/***********************************************************************/ 
/* Course:          Computer Science 402a                              */ 
/* Assignment:      Assignment 3                                       */ 
/* Instructor:      Mark Giesbrecht                                    */ 
/* Submitted by:    Dan Fraser                                         */ 
/* Student Number:  001219229                                          */ 
/* Due Date:        Wednesday, February 16                             */ 
/***********************************************************************/ 
/* nameserver.cc -- Implementation of the nameserver.                  */              
/***********************************************************************/

#define RETURN_SIZE 1024
#define TEMPINT_SIZE 50
#define HOST_SIZE 80

#include "nameserver.h"

#include "StreamSocket.h"

#include <stdio.h>
#include "HostInfo.h"
#include <strings.h>
#include <vector>
#include <map>
#include <algorithm>

vector<HostInfo> Registry;
vector<CLIENT *> Nameservers;
map<string, int> Names;
map<string, int> Names_cache;

static bool first_run = 1;


int register_gossip(rpc_hostInfo data);
int unregister_gossip(rpc_hostInfo data);

int lazy_init();

/************************************************************************
Function Name:     	register

Input Parameters:  	data - input string with name, ip, port separated by spaces

Output Parameters:  	returns result string and UID

Description:  registers user, adds to local database, returns a UID.
************************************************************************/
int *register_1_svc(rpc_hostInfo *data, struct svc_req *req) {
  static int result;
  string Name;
  lazy_init();
  printf("starting registration\n");
  printf("name: %s, ip: %s, port: %d\n",data->name, data->host, data->port);
  Name = data->name;
  HostInfo hostinfo(data->name, data->host, data->port);
  if (data->uid > 0) {
    printf("forcing uid as %d\n",data->uid);
    hostinfo.setUID() = data->uid;
  }
  if (Names_cache.find(Name) != Names_cache.end()) {
    if (find(Registry.begin(), Registry.end(),Names_cache[Name]) == Registry.end()) {
      hostinfo.setUID() = Names_cache[Name];
    } else {
      cout << "warning: attempt to have two active users with same name" << endl;
    }
  }
  int UID = hostinfo.getUID();
  Registry.insert(Registry.end(), hostinfo);
  Names[Name] = UID;
  Names_cache[Name] = UID;
  result = UID;
  cout << "register: "<< result << endl;
  if (data->gossip == 0) {
    data->uid = UID;
    if (register_gossip(*data) < 0) {
      result = -1;
    }  
  }
  return &result;
}

/************************************************************************
Function Name:     	unregister

Input Parameters:  	data - string containing uid to delete

Output Parameters:  	result string

Description:  removes user from local databases
************************************************************************/
int* unregister_1_svc(rpc_hostInfo *data, struct svc_req *req) {
  int UID = data->uid;
  static int result;
  lazy_init();
  vector<HostInfo>::iterator p = find(Registry.begin(), Registry.end(),UID);
  if ( p == Registry.end() ) {
    cout << "can't find " << UID <<" to unregister" << endl;
    result = -1;
    return &result;
  } else {
    Names.erase(p->getRealname());
    Registry.erase(p);
    cout << UID << " erased." << endl;
    result = UID;
    if (data->gossip == 0) {
      if (unregister_gossip(*data) < 0) {
	result = -1;
      }
    } 
    return &result;
  }
}

/************************************************************************
Function Name:     	find

Input Parameters:  	data - string with uid of user to find		      

Output Parameters:  	result string with hostname and portnumber.

Description:  looks up user in database, returns hostname and port.
************************************************************************/
rpc_hostInfo *find_1_svc(int *data, struct svc_req *req) {
  static rpc_hostInfo hi;
  int UID = *data;
  lazy_init();
  vector<HostInfo>::iterator p = find(Registry.begin(), Registry.end(),UID);
  if ( p == Registry.end() ) {
    cout << "can't find " << UID << endl;
    hi.name = strdup("ERROR"); 
    return &hi;  
  } else {
    cout << "found user" << endl;
    hi.name = strdup("OK"); 
    hi.host = strdup(p->getHostname().c_str());
    hi.port = p->getPort();
    return &hi;
  }
}

/************************************************************************
Function Name:     	findname

Input Parameters:  	data - string containing name to find

Output Parameters:  	result string with uid

Description:  returns result string with uid of found user.
************************************************************************/
int *findname_1_svc(char **data, struct svc_req *req) {
  static int result;
  lazy_init();
  string Name = *data;
  cout << "trying to return uid for " << Name << "." << endl;
  int UID = Names[*data];
  cout <<" got " << UID << " from map." << endl;
  if ( UID <= 0 ) {
    cout << "can't find " << UID << endl;
    result = -1;
    return &result;
  } else {
    result = UID;
    return &result;
  }  
}


/************************************************************************
Function Name:     	lazy_init

Input Parameters:  	n/a

Output Parameters:  	n/a

Description:  reads nameserver configuration file, connects to other
	nameservers in network
************************************************************************/
int lazy_init() {
  FILE *fp;
  CLIENT *clnt;
  if (first_run) {
    first_run = 0;
    char hostname[HOST_SIZE];
    printf("running initialization\n");
    // do initialize stuff
    
    if ((fp = fopen("nameserver.dat", "r")) == NULL) {
      perror("data file open");
      exit(1);
    }
    do {
      hostname[0] = 0;
      fgets(hostname, sizeof(hostname), fp);
      hostname[strlen(hostname)-1] = 0;
      if (strlen(hostname)) {
	printf("found hostname: %s\n", hostname);
	clnt = clnt_create(hostname, NAMESERVER, DATE_VERS, "tcp");
	if (clnt <= 0) {
	  clnt_pcreateerror("connecting to other nameserver");
	  exit(1);
	}
	Nameservers.push_back(clnt);
      }
    } while (!feof(fp));
    return 1;
  }
  return 0;
}

/************************************************************************
Function Name:     	register_gossip

Input Parameters:  	rpc_hostdata structure

Output Parameters:  	n/a

Description:  connects to all known nameservers and sends them
	the information requried to register the person in question.
	The remote server should then complete the registration.
************************************************************************/
int register_gossip(rpc_hostInfo data) {
  int *result;
  printf("register gossip\n");
  data.gossip = 1;
  for (vector<CLIENT *>::iterator i = Nameservers.begin();
       i != Nameservers.end(); i++) {
    result = register_1(&data, *i);
  } 
  return 0;
}

/************************************************************************
Function Name:     	unregister_gossip

Input Parameters:  	rpc_hostdata structure

Output Parameters:  	n/a

Description:  connects to all known nameservers and sends them
	the information requried to unregister the person in question.
	The remote server should then complete the unregistration.
************************************************************************/
int unregister_gossip(rpc_hostInfo data) {
  int *result;
  printf("unregsiter gossip\n");
  data.gossip = 1;
  for (vector<CLIENT *>::iterator i = Nameservers.begin();
       i != Nameservers.end(); i++) {
    result = unregister_1(&data, *i);
  }
  return 0;
}