/*

 * Copyright (c) 2022, the SerenityOS developers.

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include <LibWeb/Bindings/HTMLOptionsCollectionPrototype.h>

#include <LibWeb/Bindings/Intrinsics.h>

#include <LibWeb/DOM/ElementFactory.h>

#include <LibWeb/HTML/HTMLOptGroupElement.h>

#include <LibWeb/HTML/HTMLOptionElement.h>

#include <LibWeb/HTML/HTMLOptionsCollection.h>

#include <LibWeb/HTML/HTMLSelectElement.h>

#include <LibWeb/Namespace.h>

#include <LibWeb/WebIDL/DOMException.h>

namespace Web::HTML {

JS_DEFINE_ALLOCATOR(HTMLOptionsCollection);

JS::NonnullGCPtr<HTMLOptionsCollection> HTMLOptionsCollection::create(DOM::ParentNode& root, Function<bool(DOM::Element const&)> filter)

{

    return root.heap().allocate<HTMLOptionsCollection>(root.realm(), root, move(filter));

}

HTMLOptionsCollection::HTMLOptionsCollection(DOM::ParentNode& root, Function<bool(DOM::Element const&)> filter)

    : DOM::HTMLCollection(root, Scope::Descendants, move(filter))

{

    m_legacy_platform_object_flags->has_indexed_property_setter = true;

    m_legacy_platform_object_flags->indexed_property_setter_has_identifier = true;

}

HTMLOptionsCollection::~HTMLOptionsCollection() = default;

void HTMLOptionsCollection::initialize(JS::Realm& realm)

{

    Base::initialize(realm);

    WEB_SET_PROTOTYPE_FOR_INTERFACE(HTMLOptionsCollection);

}

// https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#dom-htmloptionscollection-length

WebIDL::ExceptionOr<void> HTMLOptionsCollection::set_length(WebIDL::UnsignedLong value)

{

    // 1. Let current be the number of nodes represented by the collection.

    auto current = static_cast<WebIDL::UnsignedLong>(length());

    // 2. If the given value is greater than current, then:

    if (value > current) {

        // 2.1. If the given value is greater than 100,000, then return.

        if (value > 100'000)

            return {};

        // 2.2. Let n be value − current.

        auto n = value - current;

        // 2.3. Append n new option elements with no attributes and no child nodes to the select element on which this is rooted.

        // Mutation events must be fired as if a DocumentFragment containing the new option elements had been inserted.

        auto root_element = root();

        for (WebIDL::UnsignedLong i = 0; i < n; i++)

            TRY(root_element->append_child(TRY(DOM::create_element(root_element->document(), HTML::TagNames::option, Namespace::HTML))));

    }

    // 3. If the given value is less than current, then:

    if (value < current) {

        // 3.1. Let n be current − value.

        auto n = current - value;

        // 3.2. Remove the last n nodes in the collection from their parent nodes.

        for (auto i = 0u; i < n; i++)

            item(length() - 1)->remove();

    }

    return {};

}

// https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#dom-htmloptionscollection-setter

WebIDL::ExceptionOr<void> HTMLOptionsCollection::set_value_of_indexed_property(u32 index, JS::Value unconverted_option)

{

    // The spec doesn't seem to require this, but it's consistent with length handling and other browsers

    if (index >= 100'000) {

        return {};

    }

    // 1. If value is null, invoke the steps for the remove method with index as the argument, and return.

    if (unconverted_option.is_null()) {

        remove(static_cast<WebIDL::Long>(index));

        return {};

    }

    if (!unconverted_option.is_object() || !is<HTMLOptionElement>(unconverted_option.as_object())) {

        return WebIDL::TypeMismatchError::create(realm(), "The value provided is not an HTMLOptionElement"_string);

    }

    auto& option = static_cast<HTMLOptionElement&>(unconverted_option.as_object());

    // 2. Let length be the number of nodes represented by the collection.

    auto length = this->length();

    auto root_element = root();

    if (index >= length) {

        // 3. Let n be index minus length.

        auto n = index - length;

        // 4. If n is greater than zero, then append a DocumentFragment consisting of n-1 new option elements with no attributes and no child nodes to the select element on which the HTMLOptionsCollection is rooted.

        if (n > 0) {

            for (WebIDL::UnsignedLong i = 0; i < n - 1; i++) {

                TRY(root_element->append_child(TRY(DOM::create_element(root_element->document(), HTML::TagNames::option, Namespace::HTML))));

            }

        }

        // 5. If n is greater than or equal to zero, append value to the select element.

        TRY(root_element->append_child(option));

    } else {

        // 5 (cont). Otherwise, replace the indexth element in the collection by value.

        TRY(root_element->replace_child(option, *item(index)));

    }

    return {};

}

// https://html.spec.whatwg.org/multipage/common-dom-interfaces.html#dom-htmloptionscollection-add

WebIDL::ExceptionOr<void> HTMLOptionsCollection::add(HTMLOptionOrOptGroupElement element, Optional<HTMLElementOrElementIndex> before)

{

    auto resolved_element = element.visit(

        [](auto& e) -> JS::Handle<HTMLElement> {

            return JS::make_handle(static_cast<HTML::HTMLElement&>(*e));

        });

Unexecuted instantiation: HTMLOptionsCollection.cpp:JS::Handle<Web::HTML::HTMLElement> Web::HTML::HTMLOptionsCollection::add(AK::Variant<JS::Handle<Web::HTML::HTMLOptionElement>, JS::Handle<Web::HTML::HTMLOptGroupElement> >, AK::Optional<AK::Variant<JS::Handle<Web::HTML::HTMLElement>, int> >)::$_0::operator()<JS::Handle<Web::HTML::HTMLOptionElement> >(JS::Handle<Web::HTML::HTMLOptionElement>&) const

Unexecuted instantiation: HTMLOptionsCollection.cpp:JS::Handle<Web::HTML::HTMLElement> Web::HTML::HTMLOptionsCollection::add(AK::Variant<JS::Handle<Web::HTML::HTMLOptionElement>, JS::Handle<Web::HTML::HTMLOptGroupElement> >, AK::Optional<AK::Variant<JS::Handle<Web::HTML::HTMLElement>, int> >)::$_0::operator()<JS::Handle<Web::HTML::HTMLOptGroupElement> >(JS::Handle<Web::HTML::HTMLOptGroupElement>&) const

    JS::GCPtr<DOM::Node> before_element;

    if (before.has_value() && before->has<JS::Handle<HTMLElement>>())

        before_element = before->get<JS::Handle<HTMLElement>>().ptr();

    // 1. If element is an ancestor of the select element on which the HTMLOptionsCollection is rooted, then throw a "HierarchyRequestError" DOMException.

    if (resolved_element->is_ancestor_of(root()))

        return WebIDL::HierarchyRequestError::create(realm(), "The provided element is an ancestor of the root select element."_string);

    // 2. If before is an element, but that element isn't a descendant of the select element on which the HTMLOptionsCollection is rooted, then throw a "NotFoundError" DOMException.

    if (before_element && !before_element->is_descendant_of(root()))

        return WebIDL::NotFoundError::create(realm(), "The 'before' element is not a descendant of the root select element."_string);

    // 3. If element and before are the same element, then return.

    if (before_element && (resolved_element.ptr() == before_element.ptr()))

        return {};

    // 4. If before is a node, then let reference be that node. Otherwise, if before is an integer, and there is a beforeth node in the collection, let reference be that node. Otherwise, let reference be null.

    JS::GCPtr<DOM::Node> reference;

    if (before_element)

        reference = move(before_element);

    else if (before.has_value() && before->has<i32>())

        reference = item(before->get<i32>());

    // 5. If reference is not null, let parent be the parent node of reference. Otherwise, let parent be the select element on which the HTMLOptionsCollection is rooted.

    DOM::Node* parent = reference ? reference->parent() : root().ptr();

    // 6. Pre-insert element into parent node before reference.

    (void)TRY(parent->pre_insert(*resolved_element, reference));

    return {};

}

// https://html.spec.whatwg.org/#dom-htmloptionscollection-remove

void HTMLOptionsCollection::remove(WebIDL::Long index)

{

    // 1. If the number of nodes represented by the collection is zero, return.

    if (length() == 0)

        return;

    // 2. If index is not a number greater than or equal to 0 and less than the number of nodes represented by the collection, return.

    if (index < 0 || static_cast<WebIDL::UnsignedLong>(index) >= length())

        return;

    // 3. Let element be the indexth element in the collection.

    auto* element = this->item(index);

    // 4. Remove element from its parent node.

    element->remove();

}

// https://html.spec.whatwg.org/#dom-htmloptionscollection-selectedindex

WebIDL::Long HTMLOptionsCollection::selected_index() const

{

    // The selectedIndex IDL attribute must act like the identically named attribute

    // on the select element on which the HTMLOptionsCollection is rooted.

    return verify_cast<HTMLSelectElement>(*root()).selected_index();

}

void HTMLOptionsCollection::set_selected_index(WebIDL::Long index)

{

    verify_cast<HTMLSelectElement>(*root()).set_selected_index(index);

}

}