#include <AK/String.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/Value.h>
#include <LibJS/Runtime/ValueInlines.h>
#include <LibWeb/Bindings/DataTransfer.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/FileAPI/FileList.h>
#include <LibWeb/HTML/DataTransfer.h>
#include <LibWeb/HTML/DataTransferItemList.h>
#include <LibWeb/WebIDL/AbstractOperations.h>
#include <LibWeb/WebIDL/Tracing.h>

namespace Web::Bindings {

void DataTransferConstructor::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, "DataTransfer"_utf16), JS::Attribute::Configurable);
    object.define_direct_property(vm.names.prototype, &ensure_web_prototype<DataTransferPrototype>(realm, "DataTransfer"_fly_string), 0);
}

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

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

    // 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<DataTransferPrototype>(*target_realm, "DataTransfer"_fly_string);
    }

    auto impl = TRY(throw_dom_exception_if_needed(vm, [&] { return HTML::DataTransfer::construct_impl(realm); }));

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

    return *impl;
}

void DataTransferPrototype::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 drop_effect_id = "dropEffect"_utf16_fly_string;
    auto native_drop_effect_getter = JS::NativeFunction::create(realm, drop_effect_getter, 0, drop_effect_id, &realm, "get"sv);
    auto native_drop_effect_setter = JS::NativeFunction::create(realm, drop_effect_setter, 1, drop_effect_id, &realm, "set"sv);

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto drop_effect_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(drop_effect_id, native_drop_effect_getter, native_drop_effect_setter, drop_effect_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 effect_allowed_id = "effectAllowed"_utf16_fly_string;
    auto native_effect_allowed_getter = JS::NativeFunction::create(realm, effect_allowed_getter, 0, effect_allowed_id, &realm, "get"sv);
    auto native_effect_allowed_setter = JS::NativeFunction::create(realm, effect_allowed_setter, 1, effect_allowed_id, &realm, "set"sv);

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto effect_allowed_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(effect_allowed_id, native_effect_allowed_getter, native_effect_allowed_setter, effect_allowed_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 items_id = "items"_utf16_fly_string;
    auto native_items_getter = JS::NativeFunction::create(realm, items_getter, 0, items_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_items_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto items_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(items_id, native_items_getter, native_items_setter, items_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 types_id = "types"_utf16_fly_string;
    auto native_types_getter = JS::NativeFunction::create(realm, types_getter, 0, types_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_types_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto types_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(types_id, native_types_getter, native_types_setter, types_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 files_id = "files"_utf16_fly_string;
    auto native_files_getter = JS::NativeFunction::create(realm, files_getter, 0, files_id, &realm, "get"sv);
    GC::Ptr<JS::NativeFunction> native_files_setter;

    // 4. Let configurable be false if attr is unforgeable and true otherwise.
    auto files_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(files_id, native_files_getter, native_files_setter, files_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, "getData"_utf16_fly_string, get_data, 1, default_attributes);

    object.define_native_function(realm, "setData"_utf16_fly_string, set_data, 2, default_attributes);

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

    object.define_direct_property("setDragImage"_utf16_fly_string, JS::js_undefined(), default_attributes | JS::Attribute::Unimplemented);

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

void DataTransferPrototype::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<HTML::DataTransfer*> impl_from(JS::VM& vm, JS::Value js_value)
{

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

[[maybe_unused]] static JS::ThrowCompletionOr<HTML::DataTransfer*> 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(DataTransferPrototype::drop_effect_getter)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::drop_effect_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->drop_effect(); }));

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

JS_DEFINE_NATIVE_FUNCTION(DataTransferPrototype::effect_allowed_getter)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::effect_allowed_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->effect_allowed(); }));

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

JS_DEFINE_NATIVE_FUNCTION(DataTransferPrototype::items_getter)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::items_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->items(); }));

    return JS::Value(R);
}

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

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

    if (auto cached_value = idl_object->cached_types())
        return JS::Value(cached_value.ptr());


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

    return [&]() -> JS::Value {
        JS::Value js_value = [&]() -> 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 = WebIDL::primitive_string_from_string(vm, 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.
        }

        MUST(sequence_array->set_integrity_level(JS::Object::IntegrityLevel::Frozen));

        // 5. Return A.
        return sequence_array;
    }();
        if (js_value.is_object())
            idl_object->set_cached_types(&js_value.as_object());
        return js_value;
    }();
}

JS_DEFINE_NATIVE_FUNCTION(DataTransferPrototype::files_getter)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::files_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->files(); }));

    return JS::Value(R);
}

JS_DEFINE_NATIVE_FUNCTION(DataTransferPrototype::drop_effect_setter)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::drop_effect_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]] HTML::DataTransfer* 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<String> {
        return TRY(WebIDL::to_string(vm, V));
    }(); }));

        // 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_drop_effect(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(DataTransferPrototype::effect_allowed_setter)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::effect_allowed_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]] HTML::DataTransfer* 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<String> {
        return TRY(WebIDL::to_string(vm, V));
    }(); }));

        // 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_effect_allowed(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(DataTransferPrototype::get_data)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::get_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] HTML::DataTransfer* idl_object = TRY(impl_from(vm));

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

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

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

JS_DEFINE_NATIVE_FUNCTION(DataTransferPrototype::set_data)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::set_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] HTML::DataTransfer* idl_object = TRY(impl_from(vm));

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

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

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

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

JS_DEFINE_NATIVE_FUNCTION(DataTransferPrototype::clear_data)
{
    WebIDL::log_trace(vm, "DataTransferPrototype::clear_data");
    [[maybe_unused]] auto& realm = *vm.current_realm();
    [[maybe_unused]] HTML::DataTransfer* idl_object = TRY(impl_from(vm));

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

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

} // namespace Web::Bindings