ladybird/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp

/*
 * Copyright (c) 2020, the SerenityOS developers.
 * Copyright (c) 2023, Sam Atkins <atkinssj@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/CSS/StyleProperties.h>
#include <LibWeb/CSS/StyleValues/DisplayStyleValue.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/DOM/ElementFactory.h>
#include <LibWeb/DOM/Event.h>
#include <LibWeb/DOM/ShadowRoot.h>
#include <LibWeb/DOM/Text.h>
#include <LibWeb/HTML/HTMLTextAreaElement.h>
#include <LibWeb/HTML/Numbers.h>
#include <LibWeb/Namespace.h>

namespace Web::HTML {

JS_DEFINE_ALLOCATOR(HTMLTextAreaElement);

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

HTMLTextAreaElement::~HTMLTextAreaElement() = default;

JS::GCPtr<Layout::Node> HTMLTextAreaElement::create_layout_node(NonnullRefPtr<CSS::StyleProperties> style)
{
    // AD-HOC: We rewrite `display: inline` to `display: inline-block`.
    //         This is required for the internal shadow tree to work correctly in layout.
    if (style->display().is_inline_outside() && style->display().is_flow_inside())
        style->set_property(CSS::PropertyID::Display, CSS::DisplayStyleValue::create(CSS::Display::from_short(CSS::Display::Short::InlineBlock)));

    return Element::create_layout_node_for_display_type(document(), style->display(), style, this);
}

void HTMLTextAreaElement::initialize(JS::Realm& realm)
{
    Base::initialize(realm);
    set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLTextAreaElementPrototype>(realm, "HTMLTextAreaElement"_fly_string));
}

void HTMLTextAreaElement::visit_edges(Cell::Visitor& visitor)
{
    Base::visit_edges(visitor);
    visitor.visit(m_placeholder_element);
    visitor.visit(m_placeholder_text_node);
    visitor.visit(m_inner_text_element);
    visitor.visit(m_text_node);
}

void HTMLTextAreaElement::did_receive_focus()
{
    auto* browsing_context = document().browsing_context();
    if (!browsing_context)
        return;
    if (!m_text_node)
        return;
    browsing_context->set_cursor_position(DOM::Position::create(realm(), *m_text_node, 0));
}

void HTMLTextAreaElement::did_lose_focus()
{
    // The change event fires when the value is committed, if that makes sense for the control,
    // or else when the control loses focus
    queue_an_element_task(HTML::Task::Source::UserInteraction, [this] {
        auto change_event = DOM::Event::create(realm(), HTML::EventNames::change);
        change_event->set_bubbles(true);
        dispatch_event(change_event);
    });
}

// https://html.spec.whatwg.org/multipage/interaction.html#dom-tabindex
i32 HTMLTextAreaElement::default_tab_index_value() const
{
    // See the base function for the spec comments.
    return 0;
}

// https://html.spec.whatwg.org/multipage/form-elements.html#the-textarea-element:concept-form-reset-control
void HTMLTextAreaElement::reset_algorithm()
{
    // The reset algorithm for textarea elements is to set the dirty value flag back to false,
    m_dirty_value = false;
    // and set the raw value of element to its child text content.
    m_raw_value = child_text_content();

    update_placeholder_visibility();
}

void HTMLTextAreaElement::form_associated_element_was_inserted()
{
    create_shadow_tree_if_needed();
}

void HTMLTextAreaElement::form_associated_element_was_removed(DOM::Node*)
{
    set_shadow_root(nullptr);
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-defaultvalue
String HTMLTextAreaElement::default_value() const
{
    // The defaultValue attribute's getter must return the element's child text content.
    return child_text_content();
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-defaultvalue
void HTMLTextAreaElement::set_default_value(String const& default_value)
{
    // The defaultValue attribute's setter must string replace all with the given value within this element.
    string_replace_all(default_value);
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-value
String HTMLTextAreaElement::value() const
{
    // The value IDL attribute must, on getting, return the element's API value.
    return m_raw_value;
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-output-value
void HTMLTextAreaElement::set_value(String const& value)
{
    // FIXME: 1. Let oldAPIValue be this element's API value.

    // 2. Set this element's raw value to the new value.
    m_raw_value = value;

    // 3. Set this element's dirty value flag to true.
    m_dirty_value = true;

    // FIXME: 4. If the new API value is different from oldAPIValue, then move the text entry cursor position to the end of the text control, unselecting any selected text and resetting the selection direction to "none".
    update_placeholder_visibility();
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-textlength
u32 HTMLTextAreaElement::text_length() const
{
    // The textLength IDL attribute must return the length of the element's API value.
    // FIXME: This is inefficient!
    auto utf16_data = MUST(AK::utf8_to_utf16(m_raw_value));
    return Utf16View { utf16_data }.length_in_code_units();
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-cols
unsigned HTMLTextAreaElement::cols() const
{
    // The cols and rows attributes are limited to only positive numbers with fallback. The cols IDL attribute's default value is 20.
    if (auto cols_string = get_attribute(HTML::AttributeNames::cols); cols_string.has_value()) {
        if (auto cols = parse_non_negative_integer(*cols_string); cols.has_value())
            return *cols;
    }
    return 20;
}

WebIDL::ExceptionOr<void> HTMLTextAreaElement::set_cols(unsigned cols)
{
    return set_attribute(HTML::AttributeNames::cols, MUST(String::number(cols)));
}

// https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-rows
unsigned HTMLTextAreaElement::rows() const
{
    // The cols and rows attributes are limited to only positive numbers with fallback. The rows IDL attribute's default value is 2.
    if (auto rows_string = get_attribute(HTML::AttributeNames::rows); rows_string.has_value()) {
        if (auto rows = parse_non_negative_integer(*rows_string); rows.has_value())
            return *rows;
    }
    return 2;
}

WebIDL::ExceptionOr<void> HTMLTextAreaElement::set_rows(unsigned rows)
{
    return set_attribute(HTML::AttributeNames::rows, MUST(String::number(rows)));
}

void HTMLTextAreaElement::create_shadow_tree_if_needed()
{
    if (shadow_root_internal())
        return;

    auto shadow_root = heap().allocate<DOM::ShadowRoot>(realm(), document(), *this, Bindings::ShadowRootMode::Closed);
    set_shadow_root(shadow_root);

    auto element = MUST(DOM::create_element(document(), HTML::TagNames::div, Namespace::HTML));
    MUST(shadow_root->append_child(element));

    m_placeholder_element = MUST(DOM::create_element(document(), HTML::TagNames::div, Namespace::HTML));
    m_placeholder_element->set_use_pseudo_element(CSS::Selector::PseudoElement::Type::Placeholder);
    MUST(element->append_child(*m_placeholder_element));

    m_placeholder_text_node = heap().allocate<DOM::Text>(realm(), document(), String {});
    m_placeholder_text_node->set_data(get_attribute_value(HTML::AttributeNames::placeholder));
    m_placeholder_text_node->set_editable_text_node_owner(Badge<HTMLTextAreaElement> {}, *this);
    MUST(m_placeholder_element->append_child(*m_placeholder_text_node));

    m_inner_text_element = MUST(DOM::create_element(document(), HTML::TagNames::div, Namespace::HTML));
    MUST(element->append_child(*m_inner_text_element));

    m_text_node = heap().allocate<DOM::Text>(realm(), document(), String {});
    handle_readonly_attribute(attribute(HTML::AttributeNames::readonly));
    m_text_node->set_editable_text_node_owner(Badge<HTMLTextAreaElement> {}, *this);
    // NOTE: If `children_changed()` was called before now, `m_raw_value` will hold the text content.
    //       Otherwise, it will get filled in whenever that does get called.
    m_text_node->set_text_content(m_raw_value);
    MUST(m_inner_text_element->append_child(*m_text_node));

    update_placeholder_visibility();
}

// https://html.spec.whatwg.org/multipage/input.html#attr-input-readonly
void HTMLTextAreaElement::handle_readonly_attribute(Optional<String> const& maybe_value)
{
    // The readonly attribute is a boolean attribute that controls whether or not the user can edit the form control. When specified, the element is not mutable.
    m_is_mutable = !maybe_value.has_value();

    if (m_text_node)
        m_text_node->set_always_editable(m_is_mutable);
}

void HTMLTextAreaElement::update_placeholder_visibility()
{
    if (!m_placeholder_element)
        return;
    if (!m_text_node)
        return;
    auto placeholder_text = get_attribute(AttributeNames::placeholder);
    if (placeholder_text.has_value() && m_text_node->data().is_empty()) {
        MUST(m_placeholder_element->style_for_bindings()->set_property(CSS::PropertyID::Display, "block"sv));
    } else {
        MUST(m_placeholder_element->style_for_bindings()->set_property(CSS::PropertyID::Display, "none"sv));
    }
}

// https://html.spec.whatwg.org/multipage/form-elements.html#the-textarea-element:children-changed-steps
void HTMLTextAreaElement::children_changed()
{
    // The children changed steps for textarea elements must, if the element's dirty value flag is false,
    // set the element's raw value to its child text content.
    if (!m_dirty_value) {
        m_raw_value = child_text_content();
        if (m_text_node)
            m_text_node->set_text_content(m_raw_value);
        update_placeholder_visibility();
    }
}

void HTMLTextAreaElement::form_associated_element_attribute_changed(FlyString const& name, Optional<String> const& value)
{
    if (name == HTML::AttributeNames::placeholder) {
        if (m_placeholder_text_node)
            m_placeholder_text_node->set_data(value.value_or(String {}));
    } else if (name == HTML::AttributeNames::readonly) {
        handle_readonly_attribute(value);
    }
}

void HTMLTextAreaElement::did_edit_text_node(Badge<Web::HTML::BrowsingContext>)
{
    // A textarea element's dirty value flag must be set to true whenever the user interacts with the control in a way that changes the raw value.
    m_dirty_value = true;

    update_placeholder_visibility();
}

}