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

#include <IMP/internal/directories.h>
#include <IMP/exception.h>
#include <fstream>
#ifdef _MSC_VER
#include <windows.h>
#endif

#ifdef IMP_USE_BOOST_LIBS
#include <boost/filesystem/path.hpp>
#endif

#include <cstdlib>

IMP_BEGIN_INTERNAL_NAMESPACE

namespace {
  std::string backup_search_path;

#ifdef IMP_USE_BOOST_LIBS
  std::string to_string(boost::filesystem::path path) {
#if BOOST_VERSION >= 103400
    return path.file_string();
#else
    return path.native_file_string();
#endif
  }
#endif

  std::string path_cat(std::string base, std::string module,
                       std::string file_name) {
#ifdef IMP_USE_BOOST_LIBS
    boost::filesystem::path basep(base);
#endif
    if (module != "kernel") {
#ifdef IMP_USE_BOOST_LIBS
      return to_string(basep/module/file_name);
#else
      return base+"/"+module+"/"+file_name;
#endif
    } else {
#ifdef IMP_USE_BOOST_LIBS
      return to_string(basep/file_name);
#else
      return base+"/"+file_name;
#endif
    }
  }
  std::string get_path(std::string envvar, std::string buildpath,
                       std::string w32path, 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;
#ifdef _MSC_VER
      // Use registry value if available, since installed copies of IMP on
      // Windows are relocatable
      const char *imp_install_key = "Software\\Microsoft\\Windows\\"
                                    "CurrentVersion\\Uninstall\\IMP-1.0";
      HKEY key;
      if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, imp_install_key, 0,
                       KEY_ALL_ACCESS, &key) == ERROR_SUCCESS) {
        DWORD keytype, keylen;
        if (RegQueryValueEx(key, "InstallDirectory", NULL,
                            &keytype, NULL, &keylen) == ERROR_SUCCESS) {
          char *installdir = new char[keylen];
          if (RegQueryValueEx(key, "InstallDirectory", NULL,
                              &keytype, (LPBYTE)installdir,
                              &keylen) == ERROR_SUCCESS) {
            base = std::string(installdir) + "/" + w32path;
          }
          delete[] installdir;
        }
      }
      RegCloseKey(key);
#endif
    }
    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", "data",
                             IMP_DATA_DIRECTORY,
                             module, file_name);
  {
    std::ifstream in(path.c_str());
    if (in) {
      return path;
    }
  }
#ifdef IMP_USE_BOOST_LIBS
  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",
                             "doc/examples",
                             IMP_EXAMPLE_DIRECTORY,
                             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;
}

IMP_END_INTERNAL_NAMESPACE