/*
 * Copyright (C) 2025 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.
 * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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
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 */

#pragma once

#include <wtf/Platform.h>
#if PLATFORM(COCOA)

#include <WebCore/AXAnnouncementTypes.h>
#include <WebCore/AXCoreObject.h>
#include <WebCore/AttributedString.h>
#include <wtf/HashMap.h>
#include <wtf/text/WTFString.h>

namespace WebCore {

class AccessibilityObject;
class AXObjectCache;

class AXLiveRegionManager {
    WTF_MAKE_NONCOPYABLE(AXLiveRegionManager);
    WTF_MAKE_TZONE_ALLOCATED(AXLiveRegionManager);
public:
    explicit AXLiveRegionManager(AXObjectCache&);
    ~AXLiveRegionManager() = default;

    void registerLiveRegion(AccessibilityObject&, bool = false);
    void unregisterLiveRegion(AXID axID) { m_liveRegions.remove(axID); }

    void handleLiveRegionChange(AccessibilityObject&, AnnouncementContents = AnnouncementContents::Changes);

    // Testing-only: number of times a live region snapshot has been (re)computed. Used to verify
    // that redundant changes to the same region within a run loop iteration are coalesced.
    unsigned snapshotBuildCount() const { return m_snapshotBuildCount; }
    void resetSnapshotBuildCount() { m_snapshotBuildCount = 0; }
private:
    struct LiveRegionDiff {
        Vector<LiveRegionObject> added;
        Vector<LiveRegionObject> removed;
        Vector<LiveRegionObject> changed;
    };

    LiveRegionSnapshot buildLiveRegionSnapshot(AccessibilityObject&) const;
    bool shouldIncludeInSnapshot(AccessibilityObject&) const;
    void postAnnouncementForChange(AccessibilityObject&, const LiveRegionSnapshot&, const LiveRegionSnapshot&);
    LiveRegionDiff computeChanges(const Vector<LiveRegionObject>&, const Vector<LiveRegionObject>&) const;
    AttributedString computeAnnouncement(const LiveRegionSnapshot&, const LiveRegionDiff&) const;

    CheckedRef<AXObjectCache> m_cache;
    HashMap<AXID, LiveRegionSnapshot> m_liveRegions;
    mutable unsigned m_snapshotBuildCount { 0 };
};

} // namespace WebCore

#endif // PLATFORM(COCOA)
