// ==========================================================================
//                 SeqAn - The Library for Sequence Analysis
// ==========================================================================
// Copyright (c) 2006-2026, Knut Reinert, FU Berlin
// All rights reserved.
//
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//
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// ==========================================================================

#ifndef SEQAN_HEADER_GRAPH_ITERATOR_EDGE_H
#define SEQAN_HEADER_GRAPH_ITERATOR_EDGE_H

namespace seqan2
{
//////////////////////////////////////////////////////////////////////////////
// Graph EdgeIterator
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

/*!
 * @class EdgeIterator
 * @extends Iter
 * @headerfile <seqan/graph_types.h>
 * @brief Edge iterator for @link Graph @endlink.
 *
 * @signature Iterator<TGraph, EdgeIterator>::Type;
 * @signature template <typename TGraph, typename TSpec>
 *            class Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> >;
 *
 * @tparam TGraph The graph to iterate the edges of.
 *
 * The first signature is the signature of the corresponding @link ContainerConcept#Iterator @endlink metafunction call.
 * The second call is the internal definition of the type.  You should always get this type using the metafunction call
 * from the first signature.
 *
 *
 * @fn EdgeIterator::EdgeIterator
 * @brief Constructor.
 *
 * @signature Iter::Iter();
 * @signature Iter::Iter(iter);
 * @signature Iter::Iter(graph);
 *
 * @param[in] iter  Other EdgeIterator to copy from.
 * @param[in] graph The @link Graph @endlink to iterate edges of.
 */

template<typename TGraph, typename TSpec>
class Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >
{
public:
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor_;
    typedef typename Iterator<TGraph, VertexIterator>::Type TVertexIterator_;
    typedef typename Iterator<TGraph, OutEdgeIterator>::Type TOutEdgeIterator_;
    TVertexIterator_ data_vertex_it;
    TOutEdgeIterator_ data_edge_it;
    TVertexDescriptor_ data_first_slot;


    Iter() : data_vertex_it(), data_edge_it(), data_first_slot()
    {}

    Iter(TGraph const& _graph) :
        data_vertex_it(_graph),
        data_first_slot()
    {
        if (numVertices(_graph) != 0)
            data_edge_it = TOutEdgeIterator_(_graph, getIdLowerBound(_getVertexIdManager(_graph)));
        else
            data_edge_it = TOutEdgeIterator_();

        while((atEnd(data_edge_it)) && (!atEnd(data_vertex_it)))
        {
                goNext(data_vertex_it);
                typedef typename Iterator<TGraph, OutEdgeIterator>::Type TOutEdgeIterator_;
                if(!atEnd(data_vertex_it))
                    data_edge_it = TOutEdgeIterator_(hostGraph(*this), value(data_vertex_it));
        }
        data_first_slot = value(data_vertex_it);
    }

    Iter(Iter const& _iter) :
        data_vertex_it(_iter.data_vertex_it),
        data_edge_it(_iter.data_edge_it),
        data_first_slot(_iter.data_first_slot)
    {
    }

    Iter const&    operator = (Iter const & _other) {
        if (this == &_other) return *this;
        data_vertex_it = _other.data_vertex_it;
        data_edge_it = _other.data_edge_it;
        data_first_slot = _other.data_first_slot;
        return *this;
    }
//____________________________________________________________________________
};

//////////////////////////////////////////////////////////////////////////////
// Graph InternalEdgeIterator - Metafunctions
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph>
struct Iterator<TGraph, EdgeIterator>
{
    typedef Iter<TGraph, GraphIterator<InternalEdgeIterator<EdgeIterator> > > Type;
};

template<typename TGraph>
struct Iterator<TGraph const, EdgeIterator>
{
    typedef Iter<TGraph const, GraphIterator<InternalEdgeIterator<EdgeIterator> > > Type;
};

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TIteratorSpec>
struct Value<Iter<TGraph, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef typename Value<Iter<TGraph, GraphIterator<InternalOutEdgeIterator<TIteratorSpec> > > >::Type Type;
};

template<typename TGraph, typename TIteratorSpec>
struct Value<Iter<TGraph const, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef typename Value<Iter<TGraph const, GraphIterator<InternalOutEdgeIterator<TIteratorSpec> > > >::Type Type;
};

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TIteratorSpec>
struct Reference<Iter<TGraph, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef typename Reference<Iter<TGraph, GraphIterator<InternalOutEdgeIterator<TIteratorSpec> > > >::Type Type;
};

template<typename TGraph, typename TIteratorSpec>
struct Reference<Iter<TGraph const, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef typename Reference<Iter<TGraph const, GraphIterator<InternalOutEdgeIterator<TIteratorSpec> > > >::Type Type;
};

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TIteratorSpec>
struct GetValue<Iter<TGraph, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef typename GetValue<Iter<TGraph, GraphIterator<InternalOutEdgeIterator<TIteratorSpec> > > >::Type Type;
};

template<typename TGraph, typename TIteratorSpec>
struct GetValue<Iter<TGraph const, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef typename GetValue<Iter<TGraph const, GraphIterator<InternalOutEdgeIterator<TIteratorSpec> > > >::Type Type;
};

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TIteratorSpec>
struct Spec<Iter<TGraph, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef TIteratorSpec Type;
};

template<typename TGraph, typename TIteratorSpec>
struct Spec<Iter<TGraph const, GraphIterator<InternalEdgeIterator<TIteratorSpec> > > >
{
    typedef TIteratorSpec Type;
};

//////////////////////////////////////////////////////////////////////////////
// Graph InternalEdgeIterator - Functions
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline typename GetValue<Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > > >::Type
getValue(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return getValue(it.data_edge_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline typename Reference<Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > > >::Type
value(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return value(it.data_edge_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline typename Reference<Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > > >::Type
operator * (Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return value(it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline typename Host<Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > > >::Type const&
hostGraph(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return hostGraph(it.data_vertex_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline bool
atBegin(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return ((it.data_first_slot == getValue(it.data_vertex_it)) &&
            atBegin(it.data_edge_it));
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline void
goBegin(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    typedef typename Iterator<TGraph, OutEdgeIterator>::Type TOutEdgeIterator;
    goBegin(it.data_vertex_it);
    while (it.data_first_slot != getValue(it.data_vertex_it)) ++it.data_vertex_it;
    it.data_edge_it = TOutEdgeIterator(hostGraph(it), getValue(it.data_vertex_it));
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline bool
atEnd(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return atEnd(it.data_vertex_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline void
goEnd(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    goEnd(it.data_edge_it);
    goEnd(it.data_vertex_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline void
_goNextInternal(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    if (!atEnd(it)) {
        goNext(it.data_edge_it);
        if(!atEnd(it.data_edge_it)) return;
        else {
            while ((atEnd(it.data_edge_it)) && (!atEnd(it.data_vertex_it))) {
                goNext(it.data_vertex_it);
                if ((atEnd(it.data_vertex_it)) ||
                    (!idInUse(_getVertexIdManager(hostGraph(it)), getValue(it.data_vertex_it)))) continue;
                typedef typename Iterator<TGraph, OutEdgeIterator>::Type TOutEdgeIterator;
                it.data_edge_it = TOutEdgeIterator(hostGraph(it), getValue(it.data_vertex_it));
            }
        }
    }
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline void
goNext(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    _goNextInternal(it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TGraphSpec, typename TSpec>
inline void
goNext(Iter<Graph<Undirected<TCargo, TGraphSpec> >, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    typedef Graph<Undirected<TCargo, TGraphSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    _goNextInternal(it);
    TVertexDescriptor sourceV = sourceVertex(it.data_edge_it);
    while((!atEnd(it)) && (targetVertex(hostGraph(it), getValue(it.data_edge_it)) == sourceV)) {
        _goNextInternal(it);
        sourceV = sourceVertex(it.data_edge_it);
    }
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >&
operator ++(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    goNext(it);
    return it;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >
operator ++(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it, int)
{
    Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > > ret = it;
    goNext(it);
    return ret;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline void
_goPreviousInternal(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    if (!atBegin(it)) {
        if ((atEnd(it)) ||
            (atBegin(it.data_edge_it)))
        {
            --it.data_vertex_it;
            typedef typename Iterator<TGraph, OutEdgeIterator>::Type TOutEdgeIterator;
            it.data_edge_it = TOutEdgeIterator(hostGraph(it), getValue(it.data_vertex_it));
            while((!atBegin(it.data_vertex_it)) &&
                    (atEnd(it.data_edge_it))) {
                --it.data_vertex_it;
                typedef typename Iterator<TGraph, OutEdgeIterator>::Type TOutEdgeIterator;
                it.data_edge_it = TOutEdgeIterator(hostGraph(it), getValue(it.data_vertex_it));
            }
            goEnd(it.data_edge_it);
        }
        --it.data_edge_it;
    }
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline void
goPrevious(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    _goPreviousInternal(it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TGraphSpec, typename TSpec>
inline void
goPrevious(Iter<Graph<Undirected<TCargo, TGraphSpec> >, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    typedef Graph<Undirected<TCargo, TGraphSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    _goPreviousInternal(it);
    TVertexDescriptor sourceV = sourceVertex(it.data_edge_it);
    while((!atBegin(it)) && (targetVertex(hostGraph(it), getValue(it.data_edge_it)) == sourceV)) {
        _goPreviousInternal(it);
        sourceV = sourceVertex(it.data_edge_it);
    }
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >&
operator --(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    goPrevious(it);
    return it;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >
operator --(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it, int)
{
    Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > > ret = it;
    goPrevious(it);
    return ret;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline bool
operator ==(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it1,
            Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it2)
{
    return ((it1.data_vertex_it==it2.data_vertex_it) &&
            (it1.data_edge_it==it2.data_edge_it));
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline bool
operator !=(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it1,
            Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it2)
{
    return ((it1.data_vertex_it!=it2.data_vertex_it) ||
            (it1.data_edge_it!=it2.data_edge_it));
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline typename VertexDescriptor<TGraph>::Type
sourceVertex(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return sourceVertex(it.data_edge_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TGraph, typename TSpec>
inline typename VertexDescriptor<TGraph>::Type
targetVertex(Iter<TGraph, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return targetVertex(it.data_edge_it);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TAlphabet, typename TCargo, typename TGraphSpec, typename TSpec>
inline typename Alphabet<Graph<Automaton<TAlphabet, TCargo, TGraphSpec> > >::Type
label(Iter<Graph<Automaton<TAlphabet, TCargo, TGraphSpec> >, GraphIterator<InternalEdgeIterator<TSpec> > >& it)
{
    return label(it.data_edge_it);
}

//////////////////////////////////////////////////////////////////////////////

}// namespace seqan2

#endif //#ifndef SEQAN_HEADER_...
