// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/nix/xdg_util.h"

#include <string>

#include "base/base_paths.h"
#include "base/environment.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/path_service.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/third_party/xdg_user_dirs/xdg_user_dir_lookup.h"

namespace {

// The KDE session version environment variable introduced in KDE 4.
const char kKDESessionEnvVar[] = "KDE_SESSION_VERSION";

}  // namespace

namespace base {
namespace nix {

const char kDotConfigDir[] = ".config";
const char kXdgConfigHomeEnvVar[] = "XDG_CONFIG_HOME";
const char kXdgCurrentDesktopEnvVar[] = "XDG_CURRENT_DESKTOP";
const char kXdgSessionTypeEnvVar[] = "XDG_SESSION_TYPE";

FilePath GetXDGDirectory(Environment* env, const char* env_name,
                         const char* fallback_dir) {
  FilePath path;
  std::string env_value;
  if (env->GetVar(env_name, &env_value) && !env_value.empty()) {
    path = FilePath(env_value);
  } else {
    PathService::Get(DIR_HOME, &path);
    path = path.Append(fallback_dir);
  }
  return path.StripTrailingSeparators();
}

FilePath GetXDGUserDirectory(const char* dir_name, const char* fallback_dir) {
  FilePath path;
  char* xdg_dir = xdg_user_dir_lookup(dir_name);
  if (xdg_dir) {
    path = FilePath(xdg_dir);
    free(xdg_dir);
  } else {
    PathService::Get(DIR_HOME, &path);
    path = path.Append(fallback_dir);
  }
  return path.StripTrailingSeparators();
}

DesktopEnvironment GetDesktopEnvironment(Environment* env) {
  // kXdgCurrentDesktopEnvVar is the newest standard circa 2012.
  std::string xdg_current_desktop;
  if (env->GetVar(kXdgCurrentDesktopEnvVar, &xdg_current_desktop)) {
    // It could have multiple values separated by colon in priority order.
    for (const auto& value : SplitStringPiece(
             xdg_current_desktop, ":", TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY)) {
      if (value == "Unity") {
        // gnome-fallback sessions set kXdgCurrentDesktopEnvVar to Unity
        // DESKTOP_SESSION can be gnome-fallback or gnome-fallback-compiz
        std::string desktop_session;
        if (env->GetVar("DESKTOP_SESSION", &desktop_session) &&
            desktop_session.find("gnome-fallback") != std::string::npos) {
          return DESKTOP_ENVIRONMENT_GNOME;
        }
        return DESKTOP_ENVIRONMENT_UNITY;
      }
      if (value == "GNOME")
        return DESKTOP_ENVIRONMENT_GNOME;
      if (value == "X-Cinnamon")
        return DESKTOP_ENVIRONMENT_CINNAMON;
      if (value == "KDE") {
        std::string kde_session;
        if (env->GetVar(kKDESessionEnvVar, &kde_session)) {
          if (kde_session == "5") {
            return DESKTOP_ENVIRONMENT_KDE5;
          }
        }
        return DESKTOP_ENVIRONMENT_KDE4;
      }
      if (value == "Pantheon")
        return DESKTOP_ENVIRONMENT_PANTHEON;
      if (value == "XFCE")
        return DESKTOP_ENVIRONMENT_XFCE;
    }
  }

  // DESKTOP_SESSION was what everyone used in 2010.
  std::string desktop_session;
  if (env->GetVar("DESKTOP_SESSION", &desktop_session)) {
    if (desktop_session == "gnome" || desktop_session == "mate")
      return DESKTOP_ENVIRONMENT_GNOME;
    if (desktop_session == "kde4" || desktop_session == "kde-plasma")
      return DESKTOP_ENVIRONMENT_KDE4;
    if (desktop_session == "kde") {
      // This may mean KDE4 on newer systems, so we have to check.
      if (env->HasVar(kKDESessionEnvVar))
        return DESKTOP_ENVIRONMENT_KDE4;
      return DESKTOP_ENVIRONMENT_KDE3;
    }
    if (desktop_session.find("xfce") != std::string::npos ||
        desktop_session == "xubuntu") {
      return DESKTOP_ENVIRONMENT_XFCE;
    }
  }

  // Fall back on some older environment variables.
  // Useful particularly in the DESKTOP_SESSION=default case.
  if (env->HasVar("GNOME_DESKTOP_SESSION_ID"))
    return DESKTOP_ENVIRONMENT_GNOME;
  if (env->HasVar("KDE_FULL_SESSION")) {
    if (env->HasVar(kKDESessionEnvVar))
      return DESKTOP_ENVIRONMENT_KDE4;
    return DESKTOP_ENVIRONMENT_KDE3;
  }

  return DESKTOP_ENVIRONMENT_OTHER;
}

const char* GetDesktopEnvironmentName(DesktopEnvironment env) {
  switch (env) {
    case DESKTOP_ENVIRONMENT_OTHER:
      return nullptr;
    case DESKTOP_ENVIRONMENT_CINNAMON:
      return "CINNAMON";
    case DESKTOP_ENVIRONMENT_GNOME:
      return "GNOME";
    case DESKTOP_ENVIRONMENT_KDE3:
      return "KDE3";
    case DESKTOP_ENVIRONMENT_KDE4:
      return "KDE4";
    case DESKTOP_ENVIRONMENT_KDE5:
      return "KDE5";
    case DESKTOP_ENVIRONMENT_PANTHEON:
      return "PANTHEON";
    case DESKTOP_ENVIRONMENT_UNITY:
      return "UNITY";
    case DESKTOP_ENVIRONMENT_XFCE:
      return "XFCE";
  }
  return nullptr;
}

const char* GetDesktopEnvironmentName(Environment* env) {
  return GetDesktopEnvironmentName(GetDesktopEnvironment(env));
}

}  // namespace nix
}  // namespace base
