/** @file
 *
 * @addtogroup nfc_api
 *
 * @defgroup nfc_library NFC Type 2 Tag
 * @ingroup nfc_api
 * @brief @tagAPI52 Implementation of NFC Type 2 Tag.
 *
 * @defgroup nfc_lib NFC Type 2 Tag library
 * @{
 * @ingroup nfc_library
 * @brief @tagAPI52 Type 2 Tag library.
 */

#ifndef NFC_LIB_H
#define NFC_LIB_H

#include <string.h>

#define NFC_SIZEOF_INTERNAL_BYTES 10
#define NFC_MAX_PAYLOAD_SIZE 988
#define NFC_MAX_PAYLOAD_SIZE_RAW 1008 /* No NDEF-TLV and no implicit lock bytes at the end */

/** @brief Return values generated by NFC_LIB functions. */
typedef enum
{
  NFC_RETVAL_OK,
  NFC_RETVAL_ERROR,
  NFC_RETVAL_INVALID_STATE,
  NFC_RETVAL_INVALID_SIZE,
  NFC_RETVAL_INVALID_ARGUMENT
} NfcRetval;

/** @brief Events passed to the callback function. */
typedef enum
{
  NFC_EVENT_NONE,
  NFC_EVENT_FIELD_ON,
  NFC_EVENT_FIELD_OFF,
  NFC_EVENT_DATA_READ,
  NFC_EVENT_STOPPED
} NfcEvent;

typedef enum
{
  NFC_PARAM_TESTING /* Used for unit tests */
} NfcParamId;

/** \brief Callback to pass events from NFCLib to application.
  *
  * \param context    Application context for callback execution.
  * \param event      The event that occurred.
  * \param data       Data to send to the application (event specific).
  * \param dataLength Length of the data.
  */
typedef void (*NfcCallbackFunction) (void *context, NfcEvent event, const char *data, size_t dataLength);

/** \brief Function for registering the application callback for event signaling.
  *
  * The callback will be called by NFCLib to notify the application of relevant
  * events. It will be called from the HAL_NFC callback context.
  *
  * \param callback  Function pointer to the callback.
  * \param cbContext Pointer to a memory area used by the callback for execution (optional).
  *
  * \retval OK If the application callback was registered successfully. If one 
  *            of the arguments was invalid, an error code is returned.
  */
NfcRetval nfcSetup (NfcCallbackFunction callback, void *cbContext);

/** \brief Function for setting an NFC parameter.
  *
  * \note Not implemented. For future use.
  *
  * This function allows to set any parameter defined as available by HAL_NFC.
  *
  * \param id         ID of the parameter to set.
  * \param data       Pointer to a buffer containing the data to set.
  * \param dataLength Size of the buffer containing the data to set.
  *
  * \retval OK If the parameter was set successfully. If one of the arguments
  *            was invalid (for example, a wrong data length), an error code
  *            is returned.
  */
NfcRetval nfcSetParameter (NfcParamId id, void *data, size_t dataLength);

/** \brief Function for querying an NFC parameter value.
  *
  * \note Not implemented. For future use.
  *
  * The queried value will be placed into the passed data buffer. If the buffer
  * is too small, maxDataLength will contain the required buffer size. If the
  * buffer is big enough, maxDataLength will contain the actual size of the
  * data.
  *
  * \param id         ID of the parameter to query.
  * \param data       Pointer to a buffer receiving the queried data.
  * \param maxDataLength Size of the buffer, receives actual size of queried data.
  *
  * \retval OK If the parameter was received successfully. If one of the arguments
  *            was invalid (for example, the buffer was too small), an error code
  *            is returned.
  */
NfcRetval nfcGetParameter (NfcParamId id, void *data, size_t *maxDataLength);

/** \brief Function for registering the payload to send on reception of a READ request.
  *
  * The payload is considered to only contain the NDEF message to deliver to a
  * reader. The required NDEF TLV will be created implicitly by NFCLib.
  *
  * The pointer to the payload must stay valid for the duration of the library
  * execution, or until it is explicitly released.
  *
  * If the pointer is not NULL, but the length is zero, the paypload is
  * considered to be an empty NDEF message.
  *
  * If a new payload is registered, the previously registered one is considered
  * released.
  *
  * Passing a NULL pointer releases the current payload without registering a
  * new one.
  *
  * If an invalid size is given (too big), the function returns with an error
  * and the currently registered payload is left unchanged.
  *
  * \param payload       Pointer to the memory area containing the payload to send.
  * \param payloadLength Size of the payload in bytes.
  *
  * \retval OK If the operation was successful. If one 
  *            of the arguments was invalid, an error code is returned.
  */
NfcRetval nfcSetPayload (const char *payload, size_t payloadLength);

/** \brief Function for registering the raw payload to send on reception of a READ request.
  *
  * The payload will be delivered directly as-is to the reader, without
  * implicitly adding an NDEF TLV container. This can be used if the
  * application wants to define the TLVs itself, for example, to provide a different
  * memory layout.
  *
  * The pointer to the payload must stay valid for the duration of the library
  * execution, or until it is explicitly released.
  *
  * If a new payload is registered, the previously registered one is considered
  * released.
  *
  * Passing a NULL pointer releases the current payload, without registering a
  * new one.
  *
  * If an invalid size is given (too big), the function returns with an error
  * and the currently registered payload is left unchanged.
  *
  * \param payload       Pointer to the memory area containing the payload to send.
  * \param payloadLength Size of the payload in bytes.
  *
  * \retval OK If the operation was successful. If one 
  *            of the arguments was invalid, an error code is returned.
  */
NfcRetval nfcSetPayloadRaw (const char *payload, size_t payloadLength);

/** \brief Function for registering the sequence of internal bytes.
  *
  * This refers to the first 10 bytes of the tag memory. The library will set
  * a sensible default for these bytes. The application can use this function
  * to override the default.
  *
  * Passing a NULL pointer reverts back to the default sequence.
  * The data will be copied by NFCLib, so the memory does not have to remain valid
  * after the function returns.
  *
  * \note When modifying the internal bytes, remember that they must be consistent
  *       with the NFC hardware register settings (see @ref nfc_t2t_format_internal).
  *
  * \param data       Pointer to the memory area containing the data.
  * \param dataLength Size of the data in bytes.
  *
  * \retval OK If the operation was successful. If the data was not NULL and the
  *            data length was not 10, an error code is returned.
  */
NfcRetval nfcSetInternal (const char *data, size_t dataLength);

/** \brief Function for activating the NFC frontend.
  *
  * You must call this function so that events are posted to the application
  * callback.
  *
  * \retval OK If the NFC frontend was activated successfully. If the lower layer
  *            could not be started, an error code is returned.
  */
NfcRetval nfcStartEmulation (void);

/** \brief Function for deactivating the NFC frontend.
  *
  * After calling this function, no more events will be posted to the
  * application callback.
  *
  * \retval OK If the NFC frontend was deactivated successfully.  If the lower layer
  *            could not be stopped, an error code is returned.
  */
NfcRetval nfcStopEmulation (void);

/** \brief Function for releasing the reference to the application callback.
  *
  * After calling this function, the passed callback pointer is no longer
  * considered valid.
  *
  * \retval OK This function always succeeds.
  */
NfcRetval nfcDone (void);

#endif /* NFC_LIB_H */

/** @} */