#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Runtime/ValueInlines.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/Bindings/Instance.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/WebAssembly/Instance.h>
#include <LibWeb/WebAssembly/Module.h>
#include <LibWeb/WebIDL/Tracing.h>

namespace Web::Bindings {

void InstanceConstructor::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, "Instance"_utf16), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.prototype, &ensure_web_prototype<InstancePrototype>(realm, "WebAssembly.Instance"_fly_string), 0);
}

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

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

    // 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<InstancePrototype>(*target_realm, "WebAssembly.Instance"_fly_string);
    }

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

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

    auto arg1 = vm.argument(1);
    GC::Ptr<JS::Object> import_object {};
    if (!arg1.is_undefined())
        import_object = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::Ref<JS::Object>> {
        if (!arg1.is_object())
            return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObject, arg1);
        return GC::Ref { arg1.as_object() };
    }(); }));

    auto impl = TRY(throw_dom_exception_if_needed(vm, [&] { return WebAssembly::Instance::construct_impl(realm, module, import_object); }));

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

    return *impl;
}

void InstancePrototype::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 exports_id = "exports"_utf16_fly_string;
    auto native_exports_getter = JS::NativeFunction::create(realm, exports_getter, 0, exports_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_exports_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto exports_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(exports_id, native_exports_getter, native_exports_setter, exports_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_direct_property(vm.well_known_symbol_to_string_tag(), JS::PrimitiveString::create(vm, "WebAssembly.Instance"_utf16), JS::Attribute::Configurable);
}

void InstancePrototype::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<WebAssembly::Instance*> impl_from(JS::VM& vm, JS::Value js_value)
{

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

[[maybe_unused]] static JS::ThrowCompletionOr<WebAssembly::Instance*> 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(InstancePrototype::exports_getter)
{
    WebIDL::log_trace(vm, "InstancePrototype::exports_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->exports(); }));

    return JS::Value(R);
}

} // namespace Web::Bindings