#include <AK/Utf16String.h>
#include <AK/Variant.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/ArrayPrototype.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/Iterator.h>
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Runtime/ValueInlines.h>
#include <LibWeb/Bindings/CSSStyleValue.h>
#include <LibWeb/Bindings/CSSUnparsedValue.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Bindings/PlatformObject.h>
#include <LibWeb/CSS/CSSUnparsedValue.h>
#include <LibWeb/CSS/CSSVariableReferenceValue.h>
#include <LibWeb/WebIDL/AbstractOperations.h>
#include <LibWeb/WebIDL/Tracing.h>
#include <LibWeb/WebIDL/Types.h>

namespace Web::Bindings {

void CSSUnparsedValueConstructor::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<CSSStyleValuePrototype>(realm, "CSSStyleValue"_fly_string));
    object.define_direct_property(vm.names.length, JS::Value(1), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.name, JS::PrimitiveString::create(vm, "CSSUnparsedValue"_utf16), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.prototype, &ensure_web_prototype<CSSUnparsedValuePrototype>(realm, "CSSUnparsedValue"_fly_string), 0);
}

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

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

    // 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<CSSUnparsedValuePrototype>(*target_realm, "CSSUnparsedValue"_fly_string);
    }

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

    auto arg0 = vm.argument(0);
    auto members = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<GC::ConservativeVector<Variant<Utf16String, GC::Ref<CSS::CSSVariableReferenceValue>>>> {
        if (!arg0.is_object())
            return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObject, arg0);

        auto method = TRY(arg0.get_method(vm, vm.well_known_symbol_iterator()));
        if (!method)
            return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotIterable, arg0);

        return TRY([&]() -> JS::ThrowCompletionOr<GC::ConservativeVector<Variant<Utf16String, GC::Ref<CSS::CSSVariableReferenceValue>>>> {
        // To create an IDL value of type sequence<T> given an iterable iterable and an iterator getter method, perform the following steps:
        // 1. Let iteratorRecord be ? GetIteratorFromMethod(iterable, method).
        auto iterator = TRY(JS::get_iterator_from_method(vm, arg0, *method));

        GC::ConservativeVector<Variant<Utf16String, GC::Ref<CSS::CSSVariableReferenceValue>>> sequence;

        // 2. Initialize i to be 0.
        // 3. Repeat
        for (;;) {
            // 1. Let next be ? IteratorStepValue(iteratorRecord).
            auto next = TRY(JS::iterator_step_value(vm, iterator));

            // 2. If next is done, then return an IDL sequence value of type sequence<T> of length i, where the value of the element at index j is Sj.
            if (!next.has_value())
                break;

            // 3. Initialize Si to the result of converting next to an IDL value of type T.
            auto next_value = next.release_value();
            auto sequence_item = TRY(throw_dom_exception_if_needed(vm, [&] { return [&]() -> JS::ThrowCompletionOr<Variant<Utf16String, GC::Ref<CSS::CSSVariableReferenceValue>>> {

        if (next_value.is_object()) {
            [[maybe_unused]] auto& object = next_value.as_object();

            if (is<PlatformObject>(object)) {

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

        auto members_string = TRY([&]() -> JS::ThrowCompletionOr<Utf16String> {
        return TRY(WebIDL::to_utf16_usv_string(vm, next_value));
    }());
        return Variant<Utf16String, GC::Ref<CSS::CSSVariableReferenceValue>> { members_string };

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

            // 4. Set i to i + 1.
            sequence.append(sequence_item);
        }

        return sequence;
    }());
    }(); }));

    auto impl = TRY(throw_dom_exception_if_needed(vm, [&] { return CSS::CSSUnparsedValue::construct_impl(realm, members); }));

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

    return *impl;
}

GC_DEFINE_ALLOCATOR(CSSUnparsedValuePrototype);

CSSUnparsedValuePrototype::CSSUnparsedValuePrototype([[maybe_unused]] JS::Realm& realm)
    : Object(ConstructWithPrototypeTag::Tag, GC::Ref { ensure_web_prototype<CSSStyleValuePrototype>(realm, "CSSStyleValue"_fly_string) })
{
}

CSSUnparsedValuePrototype::~CSSUnparsedValuePrototype()
{
}


void CSSUnparsedValuePrototype::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(GC::Ref { ensure_web_prototype<CSSStyleValuePrototype>(realm, "CSSStyleValue"_fly_string) });

    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.
    object.define_direct_property(vm.well_known_symbol_iterator(), realm.intrinsics().array_prototype()->get_without_side_effects(vm.names.values), JS::Attribute::Configurable | JS::Attribute::Writable);

    object.define_direct_property(vm.names.entries, realm.intrinsics().array_prototype()->get_without_side_effects(vm.names.entries), default_attributes);
    object.define_direct_property(vm.names.keys, realm.intrinsics().array_prototype()->get_without_side_effects(vm.names.keys), default_attributes);
    object.define_direct_property(vm.names.values, realm.intrinsics().array_prototype()->get_without_side_effects(vm.names.values), default_attributes);
    object.define_direct_property(vm.names.forEach, realm.intrinsics().array_prototype()->get_without_side_effects(vm.names.forEach), default_attributes);

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

void CSSUnparsedValuePrototype::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<CSS::CSSUnparsedValue*> impl_from(JS::VM& vm, JS::Value js_value)
{

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

[[maybe_unused]] static JS::ThrowCompletionOr<CSS::CSSUnparsedValue*> 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(CSSUnparsedValuePrototype::length_getter)
{
    WebIDL::log_trace(vm, "CSSUnparsedValuePrototype::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(); }));

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

} // namespace Web::Bindings