/**
 * @file
 * @brief Custom iterators for CAN controllers.
 */
#ifndef STA_CORE_CAN_ITER_HPP
#define STA_CORE_CAN_ITER_HPP

#include <cstdint>


namespace sta
{
    /**
     * @brief Iterable container interface for CAN RX flags.
     *
     * @ingroup sta_core_can_ids
     */
    class CanPendingRxFifos
    {
    public:
        /// @brief Value type.
        using value_type = uint8_t;
        /// @brief Pointer to value type.
        using reference = value_type &;
        /// @brief Const pointer to value type.
        using const_reference = const value_type &;
        /// @brief Size of type.
        using size_type = uint8_t;

        /**
         * @brief Custom iterator for active RX queues.
         */
        class const_iterator
        {
        public:
            /// @brief Value type.
            using value_type = CanPendingRxFifos::value_type;
            /// @brief Const pointer to value type.
            using reference = const_reference;
            /// @brief Pointer to value type.
            using pointer = const value_type *;

        public:
            /// @brief Default constructor.
            const_iterator(const const_iterator & iter);

            /// @brief Copies the contents of the given iterator.
            /// @param iter Iterator to be copied.
            const_iterator & operator=(const const_iterator & iter);

            /**
             * @brief Compare iterators by flags, index and end index.
            */
            bool operator==(const const_iterator & iter) const;
            /**
             * @brief Compare iterators by flags, index and end index.
            */
            bool operator!=(const const_iterator & iter) const;

            /**
             * @brief Increment iterator to next pending RX queue.
             */
            const_iterator & operator++();
            /**
             * @brief Increment iterator to next pending RX queue.
             */
            const_iterator operator++(int);

            /**
             * @brief Dereference iterator at index.
             */
            reference operator*() const;

        private:
            const_iterator(uint32_t rxFlags, uint8_t idx, uint8_t endIdx);

            /**
             * @brief Check if current RX queue has pending data.
             */
            bool isRxPending() const;

            friend class CanPendingRxFifos;

        private:
            uint32_t rxFlags_;  /**< RX flag bits */
            uint8_t idx_;       /**< Current flag index */
            uint8_t endIdx_;    /**< Iterator end index */
        };

    public:
        /**
         * @param rxFlags   RX flag bits
         * @param numFifos  Number of RX FIFOs
         */
        CanPendingRxFifos(uint32_t rxFlags, uint8_t numFifos);

        /**
         * @brief Get iterator to first pending RX queue.
         */
        const_iterator begin() const;
        /**
         * @brief Get iterator to end of RX queues.
         */
        const_iterator end() const;

    private:
        uint32_t rxFlags_;  /**< RX flag bits */
        uint8_t numFifos_;  /**< Number of RX FIFOs */
    };
} // namespace sta


#endif // STA_CORE_CAN_ITER_HPP