/**
   Copyright (c) 2015 Beckhoff Automation GmbH & Co. KG

   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
 */

#ifndef FRAME_H
#define FRAME_H

#include <cstddef>
#include <cstdint>
#include <memory>

struct Frame {
    /**
     * @brief Frame
     * @param length number of bytes preallocated in the internale buffer
     * @param data, if not null this frame will be initialized with <lenght> number of bytes from <data>
     */
    Frame(size_t length, const void* data = nullptr);

    /**
     * @brief operator []
     * bytewise access to the frame bytes
     * @param index should be within the frames bounds!
     * @return
     */
    uint8_t operator[](size_t index) const;

    /**
     * @brief capacity
     * @return number of bytes, which are accessable by rawData()
     */
    size_t capacity() const;

    /**
     * @brief clear
     * Reset internal buffer to an empty frame
     * @return reference to self
     */
    Frame& clear();

    /**
     * @brief limit
     * If the frame is reused as a response buffer, call limit() to lock the frames state
     * and limit its size to the length of the response
     * @param newSize length of the response
     * @return reference to self
     */
    Frame& limit(size_t newSize);

    /**
     * @brief reset
     * Prepare the frame to be reused as a response buffer
     * @param newSize expected size of the response
     * @return reference to self
     */
    Frame& reset(size_t newSize = 4096);

    /**
     * @brief data
     * @return a pointer to the beginning of the frame
     */
    const uint8_t* data() const;

    /**
     * @brief prepend
     * prepend <data> in front of the frame
     * @param data
     * @param size number of bytes in <data>
     * @return reference to self
     */
    Frame& prepend(const void* const data, const size_t size);

    /**
     * prepend a header of type <T>
     */
    template<class T> Frame& prepend(const T& header)
    {
        return prepend(&header, sizeof(T));
    }

    /**
     * @brief rawData
     * Reuse the frame as response buffer, use with care!
     * @return a raw pointer to the beginning of the internal allocated buffer
     */
    uint8_t* rawData() const;

    /**
     * @brief remove
     * remove <numBytest> from the beginning of the frame
     * @param numBytes
     * @return reference to self
     */
    Frame& remove(size_t numBytes);

    /**
     * remove header of type <T> from the beginning of the frame
     */
    template<class T> T remove()
    {
        const auto p = m_Pos;
        remove(sizeof(T));
        return T(p);
    }

    /**
     * @brief size
     * @return length of the frame in bytes
     */
    size_t size() const;

private:
    std::unique_ptr<uint8_t[]> m_Data;
    uint8_t* m_Pos;
    size_t m_Size;
    size_t m_OriginalSize;
};

#endif // FRAME_H