#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <vector>
#include <string>
#include <iostream>
#include <fstream>

#include <mpi.h>

using namespace std;

/*
These two variables sets the command to launch in each sub-directory and the arguments required. The name of the root directory of the datasets is given as an argument when starting the MPIlauncher.
const string commandToLaunch("/HA/sources/begou/SOURCES/MES-PROJETS/MPILAUNCHER/appli.exe");
const string("-l -info");
*/

/*
getListOfDir(string rep, vector<string> &files)

Gets the list of tjhe subdirectories in the directory rep and returns them
in a vector array of strings. Directories ";" and ".." are removed from the
vector array.
*/
int getListOfDir(string rep, vector<string> &files)
{
  DIR *dir;
  struct dirent *ent;
  int count;

  count=0;
  dir = opendir (rep.c_str());
  if (dir != NULL) {
    /* search for the files within directory */
    while ((ent = readdir (dir)) != NULL) 
      if (ent->d_type == DT_DIR) {
        if (strcmp(ent->d_name,".") * strcmp(ent->d_name,"..")) {
           count++;
           files.push_back(string(ent->d_name));
	   }
        }
    closedir (dir);
    } 
  else {
    cerr<<"Directory "<<rep.c_str()<<" not found"<<endl;
    }
   return count;
}
/* getListOfCommand(string rep, vector<string> &files)
Gets the list of commands in the ascii file fich. One command per line (no wrap)
in this first version.
*/
int getListOfCommand(const string & fich, vector<string> &commands)
{
  int count;
  string line;
  
  count=0;
  commands.clear();

  std::ifstream infile (fich.c_str(), std::ios_base::in);
  while (getline(infile, line, '\n'))
  {
    // remove all trailing blanks
    while(line.size() >0 && isspace(line[line.size() -1])) line.erase(line.size() -1);
    
    // no empty line
    if (line.size() > 0) {
       commands.push_back (line);
       count++;
       }
  }
  return count;
}



/*
Main program
*/
int main(int argc, char **argv)
{
vector<string> files = vector<string>();
string rep; //root directory where to find subdirectories
int rank, size, nbdir, stride;
int nbcmd;
/*
These two variables sets the command to launch in each sub-directory and the arguments required. The name of the root directory of the datasets is given as an argument when starting the MPIlauncher.
*/
string commandToLaunch;
string arguments;
string commandfile;

string finalCommand; //command to execute

MPI_Init (&argc, &argv);                      /* starts MPI */
MPI_Comm_rank (MPI_COMM_WORLD, &rank);        /* get current process id */
MPI_Comm_size (MPI_COMM_WORLD, &size);        /* get number of processes */

if (argc<3){
   cout<<"USAGE:"<<endl;
   cout<<argv[0]<<" root_directory  command [arguments]"<<endl;
   cout<<argv[0]<<" -f  command_file"<<endl;
  }
else {   
   if (strcmp(argv[1],"-f")==0) {
     /* processing a command file now. */
     commandfile=argv[2];
     nbcmd=getListOfCommand(commandfile, files);
//     if (rank==0){
//       cout<<"Command file is "<<commandfile<<endl;
//       for (unsigned int i = 0;i < nbcmd;i++)
//          cout<<"["<<files[i]<<"]"<<endl;  
//       }


     //Number of commands should divide by number of cpus
//     if (nbcmd%size != 0) {
//        if(rank ==0)
//        cerr <<nbcmd<<" command(s) to process in "<<commandfile
//	     <<" cannot fit on "<<size<<" processe(s)"
//	     <<endl<<"FAILED"<<endl;
//        }
//     else {
//         execute the command
        int reste;
        stride=nbcmd/size;
        for (unsigned int i = 0;i < stride;i++) {
          cerr<<"Process "<<rank<<" execute "<<files[stride*rank+i] <<endl;
          system(files[stride*rank+i].c_str() );
	  }
        //remaining command lines
        reste=nbcmd-stride*size;
        if(rank>0 && rank<=reste){
	     cerr<<"Process "<<rank<<" execute "<<files[nbcmd-rank] <<endl;
             system(files[nbcmd-rank].c_str() );
	     }
//	}
      }
   else {
     /* processing a list of dir now */
     rep=string(argv[1]);
     commandToLaunch=string(argv[2]);
     for (int i=3; i<argc; i++) (arguments+=argv[i])+=" ";
        
     nbdir=getListOfDir(rep, files);
     
     //Number of dir should divide by number of cpus
     if (nbdir%size != 0) {
        if(rank ==0)
        cerr <<nbdir<<" dataset(s) to process cannot fit on "<<size<<" processes"<<endl<<"FAILED"<<endl;
        }
     else {
        // execute the command
        stride=nbdir/size;
        for (unsigned int i = 0;i < stride;i++) {
          string finalCommand("cd ");
  	  finalCommand +=rep;
  	  finalCommand +="/";
          finalCommand += files[stride*rank+i];
          finalCommand +=";";
          finalCommand +=commandToLaunch;
          finalCommand +=" ";
          finalCommand +=arguments;
          //cout<<"On "<<rank<<" execute "<<finalCommand<<endl;
          system(finalCommand.c_str() );
	  }
        }
      }  
   }   
MPI_Finalize();

return 0;
}