/*
 * Copyright (C) 2022 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

#include "FilterEffect.h"
#include "FilterImageVector.h"
#include <wtf/HashMap.h>
#include <wtf/HashSet.h>

namespace WebCore {

class FilterEffect;
class FilterImage;

class FilterResults {
public:
    FilterResults() = default;

    FilterImage* effectResult(FilterEffect& effect) const
    {
        return m_results.get(effect);
    }

    void setEffectResult(FilterEffect& effect, const FilterImageVector& inputs, Ref<FilterImage>&& result)
    {
        m_results.set({ effect }, WTFMove(result));
        
        for (auto& input : inputs)
            m_resultReferences.add(input, FilterEffectSet()).iterator->value.add(effect);
    }

    void clearEffectResult(FilterEffect& effect)
    {
        auto iterator = m_results.find(effect);
        if (iterator == m_results.end())
            return;

        auto result = iterator->value;
        m_results.remove(iterator);

        for (auto& reference : m_resultReferences.get(result))
            clearEffectResult(reference);
        
        m_resultReferences.remove(result);
    }

private:
    using FilterEffectSet = HashSet<Ref<FilterEffect>>;
    HashMap<Ref<FilterEffect>, Ref<FilterImage>> m_results;
    // The value is a list of FilterEffects, whose FilterImages depend on the key FilterImage.
    HashMap<Ref<FilterImage>, FilterEffectSet> m_resultReferences;
};

} // namespace WebCore
