// Copyright Epic Games, Inc. All Rights Reserved.

/*=============================================================================
PropertyIterrator.h: TPropertyIterator implementation.
=============================================================================*/
#pragma once

#include "UObject/Field.h"

/**
 * Iterates over all structs and their properties
 */
template <class T>
class TPropertyIterator
{
private:
    /** The object being searched for the specified field */
    const UStruct* Struct;
    /** The current location in the list of fields being iterated */
    FField* Field;
    TObjectIterator<UStruct> ClassIterator;

public:
    TPropertyIterator()
        : Struct(nullptr), Field(nullptr)
    {
        if (ClassIterator)
        {
            Struct = *ClassIterator;
            Field  = Struct->ChildProperties;

            if (!Field || !Field->IsA<T>())
            {
                IterateToNext();
            }
        }
    }

    /** conversion to "bool" returning true if the iterator is valid. */
    FORCEINLINE explicit operator bool() const
    {
        return Field != nullptr;
    }
    /** inverse of the "bool" operator */
    FORCEINLINE bool operator!() const
    {
        return !(bool)*this;
    }

    inline friend bool operator==(const TPropertyIterator<T>& Lhs, const TPropertyIterator<T>& Rhs) { return Lhs.Field == Rhs.Field; }
    inline friend bool operator!=(const TPropertyIterator<T>& Lhs, const TPropertyIterator<T>& Rhs) { return Lhs.Field != Rhs.Field; }

    inline void operator++()
    {
        checkSlow(Field);
        IterateToNext();
    }
    inline T* operator*()
    {
        checkSlow(Field);
        return (T*)Field;
    }
    inline T* operator->()
    {
        checkSlow(Field);
        return (T*)Field;
    }
    inline const UStruct* GetStruct()
    {
        return Struct;
    }

protected:
    inline void IterateToNext()
    {
        FField* NewField = Field;
        do
        {
            if (NewField)
            {
                NewField = NewField->Next;
            }
            if (!NewField && ClassIterator)
            {
                ++ClassIterator;
                if (ClassIterator)
                {
                    Struct   = *ClassIterator;
                    NewField = Struct->ChildProperties;
                }
                else
                {
                    NewField = nullptr;
                }
            }
        } while (ClassIterator && (!NewField || !NewField->IsA<T>()));
        Field = NewField;
    }
};