#include <AK/Utf16String.h>
#include <AK/Variant.h>
#include <LibGC/ConservativeVector.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Runtime/ValueInlines.h>
#include <LibWeb/Bindings/CharacterData.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Bindings/MainThreadVM.h>
#include <LibWeb/Bindings/Node.h>
#include <LibWeb/Bindings/PlatformObject.h>
#include <LibWeb/DOM/CharacterData.h>
#include <LibWeb/DOM/Element.h>
#include <LibWeb/DOM/Node.h>
#include <LibWeb/HTML/Scripting/SimilarOriginWindowAgent.h>
#include <LibWeb/WebIDL/AbstractOperations.h>
#include <LibWeb/WebIDL/Tracing.h>
#include <LibWeb/WebIDL/Types.h>

namespace Web::Bindings {

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

    object.set_prototype(&ensure_web_constructor<NodePrototype>(realm, "Node"_fly_string));
    object.define_direct_property(vm.names.length, JS::Value(0), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.name, JS::PrimitiveString::create(vm, "CharacterData"_utf16), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.prototype, &ensure_web_prototype<CharacterDataPrototype>(realm, "CharacterData"_fly_string), 0);
}

JS::ThrowCompletionOr<GC::Ref<JS::Object>> CharacterDataConstructor::construct([[maybe_unused]] InterfaceConstructor& constructor, [[maybe_unused]] JS::FunctionObject& new_target)
{
    WebIDL::log_trace(constructor.vm(), "CharacterDataConstructor::construct");
    return constructor.vm().throw_completion<JS::TypeError>(JS::ErrorType::NotAConstructor, "CharacterData");
}

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

    object.set_prototype(GC::Ref { ensure_web_prototype<NodePrototype>(realm, "Node"_fly_string) });

    auto data_id = "data"_utf16_fly_string;
    auto native_data_getter = JS::NativeFunction::create(realm, data_getter, 0, data_id, &realm, "get"sv);
    auto native_data_setter = JS::NativeFunction::create(realm, data_setter, 1, data_id, &realm, "set"sv);

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto data_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(data_id, native_data_getter, native_data_setter, data_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.
    auto length_id = "length"_utf16_fly_string;
    auto native_length_getter = JS::NativeFunction::create(realm, length_getter, 0, length_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_length_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto length_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(length_id, native_length_getter, native_length_setter, length_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.
    auto previous_element_sibling_id = "previousElementSibling"_utf16_fly_string;
    auto native_previous_element_sibling_getter = JS::NativeFunction::create(realm, previous_element_sibling_getter, 0, previous_element_sibling_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_previous_element_sibling_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto previous_element_sibling_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(previous_element_sibling_id, native_previous_element_sibling_getter, native_previous_element_sibling_setter, previous_element_sibling_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.
    auto next_element_sibling_id = "nextElementSibling"_utf16_fly_string;
    auto native_next_element_sibling_getter = JS::NativeFunction::create(realm, next_element_sibling_getter, 0, next_element_sibling_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_next_element_sibling_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto next_element_sibling_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(next_element_sibling_id, native_next_element_sibling_getter, native_next_element_sibling_setter, next_element_sibling_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, "substringData"_utf16_fly_string, substring_data, 2, default_attributes);

    object.define_native_function(realm, "appendData"_utf16_fly_string, append_data, 1, default_attributes);

    object.define_native_function(realm, "insertData"_utf16_fly_string, insert_data, 2, default_attributes);

    object.define_native_function(realm, "deleteData"_utf16_fly_string, delete_data, 2, default_attributes);

    object.define_native_function(realm, "replaceData"_utf16_fly_string, replace_data, 3, default_attributes);

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

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

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

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

    auto unscopable_object = JS::Object::create(realm, nullptr);
    MUST(unscopable_object->create_data_property("before"_utf16_fly_string, JS::Value(true)));
    MUST(unscopable_object->create_data_property("after"_utf16_fly_string, JS::Value(true)));
    MUST(unscopable_object->create_data_property("replaceWith"_utf16_fly_string, JS::Value(true)));
    MUST(unscopable_object->create_data_property("remove"_utf16_fly_string, JS::Value(true)));
    object.define_direct_property(vm.well_known_symbol_unscopables(), unscopable_object, JS::Attribute::Configurable);

    object.define_direct_property(vm.well_known_symbol_to_string_tag(), JS::PrimitiveString::create(vm, "CharacterData"_utf16), JS::Attribute::Configurable);
}

void CharacterDataPrototype::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<DOM::CharacterData*> impl_from(JS::VM& vm, JS::Value js_value)
{

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

[[maybe_unused]] static JS::ThrowCompletionOr<DOM::CharacterData*> 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(CharacterDataPrototype::data_getter)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::data_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->data(); }));

    return WebIDL::primitive_string_from_string(vm, R);
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::length_getter)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::length_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->length_in_utf16_code_units(); }));

    return JS::Value(static_cast<WebIDL::UnsignedLong>(R));
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::previous_element_sibling_getter)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::previous_element_sibling_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->previous_element_sibling(); }));

    return [&]() -> JS::Value {
        // 1. If the IDL nullable type T? value is null, then the JavaScript value is null.
        if (!R)
            return JS::js_null();

        // 2. Otherwise, the JavaScript value is the result of converting the IDL nullable type value to the inner IDL type T.
        return JS::Value(JS::Value(R));
    }();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::next_element_sibling_getter)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::next_element_sibling_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->next_element_sibling(); }));

    return [&]() -> JS::Value {
        // 1. If the IDL nullable type T? value is null, then the JavaScript value is null.
        if (!R)
            return JS::js_null();

        // 2. Otherwise, the JavaScript value is the result of converting the IDL nullable type value to the inner IDL type T.
        return JS::Value(JS::Value(R));
    }();
}

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

    // 1. Let V be undefined.
    auto V = JS::js_undefined();

    // 2. If any arguments were passed, then set V to the value of the first argument passed.
    if (vm.argument_count() > 0)
        V = vm.argument(0);

    // 3. Let id be attribute’s identifier.

    // 4. Let idlObject be null.
    [[maybe_unused]] DOM::CharacterData* idl_object = nullptr;

    // 5. If attribute is a regular attribute:

    // 1. Let jsValue be the this value, if it is not null or undefined, or realm’s global object otherwise. (This will subsequently cause a TypeError in a few steps, if the global object does not implement target and [LegacyLenientThis] is not specified.)
    auto js_value = vm.this_value();
    if (js_value.is_nullish())
        js_value = &realm.global_object();

    // 2. FIXME: If jsValue is a platform object, then perform a security check, passing jsValue, attribute’s identifier, and "setter".

    // 3. Let validThis be true if jsValue implements target, or false otherwise.
    auto maybe_idl_object = impl_from(vm, js_value);

    // 4. If validThis is false and attribute was not specified with the [LegacyLenientThis] extended attribute, then throw a TypeError.
    idl_object = TRY(maybe_idl_object);

    auto original_steps = [&]() -> JS::ThrowCompletionOr<JS::Value> {
        // 6. Let idlValue be determined as follows:
        // -> Otherwise, idlValue is the result of converting V to an IDL value of attribute’s type.
        auto idl_value = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Utf16String> {
        Utf16String string;
        if (!V.is_null())
            string = TRY(WebIDL::to_utf16_string(vm, V));
        return string;
    }(); }));

        // 7. Run the setter steps of attribute with idlObject as this and idlValue as the value.
        auto setter_result = [&]() -> JS::ThrowCompletionOr<void> {
            TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->set_data(idl_value); }));
    return {};
        }();

        if (setter_result.is_error())
            return setter_result.release_error();

        return JS::js_undefined();
    };

    // 8. Return undefined.
    return TRY(original_steps());
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::substring_data)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::substring_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    if (vm.argument_count() < 2)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountMany, "substringData", "2");

    auto arg0 = vm.argument(0);
    auto offset = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg0, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    auto arg1 = vm.argument(1);
    auto count = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg1, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->substring_data(offset, count); }));
    return WebIDL::primitive_string_from_string(vm, R);
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::append_data)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::append_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

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

    auto arg0 = vm.argument(0);
    auto data = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_string(vm, arg0));
    }(); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->append_data(data); }));
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::insert_data)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::insert_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    if (vm.argument_count() < 2)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountMany, "insertData", "2");

    auto arg0 = vm.argument(0);
    auto offset = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg0, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    auto arg1 = vm.argument(1);
    auto data = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_string(vm, arg1));
    }(); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->insert_data(offset, data); }));
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::delete_data)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::delete_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    if (vm.argument_count() < 2)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountMany, "deleteData", "2");

    auto arg0 = vm.argument(0);
    auto offset = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg0, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    auto arg1 = vm.argument(1);
    auto count = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg1, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->delete_data(offset, count); }));
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::replace_data)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::replace_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    if (vm.argument_count() < 3)
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::BadArgCountMany, "replaceData", "3");

    auto arg0 = vm.argument(0);
    auto offset = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg0, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    auto arg1 = vm.argument(1);
    auto count = TRY(throw_dom_exception_if_needed(vm, [&] { return WebIDL::convert_to_int<WebIDL::UnsignedLong>(vm, arg1, WebIDL::EnforceRange::No, WebIDL::Clamp::No); }));

    auto arg2 = vm.argument(2);
    auto data = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_string(vm, arg2));
    }(); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->replace_data(offset, count, data); }));
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::before)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::before");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    GC::ConservativeVector<Variant<GC::Ref<DOM::Node>, Utf16String>> nodes;
    if (vm.argument_count() > 0) {
        nodes.ensure_capacity(vm.argument_count() - 0);
        for (size_t i = 0; i < vm.argument_count(); ++i) {
            auto argument = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Variant<GC::Ref<DOM::Node>, Utf16String>> {

        if (vm.argument(i).is_object()) {
            [[maybe_unused]] auto& object = vm.argument(i).as_object();

            if (is<PlatformObject>(object)) {

                if (auto* result = as_if<DOM::Node>(object))
                    return Variant<GC::Ref<DOM::Node>, Utf16String> { GC::Ref { *result } };
            }
        }

        auto nodes_string = TRY([&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_string(vm, vm.argument(i)));
    }());
        return Variant<GC::Ref<DOM::Node>, Utf16String> { nodes_string };

        return vm.throw_completion<JS::TypeError>("No union types matched"_utf16);
    }(); }));
            nodes.unchecked_append(move(argument));
        }
    }

    auto original_steps = [&] {
        return throw_dom_exception_if_needed(vm, [&] { return idl_object->before(nodes); });
    };

    [[maybe_unused]] auto R = TRY([&]() -> decltype(original_steps()) {
        // For [CEReactions]: https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions

        // 1. Push a new element queue onto this object's relevant agent's custom element reactions stack.
        auto& reactions_stack = HTML::relevant_similar_origin_window_agent(*idl_object).custom_element_reactions_stack;
        reactions_stack.element_queue_stack.append({});

        // 2. Run the originally-specified steps for this construct, catching any exceptions. If the steps return a value, let value be the returned value. If they throw an exception, let exception be the thrown exception.
        auto value_or_exception = original_steps();

        // 3. Let queue be the result of popping from this object's relevant agent's custom element reactions stack.
        // 4. Invoke custom element reactions in queue.
        auto queue = reactions_stack.element_queue_stack.take_last();
        Bindings::invoke_custom_element_reactions(queue);

        // 5. If an exception exception was thrown by the original steps, rethrow exception.
        if (value_or_exception.is_error())
            return value_or_exception.release_error();

        // 6. If a value value was returned from the original steps, return value.
        return value_or_exception.release_value();
    }());
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::after)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::after");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    GC::ConservativeVector<Variant<GC::Ref<DOM::Node>, Utf16String>> nodes;
    if (vm.argument_count() > 0) {
        nodes.ensure_capacity(vm.argument_count() - 0);
        for (size_t i = 0; i < vm.argument_count(); ++i) {
            auto argument = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Variant<GC::Ref<DOM::Node>, Utf16String>> {

        if (vm.argument(i).is_object()) {
            [[maybe_unused]] auto& object = vm.argument(i).as_object();

            if (is<PlatformObject>(object)) {

                if (auto* result = as_if<DOM::Node>(object))
                    return Variant<GC::Ref<DOM::Node>, Utf16String> { GC::Ref { *result } };
            }
        }

        auto nodes_string = TRY([&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_string(vm, vm.argument(i)));
    }());
        return Variant<GC::Ref<DOM::Node>, Utf16String> { nodes_string };

        return vm.throw_completion<JS::TypeError>("No union types matched"_utf16);
    }(); }));
            nodes.unchecked_append(move(argument));
        }
    }

    auto original_steps = [&] {
        return throw_dom_exception_if_needed(vm, [&] { return idl_object->after(nodes); });
    };

    [[maybe_unused]] auto R = TRY([&]() -> decltype(original_steps()) {
        // For [CEReactions]: https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions

        // 1. Push a new element queue onto this object's relevant agent's custom element reactions stack.
        auto& reactions_stack = HTML::relevant_similar_origin_window_agent(*idl_object).custom_element_reactions_stack;
        reactions_stack.element_queue_stack.append({});

        // 2. Run the originally-specified steps for this construct, catching any exceptions. If the steps return a value, let value be the returned value. If they throw an exception, let exception be the thrown exception.
        auto value_or_exception = original_steps();

        // 3. Let queue be the result of popping from this object's relevant agent's custom element reactions stack.
        // 4. Invoke custom element reactions in queue.
        auto queue = reactions_stack.element_queue_stack.take_last();
        Bindings::invoke_custom_element_reactions(queue);

        // 5. If an exception exception was thrown by the original steps, rethrow exception.
        if (value_or_exception.is_error())
            return value_or_exception.release_error();

        // 6. If a value value was returned from the original steps, return value.
        return value_or_exception.release_value();
    }());
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::replace_with)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::replace_with");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    GC::ConservativeVector<Variant<GC::Ref<DOM::Node>, Utf16String>> nodes;
    if (vm.argument_count() > 0) {
        nodes.ensure_capacity(vm.argument_count() - 0);
        for (size_t i = 0; i < vm.argument_count(); ++i) {
            auto argument = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Variant<GC::Ref<DOM::Node>, Utf16String>> {

        if (vm.argument(i).is_object()) {
            [[maybe_unused]] auto& object = vm.argument(i).as_object();

            if (is<PlatformObject>(object)) {

                if (auto* result = as_if<DOM::Node>(object))
                    return Variant<GC::Ref<DOM::Node>, Utf16String> { GC::Ref { *result } };
            }
        }

        auto nodes_string = TRY([&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_string(vm, vm.argument(i)));
    }());
        return Variant<GC::Ref<DOM::Node>, Utf16String> { nodes_string };

        return vm.throw_completion<JS::TypeError>("No union types matched"_utf16);
    }(); }));
            nodes.unchecked_append(move(argument));
        }
    }

    auto original_steps = [&] {
        return throw_dom_exception_if_needed(vm, [&] { return idl_object->replace_with(nodes); });
    };

    [[maybe_unused]] auto R = TRY([&]() -> decltype(original_steps()) {
        // For [CEReactions]: https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions

        // 1. Push a new element queue onto this object's relevant agent's custom element reactions stack.
        auto& reactions_stack = HTML::relevant_similar_origin_window_agent(*idl_object).custom_element_reactions_stack;
        reactions_stack.element_queue_stack.append({});

        // 2. Run the originally-specified steps for this construct, catching any exceptions. If the steps return a value, let value be the returned value. If they throw an exception, let exception be the thrown exception.
        auto value_or_exception = original_steps();

        // 3. Let queue be the result of popping from this object's relevant agent's custom element reactions stack.
        // 4. Invoke custom element reactions in queue.
        auto queue = reactions_stack.element_queue_stack.take_last();
        Bindings::invoke_custom_element_reactions(queue);

        // 5. If an exception exception was thrown by the original steps, rethrow exception.
        if (value_or_exception.is_error())
            return value_or_exception.release_error();

        // 6. If a value value was returned from the original steps, return value.
        return value_or_exception.release_value();
    }());
    return JS::js_undefined();
}

JS_DEFINE_NATIVE_FUNCTION(CharacterDataPrototype::remove)
{
    WebIDL::log_trace(vm, "CharacterDataPrototype::remove");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::CharacterData* idl_object = TRY(impl_from(vm));

    auto original_steps = [&] {
        return throw_dom_exception_if_needed(vm, [&] { return idl_object->remove_binding(); });
    };

    [[maybe_unused]] auto R = TRY([&]() -> decltype(original_steps()) {
        // For [CEReactions]: https://html.spec.whatwg.org/multipage/custom-elements.html#cereactions

        // 1. Push a new element queue onto this object's relevant agent's custom element reactions stack.
        auto& reactions_stack = HTML::relevant_similar_origin_window_agent(*idl_object).custom_element_reactions_stack;
        reactions_stack.element_queue_stack.append({});

        // 2. Run the originally-specified steps for this construct, catching any exceptions. If the steps return a value, let value be the returned value. If they throw an exception, let exception be the thrown exception.
        auto value_or_exception = original_steps();

        // 3. Let queue be the result of popping from this object's relevant agent's custom element reactions stack.
        // 4. Invoke custom element reactions in queue.
        auto queue = reactions_stack.element_queue_stack.take_last();
        Bindings::invoke_custom_element_reactions(queue);

        // 5. If an exception exception was thrown by the original steps, rethrow exception.
        if (value_or_exception.is_error())
            return value_or_exception.release_error();

        // 6. If a value value was returned from the original steps, return value.
        return value_or_exception.release_value();
    }());
    return JS::js_undefined();
}

} // namespace Web::Bindings