//Name, Matrikelnummer
#include <LEDA/graphics/graphwin.h>

using namespace leda;
using namespace std;

GRAPH<int,int> G;
node s = nil;

void run_bellmann_ford(GraphWin& gw)
{
  // ...
}

void init_edge(GraphWin& gw, edge e)
{
  G[e] = rand_int(-49,49);
  gw.set_slider_value(e,G[e]/100.0+0.5);
}

void init_handler(GraphWin& gw)
{
  edge e;
  

  forall_edges(e,G)
    {
      init_edge(gw,e);
    }
  if(s==nil){
    s = G.choose_node();

    gw.set_label_type(s,user_label);
    gw.set_user_label(s,"s");
    gw.set_shape(s,square_node);
    gw.set_width(s,20);
    gw.set_color(s,blue);
  }
  else if(gw.get_user_label(s)!="s"){
    s = G.choose_node();

    gw.set_label_type(s,user_label);
    gw.set_user_label(s,"s");
    gw.set_shape(s,square_node);
    gw.set_width(s,20);
    gw.set_color(s,blue);
  }
 
  run_bellmann_ford(gw);
}

void new_edge_handler(GraphWin& gw, edge e)
{
  init_edge(gw,e);
  run_bellmann_ford(gw);
}

void new_node_handler(GraphWin& gw, node v)
{
  if(G.number_of_nodes() == 1)
    {
      s=v;
      gw.set_label_type(s,user_label);
      gw.set_user_label(s,"s");
      gw.set_shape(s,square_node);
      gw.set_width(s,20);
      gw.set_color(s,blue);
    }

  run_bellmann_ford(gw);
}

bool pre_del_node_handler(GraphWin& gw, node v)
{
 
  if(G.number_of_nodes() > 1)
    {
      if(v == s)
	{
	  s = G.choose_node();

	  while(s == v)
	    s = G.choose_node();

	  gw.set_label_type(s,user_label);
	  gw.set_user_label(s,"s");
	  gw.set_shape(s,square_node);
	  gw.set_width(s,20);
	  gw.set_color(s,blue);
	    
	}
    }

  else if(G.number_of_nodes() == 1){
    s=nil;

  }


  return true;
}

void del_node_handler(GraphWin& gw)
{
  run_bellmann_ford(gw);
}

void edge_slider_handler(GraphWin& gw, edge e, double f)
{
  G[e] = static_cast<int>(100*f-50);
  run_bellmann_ford(gw);
}

int main()
{
  GraphWin gw(G);

  gw.set_node_label_type(data_label);
  gw.set_edge_label_type(data_label);
  gw.set_directed(true);
  gw.set_node_width(20);

  gw.set_init_graph_handler(init_handler);
  gw.set_new_edge_handler(new_edge_handler);
  gw.set_new_node_handler(new_node_handler);
  gw.set_del_edge_handler(run_bellmann_ford);
  gw.set_del_node_handler(pre_del_node_handler);
  gw.set_del_node_handler(del_node_handler);

  gw.set_edge_slider_handler(edge_slider_handler);

  gw.display();
  gw.edit();
}