#ifndef CLICK_LINKTABLE_HH
#define CLICK_LINKTABLE_HH
#include <click/ipaddress.hh>
#include <click/glue.hh>
#include <click/timer.hh>
#include <click/element.hh>
#include <click/bighashmap.hh>
#include <click/hashmap.hh>
#include "path.hh"
CLICK_DECLS

/*
 * =c
 * LinkTable(IP Address, [STALE timeout])
 * =s Wifi
 * Keeps a Link state database and calculates Weighted Shortest Path 
 * for other elements
 * =d
 * Runs dijkstra's algorithm occasionally.
 * =a ARPTable
 *
 */
class IPPair {
public:

  IPAddress _to;
  IPAddress _from;

  IPPair() : _to(), _from() { }

  IPPair(IPAddress from, IPAddress to) {
      _to = to;
      _from = from;
  }

  bool contains(IPAddress foo) {
    return ((foo == _to) || (foo == _from));
  }
  bool other(IPAddress foo) { return ((_to == foo) ? _from : _to); }


  inline bool
  operator==(IPPair other)
  {
    return (other._to == _to && other._from == _from);
  }

};

inline unsigned
hashcode(IPPair p) 
{
return hashcode(p._to) + hashcode(p._from);
}





class LinkTable: public Element{
public: 

  /* generic click-mandated stuff*/
  LinkTable();
  ~LinkTable();
  void add_handlers();
  const char* class_name() const { return "LinkTable"; }
  int initialize(ErrorHandler *);
  void run_timer(Timer *);
  int configure(Vector<String> &conf, ErrorHandler *errh);
  void take_state(Element *, ErrorHandler *);
  void *cast(const char *n);
  /* read/write handlers */
  String print_routes(bool, bool);
  String print_links();
  String print_hosts();

  static int static_update_link(const String &arg, Element *e,
				void *, ErrorHandler *errh);
  void clear();

  /* other public functions */
  String route_to_string(Path p);
  bool update_link(IPAddress from, IPAddress to, 
		   uint32_t seq, uint32_t age, uint32_t metric);
  bool update_both_links(IPAddress a, IPAddress b, 
			 uint32_t seq, uint32_t age, uint32_t metric) {
    if (update_link(a,b,seq,age, metric)) {
      return update_link(b,a,seq,age, metric);
    }
    return false;
  }

  uint32_t get_link_metric(IPAddress from, IPAddress to);
  uint32_t get_link_seq(IPAddress from, IPAddress to);
  uint32_t get_link_age(IPAddress from, IPAddress to);
  bool valid_route(Vector<IPAddress> route);
  unsigned get_route_metric(Vector<IPAddress> route);
  Vector<IPAddress> get_neighbors(IPAddress ip);
  void dijkstra(bool);
  void clear_stale();
  Vector<IPAddress> best_route(IPAddress dst, bool from_me);

  Vector< Vector<IPAddress> > top_n_routes(IPAddress dst, int n);
  uint32_t get_host_metric_to_me(IPAddress s);
  uint32_t get_host_metric_from_me(IPAddress s);
  Vector<IPAddress> get_hosts();

  class Link {
  public:
    IPAddress _from;
    IPAddress _to;
    uint32_t _seq;
    uint32_t _metric;
    Link() : _from(), _to(), _seq(0), _metric(0) { }
    Link(IPAddress from, IPAddress to, uint32_t seq, uint32_t metric) {
      _from = from;
      _to = to;
      _seq = seq;
      _metric = metric;
    }
  };

  Link random_link();


  typedef HashMap<IPAddress, IPAddress> IPTable;
  typedef IPTable::const_iterator IPIter;
  
  IPTable _blacklist;
  
  struct timeval dijkstra_time;
private: 
  class LinkInfo {
  public:
    IPAddress _from;
    IPAddress _to;
    unsigned _metric;
    uint32_t _seq;
    uint32_t _age;
    struct timeval _last_updated;
    LinkInfo() { 
      _from = IPAddress(); 
      _to = IPAddress(); 
      _metric = 0; 
      _seq = 0;
      _age = 0;
      _last_updated.tv_sec = 0; 
    }
    
    LinkInfo(IPAddress from, IPAddress to, 
	     uint32_t seq, uint32_t age, unsigned metric) { 
      _from = from;
      _to = to;
      _metric = metric;
      _seq = seq;
      _age = age;
      click_gettimeofday(&_last_updated);
    }

    LinkInfo(const LinkInfo &p) : 
      _from(p._from), _to(p._to), 
      _metric(p._metric), _seq(p._seq), 
      _age(p._age),
      _last_updated(p._last_updated) 
    { }

    uint32_t age() {
      struct timeval now;
      click_gettimeofday(&now);
      return _age + (now.tv_sec - _last_updated.tv_sec);
    }
    void update(uint32_t seq, uint32_t age, unsigned metric) {
      if (seq <= _seq) {
	return;
      }
      _metric = metric; 
      _seq = seq;
      _age = age;
      click_gettimeofday(&_last_updated); 
    }
    
  };

  class HostInfo {
  public:
    IPAddress _ip;
    uint32_t _metric_from_me;
    uint32_t _metric_to_me;
    
    IPAddress _prev_from_me;
    IPAddress _prev_to_me;

    bool _marked_from_me;
    bool _marked_to_me;

    HostInfo(IPAddress p) { 
      _ip = p; 
      _metric_from_me = 0; 
      _metric_to_me = 0; 
      _prev_from_me = IPAddress(); 
      _prev_to_me = IPAddress(); 
      _marked_from_me = false; 
      _marked_to_me = false; 
    }
    HostInfo() { 
      HostInfo(IPAddress());
    }

    HostInfo(const HostInfo &p) : 
      _ip(p._ip), 
      _metric_from_me(p._metric_from_me), 
      _metric_to_me(p._metric_to_me), 
      _prev_from_me(p._prev_from_me), 
      _prev_to_me(p._prev_to_me), 
      _marked_from_me(p._marked_from_me), 
      _marked_to_me(p._marked_to_me)
    { }
    
    void clear(bool from_me) { 
      if (from_me ) {
	_prev_from_me = IPAddress(); 
	_metric_from_me = 0; 
	_marked_from_me = false;
      } else {
	_prev_to_me = IPAddress(); 
	_metric_to_me = 0; 
	_marked_to_me = false;
      }
    }

  };

  typedef HashMap<IPAddress, HostInfo> HTable;
  typedef HTable::const_iterator HTIter;
  

  typedef HashMap<IPPair, LinkInfo> LTable;
  typedef LTable::const_iterator LTIter;

  HTable _hosts;
  LTable _links;


  IPAddress _ip;
  struct timeval _stale_timeout;
  Timer _timer;
};
  


CLICK_ENDDECLS
#endif /* CLICK_LINKTABLE_HH */