/*
 * Copyright (c) 2018-2025, Andreas Kling <andreas@ladybird.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/DistinctNumeric.h>
#include <AK/FlyString.h>
#include <AK/GenericShorthands.h>
#include <AK/JsonObjectSerializer.h>
#include <AK/TypeCasts.h>
#include <AK/Vector.h>
#include <LibWeb/CSS/InvalidationSet.h>
#include <LibWeb/DOM/AccessibilityTreeNode.h>
#include <LibWeb/DOM/EventTarget.h>
#include <LibWeb/DOM/NodeType.h>
#include <LibWeb/DOM/Slottable.h>
#include <LibWeb/HTML/XMLSerializer.h>
#include <LibWeb/TraversalDecision.h>
#include <LibWeb/TreeNode.h>
#include <LibWeb/WebIDL/ExceptionOr.h>

namespace Web::DOM {

enum class NameOrDescription {
    Name,
    Description
};

struct GetRootNodeOptions {
    bool composed { false };
};

enum class FragmentSerializationMode {
    Inner,
    Outer,
};

enum class IsDescendant {
    No,
    Yes,
};

enum class ShouldComputeRole {
    No,
    Yes,
};

#define ENUMERATE_STYLE_INVALIDATION_REASONS(X)     \
    X(AdoptedStyleSheetsList)                       \
    X(CSSFontLoaded)                                \
    X(CSSImportRule)                                \
    X(CSSStylePropertiesTextChange)                 \
    X(CustomElementStateChange)                     \
    X(DidLoseFocus)                                 \
    X(DidReceiveFocus)                              \
    X(EditingInsertion)                             \
    X(ElementAttributeChange)                       \
    X(ElementSetShadowRoot)                         \
    X(HTMLHyperlinkElementHrefChange)               \
    X(HTMLIFrameElementGeometryChange)              \
    X(HTMLInputElementSetChecked)                   \
    X(HTMLInputElementSetIsOpen)                    \
    X(HTMLObjectElementUpdateLayoutAndChildObjects) \
    X(HTMLOptionElementSelectedChange)              \
    X(HTMLSelectElementSetIsOpen)                   \
    X(MediaListSetMediaText)                        \
    X(MediaListAppendMedium)                        \
    X(MediaListDeleteMedium)                        \
    X(MediaQueryChangedMatchState)                  \
    X(NavigableSetViewportSize)                     \
    X(NodeInsertBefore)                             \
    X(NodeRemove)                                   \
    X(NodeSetTextContent)                           \
    X(Other)                                        \
    X(SetSelectorText)                              \
    X(SettingsChange)                               \
    X(StyleSheetDeleteRule)                         \
    X(StyleSheetInsertRule)                         \
    X(StyleSheetListAddSheet)                       \
    X(StyleSheetListRemoveSheet)

enum class StyleInvalidationReason {
#define __ENUMERATE_STYLE_INVALIDATION_REASON(reason) reason,
    ENUMERATE_STYLE_INVALIDATION_REASONS(__ENUMERATE_STYLE_INVALIDATION_REASON)
#undef __ENUMERATE_STYLE_INVALIDATION_REASON
};

#define ENUMERATE_SET_NEEDS_LAYOUT_REASONS(X)         \
    X(CharacterDataReplaceData)                       \
    X(FinalizeACrossDocumentNavigation)               \
    X(HTMLImageElementReactToChangesInTheEnvironment) \
    X(HTMLImageElementUpdateTheImageData)             \
    X(HTMLVideoElementSetVideoTrack)                  \
    X(KeyframeEffect)                                 \
    X(LayoutTreeUpdate)                               \
    X(NavigableSetViewportSize)                       \
    X(SVGImageElementFetchTheDocument)                \
    X(StyleChange)

enum class SetNeedsLayoutReason {
#define ENUMERATE_SET_NEEDS_LAYOUT_REASON(e) e,
    ENUMERATE_SET_NEEDS_LAYOUT_REASONS(ENUMERATE_SET_NEEDS_LAYOUT_REASON)
#undef ENUMERATE_SET_NEEDS_LAYOUT_REASON
};

[[nodiscard]] StringView to_string(SetNeedsLayoutReason);

class Node : public EventTarget
    , public TreeNode<Node> {
    WEB_PLATFORM_OBJECT(Node, EventTarget);

public:
    ParentNode* parent_or_shadow_host();
    ParentNode const* parent_or_shadow_host() const { return const_cast<Node*>(this)->parent_or_shadow_host(); }

    Element* parent_or_shadow_host_element();
    Element const* parent_or_shadow_host_element() const { return const_cast<Node*>(this)->parent_or_shadow_host_element(); }

    virtual ~Node();

    NodeType type() const { return m_type; }
    bool is_element() const { return type() == NodeType::ELEMENT_NODE; }
    bool is_text() const { return type() == NodeType::TEXT_NODE || type() == NodeType::CDATA_SECTION_NODE; }
    bool is_exclusive_text() const { return type() == NodeType::TEXT_NODE; }
    bool is_document() const { return type() == NodeType::DOCUMENT_NODE; }
    bool is_document_type() const { return type() == NodeType::DOCUMENT_TYPE_NODE; }
    bool is_comment() const { return type() == NodeType::COMMENT_NODE; }
    bool is_character_data() const { return first_is_one_of(type(), NodeType::TEXT_NODE, NodeType::COMMENT_NODE, NodeType::CDATA_SECTION_NODE, NodeType::PROCESSING_INSTRUCTION_NODE); }
    bool is_document_fragment() const { return type() == NodeType::DOCUMENT_FRAGMENT_NODE; }
    bool is_parent_node() const { return is_element() || is_document() || is_document_fragment(); }
    bool is_slottable() const { return is_element() || is_text() || is_cdata_section(); }
    bool is_attribute() const { return type() == NodeType::ATTRIBUTE_NODE; }
    bool is_cdata_section() const { return type() == NodeType::CDATA_SECTION_NODE; }
    virtual bool is_shadow_root() const { return false; }

    virtual bool requires_svg_container() const { return false; }
    virtual bool is_svg_container() const { return false; }
    virtual bool is_svg_element() const { return false; }
    virtual bool is_svg_graphics_element() const { return false; }
    virtual bool is_svg_script_element() const { return false; }
    virtual bool is_svg_style_element() const { return false; }
    virtual bool is_svg_svg_element() const { return false; }
    virtual bool is_svg_use_element() const { return false; }
    virtual bool is_svg_a_element() const { return false; }
    virtual bool is_svg_foreign_object_element() const { return false; }

    bool in_a_document_tree() const;

    // NOTE: This is intended for the JS bindings.
    u16 node_type() const { return (u16)m_type; }

    bool is_editable() const;
    bool is_editing_host() const;
    bool is_editable_or_editing_host() const { return is_editable() || is_editing_host(); }

    virtual bool is_dom_node() const final { return true; }
    virtual bool is_html_element() const { return false; }
    virtual bool is_html_html_element() const { return false; }
    virtual bool is_html_anchor_element() const { return false; }
    virtual bool is_html_area_element() const { return false; }
    virtual bool is_html_base_element() const { return false; }
    virtual bool is_html_body_element() const { return false; }
    virtual bool is_html_head_element() const { return false; }
    virtual bool is_html_input_element() const { return false; }
    virtual bool is_html_link_element() const { return false; }
    virtual bool is_html_media_element() const { return false; }
    virtual bool is_html_progress_element() const { return false; }
    virtual bool is_html_script_element() const { return false; }
    virtual bool is_html_style_element() const { return false; }
    virtual bool is_html_template_element() const { return false; }
    virtual bool is_html_table_element() const { return false; }
    virtual bool is_html_table_section_element() const { return false; }
    virtual bool is_html_table_row_element() const { return false; }
    virtual bool is_html_table_cell_element() const { return false; }
    virtual bool is_html_title_element() const { return false; }
    virtual bool is_html_br_element() const { return false; }
    virtual bool is_html_button_element() const { return false; }
    virtual bool is_html_slot_element() const { return false; }
    virtual bool is_html_embed_element() const { return false; }
    virtual bool is_html_object_element() const { return false; }
    virtual bool is_html_form_element() const { return false; }
    virtual bool is_html_image_element() const { return false; }
    virtual bool is_html_iframe_element() const { return false; }
    virtual bool is_html_frameset_element() const { return false; }
    virtual bool is_html_fieldset_element() const { return false; }
    virtual bool is_navigable_container() const { return false; }
    virtual bool is_lazy_loading() const { return false; }

    WebIDL::ExceptionOr<GC::Ref<Node>> pre_insert(GC::Ref<Node>, GC::Ptr<Node>);
    WebIDL::ExceptionOr<GC::Ref<Node>> pre_remove(GC::Ref<Node>);

    WebIDL::ExceptionOr<GC::Ref<Node>> append_child(GC::Ref<Node>);
    WebIDL::ExceptionOr<GC::Ref<Node>> remove_child(GC::Ref<Node>);

    void insert_before(GC::Ref<Node> node, GC::Ptr<Node> child, bool suppress_observers = false);
    void remove(bool suppress_observers = false);
    void remove_all_children(bool suppress_observers = false);

    enum DocumentPosition : u16 {
        DOCUMENT_POSITION_EQUAL = 0,
        DOCUMENT_POSITION_DISCONNECTED = 1,
        DOCUMENT_POSITION_PRECEDING = 2,
        DOCUMENT_POSITION_FOLLOWING = 4,
        DOCUMENT_POSITION_CONTAINS = 8,
        DOCUMENT_POSITION_CONTAINED_BY = 16,
        DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC = 32,
    };

    u16 compare_document_position(GC::Ptr<Node> other);

    WebIDL::ExceptionOr<GC::Ref<Node>> replace_child(GC::Ref<Node> node, GC::Ref<Node> child);

    WebIDL::ExceptionOr<GC::Ref<Node>> clone_node(Document* document = nullptr, bool subtree = false, Node* parent = nullptr) const;
    WebIDL::ExceptionOr<GC::Ref<Node>> clone_single_node(Document&) const;
    WebIDL::ExceptionOr<GC::Ref<Node>> clone_node_binding(bool subtree);

    // NOTE: This is intended for the JS bindings.
    bool has_child_nodes() const { return has_children(); }
    GC::Ref<NodeList> child_nodes();
    Vector<GC::Root<Node>> children_as_vector() const;

    virtual FlyString node_name() const = 0;

    String base_uri() const;

    virtual Optional<String> alternative_text() const;

    String descendant_text_content() const;
    Optional<String> text_content() const;
    void set_text_content(Optional<String> const&);

    WebIDL::ExceptionOr<void> normalize();

    Optional<String> node_value() const;
    void set_node_value(Optional<String> const&);

    GC::Ptr<HTML::Navigable> navigable() const;

    Document& document() { return *m_document; }
    Document const& document() const { return *m_document; }

    GC::Ptr<Document> owner_document() const;

    const HTML::HTMLAnchorElement* enclosing_link_element() const;
    const HTML::HTMLElement* enclosing_html_element() const;
    const HTML::HTMLElement* enclosing_html_element_with_attribute(FlyString const&) const;

    String child_text_content() const;

    Node& root();
    Node const& root() const
    {
        return const_cast<Node*>(this)->root();
    }

    Node& shadow_including_root();
    Node const& shadow_including_root() const
    {
        return const_cast<Node*>(this)->shadow_including_root();
    }

    bool is_connected() const;

    [[nodiscard]] bool is_browsing_context_connected() const;

    Node* parent_node() { return parent(); }
    Node const* parent_node() const { return parent(); }

    GC::Ptr<Element> parent_element();
    GC::Ptr<Element const> parent_element() const;

    virtual void inserted();
    virtual void post_connection();
    virtual void removed_from(Node* old_parent, Node& old_root);
    struct ChildrenChangedMetadata {
        enum class Type {
            Inserted,
            Removal,
            Mutation,
        };
        Type type {};
        GC::Ref<Node> node;
    };
    // FIXME: It would be good if we could always provide this metadata for use in optimizations.
    virtual void children_changed(ChildrenChangedMetadata const*) { }

    virtual void adopted_from(Document&) { }
    virtual WebIDL::ExceptionOr<void> cloned(Node&, bool) const { return {}; }

    Layout::Node const* layout_node() const { return m_layout_node; }
    Layout::Node* layout_node() { return m_layout_node; }

    Painting::PaintableBox const* paintable_box() const;
    Painting::PaintableBox* paintable_box();
    Painting::Paintable const* paintable() const;
    Painting::Paintable* paintable();

    void set_paintable(GC::Ptr<Painting::Paintable>);
    void clear_paintable();

    void set_layout_node(Badge<Layout::Node>, GC::Ref<Layout::Node>);
    void detach_layout_node(Badge<Layout::TreeBuilder>);

    virtual bool is_child_allowed(Node const&) const { return true; }

    [[nodiscard]] bool needs_layout_tree_update() const { return m_needs_layout_tree_update; }
    void set_needs_layout_tree_update(bool);

    [[nodiscard]] bool child_needs_layout_tree_update() const { return m_child_needs_layout_tree_update; }
    void set_child_needs_layout_tree_update(bool b) { m_child_needs_layout_tree_update = b; }

    bool needs_style_update() const { return m_needs_style_update; }
    void set_needs_style_update(bool);
    void set_needs_style_update_internal(bool) { m_needs_style_update = true; }

    bool needs_layout_update() const { return m_needs_layout_update; }
    void set_needs_layout_update(SetNeedsLayoutReason);
    void reset_needs_layout_update() { m_needs_layout_update = false; }

    bool child_needs_style_update() const { return m_child_needs_style_update; }
    void set_child_needs_style_update(bool b) { m_child_needs_style_update = b; }

    [[nodiscard]] bool entire_subtree_needs_style_update() const { return m_entire_subtree_needs_style_update; }
    void set_entire_subtree_needs_style_update(bool b) { m_entire_subtree_needs_style_update = b; }

    void invalidate_style(StyleInvalidationReason);
    struct StyleInvalidationOptions {
        bool invalidate_self { false };
        bool invalidate_elements_that_use_css_custom_properties { false };
    };
    void invalidate_style(StyleInvalidationReason, Vector<CSS::InvalidationSet::Property> const&, StyleInvalidationOptions);

    void set_document(Badge<Document>, Document&);
    void set_document(Badge<NamedNodeMap>, Document&);

    virtual EventTarget* get_parent(Event const&) override;

    template<typename T>
    bool fast_is() const = delete;

    WebIDL::ExceptionOr<void> ensure_pre_insertion_validity(GC::Ref<Node> node, GC::Ptr<Node> child) const;

    bool is_host_including_inclusive_ancestor_of(Node const&) const;

    bool is_scripting_enabled() const;
    bool is_scripting_disabled() const;

    bool contains(GC::Ptr<Node>) const;

    // Used for dumping the DOM Tree
    void serialize_tree_as_json(JsonObjectSerializer<StringBuilder>&) const;

    bool is_shadow_including_descendant_of(Node const&) const;
    bool is_shadow_including_inclusive_descendant_of(Node const&) const;
    bool is_shadow_including_ancestor_of(Node const&) const;
    bool is_shadow_including_inclusive_ancestor_of(Node const&) const;

    [[nodiscard]] UniqueNodeID unique_id() const { return m_unique_id; }
    static Node* from_unique_id(UniqueNodeID);

    WebIDL::ExceptionOr<String> serialize_fragment(HTML::RequireWellFormed, FragmentSerializationMode = FragmentSerializationMode::Inner) const;

    WebIDL::ExceptionOr<void> unsafely_set_html(Element&, StringView);

    void replace_all(GC::Ptr<Node>);
    void string_replace_all(String const&);

    bool is_same_node(Node const*) const;
    bool is_equal_node(Node const*) const;

    GC::Ref<Node> get_root_node(GetRootNodeOptions const& options = {});

    bool is_uninteresting_whitespace_node() const;

    String debug_description() const;

    size_t length() const;

    auto& registered_observer_list() { return m_registered_observer_list; }
    auto const& registered_observer_list() const { return m_registered_observer_list; }

    void add_registered_observer(RegisteredObserver&);

    void queue_mutation_record(FlyString const& type, Optional<FlyString> const& attribute_name, Optional<FlyString> const& attribute_namespace, Optional<String> const& old_value, Vector<GC::Root<Node>> added_nodes, Vector<GC::Root<Node>> removed_nodes, Node* previous_sibling, Node* next_sibling);

    // https://dom.spec.whatwg.org/#concept-shadow-including-inclusive-descendant
    template<typename Callback>
    TraversalDecision for_each_shadow_including_inclusive_descendant(Callback);

    // https://dom.spec.whatwg.org/#concept-shadow-including-descendant
    template<typename Callback>
    TraversalDecision for_each_shadow_including_descendant(Callback);

    Slottable as_slottable();

    size_t child_count() const
    {
        size_t count = 0;
        for (auto* child = first_child(); child; child = child->next_sibling())
            ++count;
        return count;
    }

    Node* child_at_index(int index)
    {
        int count = 0;
        for (auto* child = first_child(); child; child = child->next_sibling()) {
            if (count == index)
                return child;
            ++count;
        }
        return nullptr;
    }

    Node const* child_at_index(int index) const
    {
        return const_cast<Node*>(this)->child_at_index(index);
    }

    bool is_descendant_of(Node const&) const;
    bool is_inclusive_descendant_of(Node const&) const;

    bool is_following(Node const&) const;

    bool is_before(Node const& other) const
    {
        if (this == &other)
            return false;
        for (auto* node = this; node; node = node->next_in_pre_order()) {
            if (node == &other)
                return true;
        }
        return false;
    }

    // https://dom.spec.whatwg.org/#concept-tree-preceding (Object A is 'typename U' and Object B is 'this')
    template<typename U>
    bool has_preceding_node_of_type_in_tree_order() const
    {
        for (auto* node = previous_in_pre_order(); node; node = node->previous_in_pre_order()) {
            if (is<U>(node))
                return true;
        }
        return false;
    }

    // https://dom.spec.whatwg.org/#concept-tree-following (Object A is 'typename U' and Object B is 'this')
    template<typename U>
    bool has_following_node_of_type_in_tree_order() const
    {
        for (auto* node = next_in_pre_order(); node; node = node->next_in_pre_order()) {
            if (is<U>(node))
                return true;
        }
        return false;
    }

    template<typename Callback>
    void for_each_ancestor(Callback callback) const
    {
        return const_cast<Node*>(this)->for_each_ancestor(move(callback));
    }

    template<typename Callback>
    void for_each_ancestor(Callback callback)
    {
        for (auto* ancestor = parent(); ancestor; ancestor = ancestor->parent()) {
            if (callback(*ancestor) == IterationDecision::Break)
                break;
        }
    }

    template<typename Callback>
    void for_each_inclusive_ancestor(Callback callback) const
    {
        return const_cast<Node*>(this)->for_each_inclusive_ancestor(move(callback));
    }

    template<typename Callback>
    void for_each_inclusive_ancestor(Callback callback)
    {
        for (auto* ancestor = this; ancestor; ancestor = ancestor->parent()) {
            if (callback(*ancestor) == IterationDecision::Break)
                break;
        }
    }

    template<typename U, typename Callback>
    WebIDL::ExceptionOr<void> for_each_child_of_type_fallible(Callback callback)
    {
        for (auto* node = first_child(); node; node = node->next_sibling()) {
            if (auto* maybe_node_of_type = as_if<U>(node)) {
                if (TRY(callback(*maybe_node_of_type)) == IterationDecision::Break)
                    return {};
            }
        }
        return {};
    }

    template<typename U>
    bool has_child_of_type() const
    {
        return first_child_of_type<U>() != nullptr;
    }

    template<typename U>
    U const* shadow_including_first_ancestor_of_type() const
    {
        return const_cast<Node*>(this)->template shadow_including_first_ancestor_of_type<U>();
    }

    template<typename U>
    U* shadow_including_first_ancestor_of_type();

    bool is_parent_of(Node const& other) const
    {
        for (auto* child = first_child(); child; child = child->next_sibling()) {
            if (&other == child)
                return true;
        }
        return false;
    }

    ErrorOr<String> accessible_name(Document const&, ShouldComputeRole = ShouldComputeRole::Yes) const;
    ErrorOr<String> accessible_description(Document const&) const;

    Optional<String> locate_a_namespace(Optional<String> const& prefix) const;
    Optional<String> lookup_namespace_uri(Optional<String> prefix) const;
    Optional<String> lookup_prefix(Optional<String> namespace_) const;
    bool is_default_namespace(Optional<String> namespace_) const;

    bool is_inert() const;

    bool has_inclusive_ancestor_with_display_none();
    void play_or_cancel_animations_after_display_property_change();

protected:
    Node(JS::Realm&, Document&, NodeType);
    Node(Document&, NodeType);

    void set_document(Document&);

    virtual void visit_edges(Cell::Visitor&) override;
    virtual void finalize() override;

    GC::Ptr<Document> m_document;
    GC::Ptr<Layout::Node> m_layout_node;
    GC::Ptr<Painting::Paintable> m_paintable;
    NodeType m_type { NodeType::INVALID };
    bool m_needs_layout_tree_update { false };
    bool m_child_needs_layout_tree_update { false };

    bool m_needs_style_update { false };
    bool m_child_needs_style_update { false };
    bool m_entire_subtree_needs_style_update { false };

    bool m_needs_layout_update { false };

    UniqueNodeID m_unique_id;

    // https://dom.spec.whatwg.org/#registered-observer-list
    // "Nodes have a strong reference to registered observers in their registered observer list." https://dom.spec.whatwg.org/#garbage-collection
    OwnPtr<Vector<GC::Ref<RegisteredObserver>>> m_registered_observer_list;

    void build_accessibility_tree(AccessibilityTreeNode& parent);

    ErrorOr<String> name_or_description(NameOrDescription, Document const&, HashTable<UniqueNodeID>&, IsDescendant = IsDescendant::No, ShouldComputeRole = ShouldComputeRole::Yes) const;

private:
    void queue_tree_mutation_record(Vector<GC::Root<Node>> added_nodes, Vector<GC::Root<Node>> removed_nodes, Node* previous_sibling, Node* next_sibling);

    void insert_before_impl(GC::Ref<Node>, GC::Ptr<Node> child);
    void append_child_impl(GC::Ref<Node>);
    void remove_child_impl(GC::Ref<Node>);

    static Optional<StringView> first_valid_id(StringView, Document const&);

    GC::Ptr<NodeList> m_child_nodes;
};

}

template<>
inline bool JS::Object::fast_is<Web::DOM::Node>() const { return is_dom_node(); }