// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
// vim: ts=8 sw=2 sts=2 expandtab

#pragma once

#include <boost/intrusive_ptr.hpp>
#include <boost/smart_ptr/intrusive_ref_counter.hpp>
#include <seastar/core/future.hh>

#include "crimson/os/seastore/segment_manager.h"

#include "crimson/os/seastore/segment_manager/ephemeral.h"

namespace crimson::os::seastore::segment_manager {

class EphemeralSegmentManager;
using EphemeralSegmentManagerRef = std::unique_ptr<EphemeralSegmentManager>;

struct ephemeral_config_t {
  size_t size = 0;
  size_t block_size = 0;
  size_t segment_size = 0;

  void validate() const {
    ceph_assert_always(size > 0);
    ceph_assert_always(size <= DEVICE_OFF_MAX);
    ceph_assert_always(segment_size > 0);
    ceph_assert_always(segment_size <= SEGMENT_OFF_MAX);
    ceph_assert_always(size / segment_size > 0);
    ceph_assert_always(size / segment_size <= DEVICE_SEGMENT_ID_MAX);
  }
};

constexpr ephemeral_config_t DEFAULT_TEST_EPHEMERAL = {
  1 << 30,
  4 << 10,
  8 << 20
};

std::ostream &operator<<(std::ostream &, const ephemeral_config_t &);

EphemeralSegmentManagerRef create_test_ephemeral();

device_config_t get_ephemeral_device_config(
    std::size_t index,
    std::size_t num_main_devices,
    std::size_t num_cold_devices);

class EphemeralSegment final : public Segment {
  friend class EphemeralSegmentManager;
  EphemeralSegmentManager &manager;
  const segment_id_t id;
  segment_off_t write_pointer = 0;
public:
  EphemeralSegment(EphemeralSegmentManager &manager, segment_id_t id);

  segment_id_t get_segment_id() const final { return id; }
  segment_off_t get_write_capacity() const final;
  segment_off_t get_write_ptr() const final { return write_pointer; }
  close_ertr::future<> close() final;
  write_ertr::future<> write(segment_off_t offset, ceph::bufferlist bl) final;
  write_ertr::future<> advance_wp(segment_off_t offset) final;

  ~EphemeralSegment() {}
};

class EphemeralSegmentManager final : public SegmentManager {
  friend class EphemeralSegment;
  using segment_state_t = Segment::segment_state_t;

  const ephemeral_config_t config;
  std::optional<device_config_t> device_config;

  device_type_t get_device_type() const final {
    assert(device_config);
    return device_config->spec.dtype;
  }

  size_t get_offset(paddr_t addr) {
    auto& seg_addr = addr.as_seg_paddr();
    return (seg_addr.get_segment_id().device_segment_id() * config.segment_size) +
	     seg_addr.get_segment_off();
  }

  std::vector<segment_state_t> segment_state;

  char *buffer = nullptr;

  Segment::close_ertr::future<> segment_close(segment_id_t id);

public:
  EphemeralSegmentManager(
    ephemeral_config_t config)
    : config(config) {
    config.validate();
  }

  ~EphemeralSegmentManager();

  close_ertr::future<> close() final {
    return close_ertr::now();
  }

  device_id_t get_device_id() const final {
    assert(device_config);
    return device_config->spec.id;
  }

  mount_ret mount() final {
    return mount_ertr::now();
  }

  mkfs_ret mkfs(device_config_t) final;

  open_ertr::future<SegmentRef> open(segment_id_t id) final;

  release_ertr::future<> release(segment_id_t id) final;

  read_ertr::future<> read(
    paddr_t addr,
    size_t len,
    ceph::bufferptr &out) final;

  size_t get_available_size() const final {
    return config.size;
  }
  extent_len_t get_block_size() const final {
    return config.block_size;
  }
  segment_off_t get_segment_size() const final {
    return config.segment_size;
  }

  const seastore_meta_t &get_meta() const final {
    assert(device_config);
    return device_config->meta;
  }

  secondary_device_set_t& get_secondary_devices() final {
    assert(device_config);
    return device_config->secondary_devices;
  }

  magic_t get_magic() const final {
    return device_config->spec.magic;
  }

  using init_ertr = crimson::errorator<
    crimson::ct_error::enospc,
    crimson::ct_error::invarg>;
  init_ertr::future<> init();

  void remount();

  // public so tests can bypass segment interface when simpler
  Segment::write_ertr::future<> segment_write(
    paddr_t addr,
    ceph::bufferlist bl,
    bool ignore_check=false);
};

}

#if FMT_VERSION >= 90000
template <> struct fmt::formatter<crimson::os::seastore::segment_manager::ephemeral_config_t> : fmt::ostream_formatter {};
#endif
