// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SMBPROVIDER_KERBEROS_ARTIFACT_SYNCHRONIZER_H_
#define SMBPROVIDER_KERBEROS_ARTIFACT_SYNCHRONIZER_H_

#include <memory>
#include <string>

#include <base/callback.h>

#include "smbprovider/kerberos_artifact_client_interface.h"

namespace dbus {

class Signal;

}  // namespace dbus

namespace smbprovider {

// KerberosArtifactSynchronizer manages a Kerberos user's kr5conf and krb5ccache
// files. It takes ownership of a KerberosArtifactClientInterface on
// construction. SetupKerberos fetches a users Kerberos files from AuthPolicy or
// Kerberos daemons and writes a copy to the tempfs. The Kerberos files are kept
// up-to-date by connecting to AuthPolicy's or Kerberos's D-Bus signal.
class KerberosArtifactSynchronizer {
 public:
  using SetupKerberosCallback = base::Callback<void(bool setup_success)>;

  KerberosArtifactSynchronizer(
      const std::string& krb5_conf_path,
      const std::string& krb5_ccache_path,
      std::unique_ptr<KerberosArtifactClientInterface> client,
      bool allow_credentials_update);

  // Sets up Keberos for user with |account_identifier|.
  // |account_identifier| is run with the result. If |allow_credentials_update|
  // is false it may only be called once per instance.
  // If |account_identifier| is empty, credential files will not be created
  // or will be removed.
  void SetupKerberos(const std::string& account_identifier,
                     SetupKerberosCallback callback);

 private:
  // Calls GetUserKerberosFiles on |client_|.
  void GetFiles(SetupKerberosCallback callback);

  // Response handler for GetUserKerberosFiles.
  void OnGetFilesResponse(SetupKerberosCallback callback,
                          bool success,
                          const std::string& krb5_ccache,
                          const std::string& krb5_conf);

  // Writes |kerberos_files| to |krb5_conf_path_| and |krb5_ccache_path_|
  // respectively. If Kerberos is not yet fully setup, calls
  // ConnectToKerberosFilesChangedSignal.
  void WriteFiles(const std::string& krb5_ccache,
                  const std::string& krb5_conf,
                  SetupKerberosCallback callback);

  // Writes |kerberos_file| to |path|. First writes into a temporary file
  // and then replaces the existing one. Returns true if the write succeeds,
  // false if it fails. The parent directory of |path| must exist.
  bool WriteFile(const std::string& path, const std::string& kerberos_file);

  // Connects to the 'UserKerberosFilesChanged' D-Bus signal. Called by
  // WriteFiles() on initial setup.
  void ConnectToKerberosFilesChangedSignal(SetupKerberosCallback callback);

  // Callback for 'UserKerberosFilesChanged' D-Bus signal.
  void OnKerberosFilesChanged(dbus::Signal* signal);

  // Called after connecting to 'UserKerberosFilesChanged' signal. Verifies that
  // the signal connected successfully.
  void OnKerberosFilesChangedSignalConnected(SetupKerberosCallback callback,
                                             const std::string& interface_name,
                                             const std::string& signal_name,
                                             bool success);

  // Remove Kerberos credential files.
  void RemoveFiles(SetupKerberosCallback callback);

  // Remove a file at a given |path|. Returns true if the remove succeeds,
  // false if it fails.
  bool RemoveFile(const std::string& path);

  bool is_kerberos_setup_ = false;
  const std::string krb5_conf_path_;
  const std::string krb5_ccache_path_;
  std::string account_identifier_;

  std::unique_ptr<KerberosArtifactClientInterface> client_;

  const bool allow_credentials_update_ = false;

  DISALLOW_COPY_AND_ASSIGN(KerberosArtifactSynchronizer);
};

}  // namespace smbprovider

#endif  // SMBPROVIDER_KERBEROS_ARTIFACT_SYNCHRONIZER_H_