/*
 * Copyright (c) 2020, the SerenityOS developers.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibWeb/Bindings/HTMLOListElement.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/CSS/PropertyID.h>
#include <LibWeb/CSS/StyleValues/CounterStyleStyleValue.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/HTML/AttributeNames.h>
#include <LibWeb/HTML/HTMLOListElement.h>
#include <LibWeb/HTML/Numbers.h>
#include <LibWeb/WebIDL/Types.h>

namespace Web::HTML {

GC_DEFINE_ALLOCATOR(HTMLOListElement);

HTMLOListElement::HTMLOListElement(DOM::Document& document, DOM::QualifiedName qualified_name)
    : HTMLElement(document, move(qualified_name))
{
}

HTMLOListElement::~HTMLOListElement() = default;

void HTMLOListElement::initialize(JS::Realm& realm)
{
    WEB_SET_PROTOTYPE_FOR_INTERFACE(HTMLOListElement);
    Base::initialize(realm);
}

void HTMLOListElement::attribute_changed(FlyString const& local_name, Optional<String> const& old_value, Optional<String> const& value, Optional<FlyString> const& namespace_)
{
    Base::attribute_changed(local_name, old_value, value, namespace_);

    if (local_name.is_one_of(HTML::AttributeNames::reversed, HTML::AttributeNames::start, HTML::AttributeNames::type)) {
        set_needs_layout_tree_update(true, DOM::SetNeedsLayoutTreeUpdateReason::HTMLOListElementOrdinalValues);
        if (auto* first_child_element = first_child_of_type<Element>())
            first_child_element->maybe_invalidate_ordinals_for_list_owner();
    }
}

// https://html.spec.whatwg.org/multipage/grouping-content.html#dom-ol-start
WebIDL::Long HTMLOListElement::start()
{
    // The start IDL attribute must reflect the content attribute of the same name, with a default value of 1.
    auto content_attribute_value = get_attribute(AttributeNames::start).value_or("1"_string);
    if (auto maybe_number = HTML::parse_integer(content_attribute_value); maybe_number.has_value())
        return *maybe_number;
    return 1;
}

void HTMLOListElement::set_start(WebIDL::Long start)
{
    set_attribute_value(AttributeNames::start, String::number(start));
}

// https://html.spec.whatwg.org/multipage/grouping-content.html#concept-ol-start
AK::Checked<i32> HTMLOListElement::starting_value() const
{
    // 1. If the ol element has a start attribute, then:
    auto start = get_attribute(AttributeNames::start);
    if (start.has_value()) {
        // 1. Let parsed be the result of parsing the value of the attribute as an integer.
        auto parsed = parse_integer(start.value());

        // 2. If parsed is not an error, then return parsed.
        if (parsed.has_value())
            return parsed.value();
    }
    // 2. If the ol element has a reversed attribute, then return the number of owned li elements.
    if (has_attribute(AttributeNames::reversed)) {
        auto const reverse_list_starting_value = number_of_owned_list_items();
        VERIFY(reverse_list_starting_value <= NumericLimits<WebIDL::Long>::max());
        return reverse_list_starting_value;
    }

    // 3. Return 1.
    return 1;
}

bool HTMLOListElement::is_presentational_hint(FlyString const& name) const
{
    if (Base::is_presentational_hint(name))
        return true;

    return name == HTML::AttributeNames::type;
}

void HTMLOListElement::apply_presentational_hints(Vector<CSS::StyleProperty>& properties) const
{
    Base::apply_presentational_hints(properties);

    // https://html.spec.whatwg.org/multipage/rendering.html#lists
    for_each_attribute([&](auto& name, auto& value) {
        if (name == HTML::AttributeNames::type) {
            if (value == "1"sv) {
                properties.append({ .property_id = CSS::PropertyID::ListStyleType, .value = CSS::CounterStyleStyleValue::create("decimal"_fly_string) });
            } else if (value == "a"sv) {
                properties.append({ .property_id = CSS::PropertyID::ListStyleType, .value = CSS::CounterStyleStyleValue::create("lower-alpha"_fly_string) });
            } else if (value == "A"sv) {
                properties.append({ .property_id = CSS::PropertyID::ListStyleType, .value = CSS::CounterStyleStyleValue::create("upper-alpha"_fly_string) });
            } else if (value == "i"sv) {
                properties.append({ .property_id = CSS::PropertyID::ListStyleType, .value = CSS::CounterStyleStyleValue::create("lower-roman"_fly_string) });
            } else if (value == "I"sv) {
                properties.append({ .property_id = CSS::PropertyID::ListStyleType, .value = CSS::CounterStyleStyleValue::create("upper-roman"_fly_string) });
            }
        }
    });
}

}