/*
 * Copyright (c) 2022 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ECMASCRIPT_MEM_VISITOR_H
#define ECMASCRIPT_MEM_VISITOR_H

#include <functional>

#include <ecmascript/mem/slots.h>
#include <ecmascript/mem/tagged_object.h>

namespace panda::ecmascript {
enum class Root {
    ROOT_FRAME,
    ROOT_HANDLE,
    ROOT_VM,
    ROOT_STRING,
    ROOT_INTERNAL_CALL_PARAMS,
};

enum class VisitObjectArea {
    NORMAL,
    NATIVE_POINTER,
    IN_OBJECT,
    RAW_DATA
};

enum class VisitType : size_t { SEMI_GC_VISIT, OLD_GC_VISIT, SNAPSHOT_VISIT, ALL_VISIT };

using RootVisitor = std::function<void(Root type, ObjectSlot p)>;
using RootRangeVisitor = std::function<void(Root type, ObjectSlot start, ObjectSlot end)>;
using RootBaseAndDerivedVisitor =
    std::function<void(Root type, ObjectSlot base, ObjectSlot derived, uintptr_t baseOldObject)>;
using EcmaObjectRangeVisitor = std::function<void(TaggedObject *root, ObjectSlot start, ObjectSlot end,
                                                  VisitObjectArea area)>;
using WeakRootVisitor = std::function<TaggedObject *(TaggedObject *p)>;

template <VisitType visitType, size_t size>
class PrimitiveObjectBodyIterator {
public:
    static inline void IterateBody(TaggedObject *root, const EcmaObjectRangeVisitor& visitor)
    {
        if (visitType == VisitType::ALL_VISIT) {
            size_t hclassEnd = sizeof(JSTaggedType);
            visitor(root, ObjectSlot(ToUintPtr(root)),
                ObjectSlot(ToUintPtr(root) + hclassEnd), VisitObjectArea::NORMAL);
            if (size > hclassEnd) {
                visitor(root, ObjectSlot(ToUintPtr(root) + hclassEnd),
                    ObjectSlot(ToUintPtr(root) + size), VisitObjectArea::RAW_DATA);
            }
        }
    }
};

template <VisitType visitType, size_t startOffset, size_t endOffset, size_t size>
class ObjectBodyIterator {
public:
    template <VisitObjectArea area, bool visitHClass>
    static inline void IterateBody(TaggedObject *root, const EcmaObjectRangeVisitor& visitor, size_t startSize)
    {
        if (visitType == VisitType::ALL_VISIT) {
            if (visitHClass) {
                IterateHClass(root, visitor);
            }
            IterateBefore(root, visitor, startSize);
        }
        visitor(root, ObjectSlot(ToUintPtr(root) + startOffset),
            ObjectSlot(ToUintPtr(root) + endOffset), area);
        if (visitType == VisitType::ALL_VISIT) {
            IterateAfter(root, visitor);
        }
    }

    static inline void IterateRefBody(TaggedObject *root, const EcmaObjectRangeVisitor& visitor)
    {
        IterateBody<VisitObjectArea::NORMAL, true>(root, visitor, sizeof(JSTaggedType));
    }

    static inline void IterateNativeBody(TaggedObject *root, const EcmaObjectRangeVisitor& visitor)
    {
        IterateBody<VisitObjectArea::NATIVE_POINTER, true>(root, visitor, sizeof(JSTaggedType));
    }

    static inline void IterateRefBody(TaggedObject *root, const EcmaObjectRangeVisitor& visitor, size_t parentSize)
    {
        IterateBody<VisitObjectArea::NORMAL, false>(root, visitor, parentSize);
    }

    static inline void IterateHClass(TaggedObject *root, const EcmaObjectRangeVisitor& visitor)
    {
        size_t hclassEnd = sizeof(JSTaggedType);
        visitor(root, ObjectSlot(ToUintPtr(root)),
            ObjectSlot(ToUintPtr(root) + hclassEnd), VisitObjectArea::NORMAL);
    }

    static inline void IterateBefore(TaggedObject *root, const EcmaObjectRangeVisitor& visitor, size_t startSize)
    {
        if (startOffset > startSize) {
            IteratorRange(root, visitor, startSize, startOffset);
        }
    }

    static inline void IterateAfter(TaggedObject *root, const EcmaObjectRangeVisitor& visitor)
    {
        if (size > endOffset) {
            IteratorRange(root, visitor, endOffset, size);
        }
    }

    static inline void IteratorRange(TaggedObject *root, const EcmaObjectRangeVisitor& visitor,
        size_t start, size_t end)
    {
        visitor(root, ObjectSlot(ToUintPtr(root) + start),
                ObjectSlot(ToUintPtr(root) + end), VisitObjectArea::RAW_DATA);
    }
};

template <VisitType visitType, size_t startOffset>
class ArrayBodyIterator {
public:
    static inline void IterateBody(TaggedObject *root, const EcmaObjectRangeVisitor& visitor,
        size_t refLength, size_t length)
    {
        if (visitType == VisitType::ALL_VISIT) {
            IterateBefore(root, visitor);
        }
        if (LIKELY(refLength != 0)) {
            size_t endOffset = startOffset + refLength * JSTaggedValue::TaggedTypeSize();
            visitor(root, ObjectSlot(ToUintPtr(root) + startOffset),
                ObjectSlot(ToUintPtr(root) + endOffset), VisitObjectArea::NORMAL);
        }
        if (visitType == VisitType::ALL_VISIT) {
            IterateAfter(root, visitor, refLength, length);
        }
    }

    static inline void IterateBefore(TaggedObject *root, const EcmaObjectRangeVisitor& visitor)
    {
        size_t hclassEnd = sizeof(JSTaggedType);
        ASSERT(startOffset > hclassEnd);
        visitor(root, ObjectSlot(ToUintPtr(root)), ObjectSlot(ToUintPtr(root) + hclassEnd), VisitObjectArea::NORMAL);
        IteratorRange(root, visitor, hclassEnd, startOffset);
    }

    static inline void IterateAfter(TaggedObject *root, const EcmaObjectRangeVisitor& visitor,
        size_t refLength, size_t length)
    {
        if (length > refLength) {
            size_t endOffset = startOffset + refLength * JSTaggedValue::TaggedTypeSize();
            size_t size = startOffset + length * JSTaggedValue::TaggedTypeSize();
            IteratorRange(root, visitor, endOffset, size);
        }
    }

    static inline void IteratorRange(TaggedObject *root, const EcmaObjectRangeVisitor& visitor,
        size_t start, size_t end)
    {
        visitor(root, ObjectSlot(ToUintPtr(root) + start),
                ObjectSlot(ToUintPtr(root) + end), VisitObjectArea::RAW_DATA);
    }
};
}  // namespace panda::ecmascript
#endif  // ECMASCRIPT_MEM_VISITOR_H