GC::Ref<Streams::ReadableStreamBYOBReader> const& visited_union_value1) -> JS::Value
        {
            return JS::Value(visited_union_value1);
        }
    );
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::pipe_through)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::pipe_through");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] Streams::ReadableStream* idl_object = TRY(impl_from(vm));

    if (vm.argument_count() < 1)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountOne, "pipeThrough");

    auto arg0 = vm.argument(0);
    auto transform = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_readable_writable_pair(vm, arg0); }));

    auto arg1 = vm.argument(1);
    StreamPipeOptions options = StreamPipeOptions {};
    if (!arg1.is_undefined())
        options = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_stream_pipe_options(vm, arg1); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->pipe_through(transform, options); }));
    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::pipe_to)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::pipe_to");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    auto steps = [&realm, &vm]() -> JS::ThrowCompletionOr<GC::Ref<WebIDL::Promise>> {
        (void)realm;
    [[maybe_unused]] Streams::ReadableStream* idl_object = TRY(impl_from(vm));

    if (vm.argument_count() < 1)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountOne, "pipeTo");

    auto arg0 = vm.argument(0);
    auto destination = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::Ref<Streams::WritableStream>> {
        if (auto impl = arg0.as_if<Streams::WritableStream>())
            return *impl;
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "WritableStream");
    }(); }));

    auto arg1 = vm.argument(1);
    StreamPipeOptions options = StreamPipeOptions {};
    if (!arg1.is_undefined())
        options = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_stream_pipe_options(vm, arg1); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->pipe_to(destination, options); }));
        return R;
    };

    auto maybe_R = steps();

    // And then, if an exception E was thrown:
    // 1. If op has a return type that is a promise type, then return ! Call(%Promise.reject%, %Promise%, «E»).
    // 2. Otherwise, end these steps and allow the exception to propagate.
    if (maybe_R.is_throw_completion())
        return WebIDL::create_rejected_promise(realm, maybe_R.error_value())->promise();

    return GC::Ref { as<JS::Promise>(*maybe_R.release_value()->promise()) };
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::tee)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::tee");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] Streams::ReadableStream* idl_object = TRY(impl_from(vm));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->tee(); }));
    return [&]() -> JS::Value {
        // An IDL sequence<T> value S is converted to a JavaScript value as follows:
        // 1. Let n be the length of S.
        auto sequence_length = R.size();

        // 2. Let A be a new Array object created as if by the expression [].
        auto sequence_array = MUST(JS::Array::create(realm, sequence_length));

        // 3. Initialize i to be 0.
        // 4. While i < n:
        for (size_t sequence_index = 0; sequence_index < sequence_length; ++sequence_index) {
            // 1. Let V be the value in S at index i.
            auto& sequence_element = R.at(sequence_index);

            // 2. Let E be the result of converting V to a JavaScript value.
            JS::Value js_sequence_element = JS::Value(sequence_element);

            // 3. Let P be the result of calling ! ToString(i).
            // 4. Perform ! CreateDataPropertyOrThrow(A, P, E).
            MUST(sequence_array->create_data_property(JS::PropertyKey { sequence_index }, js_sequence_element));

            // 5. Set i to i + 1.
        }

        // 5. Return A.
        return sequence_array;
    }();
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamPrototype::values)
{
    WebIDL::log_trace(vm, "ReadableStreamPrototype::values");
    auto& realm = *vm.current_realm();
    auto* impl = TRY(impl_from(vm));

    auto arg0 = vm.argument(0);
    ReadableStreamIteratorOptions options = ReadableStreamIteratorOptions {};
    if (!arg0.is_undefined())
        options = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_readable_stream_iterator_options(vm, arg0); }));

    return TRY(throw_dom_exception_if_needed(vm, [&] { return Streams::ReadableStreamAsyncIterator::create(realm, JS::Object::PropertyKind::Value, *impl, options); }));
}

GC_DEFINE_ALLOCATOR(ReadableStreamAsyncIteratorPrototype);

ReadableStreamAsyncIteratorPrototype::ReadableStreamAsyncIteratorPrototype(JS::Realm& realm)
    : Object(ConstructWithPrototypeTag::Tag, realm.intrinsics().async_iterator_prototype())
{
}

ReadableStreamAsyncIteratorPrototype::~ReadableStreamAsyncIteratorPrototype()
{
}

void ReadableStreamAsyncIteratorPrototype::initialize(JS::Realm& realm)
{
    auto& vm = this->vm();
    Base::initialize(realm);
    define_direct_property(vm.well_known_symbol_to_string_tag(), JS::PrimitiveString::create(vm, "ReadableStream AsyncIterator"_utf16), JS::Attribute::Configurable);

    define_native_function(realm, vm.names.next, next, 0, JS::default_attributes);
    define_native_function(realm, vm.names.return_, return_, 1, JS::default_attributes);
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamAsyncIteratorPrototype::next)
{
    WebIDL::log_trace(vm, "ReadableStreamAsyncIteratorPrototype::next");
    auto& realm = *vm.current_realm();

    return TRY(throw_dom_exception_if_needed(vm, [&] {
        return WebIDL::AsyncIterator::next<Streams::ReadableStreamAsyncIterator>(realm, "ReadableStreamAsyncIterator"sv);
    }));
}

JS_DEFINE_NATIVE_FUNCTION(ReadableStreamAsyncIteratorPrototype::return_)
{
    WebIDL::log_trace(vm, "ReadableStreamAsyncIteratorPrototype::return");
    auto& realm = *vm.current_realm();

    auto value = vm.argument(0);

    return TRY(throw_dom_exception_if_needed(vm, [&] {
        return WebIDL::AsyncIterator::return_<Streams::ReadableStreamAsyncIterator>(realm, "ReadableStreamAsyncIterator"sv, value);
    }));
}
// https://webidl.spec.whatwg.org/#idl-enumeration
JS::ThrowCompletionOr<ReadableStreamReaderMode> convert_to_idl_value_for_readable_stream_reader_mode(JS::VM& vm, JS::Value value)
{
    // 1. Let S be the result of calling ? ToString(V).
    auto value_as_string = TRY(value.to_utf16_string(vm));

    // 2. If S is not one of E’s enumeration values, then throw a TypeError.
    // 3. Return the enumeration value of type E that is equal to S.
    if (value_as_string == "byob"sv)
        return ReadableStreamReaderMode::Byob;
    return vm.throw_completion<JS::TypeError>(JS::ErrorType::InvalidEnumerationValue, value_as_string, "ReadableStreamReaderMode");
}

// https://webidl.spec.whatwg.org/#idl-enumeration
Utf16String idl_enum_to_string(ReadableStreamReaderMode value)
{
    // The result of converting an IDL enumeration type value to a JavaScript value is the String value that represents the same sequence of code units as the enumeration value.
    switch (value) {
    case ReadableStreamReaderMode::Byob:
        return "byob"_utf16;
    }
    VERIFY_NOT_REACHED();
}

// https://webidl.spec.whatwg.org/#es-dictionary
JS::ThrowCompletionOr<ReadableWritablePair> convert_to_idl_value_for_readable_writable_pair(JS::VM& vm, JS::Value js_dict)
{
    // 1. If jsDict is not an Object and jsDict is neither undefined nor null, then throw a TypeError.
    if (!js_dict.is_object() && !js_dict.is_nullish())
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "ReadableWritablePair");

    // 2. Let idlDict be an empty ordered map, representing a dictionary of type D.
    // 3. Let dictionaries be a list consisting of D and all of D’s inherited dictionaries, in order from least to most derived.
    // 4. For each dictionary dictionary in dictionaries, in order:
    // NB: We defer construction until the return initializer because some members may not be default-constructible. Inherited dictionaries are represented by the generated C++ struct inheritance.

    // 5. Return idlDict.
    return ReadableWritablePair {
        .readable = TRY([&]() -> JS::ThrowCompletionOr<GC::Ref<Streams::ReadableStream>> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("readable"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::Ref<Streams::ReadableStream>> {
        if (auto impl = js_member_value.as_if<Streams::ReadableStream>())
            return *impl;
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "ReadableStream");
    }(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 6. Otherwise, if jsMemberValue is undefined and member is required, then throw a TypeError.
            return vm.throw_completion<JS::TypeError>(JS::ErrorType::MissingRequiredProperty, "readable");
        }()),
        .writable = TRY([&]() -> JS::ThrowCompletionOr<GC::Ref<Streams::WritableStream>> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("writable"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::Ref<Streams::WritableStream>> {
        if (auto impl = js_member_value.as_if<Streams::WritableStream>())
            return *impl;
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "WritableStream");
    }(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 6. Otherwise, if jsMemberValue is undefined and member is required, then throw a TypeError.
            return vm.throw_completion<JS::TypeError>(JS::ErrorType::MissingRequiredProperty, "writable");
        }()),
    };
}

// https://webidl.spec.whatwg.org/#es-dictionary
JS::ThrowCompletionOr<StreamPipeOptions> convert_to_idl_value_for_stream_pipe_options(JS::VM& vm, JS::Value js_dict)
{
    // 1. If jsDict is not an Object and jsDict is neither undefined nor null, then throw a TypeError.
    if (!js_dict.is_object() && !js_dict.is_nullish())
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "StreamPipeOptions");

    // 2. Let idlDict be an empty ordered map, representing a dictionary of type D.
    // 3. Let dictionaries be a list consisting of D and all of D’s inherited dictionaries, in order from least to most derived.
    // 4. For each dictionary dictionary in dictionaries, in order:
    // NB: We defer construction until the return initializer because some members may not be default-constructible. Inherited dictionaries are represented by the generated C++ struct inheritance.

    // 5. Return idlDict.
    return StreamPipeOptions {
        .prevent_abort = TRY([&]() -> JS::ThrowCompletionOr<bool> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("preventAbort"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return js_member_value.to_boolean(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 5. Otherwise, if jsMemberValue is undefined but member has a default value, then:
            // 1. Let idlMemberValue be the result of converting member's default value to an IDL value whose type is the type member is declared to be of.
            auto idl_member_value = false;

            // 2. Set idlDict[key] to idlMemberValue.
            return idl_member_value;
        }()),
        .prevent_cancel = TRY([&]() -> JS::ThrowCompletionOr<bool> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("preventCancel"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return js_member_value.to_boolean(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 5. Otherwise, if jsMemberValue is undefined but member has a default value, then:
            // 1. Let idlMemberValue be the result of converting member's default value to an IDL value whose type is the type member is declared to be of.
            auto idl_member_value = false;

            // 2. Set idlDict[key] to idlMemberValue.
            return idl_member_value;
        }()),
        .prevent_close = TRY([&]() -> JS::ThrowCompletionOr<bool> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("preventClose"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return js_member_value.to_boolean(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 5. Otherwise, if jsMemberValue is undefined but member has a default value, then:
            // 1. Let idlMemberValue be the result of converting member's default value to an IDL value whose type is the type member is declared to be of.
            auto idl_member_value = false;

            // 2. Set idlDict[key] to idlMemberValue.
            return idl_member_value;
        }()),
        .signal = TRY([&]() -> JS::ThrowCompletionOr<GC::Ptr<DOM::AbortSignal>> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("signal"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::Ref<DOM::AbortSignal>> {
        if (auto impl = js_member_value.as_if<DOM::AbortSignal>())
            return *impl;
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "AbortSignal");
    }(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 7. Otherwise, jsMemberValue is undefined and the member is optional.
            return nullptr;
        }()),
    };
}

// https://webidl.spec.whatwg.org/#es-dictionary
JS::ThrowCompletionOr<ReadableStreamGetReaderOptions> convert_to_idl_value_for_readable_stream_get_reader_options(JS::VM& vm, JS::Value js_dict)
{
    // 1. If jsDict is not an Object and jsDict is neither undefined nor null, then throw a TypeError.
    if (!js_dict.is_object() && !js_dict.is_nullish())
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "ReadableStreamGetReaderOptions");

    // 2. Let idlDict be an empty ordered map, representing a dictionary of type D.
    // 3. Let dictionaries be a list consisting of D and all of D’s inherited dictionaries, in order from least to most derived.
    // 4. For each dictionary dictionary in dictionaries, in order:
    // NB: We defer construction until the return initializer because some members may not be default-constructible. Inherited dictionaries are represented by the generated C++ struct inheritance.

    // 5. Return idlDict.
    return ReadableStreamGetReaderOptions {
        .mode = TRY([&]() -> JS::ThrowCompletionOr<Optional<ReadableStreamReaderMode>> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("mode"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_readable_stream_reader_mode(vm, js_member_value); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 7. Otherwise, jsMemberValue is undefined and the member is optional.
            return OptionalNone {};
        }()),
    };
}

// https://webidl.spec.whatwg.org/#es-dictionary
JS::ThrowCompletionOr<ReadableStreamIteratorOptions> convert_to_idl_value_for_readable_stream_iterator_options(JS::VM& vm, JS::Value js_dict)
{
    // 1. If jsDict is not an Object and jsDict is neither undefined nor null, then throw a TypeError.
    if (!js_dict.is_object() && !js_dict.is_nullish())
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "ReadableStreamIteratorOptions");

    // 2. Let idlDict be an empty ordered map, representing a dictionary of type D.
    // 3. Let dictionaries be a list consisting of D and all of D’s inherited dictionaries, in order from least to most derived.
    // 4. For each dictionary dictionary in dictionaries, in order:
    // NB: We defer construction until the return initializer because some members may not be default-constructible. Inherited dictionaries are represented by the generated C++ struct inheritance.

    // 5. Return idlDict.
    return ReadableStreamIteratorOptions {
        .prevent_cancel = TRY([&]() -> JS::ThrowCompletionOr<bool> {
            // 1. Let key be the identifier of member.
            // 2. If jsDict is either undefined or null, then:
            //     1. Let jsMemberValue be undefined.
            // 3. Otherwise,
            //     1. Let jsMemberValue be ? Get(jsDict, key).
            auto js_member_value = JS::js_undefined();
            if (js_dict.is_object())
                js_member_value = TRY(js_dict.as_object().get("preventCancel"_utf16_fly_string));

            // 4. If jsMemberValue is not undefined, then:
            if (!js_member_value.is_undefined()) {
                // 1. Let idlMemberValue be the result of converting jsMemberValue to an IDL value whose type is the type member is declared to be of.
                auto idl_member_value = TRY(throw_dom_exception_if_needed(vm, [&] { return js_member_value.to_boolean(); }));

                // 2. Set idlDict[key] to idlMemberValue.
                return idl_member_value;
            }
            // 5. Otherwise, if jsMemberValue is undefined but member has a default value, then:
            // 1. Let idlMemberValue be the result of converting member's default value to an IDL value whose type is the type member is declared to be of.
            auto idl_member_value = false;

            // 2. Set idlDict[key] to idlMemberValue.
            return idl_member_value;
        }()),
    };
}

} // namespace Web::Bindings