// Copyright 2017 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_SMBPROVIDER_H_
#define SMBPROVIDER_SMBPROVIDER_H_

#include <map>
#include <memory>
#include <string>
#include <vector>

#include <base/memory/weak_ptr.h>
#include <dbus_adaptors/org.chromium.SmbProvider.h>

#include "smbprovider/proto.h"
#include "smbprovider/proto_bindings/directory_entry.pb.h"
#include "smbprovider/smbprovider_helper.h"
#include "smbprovider/temp_file_manager.h"

using brillo::dbus_utils::AsyncEventSequencer;

namespace smbprovider {

class DirectoryEntryListProto;
class DirectoryIterator;
class MountManager;
class SambaInterface;

// Implementation of smbprovider's DBus interface. Mostly routes stuff between
// DBus and samba_interface.
class SmbProvider : public org::chromium::SmbProviderAdaptor,
                    public org::chromium::SmbProviderInterface {
 public:
  SmbProvider(std::unique_ptr<brillo::dbus_utils::DBusObject> dbus_object,
              std::unique_ptr<SambaInterface> samba_interface,
              std::unique_ptr<MountManager> mount_manager,
              size_t buffer_size);

  SmbProvider(std::unique_ptr<brillo::dbus_utils::DBusObject> dbus_object,
              std::unique_ptr<SambaInterface> samba_interface,
              std::unique_ptr<MountManager> mount_manager);

  // org::chromium::SmbProviderInterface: (see org.chromium.SmbProvider.xml).
  void Mount(const ProtoBlob& options_blob,
             int32_t* error_code,
             int32_t* mount_id) override;

  int32_t Unmount(const ProtoBlob& options_blob) override;

  void ReadDirectory(const ProtoBlob& options_blob,
                     int32_t* error_code,
                     ProtoBlob* out_entries) override;

  void GetMetadataEntry(const ProtoBlob& options_blob,
                        int32_t* error_code,
                        ProtoBlob* out_entry) override;

  void OpenFile(const ProtoBlob& options_blob,
                int32_t* error_code,
                int32_t* file_id) override;

  int32_t CloseFile(const ProtoBlob& options_blob) override;

  int32_t DeleteEntry(const ProtoBlob& options_blob) override;

  void ReadFile(const ProtoBlob& options_blob,
                int32_t* error_code,
                dbus::FileDescriptor* temp_fd) override;

  int32_t CreateFile(const ProtoBlob& options_blob) override;

  int32_t Truncate(const ProtoBlob& options_blob) override;

  int32_t WriteFile(const ProtoBlob& options_blob,
                    const dbus::FileDescriptor& temp_fd) override;

  int32_t CreateDirectory(const ProtoBlob& options_blob) override;

  // Register DBus object and interfaces.
  void RegisterAsync(
      const AsyncEventSequencer::CompletionAction& completion_callback);

 private:
  // Looks up the |mount_id| and appends |entry_path| to the root share path
  // and sets |full_path| to the result. |full_path| will be unmodified on
  // failure.
  // |operation_name| is used for logging purposes only.
  bool GetFullPath(const char* operation_name,
                   int32_t mount_id,
                   const std::string& entry_path,
                   std::string* full_path) const;

  // Parses the raw contents of |blob| into |options| and validates that
  // the required fields are all correctly set.
  // |full_path| will contain the full path, including the mount root, based
  // on the mount id and entry path supplied in |options|.
  // On failure |error_code| will be populated and |options| and |full_path|
  // are undefined.
  template <typename Proto>
  bool ParseOptionsAndPath(const ProtoBlob& blob,
                           Proto* options,
                           std::string* full_path,
                           int32_t* error_code);

  // Tests whether |mount_root| is a valid path to be mounted by attemping
  // to open the directory.
  bool CanMountPath(const std::string& mount_root, int32_t* error_code);

  // Helper method to get the type of an entry. Returns boolean indicating
  // success. Sets is_directory to true for directory, and false for file.
  // Fails when called on non-file, non-directory.
  // On failure, returns false and sets |error_code|.
  bool GetEntryType(const std::string& full_path,
                    int32_t* error_code,
                    bool* is_directory);

  // Helper method to close the directory with id |dir_id|. Logs an error if the
  // directory fails to close.
  void CloseDirectory(int32_t dir_id);

  // Removes |mount_id| from the |mount_manager_| object and sets |error_code|
  // on failure.
  bool RemoveMount(int32_t mount_id, int32_t* error_code);

  // Helper method to read a file with valid |options| and output the results
  // into a |buffer|. This sets |error_code| on failure.
  bool ReadFileIntoBuffer(const ReadFileOptionsProto& options,
                          int32_t* error_code,
                          std::vector<uint8_t>* buffer);

  // Helper method to write data from a |buffer| into a temporary file and
  // outputs the resulting file descriptor into |temp_fd|. |options| is used for
  // logging purposes. This sets |error_code| on failure.
  bool WriteTempFile(const ReadFileOptionsProto& options,
                     const std::vector<uint8_t>& buffer,
                     int32_t* error_code,
                     dbus::FileDescriptor* temp_fd);

  // Helper method to write data from a |buffer| into a file specified in
  // |options|. Returns true on success, and sets |error_code| on failure.
  bool WriteFileFromBuffer(const WriteFileOptionsProto& options,
                           const std::vector<uint8_t>& buffer,
                           int32_t* error_code);

  // Helper method to construct a DirectoryIterator for a given |full_path|.
  DirectoryIterator GetDirectoryIterator(const std::string& full_path);

  // Opens a file located at |full_path| with permissions based on the protobuf.
  // |file_id| is the file handle for the opened file, and error will be set on
  // failure. |options| is used for logging purposes. GetOpenFilePermissions
  // must be overloaded to new protobufs using this method. Returns true on
  // success.
  template <typename Proto>
  bool OpenFile(const Proto& options,
                const std::string& full_path,
                int32_t* error,
                int32_t* file_id);

  // Closes a file with handle |file_id|. |options| is used for logging
  // purposes. |error| is set on failure. Returns true on success.
  template <typename Proto>
  bool CloseFile(const Proto& options, int32_t file_id, int32_t* error);

  // Truncates a file with handle |file_id| to the desired |length| and closes
  // the file whether or not the truncate was successful. |options| is used for
  // logging purposes. |error| is set on failure. Returns true on success.
  template <typename Proto>
  bool TruncateAndCloseFile(const Proto& options,
                            int32_t file_id,
                            int64_t length,
                            int32_t* error);

  // Helper method to seek given a proto |options|.
  // On failure |error_code| will be populated.
  template <typename Proto>
  bool Seek(const Proto& options, int32_t* error_code);

  // Helper method to create a directory at |full_path|. |options|
  // determines if the creation will be recursive. Returns true on success and
  // sets |error_code| on failure.
  bool CreateDirectory(const CreateDirectoryOptionsProto& options,
                       const std::string& full_path,
                       int32_t* error_code);

  // Generates a vector of |parent_paths| from a directory path in |options|.
  // The path must be prefixed with "/". |parent_paths| will include the mount
  // root and will exclude the path in |options|. Passing in "/1/2/3" will
  // generate ["smb://{mount}/1", "smb://{mount}/1/2"]. If the path has no
  // parents aside from "/", no paths will be generated. Returns true on success
  // and sets |error_code| on failure.
  bool GenerateParentPaths(const CreateDirectoryOptionsProto& options,
                           int32_t* error_code,
                           std::vector<std::string>* parent_paths);

  std::unique_ptr<SambaInterface> samba_interface_;
  std::unique_ptr<brillo::dbus_utils::DBusObject> dbus_object_;
  std::unique_ptr<MountManager> mount_manager_;
  TempFileManager temp_file_manager_;

  DISALLOW_COPY_AND_ASSIGN(SmbProvider);
};

}  // namespace smbprovider

#endif  // SMBPROVIDER_SMBPROVIDER_H_