/*
 Copyright (c) 2026 - SD-Innovation S.A.S. - FRANCE
*/

/*
ver: 2.x.x - build: 2026-04-28
*/

/*
The zlib License

Copyright (c) 2026 SD-Innovation S.A.S.

This software is provided ‘as-is’, without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.

3. This notice may not be removed or altered from any source
distribution.
*/

#pragma once

#include "ringBuffer.h"

namespace sdi_toolBox::common::utils
{
//--------------------------------------------------------------
/**
 * @brief Fixed-size circular buffer with compile-time capacity
 * and no-overwrite behavior.
 *
 * This template wraps a RingBuffer and prevents new elements from being
 * written when the buffer is full. Existing data is never overwritten;
 * push() simply fails and returns false when capacity is reached.
 *
 * @tparam T        Element type stored in the buffer.
 * @tparam CAPACITY Compile-time buffer capacity. Must be > 0.
 *
 * @note The class provides both optional-returning and out-parameter
 *       overloads for pop/front/back to suit different runtime constraints.
 * @warning Instantiating with CAPACITY == 0 is forbidden (static_assert).
 *
 * @code{.cpp}
 *   CircularBuffer<int, 8> cb;
 *   if (cb.push(42))
 *   {
 *     // element was inserted
 *   }
 *   else
 *   {
 *     // buffer was full, element was discarded
 *   }
 * @endcode
 */
template<class T, std::size_t CAPACITY>
class CircularBuffer
{
  static_assert(CAPACITY > 0, "CAPACITY must be > 0");

  public:
  ///@name Write operations
  ///@{

  /**
   * @brief Try to append a value to the buffer.
   *
   * If the buffer is full, the value is discarded and no overwrite occurs.
   * @param value Value to append (copied).
   *
   * @return true if the value was inserted, false if the buffer was full.
   */
  bool push(const T &value);

  ///@}
  ///@name Read operations
  ///@{

  /**
   * @brief Remove and return the oldest element from the buffer.
   *
   * @return std::optional<T> The oldest element if present, std::nullopt if empty.
   */

  std::optional<T> pop();
  /**
   * @brief Remove the oldest element and store it in the provided reference.
   *
   * @param value Output reference that receives the removed element.
   *
   * @return true if an element was removed, false if the buffer was empty.
   */
  bool pop(T &value);

  /**
   * @brief Return (without removing) the oldest element.
   *
   * @return std::optional<T> The oldest element if present, std::nullopt if empty.
   */
  [[nodiscard]] std::optional<T> front() const;

  /**
   * @brief Copy the oldest element into the provided reference without removing it.
   *
   * @param value Output reference that receives the element.
   *
   * @return true if the element was copied, false if the buffer is empty.
   */
  [[nodiscard]] bool front(T &value) const;

  /**
   * @brief Return (without removing) the newest element.
   *
   * @return std::optional<T> The newest element if present, std::nullopt if empty.
   */
  [[nodiscard]] std::optional<T> back() const;

  /**
   * @brief Copy the newest element into the provided reference without removing it.
   *
   * @param value Output reference that receives the element.
   *
   * @return true if the element was copied, false if the buffer is empty.
   */
  [[nodiscard]] bool back(T &value) const;

  ///@}
  ///@name State queries
  ///@{

  /**
   * @brief Check whether the buffer is empty.
   *
   * @return true if empty, false otherwise.
   */
  [[nodiscard]] bool empty() const;

  /**
   * @brief Check whether the buffer is full.
   *
   * @return true if full, false otherwise.
   */
  [[nodiscard]] bool full() const;

  /**
   * @brief Number of elements currently stored in the buffer.
   *
   * @return Current size (0 .. CAPACITY).
   */
  [[nodiscard]] std::size_t size() const;

  /**
   * @brief Compile-time capacity of the buffer.
   *
   * @return The maximum number of elements the buffer can hold.
   */
  [[nodiscard]] constexpr std::size_t capacity() const;

  ///@}
  ///@name Modifiers
  ///@{

  /**
   * @brief Clear the buffer and reset internal indices.
   *
   * After calling clear(), empty() returns true and size() returns 0.
   */
  void clear();

  ///@}

  private:
  ///@name Data members
  ///@{

  RingBuffer<T, CAPACITY> m_buffer{};     ///< Underlying ring buffer

  ///@}
};
//--------------------------------------------------------------

//--------------------------------------------------------------
/* Try to append a value to the buffer. If the buffer is full,
 * the value is discarded. Return true if the value was inserted,
 * false if the buffer was full. */
template<class T, std::size_t CAPACITY>
bool CircularBuffer<T, CAPACITY>::push(const T &value)
{
  if (m_buffer.full())
    return false;
  return m_buffer.push(value);
}
//--------------------------------------------------------------
/* Remove and return the oldest value from the buffer. If the
 * buffer is empty, return std::nullopt */
template<class T, std::size_t CAPACITY>
std::optional<T> CircularBuffer<T, CAPACITY>::pop()
{
  return m_buffer.pop();
}
//--------------------------------------------------------------
/* Remove the oldest value from the buffer and store it in
 * 'value'. Return true if successful, false if the buffer is empty */
template<class T, std::size_t CAPACITY>
bool CircularBuffer<T, CAPACITY>::pop(T &value)
{
  return m_buffer.pop(value);
}
//--------------------------------------------------------------
/* Return the oldest value without removing it. If the buffer is
 * empty, return std::nullopt */
template<class T, std::size_t CAPACITY>
std::optional<T> CircularBuffer<T, CAPACITY>::front() const
{
  return m_buffer.front();
}
//--------------------------------------------------------------
/* Return the oldest value without removing it and store it in
 * 'value'. Return true if successful, false if the buffer is empty */
template<class T, std::size_t CAPACITY>
bool CircularBuffer<T, CAPACITY>::front(T &value) const
{
  return m_buffer.front(value);
}
//--------------------------------------------------------------
/* Return the newest value without removing it. If the buffer is
 * empty, return std::nullopt */
template<class T, std::size_t CAPACITY>
std::optional<T> CircularBuffer<T, CAPACITY>::back() const
{
  return m_buffer.back();
}
//--------------------------------------------------------------
/* Return the newest value without removing it and store it in
 * 'value'. Return true if successful, false if the buffer is empty */
template<class T, std::size_t CAPACITY>
bool CircularBuffer<T, CAPACITY>::back(T &value) const
{
  return m_buffer.back(value);
}
//--------------------------------------------------------------
/* Check if the buffer is empty */
template<class T, std::size_t CAPACITY>
bool CircularBuffer<T, CAPACITY>::empty() const
{
  return m_buffer.empty();
}
//--------------------------------------------------------------
/* Check if the buffer is full */
template<class T, std::size_t CAPACITY>
bool CircularBuffer<T, CAPACITY>::full() const
{
  return m_buffer.full();
}
//--------------------------------------------------------------
/* Get the number of elements currently in the buffer */
template<class T, std::size_t CAPACITY>
std::size_t CircularBuffer<T, CAPACITY>::size() const
{
  return m_buffer.size();
}
//--------------------------------------------------------------
/* Get the maximum capacity of the buffer */
template<class T, std::size_t CAPACITY>
[[nodiscard]] constexpr std::size_t CircularBuffer<T, CAPACITY>::capacity() const
{
  return CAPACITY;
}
//--------------------------------------------------------------
/* Clear the buffer, resetting it to an empty state */
template<class T, std::size_t CAPACITY>
void CircularBuffer<T, CAPACITY>::clear()
{
  m_buffer.clear();
}
//--------------------------------------------------------------
}     // namespace sdi_toolBox::common::utils