/****************************************************************************
 * Copyright (C) 2011 EPAM Systems
 * 
 * This file is part of Indigo toolkit.
 * 
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 3 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 * 
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 ***************************************************************************/

#include "graph/graph_fast_access.h"

#include "graph/graph.h"

using namespace indigo;

void GraphFastAccess::setGraph (Graph &g)
{
   _g = &g;

   _vertices.clear();

   _vertices_nei.resize(g.vertexEnd());
   _vertices_nei.fffill();

   _nei_vertices_data.clear();
   _nei_edges_data.clear();
}

int* GraphFastAccess::prepareVertices (int &count)
{
   count = _vertices.size();
   if (count != 0)
      return _vertices.ptr();

   for (int v = _g->vertexBegin(); v != _g->vertexEnd(); v = _g->vertexNext(v))
      _vertices.push(v);

   count = _vertices.size();
   return _vertices.ptr();
}

int GraphFastAccess::getVertex (int idx)
{
   return _vertices.ptr()[idx];
}

int GraphFastAccess::vertexCount ()
{
   return _vertices.size();
}

// Prepare both nei vertices and edges list. Runs faster then 
// preparing them one by one.
void GraphFastAccess::prepareVertexNeiVerticesAndEdges (int v)
{
   if (_vertices_nei[v].v_begin != -1 && _vertices_nei[v].e_begin != -1)
      return;

   _vertices_nei[v].v_begin = _nei_vertices_data.size();
   _vertices_nei[v].e_begin = _nei_edges_data.size();

   const Vertex &vertex = _g->getVertex(v);
   for (int i = vertex.neiBegin(); i != vertex.neiEnd(); i = vertex.neiNext(i))
   {
      _nei_vertices_data.push(vertex.neiVertex(i));
      _nei_edges_data.push(vertex.neiEdge(i));
   }

   _vertices_nei[v].v_count = _nei_vertices_data.size() - _vertices_nei[v].v_begin;
   _vertices_nei[v].e_count = _nei_edges_data.size() - _vertices_nei[v].e_begin;
}

// Returns nei vertices and nei edges for specified vertex
// Numeration is coherent
int* GraphFastAccess::getVertexNeiVertices (int v, int &count)
{
   int offset = prepareVertexNeiVertices(v, count);
   return _nei_vertices_data.ptr() + offset;
}

int* GraphFastAccess::getVertexNeiEdges (int v, int &count)
{
   if (_vertices_nei[v].e_begin == -1)
      prepareVertexNeiVerticesAndEdges(v);

   count = _vertices_nei[v].e_count;
   return _nei_edges_data.ptr() + _vertices_nei[v].e_begin;
}

int GraphFastAccess::findEdgeIndex (int v1, int v2)
{
   int count;
   int *vertices = getVertexNeiVertices(v1, count);
   int *edges = getVertexNeiEdges(v1, count);
   for (int i = 0; i < count; i++)
      if (vertices[i] == v2)
         return edges[i];
   return -1;
}

void GraphFastAccess::prepareEdges ()
{
   _edges.clear_resize(_g->edgeEnd());
   for (int e = _g->edgeBegin(); e != _g->edgeEnd(); e = _g->edgeNext(e))
      _edges[e] = _g->getEdge(e);
}

const Edge& GraphFastAccess::getEdge (int e)
{
   return _edges[e];
}

const Edge* GraphFastAccess::getEdges ()
{
   return _edges.ptr();
}


int GraphFastAccess::prepareVertexNeiVertices (int v, int &count)
{
   getVertexNeiEdges(v, count);
   return _vertices_nei.ptr()[v].v_begin;
}

int GraphFastAccess::getVertexNeiVertiex (int v_id, int index)
{
   return _nei_vertices_data.ptr()[v_id + index];
}