/*
    This file is part of TON Blockchain Library.

    TON Blockchain Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    TON Blockchain Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2017-2020 Telegram Systems LLP
*/
#pragma once

#include "td/utils/port/config.h"

#include "td/utils/common.h"
#include "td/utils/port/detail/NativeFd.h"
#include "td/utils/port/detail/PollableFd.h"
#include "td/utils/port/IoSlice.h"
#include "td/utils/port/Stat.h"
#include "td/utils/Slice.h"
#include "td/utils/Span.h"
#include "td/utils/Status.h"

namespace td {
namespace detail {
class FileFdImpl;
}

class FileFd {
 public:
  FileFd();
  FileFd(FileFd &&);
  FileFd &operator=(FileFd &&);
  ~FileFd();
  FileFd(const FileFd &) = delete;
  FileFd &operator=(const FileFd &) = delete;

  enum Flags : int32 { Write = 1, Read = 2, Truncate = 4, Create = 8, Append = 16, CreateNew = 32, Direct = 64 };
  enum PrivateFlags : int32 { WinStat = 128 };

  static Result<FileFd> open(CSlice filepath, int32 flags, int32 mode = 0600) TD_WARN_UNUSED_RESULT;
  static FileFd from_native_fd(NativeFd fd) TD_WARN_UNUSED_RESULT;

  Result<size_t> write(Slice slice) TD_WARN_UNUSED_RESULT;
  Result<size_t> writev(Span<IoSlice> slices) TD_WARN_UNUSED_RESULT;
  Result<size_t> read(MutableSlice slice) TD_WARN_UNUSED_RESULT;

  Result<size_t> pwrite(Slice slice, int64 offset) TD_WARN_UNUSED_RESULT;
  Result<size_t> pread(MutableSlice slice, int64 offset) const TD_WARN_UNUSED_RESULT;

  enum class LockFlags { Write, Read, Unlock };
  Status lock(const LockFlags flags, const string &path, int32 max_tries) TD_WARN_UNUSED_RESULT;
  static void remove_local_lock(const string &path);

  PollableFdInfo &get_poll_info();
  const PollableFdInfo &get_poll_info() const;

  void close();

  bool empty() const;

  Result<int64> get_size() const;

  Result<int64> get_real_size() const;

  Result<Stat> stat() const;

  Status sync() TD_WARN_UNUSED_RESULT;

  Status seek(int64 position) TD_WARN_UNUSED_RESULT;

  Status truncate_to_current_position(int64 current_position) TD_WARN_UNUSED_RESULT;

  const NativeFd &get_native_fd() const;
  NativeFd move_as_native_fd();

 private:
  unique_ptr<detail::FileFdImpl> impl_;

  explicit FileFd(unique_ptr<detail::FileFdImpl> impl);
};

}  // namespace td