/**
 *  \file directories.cpp
 *  \brief Get directories used by IMP.
 *  \note @AUTOGEN@
 *
 *  Copyright 2007-2010 IMP Inventors. All rights reserved.
 *
 */

#include <IMP/internal/directories.h>
#include <IMP/exception.h>
#include <fstream>

#ifdef IMP_USE_BOOST_FILESYSTEM
#include <boost/filesystem/path.hpp>
#include <boost/filesystem/exception.hpp>
#include <boost/version.hpp>
#endif

#include <cstdlib>

IMP_BEGIN_INTERNAL_NAMESPACE

extern const char* imp_data_path;
extern const char* imp_example_path;

namespace {
/** Boost versions older than 1.35 cannot handle "hidden" paths,
    e.g. /etc/skel/.bashrc; see https://svn.boost.org/trac/boost/ticket/1378
 */
#if defined(IMP_USE_BOOST_FILESYSTEM) && BOOST_VERSION >= 103500
  std::string to_string(boost::filesystem::path path) {
    return path.file_string();
  }
#else
  const std::string& to_string(const std::string& s) {return s;}
#endif
}
std::string get_concatenated_path(std::string part0,
                                   std::string part1) {
#if defined(IMP_USE_BOOST_FILESYSTEM) && BOOST_VERSION >= 103500
  boost::filesystem::path b0(part0), b1(part1);
  return to_string(b0/b1);
#else
  return to_string(part0+"/"+part1);
#endif
}

namespace {
  std::string backup_search_path;

  std::string path_cat(std::string base, std::string module,
                       std::string file_name) {
    IMP_USAGE_CHECK(!file_name.empty() && file_name[0] != '/',
                    "File name should be relative to the IMP directory and"
                    << " non-empty, not " << file_name);
    if (module != "kernel") {
      return get_concatenated_path(base,
                                   get_concatenated_path(module, file_name));
    } else {
      return get_concatenated_path(base, file_name);
    }
  }

  std::string get_path(std::string envvar, std::string buildpath,
                       std::string def,
                       std::string module, std::string file_name) {
    char *env = getenv(envvar.c_str());
    std::string base;
    if (env) {
      base=std::string(env)+"/"+buildpath;
    } else {
      // Default to compiled-in value
      base=def;
    }
    return path_cat(base, module, file_name);
  }
}

void set_backup_data_path(std::string path) {
  // should check that it is a valid path
  backup_search_path=path;
}

std::string get_data_path(std::string module, std::string file_name)
{
  std::string path= get_path("IMP_BUILD_ROOT",
                             "build/data",
                             imp_data_path,
                             module, file_name);
  {
    std::ifstream in(path.c_str());
    if (in) {
      return path;
    }
  }
#if defined(IMP_USE_BOOST_FILESYSTEM) && BOOST_VERSION >= 103500
  if (!backup_search_path.empty()) {
    boost::filesystem::path path
      = boost::filesystem::path(backup_search_path)/file_name;
    std::ifstream in(path.native_file_string().c_str());
    if (in) return path.native_file_string();
  }
#endif
  IMP_THROW("Unable to find data file "
            << file_name << " at " << path
            << ". IMP is not installed or set up correctly.",
            IOException);
}
std::string get_example_path(std::string module, std::string file_name)
{
  std::string path= get_path("IMP_BUILD_ROOT", "build/doc/examples",
                             imp_example_path,
                             module, file_name);
  std::ifstream in(path.c_str());
  if (!in) {
    IMP_THROW("Unable to find example file "
              << file_name << " at " << path
              << ". IMP is not installed or set up correctly.",
              IOException);
  }
  return path;
}


std::string get_directory_path(std::string fileordirectory) {
#if defined(IMP_USE_BOOST_FILESYSTEM) && BOOST_VERSION >= 103500
  try {
    boost::filesystem::path fnp(fileordirectory);
    boost::filesystem::path dir=
#if BOOST_VERSION >= 103600
      fnp.remove_filename();
#else
      fnp.branch_path();
#endif
    return to_string(dir);
  } catch (boost::filesystem::filesystem_error e) {
    IMP_THROW("Error splitting file name \""
              << fileordirectory
              << "\" got " << e.what(), IOException);
  }
#else
  for (int i = fileordirectory.size()-1; i>=0; --i) {
    if (fileordirectory[i] == '/'
        || fileordirectory[i] == '\\') {
      return std::string(fileordirectory, 0, i);
    }
  }
  return std::string();
#endif
}

IMP_END_INTERNAL_NAMESPACE