/*
 * Copyright (C) 2019 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#if ENABLE(ACCESSIBILITY_ISOLATED_TREE)

#include "AccessibilityObjectInterface.h"
#include "PageIdentifier.h"
#include <pal/SessionID.h>
#include <wtf/HashMap.h>
#include <wtf/Lock.h>
#include <wtf/RefPtr.h>
#include <wtf/ThreadSafeRefCounted.h>

namespace WTF {
class TextStream;
}

namespace WebCore {

class AXIsolatedObject;
class AXObjectCache;
class Page;

using AXIsolatedTreeID = unsigned;

enum class AXPropertyName : uint16_t {
    ARIAControlsElements,
    ARIADetailsElements,
    DropEffects,
    ARIAErrorMessageElements,
    ARIAIsMultiline,
    ARIAFlowToElements,
    ARIALandmarkRoleDescription,
    ARIATreeItemContent,
    ARIATreeRows,
    ARIARoleAttribute,
    ARIAOwnsElements,
    AXColumnCount,
    AXColumnIndex,
    AXRowCount,
    AXRowIndex,
    AccessKey,
    AccessibilityButtonState,
    AccessibilityDescription,
    AccessibilityText,
    ActionVerb,
    AncestorFlags,
    AutoCompleteValue,
    BlockquoteLevel,
    BoundingBoxRect,
    BrailleLabel,
    BrailleRoleDescription,
    CanHaveSelectedChildren,
    CanSetExpandedAttribute,
    CanSetFocusAttribute,
    CanSetNumericValue,
    CanSetSelectedAttribute,
    CanSetSelectedChildren,
    CanSetTextRangeAttributes,
    CanSetValueAttribute,
    CanvasHasFallbackContent,
#if PLATFORM(MAC)
    CaretBrowsingEnabled,
#endif
    Cells,
    ClassList,
    ClickPoint,
    ColorValue,
    Columns,
    ColumnCount,
    ColumnHeader,
    ColumnHeaders,
    ColumnIndex,
    ColumnIndexRange,
    ComputedRoleString,
    Contents,
    CurrentState,
    CurrentValue,
    DatetimeAttributeValue,
    DecrementButton,
    Description,
    DisclosedByRow,
    DisclosedRows,
    DocumentEncoding,
    DocumentLinks,
    DocumentURI,
    EditableAncestor,
    ElementRect,
    EmbeddedImageDescription,
    EstimatedLoadingProgress,
    ExpandedTextValue,
    FileUploadButtonReturnsValueInTitle,
    FocusableAncestor,
    HasARIAValueNow,
    HasApplePDFAnnotationAttribute,
    HasBoldFont,
    HasHighlighting,
    HasItalicFont,
    HasPlainText,
    HasPopup,
    HasUnderline,
    HeaderContainer,
    HeadingLevel,
    HelpText,
    HierarchicalLevel,
    HighestEditableAncestor,
    HorizontalScrollBar,
    IdentifierAttribute,
    IncrementButton,
    InnerHTML,
    InvalidStatus,
    IsAccessibilityIgnored,
    IsActiveDescendantOfFocusedContainer,
    IsAnonymousMathOperator,
    IsGrabbed,
    IsARIATreeGridRow,
    IsAttachment,
    IsButton,
    IsBusy,
    IsChecked,
    IsCollapsed,
    IsColumnHeaderCell,
    IsControl,
    IsDataTable,
    IsDescriptionList,
    IsEnabled,
    IsExpanded,
    IsExposable,
    IsFieldset,
    IsFileUploadButton,
    IsFocused,
    IsGroup,
    IsImageMapLink,
    IsIncrementor,
    IsIndeterminate,
    IsInlineText,
    IsInputImage,
    IsInsideLiveRegion,
    IsHeading,
    IsHovered,
    IsKeyboardFocusable,
    IsLandmark,
    IsLink,
    IsLinked,
    IsList,
    IsListBox,
    IsLoaded,
    IsMathElement,
    IsMathFraction,
    IsMathFenced,
    IsMathSubscriptSuperscript,
    IsMathRow,
    IsMathUnderOver,
    IsMathRoot,
    IsMathSquareRoot,
    IsMathText,
    IsMathNumber,
    IsMathOperator,
    IsMathFenceOperator,
    IsMathSeparatorOperator,
    IsMathIdentifier,
    IsMathTable,
    IsMathTableRow,
    IsMathTableCell,
    IsMathMultiscript,
    IsMathToken,
    IsMathScriptObject,
    IsMediaTimeline,
    IsMenu,
    IsMenuBar,
    IsMenuButton,
    IsMenuItem,
    IsMenuList,
    IsMenuListOption,
    IsMenuListPopup,
    IsMenuRelated,
    IsMeter,
    IsMultiSelectable,
    IsOrderedList,
    IsOutput,
    IsPasswordField,
    IsPressed,
    IsProgressIndicator,
    IsRangeControl,
    IsRequired,
    IsRowHeaderCell,
    IsScrollbar,
    IsSearchField,
    IsSelected,
    IsSelectedOptionActive,
    IsShowingValidationMessage,
    IsSlider,
    IsStyleFormatGroup,
    IsTable,
    IsTableCell,
    IsTableColumn,
    IsTableRow,
    IsTextControl,
    IsTree,
    IsTreeItem,
    IsUnorderedList,
    IsUnvisited,
    IsValueAutofilled,
    IsValueAutofillAvailable,
    IsVisible,
    IsVisited,
    IsWidget,
    KeyShortcutsValue,
    Language,
    LayoutCount,
    LinkRelValue,
    LinkedUIElements,
    LiveRegionAtomic,
    LiveRegionRelevant,
    LiveRegionStatus,
    LocalizedActionVerb,
    MathFencedOpenString,
    MathFencedCloseString,
    MathLineThickness,
    MathPrescripts,
    MathPostscripts,
    MathRadicand,
    MathRootIndexObject,
    MathUnderObject,
    MathOverObject,
    MathNumeratorObject,
    MathDenominatorObject,
    MathBaseObject,
    MathSubscriptObject,
    MathSuperscriptObject,
    MaxValueForRange,
    MinValueForRange,
    NameAttribute,
    NextSibling,
    Orientation,
    OuterHTML,
    Path,
    PlaceholderValue,
    PressedIsPresent,
    PreviousSibling,
    PopupValue,
    PosInSet,
    PreventKeyboardDOMEventDispatch,
    ReadOnlyValue,
    RoleValue,
    RolePlatformString,
    RoleDescription,
    Rows,
    RowCount,
    RowHeaders,
    RowIndex,
    RowIndexRange,
    SelectedChildren,
    SelectedRadioButton,
    SelectedTabItem,
    SessionID,
    SetSize,
    SortDirection,
    SpeakAs,
    SpeechHint,
    StringValue,
    SubrolePlatformString,
    SupportsRowCountChange,
    SupportsDragging,
    SupportsDropping,
    SupportsARIAOwns,
    SupportsCheckedState,
    SupportsCurrent,
    SupportsDatetimeAttribute,
    SupportsExpanded,
    SupportsExpandedTextValue,
    SupportsLiveRegion,
    SupportsPath,
    SupportsPosInSet,
    SupportsPressAction,
    SupportsRangeValue,
    SupportsRequiredAttribute,
    SupportsSelectedRows,
    SupportsSetSize,
    TabChildren,
    TableLevel,
    TagName,
    TextLength,
    Title,
    TitleAttributeValue,
    TitleUIElement,
    URL,
    ValueAutofillButtonType,
    ValueDescription,
    ValueForRange,
    ValidationMessage,
    VerticalScrollBar,
    VisibleChildren,
    VisibleRows,
    WebArea,
};

using AXPropertyValueVariant = std::variant<std::nullptr_t, AXID, String, bool, int, unsigned, double, float, uint64_t, Color, URL, LayoutRect, FloatRect, PAL::SessionID, IntPoint, OptionSet<SpeakAs>, std::pair<unsigned, unsigned>, Vector<AccessibilityText>, Vector<AXID>, Vector<std::pair<AXID, AXID>>, Vector<String>, Path, OptionSet<AXAncestorFlag>>;
using AXPropertyMap = HashMap<AXPropertyName, AXPropertyValueVariant, IntHash<AXPropertyName>, WTF::StrongEnumHashTraits<AXPropertyName>>;

struct AXPropertyChange {
    AXID axID; // ID of the object whose properties changed.
    AXPropertyMap properties; // Changed properties.
};

class AXIsolatedTree : public ThreadSafeRefCounted<AXIsolatedTree> {
    WTF_MAKE_NONCOPYABLE(AXIsolatedTree); WTF_MAKE_FAST_ALLOCATED;
    friend WTF::TextStream& operator<<(WTF::TextStream&, AXIsolatedTree&);
public:
    static Ref<AXIsolatedTree> create(AXObjectCache*);
    virtual ~AXIsolatedTree();

    static void removeTreeForPageID(PageIdentifier);

    static RefPtr<AXIsolatedTree> treeForPageID(PageIdentifier);
    static RefPtr<AXIsolatedTree> treeForID(AXIsolatedTreeID);
    AXObjectCache* axObjectCache() const;

    RefPtr<AXIsolatedObject> rootNode();
    RefPtr<AXIsolatedObject> focusedNode();
    RefPtr<AXIsolatedObject> nodeForID(AXID) const;
    Vector<RefPtr<AXCoreObject>> objectsForIDs(const Vector<AXID>&) const;
    Vector<AXID> idsForObjects(const Vector<RefPtr<AXCoreObject>>&) const;

    struct NodeChange {
        Ref<AXIsolatedObject> isolatedObject;
#if PLATFORM(COCOA)
        RetainPtr<AccessibilityObjectWrapper> wrapper;
#elif USE(ATSPI)
        RefPtr<AccessibilityObjectWrapper> wrapper;
#endif
    };

    void generateSubtree(AXCoreObject&, AXCoreObject*, bool attachWrapper);
    void updateNode(AXCoreObject&);
    void updateNodeProperty(const AXCoreObject&, AXPropertyName);
    void updateSubtree(AXCoreObject&);
    void updateChildren(AXCoreObject&);

    // Removes the given node leaving all descendants alone.
    void removeNode(AXID);
    // Removes the given node and all its descendants.
    void removeSubtree(AXID);

    // Both setRootNodeID and setFocusedNodeID are called during the generation
    // of the IsolatedTree.
    // Focused node updates in AXObjectCache use setFocusNodeID.
    void setRootNode(AXIsolatedObject*) WTF_REQUIRES_LOCK(m_changeLogLock);
    void setFocusedNodeID(AXID);

    // Called on AX thread from WebAccessibilityObjectWrapper methods.
    // During layout tests, it is called on the main thread.
    void applyPendingChanges();

    AXIsolatedTreeID treeID() const { return m_treeID; }

private:
    AXIsolatedTree(AXObjectCache*);
    void clear();

    static Lock s_cacheLock;
    static HashMap<AXIsolatedTreeID, Ref<AXIsolatedTree>>& treeIDCache() WTF_REQUIRES_LOCK(s_cacheLock);
    static HashMap<PageIdentifier, Ref<AXIsolatedTree>>& treePageCache() WTF_REQUIRES_LOCK(s_cacheLock);

    // Called on main thread.
    NodeChange nodeChangeForObject(AXCoreObject&, AXID parentID, bool attachWrapper);
    void queueChanges(const NodeChange&, Vector<AXID>&& childrenIDs);
    Ref<AXIsolatedObject> createSubtree(AXCoreObject&, AXID parentID, bool attachWrapper);
    // Called on main thread to update both m_nodeMap and m_pendingChildrenUpdates.
    void updateChildrenIDs(AXID parentID, Vector<AXID>&& childrenIDs) WTF_REQUIRES_LOCK(m_changeLogLock);

    AXIsolatedTreeID m_treeID;
    AXObjectCache* m_axObjectCache { nullptr };
    bool m_usedOnAXThread { true };

    // Only accessed on main thread.
    HashMap<AXID, Vector<AXID>> m_nodeMap;
    // Only accessed on AX thread requesting data.
    HashMap<AXID, Ref<AXIsolatedObject>> m_readerThreadNodeMap;

    // Written to by main thread under lock, accessed and applied by AX thread.
    RefPtr<AXIsolatedObject> m_rootNode WTF_GUARDED_BY_LOCK(m_changeLogLock);
    Vector<NodeChange> m_pendingAppends WTF_GUARDED_BY_LOCK(m_changeLogLock); // Nodes to be added to the tree and platform-wrapped.
    Vector<AXPropertyChange> m_pendingPropertyChanges WTF_GUARDED_BY_LOCK(m_changeLogLock);
    Vector<AXID> m_pendingNodeRemovals WTF_GUARDED_BY_LOCK(m_changeLogLock); // Nodes to be removed from the tree.
    Vector<AXID> m_pendingSubtreeRemovals WTF_GUARDED_BY_LOCK(m_changeLogLock); // Nodes whose subtrees are to be removed from the tree.
    Vector<std::pair<AXID, Vector<AXID>>> m_pendingChildrenUpdates WTF_GUARDED_BY_LOCK(m_changeLogLock);
    AXID m_pendingFocusedNodeID WTF_GUARDED_BY_LOCK(m_changeLogLock);
    AXID m_focusedNodeID;
    Lock m_changeLogLock;

    bool m_creatingSubtree { false };
};

inline AXObjectCache* AXIsolatedTree::axObjectCache() const
{
    ASSERT(isMainThread());
    return m_axObjectCache;
}

} // namespace WebCore

#endif