/*
 # ---------------------------------------------------------------------
 #
 # Copyright (c) CREATIS (Centre de Recherche en Acquisition et Traitement de l'Image
 #                        pour la SantÈ)
 # Authors : Eduardo Davila, Frederic Cervenansky, Claire Mouton
 # Previous Authors : Laurent Guigues, Jean-Pierre Roux
 # CreaTools website : www.creatis.insa-lyon.fr/site/fr/creatools_accueil
 #
 #  This software is governed by the CeCILL-B license under French law and
 #  abiding by the rules of distribution of free software. You can  use,
 #  modify and/ or redistribute the software under the terms of the CeCILL-B
 #  license as circulated by CEA, CNRS and INRIA at the following URL
 #  http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html
 #  or in the file LICENSE.txt.
 #
 #  As a counterpart to the access to the source code and  rights to copy,
 #  modify and redistribute granted by the license, users are provided only
 #  with a limited warranty  and the software's author,  the holder of the
 #  economic rights,  and the successive licensors  have only  limited
 #  liability.
 #
 #  The fact that you are presently reading this means that you have had
 #  knowledge of the CeCILL-B license and that you accept its terms.
 # ------------------------------------------------------------------------ */

#include <cstdlib>
#include <fstream>
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include "boost/filesystem.hpp"
#include "bbtkBBPInterpreter.h"

namespace bf = boost::filesystem;

typedef std::vector<std::vector<int> > Graph;

typedef std::set<std::string> Dependencies;
typedef std::vector<Dependencies> DependenciesVector;
typedef std::vector<std::string> BoxesVector;

std::vector<bf::path> getFileList(const std::string& path);

bool isCycle(const Graph& g);
bool checkCycle(const Graph& g, const int& i, std::vector<bool>& v);

void setPriorities(const Graph& g, std::vector<int>& p);
void setPriority(const Graph& g, const int i, std::vector<int>& p);

int main(int argc, char **argv)
{
  // Check arguments
  if (argc != 4)
  {
    std::cout << "usage : bbConfigurator <path_to_bbs> <package_name> <output_path>" << std::endl;
    return 1;
  }

  std::string path_bbs(argv[1]);
  std::string package_name(argv[2]);
  std::string path_out(argv[3]);
  
  // Get bbs files in path_bbs
  std::vector<bf::path> files = getFileList(path_bbs);
  if(files.size() == 0)
  {
    std::cout << "No files to check." << std::endl;

    // Write results to bbp file
    #ifdef WIN32
      std::string fname = path_out + "\\" + package_name + ".bbp";
    #else
      std::string fname = path_out + "/" + package_name + ".bbp";
    #endif

      std::ofstream out(fname.c_str());
      out << "#-----------------------------------------" << std::endl;
      out << "# Include script for bbtk package '" << package_name << "'" << std::endl;
      out << "# Automatically generated by bbpConfigurator" << std::endl;
      out << "#-----------------------------------------" << std::endl;
      out << "load "<< package_name << std::endl;
      out << "#-----------------------------------------" << std::endl;
      out << "package "<< package_name << std::endl;
      out << "#-----------------------------------------" << std::endl;
      out << "endpackage" << std::endl;
      out << "#-- EOF ----------------------------------" << std::endl;

      out.close();


    return 0;
  }


  // Order files by dependencies
  //  Get DependenciesVector and Box Names
  DependenciesVector deps;
  BoxesVector boxs;


  for (int i = 0; i < (int)files.size(); ++i) {
    bbtk::BBPInterpreter::Pointer I = bbtk::BBPInterpreter::New();
    I->InterpretFile(files[i].string());
    boxs.push_back( ((bbtk::BBPInterpreter*)(I.get()))->boxName );
    deps.push_back( ((bbtk::BBPInterpreter*)(I.get()))->dependencies );

    //print box name and dependencies
//    std::cout << ((bbtk::BBPInterpreter*)(I.get()))->boxName << ": ";
//    for(
//      Dependencies::iterator it = ((bbtk::BBPInterpreter*)(I.get()))->dependencies.begin();
//      it != ((bbtk::BBPInterpreter*)(I.get()))->dependencies.end();
//      it++) {
//      std::cout << *it << ", ";
//    }
//    std::cout << std::endl;

  }

  // Only keep dependencies from package
  Dependencies boxNamesSet(boxs.begin(), boxs.end());

  //std::cout << "after: " << std::endl;
  for (DependenciesVector::iterator it = deps.begin(); it != deps.end(); it++) {
    BoxesVector tmp;
    std::set_intersection(it->begin(), it->end(), boxNamesSet.begin(), boxNamesSet.end(),std::back_inserter(tmp));
    Dependencies tmp1(tmp.begin(),tmp.end());
    it->swap( tmp1 );
    //print clean dependencies
//    for(
//      Dependencies::iterator it1 = it->begin();
//      it1 != it->end();
//      it1++) {
//      std::cout << *it1 << ", ";
//    }
//    std::cout << std::endl;

  }

  // Create dependencies graph
  std::vector<std::vector<int> > g(boxs.size(), std::vector<int>());
  std::map<std::string, int> idxs;


  for (int i = 0; i < (int)boxs.size(); ++i)
  {
    idxs[boxs[i]] = i;
  }

  int boxit = 0;
  for (DependenciesVector::iterator dit = deps.begin(); dit != deps.end(); dit++, boxit++)
  {
    for (Dependencies::iterator ddit = dit->begin(); ddit != dit->end(); ddit++)
    {
      g[boxit].push_back(idxs[*ddit]);
    }
  }

  // Check there are no cycles in graph
  if(isCycle(g))
  {
    std::cout << "there are dependency cycles, please check your scripts." << std::endl;
    return 2;
  }
  else
  {
    std::cout << "no cycles, we keep going." << std::endl;
    std::vector<int> priorities(boxs.size(), -1);
    setPriorities(g, priorities);
//    for (int i = 0; i < (int)priorities.size(); i++)
//    {
//      std::cout << priorities[i] << " ";
//    }
//    std::cout << std::endl;

    // Write results to bbp file
  #ifdef WIN32
    std::string fname = path_out + "\\" + package_name + ".bbp";
  #else
    std::string fname = path_out + "/" + package_name + ".bbp";
  #endif

    std::ofstream out(fname.c_str());
    out << "#-----------------------------------------" << std::endl;
    out << "# Include script for bbtk package '" << package_name << "'" << std::endl;
    out << "# Automatically generated by bbpConfigurator" << std::endl;
    out << "#-----------------------------------------" << std::endl;
    out << "load "<< package_name << std::endl;
    out << "#-----------------------------------------" << std::endl;
    out << "package "<< package_name << std::endl;
    out << "#-----------------------------------------" << std::endl;

    //each bbs file ordered.
    //include [package_name]/boxes/[file_bbs]
    //#-----------------------------------------

  //  for (int i = 0; i < (int)files.size(); ++i) {
  //    out << "include " << package_name << "/boxes/" << files[i].filename().string() << std::endl;
  //    out << "#-----------------------------------------" << std::endl;
  //  }

    // find max priority level
    int mx_priority = 0;
    for (int i = 0; i < (int)priorities.size(); i++)
      mx_priority = std::max(mx_priority, priorities[i]);

    // for each priority level print scripts in that level.
    for (int i = 0; i <= mx_priority; i++)
    {
      for (int j = 0; j < (int)priorities.size(); j++)
      {
        if(priorities[j] == i)
        {
          out << "include " << package_name << "/boxes/" << files[j].filename().string() << std::endl;
          out << "#-----------------------------------------" << std::endl;
        }
      }
    }
    out << "endpackage" << std::endl;
    out << "#-- EOF ----------------------------------" << std::endl;
  
    out.close();
  }
  return 0;
}
//==========================================================================

// extract of the tarjan's algorithm for strongly connected components
bool isCycle(const Graph& g)
{
  for (int it = 0; it < (int)g.size(); ++it) {
    std::vector<bool> visited (g.size(), false);
    if (checkCycle(g, it, visited))
    {
      //std::cout << "At " << it << std::endl;
      return true;
    }
  }
  return false;
}

//==========================================================================

// dfs search to check cycles.
bool checkCycle(const Graph& g, const int& i, std::vector<bool>& v)
{

  v[i] = true;
  for(int dit = 0; dit < (int)g[i].size(); dit++)
  {
    int d = g[i][dit];
    if(d < 0 || d >= (int)g.size() || v[d])
    {
      //std::cout << "Checking " << i << " dependency " << dit << "=" << d << std::endl;
      return true;
    }
    if(checkCycle(g,d,v))
      return true;
  }
  v[i] = false;
  return false;
}

//==========================================================================

// find precedence in graph. 0 are the boxes that have no deps, 1 boxes that have deps from 0 or less, 2 boxes that have deps from 1 or less, etc.
void setPriorities(const Graph& g, std::vector<int>& p)
{
  for(int i = 0; i < (int)g.size(); i++)
  {
    if(p[i] == -1)
      setPriority(g, i, p);
  }
}

//==========================================================================

// dfs search to find dependencies
void setPriority(const Graph& g, const int i, std::vector<int>& p)
{
  int pi = -1;
  for(int j = 0; j < (int)g[i].size(); j++)
  {
    setPriority(g, g[i][j], p);
    pi = std::max(pi, p[g[i][j]]);
  }
  p[i]=pi+1;
}

//==========================================================================

std::vector<bf::path> getFileList(const std::string& path)
{
  std::vector<bf::path> files;

  bf::path pth(path.c_str());
  if(bf::exists(pth) && bf::is_directory(pth))
  {
    bf::directory_iterator end_itr;
    for(bf::directory_iterator itr(pth); itr != end_itr; ++itr)
    {
      if(!is_directory(itr->status()))
      {
        std::string nm(itr->path().filename().string());
        if(nm.substr(nm.size()-4) == ".bbs")
        {
          //std::cout << itr->path().filename().string() << std::endl;
          files.push_back(itr->path());
        }
      }
    }
  }
  else
  {
    std::cout<< "the path to the bbs's should be a folder and not a file.";
    return files;
  }

  // Order files by name
  for (int i = 0; i < (int)files.size()-1; ++i) {
    for (int j = i+1; j < (int)files.size(); ++j) {
      if(files[j].filename().string() < files[i].filename().string())
      {
        bf::path tmp = files[i];
        files[i] = files[j];
        files[j] = tmp;
      }
    }
  }

  return files;
}