/*

 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>

 * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>

 *

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

 */

#include <LibWeb/ARIA/Roles.h>

#include <LibWeb/Bindings/HTMLAnchorElementPrototype.h>

#include <LibWeb/DOM/DOMTokenList.h>

#include <LibWeb/DOM/Event.h>

#include <LibWeb/HTML/AttributeNames.h>

#include <LibWeb/HTML/HTMLAnchorElement.h>

#include <LibWeb/HTML/HTMLImageElement.h>

#include <LibWeb/HTML/Window.h>

#include <LibWeb/PixelUnits.h>

#include <LibWeb/ReferrerPolicy/ReferrerPolicy.h>

#include <LibWeb/UIEvents/MouseEvent.h>

namespace Web::HTML {

JS_DEFINE_ALLOCATOR(HTMLAnchorElement);

HTMLAnchorElement::HTMLAnchorElement(DOM::Document& document, DOM::QualifiedName qualified_name)

    : HTMLElement(document, move(qualified_name))

{

}

HTMLAnchorElement::~HTMLAnchorElement() = default;

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

{

    Base::initialize(realm);

    WEB_SET_PROTOTYPE_FOR_INTERFACE(HTMLAnchorElement);

}

void HTMLAnchorElement::visit_edges(Cell::Visitor& visitor)

{

    Base::visit_edges(visitor);

    visitor.visit(m_rel_list);

}

void HTMLAnchorElement::attribute_changed(FlyString const& name, Optional<String> const& old_value, Optional<String> const& value)

{

    HTMLElement::attribute_changed(name, old_value, value);

    if (name == HTML::AttributeNames::href) {

        set_the_url();

    } else if (name == HTML::AttributeNames::rel) {

        if (m_rel_list)

            m_rel_list->associated_attribute_changed(value.value_or(String {}));

    }

}

Optional<String> HTMLAnchorElement::hyperlink_element_utils_href() const

{

    return attribute(HTML::AttributeNames::href);

}

WebIDL::ExceptionOr<void> HTMLAnchorElement::set_hyperlink_element_utils_href(String href)

{

    return set_attribute(HTML::AttributeNames::href, move(href));

}

Optional<String> HTMLAnchorElement::hyperlink_element_utils_referrerpolicy() const

{

    return attribute(HTML::AttributeNames::referrerpolicy);

}

bool HTMLAnchorElement::has_activation_behavior() const

{

    return true;

}

// https://html.spec.whatwg.org/multipage/links.html#links-created-by-a-and-area-elements

void HTMLAnchorElement::activation_behavior(Web::DOM::Event const& event)

{

    // The activation behavior of an a or area element element given an event event is:

    // 1. If element has no href attribute, then return.

    if (href().is_empty())

        return;

    // AD-HOC: Do not activate the element for clicks with the ctrl/cmd modifier present. This lets

    //         the chrome open the link in a new tab.

    if (is<UIEvents::MouseEvent>(event)) {

        auto const& mouse_event = static_cast<UIEvents::MouseEvent const&>(event);

        if (mouse_event.platform_ctrl_key())

            return;

    }

    // 2. Let hyperlinkSuffix be null.

    Optional<String> hyperlink_suffix {};

    // 3. If element is an a element, and event's target is an img with an ismap attribute specified, then:

    if (event.target() && is<HTMLImageElement>(*event.target()) && static_cast<HTMLImageElement const&>(*event.target()).has_attribute(AttributeNames::ismap)) {

        // 1. Let x and y be 0.

        CSSPixels x { 0 };

        CSSPixels y { 0 };

        // 2. If event's isTrusted attribute is initialized to true, then set x to the distance in CSS pixels from the left edge of the image

        //    to the location of the click, and set y to the distance in CSS pixels from the top edge of the image to the location of the click.

        if (event.is_trusted() && is<UIEvents::MouseEvent>(event)) {

            auto const& mouse_event = static_cast<UIEvents::MouseEvent const&>(event);

            x = CSSPixels { mouse_event.offset_x() };

            y = CSSPixels { mouse_event.offset_y() };

        }

        // 3. If x is negative, set x to 0.

        x = max(x, 0);

        // 4. If y is negative, set y to 0.

        y = max(y, 0);

        // 5. Set hyperlinkSuffix to the concatenation of U+003F (?), the value of x expressed as a base-ten integer using ASCII digits,

        //    U+002C (,), and the value of y expressed as a base-ten integer using ASCII digits.

        hyperlink_suffix = MUST(String::formatted("?{},{}", x.to_int(), y.to_int()));

    }

    // 4. Let userInvolvement be event's user navigation involvement.

    auto user_involvement = user_navigation_involvement(event);

    // 5. If the user has expressed a preference to download the hyperlink, then set userInvolvement to "browser UI".

    // NOTE: That is, if the user has expressed a specific preference for downloading, this no longer counts as merely "activation".

    if (has_download_preference())

        user_involvement = UserNavigationInvolvement::BrowserUI;

    // FIXME: 6. If element has a download attribute, or if the user has expressed a preference to download the

    //     hyperlink, then download the hyperlink created by element with hyperlinkSuffix set to hyperlinkSuffix and

    //     userInvolvement set to userInvolvement.

    // 7. Otherwise, follow the hyperlink created by element with hyperlinkSuffix set to hyperlinkSuffix and userInvolvement set to userInvolvement.

    follow_the_hyperlink(hyperlink_suffix, user_involvement);

}

bool HTMLAnchorElement::has_download_preference() const

{

    return has_attribute(HTML::AttributeNames::download);

}

// https://html.spec.whatwg.org/multipage/interaction.html#dom-tabindex

i32 HTMLAnchorElement::default_tab_index_value() const

{

    // See the base function for the spec comments.

    return 0;

}

Optional<ARIA::Role> HTMLAnchorElement::default_role() const

{

    // https://www.w3.org/TR/html-aria/#el-a-no-href

    if (!href().is_empty())

        return ARIA::Role::link;

    // https://www.w3.org/TR/html-aria/#el-a

    return ARIA::Role::generic;

}

// https://html.spec.whatwg.org/multipage/text-level-semantics.html#dom-a-rellist

JS::NonnullGCPtr<DOM::DOMTokenList> HTMLAnchorElement::rel_list()

{

    // The IDL attribute relList must reflect the rel content attribute.

    if (!m_rel_list)

        m_rel_list = DOM::DOMTokenList::create(*this, HTML::AttributeNames::rel);

    return *m_rel_list;

}

// https://html.spec.whatwg.org/multipage/text-level-semantics.html#dom-a-text

String HTMLAnchorElement::text() const

{

    // The text attribute's getter must return this element's descendant text content.

    return descendant_text_content();

}

// https://html.spec.whatwg.org/multipage/text-level-semantics.html#dom-a-text

void HTMLAnchorElement::set_text(String const& text)

{

    // The text attribute's setter must string replace all with the given value within this element.

    string_replace_all(text);

}

}