/*++
Copyright (c) Microsoft Corporation
Licensed under the MIT license.

Module Name:
- AttrRowIterator.hpp

Abstract:
- iterator for ATTR_ROW to walk the TextAttributes of the run
- read only iterator

Author(s):
- Austin Diviness (AustDi) 04-Jun-2018
--*/


#pragma once

#include "TextAttribute.hpp"
#include "TextAttributeRun.hpp"

class ATTR_ROW;

class AttrRowIterator final
{
public:
    using iterator_category = std::bidirectional_iterator_tag;
    using value_type = TextAttribute;
    using difference_type = std::ptrdiff_t;
    using pointer = TextAttribute*;
    using reference = TextAttribute&;

    static AttrRowIterator CreateEndIterator(const ATTR_ROW* const attrRow);

    AttrRowIterator(const ATTR_ROW* const attrRow);

    operator bool() const noexcept;

    bool operator==(const AttrRowIterator& it) const;
    bool operator!=(const AttrRowIterator& it) const;

    AttrRowIterator& operator++();
    AttrRowIterator operator++(int);

    AttrRowIterator& operator+=(const ptrdiff_t& movement);
    AttrRowIterator& operator-=(const ptrdiff_t& movement);

    AttrRowIterator& operator--();
    AttrRowIterator operator--(int);

    const TextAttribute* operator->() const;
    const TextAttribute& operator*() const;

private:
    std::vector<TextAttributeRun>::const_iterator _run;
    const ATTR_ROW* _pAttrRow;
    size_t _currentAttributeIndex; // index of TextAttribute within the current TextAttributeRun
    
    void _increment(size_t count);
    void _decrement(size_t count);
    void _setToEnd();
};