/*
 * Copyright (c) 2019, 2022, Oracle and/or its affiliates.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0,
 * as published by the Free Software Foundation.
 *
 * This program is also distributed with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms,
 * as designated in a particular file or component or in included license
 * documentation.  The authors of MySQL hereby grant you an additional
 * permission to link the program and your derivative works with the
 * separately licensed software that they have included with MySQL.
 *
 * This program 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 General Public License, version 2.0, for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */

#pragma once

#include <assert.h>
#include <cassert>
#include <cstdint>
#include <vector>

// NOLINT(build/include_subdir)

#include "encoding_pool.h"

namespace protocol {

class Encoding_buffer final {
public:
  constexpr static uint32_t k_page_size = 4096;

public:
  explicit Encoding_buffer(Encoding_pool *local_pool)
      : m_local_pool(local_pool) {
    assert(k_page_size == local_pool->get_page_size());
    m_front = m_current = m_local_pool->alloc_page();
  }
  ~Encoding_buffer() {
    remove_page_list(m_front);
    m_front = m_current = nullptr;
  }

  Page *get_next_page() {
    auto page = m_local_pool->alloc_page();

    m_current->m_next_page = page;
    m_current = page;

    return m_current;
  }

  void remove_page_list(Page *page) {
    while (page) {
      auto page_to_delete = page;
      page = page_to_delete->m_next_page;

      m_local_pool->release_page(page_to_delete);
    }
  }

  template <uint32_t size> void ensure_buffer_size() {
    static_assert(size < k_page_size,
                  "Page size might be too small to put those data in.");

    if (!m_current->is_at_least(size))
      get_next_page();
  }

  bool ensure_buffer_size(const uint32_t size) {
    if (!m_current->is_at_least(size)) {
      get_next_page();

      // Page size limits the number of bytes that
      // user can acquire in single call
      assert(m_current->is_at_least(size));
      return true;
    }

    return false;
  }

  inline bool is_empty() const {
    auto page = m_front;
    while (page) {
      if (page->get_used_bytes() > 0)
        return false;
      page = page->m_next_page;
    }
    return true;
  }

  Page *m_front;
  Page *m_current;

private:
  Encoding_pool *const m_local_pool;
};

} // namespace protocol