#include <AK/String.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/PropertyDescriptor.h>
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/VM.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Runtime/ValueInlines.h>
#include <LibWeb/Bindings/Event.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/DOM/Event.h>
#include <LibWeb/DOM/EventTarget.h>
#include <LibWeb/WebIDL/AbstractOperations.h>
#include <LibWeb/WebIDL/Tracing.h>
#include <LibWeb/WebIDL/Types.h>

namespace Web::Bindings {

void EventConstructor::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(1), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.name, JS::PrimitiveString::create(vm, "Event"_utf16), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.prototype, &ensure_web_prototype<EventPrototype>(realm, "Event"_fly_string), 0);

    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("NONE"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(0)), JS::Attribute::Enumerable);
    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("CAPTURING_PHASE"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(1)), JS::Attribute::Enumerable);
    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("AT_TARGET"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(2)), JS::Attribute::Enumerable);
    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("BUBBLING_PHASE"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(3)), JS::Attribute::Enumerable);
}

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

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

    // 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<EventPrototype>(*target_realm, "Event"_fly_string);
    }

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

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

    auto arg1 = vm.argument(1);
    EventInit event_init_dict = EventInit {};
    if (!arg1.is_undefined())
        event_init_dict = TRY(throw_dom_exception_if_needed(vm, [&] { return convert_to_idl_value_for_event_init(vm, arg1); }));

    auto impl = TRY(throw_dom_exception_if_needed(vm, [&] { return DOM::Event::construct_impl(realm, type, event_init_dict); }));

    // 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 Event" algorithm
    // (https://webidl.spec.whatwg.org/#js-platform-objects) are currently not handled, or are handled within DOM::Event::construct_impl().

    return *impl;
}

void EventPrototype::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(realm.intrinsics().object_prototype());

    auto type_id = "type"_utf16_fly_string;
    auto native_type_getter = JS::NativeFunction::create(realm, type_getter, 0, type_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_type_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto type_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(type_id, native_type_getter, native_type_setter, type_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 target_id = "target"_utf16_fly_string;
    auto native_target_getter = JS::NativeFunction::create(realm, target_getter, 0, target_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_target_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto target_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(target_id, native_target_getter, native_target_setter, target_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 src_element_id = "srcElement"_utf16_fly_string;
    auto native_src_element_getter = JS::NativeFunction::create(realm, src_element_getter, 0, src_element_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_src_element_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto src_element_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(src_element_id, native_src_element_getter, native_src_element_setter, src_element_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 current_target_id = "currentTarget"_utf16_fly_string;
    auto native_current_target_getter = JS::NativeFunction::create(realm, current_target_getter, 0, current_target_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_current_target_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto current_target_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(current_target_id, native_current_target_getter, native_current_target_setter, current_target_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 event_phase_id = "eventPhase"_utf16_fly_string;
    auto native_event_phase_getter = JS::NativeFunction::create(realm, event_phase_getter, 0, event_phase_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_event_phase_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto event_phase_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(event_phase_id, native_event_phase_getter, native_event_phase_setter, event_phase_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 cancel_bubble_id = "cancelBubble"_utf16_fly_string;
    auto native_cancel_bubble_getter = JS::NativeFunction::create(realm, cancel_bubble_getter, 0, cancel_bubble_id, &realm, "get"sv);
    auto native_cancel_bubble_setter = JS::NativeFunction::create(realm, cancel_bubble_setter, 1, cancel_bubble_id, &realm, "set"sv);

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto cancel_bubble_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(cancel_bubble_id, native_cancel_bubble_getter, native_cancel_bubble_setter, cancel_bubble_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 bubbles_id = "bubbles"_utf16_fly_string;
    auto native_bubbles_getter = JS::NativeFunction::create(realm, bubbles_getter, 0, bubbles_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_bubbles_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto bubbles_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(bubbles_id, native_bubbles_getter, native_bubbles_setter, bubbles_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 cancelable_id = "cancelable"_utf16_fly_string;
    auto native_cancelable_getter = JS::NativeFunction::create(realm, cancelable_getter, 0, cancelable_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_cancelable_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto cancelable_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(cancelable_id, native_cancelable_getter, native_cancelable_setter, cancelable_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 return_value_id = "returnValue"_utf16_fly_string;
    auto native_return_value_getter = JS::NativeFunction::create(realm, return_value_getter, 0, return_value_id, &realm, "get"sv);
    auto native_return_value_setter = JS::NativeFunction::create(realm, return_value_setter, 1, return_value_id, &realm, "set"sv);

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto return_value_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(return_value_id, native_return_value_getter, native_return_value_setter, return_value_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 default_prevented_id = "defaultPrevented"_utf16_fly_string;
    auto native_default_prevented_getter = JS::NativeFunction::create(realm, default_prevented_getter, 0, default_prevented_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_default_prevented_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto default_prevented_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(default_prevented_id, native_default_prevented_getter, native_default_prevented_setter, default_prevented_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 composed_id = "composed"_utf16_fly_string;
    auto native_composed_getter = JS::NativeFunction::create(realm, composed_getter, 0, composed_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_composed_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto composed_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(composed_id, native_composed_getter, native_composed_setter, composed_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 time_stamp_id = "timeStamp"_utf16_fly_string;
    auto native_time_stamp_getter = JS::NativeFunction::create(realm, time_stamp_getter, 0, time_stamp_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_time_stamp_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto time_stamp_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(time_stamp_id, native_time_stamp_getter, native_time_stamp_setter, time_stamp_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, "composedPath"_utf16_fly_string, composed_path, 0, default_attributes);

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

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

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

    object.define_native_function(realm, "initEvent"_utf16_fly_string, init_event, 1, default_attributes);


    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("NONE"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(0)), JS::Attribute::Enumerable);
    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("CAPTURING_PHASE"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(1)), JS::Attribute::Enumerable);
    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("AT_TARGET"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(2)), JS::Attribute::Enumerable);
    // 1. FIXME: If const is not exposed in realm, then continue.
    // 2. Let value be the result of converting const’s IDL value to a JavaScript value.
    // 3. Let desc be the PropertyDescriptor{[[Writable]]: false, [[Enumerable]]: true, [[Configurable]]: false, [[Value]]: value}.
    // 4. Let id be const’s identifier.
    // 5. Perform ! DefinePropertyOrThrow(target, id, desc).
    object.define_direct_property("BUBBLING_PHASE"_utf16_fly_string, JS::Value(static_cast<WebIDL::UnsignedShort>(3)), JS::Attribute::Enumerable);
    object.define_direct_property(vm.well_known_symbol_to_string_tag(), JS::PrimitiveString::create(vm, "Event"_utf16), JS::Attribute::Configurable);
}

void EventPrototype::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;

    auto is_trusted_id = "isTrusted"_utf16_fly_string;
    auto native_is_trusted_getter = host_defined_intrinsics(realm).ensure_web_unforgeable_function("Event"_utf16_fly_string, is_trusted_id, is_trusted_getter, UnforgeableKey::Type::Getter);
    GC::Ptr<JS::NativeFunction> native_is_trusted_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto is_trusted_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(is_trusted_id, native_is_trusted_getter, native_is_trusted_setter, is_trusted_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.
}

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

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

[[maybe_unused]] static JS::ThrowCompletionOr<DOM::Event*> 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(EventPrototype::type_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::type_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->type(); }));

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

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::target_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::target_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->target(); }));

    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(EventPrototype::src_element_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::src_element_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->src_element(); }));

    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(EventPrototype::current_target_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::current_target_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->current_target_for_bindings(); }));

    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(EventPrototype::event_phase_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::event_phase_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->event_phase(); }));

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

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::cancel_bubble_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::cancel_bubble_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->cancel_bubble(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::bubbles_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::bubbles_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->bubbles(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::cancelable_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::cancelable_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->cancelable(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::return_value_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::return_value_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->return_value(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::default_prevented_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::default_prevented_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->default_prevented(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::composed_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::composed_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->composed(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::is_trusted_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::is_trusted_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->is_trusted(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::time_stamp_getter)
{
    WebIDL::log_trace(vm, "EventPrototype::time_stamp_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->time_stamp(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(EventPrototype::cancel_bubble_setter)
{
    WebIDL::log_trace(vm, "EventPrototype::cancel_bubble_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::Event* 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 V.to_boolean(); }));

        // 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_cancel_bubble(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(EventPrototype::return_value_setter)
{
    WebIDL::log_trace(vm, "EventPrototype::return_value_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::Event* 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 V.to_boolean(); }));

        // 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_return_value(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(EventPrototype::composed_path)
{
    WebIDL::log_trace(vm, "EventPrototype::composed_path");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::Event* idl_object = TRY(impl_from(vm));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->composed_path(); }));
    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(EventPrototype::stop_propagation)
{
    WebIDL::log_trace(vm, "EventPrototype::stop_propagation");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] DOM::Event* idl_object = TRY(impl_from(vm));

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

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

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

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

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

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

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

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

    auto arg1 = vm.argument(1);
    bool bubbles = false;
    if (!arg1.is_undefined())
        bubbles = TRY(throw_dom_exception_if_needed(vm, [&] { return arg1.to_boolean(); }));

    auto arg2 = vm.argument(2);
    bool cancelable = false;
    if (!arg2.is_undefined())
        cancelable = TRY(throw_dom_exception_if_needed(vm, [&] { return arg2.to_boolean(); }));

    [[maybe_unused]] auto R = TRY(throw_dom_exception_if_needed(vm, [&] { return idl_object->init_event(type, bubbles, cancelable); }));
    return JS::js_undefined();
}

// https://webidl.spec.whatwg.org/#es-dictionary
JS::ThrowCompletionOr<EventInit> convert_to_idl_value_for_event_init(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, "EventInit");

    // 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 EventInit {
        .bubbles = 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("bubbles"_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;
        }()),
        .cancelable = 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("cancelable"_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;
        }()),
        .composed = 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("composed"_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