/**
 * @file mmr_can.h
 * @brief
 * Main header for the mmr_can library.
 */

#ifndef INC_MMR_CAN_H_
#define INC_MMR_CAN_H_

#include <stdint.h>
#include <stdbool.h>
#include "mmr_can_includes.h"
#include "mmr_can_header.h"
#include "mmr_can_types.h"
#include "mmr_can_optimize.h"
#include "mmr_can_binary_literals.h"
#include "mmr_can_scs.h"

#ifndef MMR_CAN_RX_FIFO
#define MMR_CAN_RX_FIFO CAN_RX_FIFO0
#endif

#if MMR_CAN_RX_FIFO == CAN_RX_FIFO0
#define MMR_CAN_FILTER_FIFO CAN_FILTER_FIFO0
#else
#define MMR_CAN_FILTER_FIFO CAN_FILTER_FIFO1
#endif

#if MMR_CAN_RX_FIFO == CAN_RX_FIFO0
#define MMR_CAN_RX_INTERRUPT CAN_IT_RX_FIFO0_MSG_PENDING
#else
#define MMR_CAN_RX_INTERRUPT CAN_IT_RX_FIFO1_MSG_PENDING
#endif

#ifndef MMR_CAN_MAX_DATA_LENGTH
#define MMR_CAN_MAX_DATA_LENGTH 8
#endif


typedef uint32_t (*MmrCanTickProvider)();

/**
 * @brief
 * A buffer large enough to hold a CAN payload.
 */
typedef uint8_t CanRxBuffer[MMR_CAN_MAX_DATA_LENGTH];


typedef struct {
  bool enabled;

  /**
   * The fifo that the filter should operate
   * on
   */
  CanFilterFifo fifo;

  /**
   * The filter bank to use
   *
   * In systems with more than one CAN interface,
   * this must go from 0 to slaveBankStart for the master CAN
   * and from slaveBankStart to 27 for the slave CAN
   * 
   * Master CAN is usually CAN1, while slave CAN is CAN2
   */
  CanFilterBank bank;

  /**
   * The start of the slave filter banks.
   * This value is ignored for single-CAN boards.
   */
  CanFilterBank slaveBankStart;

  /**
   * The mask to use with this filter.
   */
  CanFilterMask idMask;
} MmrCanFilterSettings;


/**
 * @brief
 * A packet that can be sent over a CAN
 * network.
 *
 * @example
 * typedef struct {
 *   int x;
 *   int y;
 * } Point;
 *
 * HalStatus send(Point point) {
 *   MmrCanPacket packet = {
 *     .header = {
 *       .priority = MMR_CAN_MESSAGE_PRIORITY_NORMAL,
 *       .messageId = MMR_CAN_EXAMPLES_POINT,
 *       .senderId = 0xXXX,
 *     },
 *     .data = (uint8_t*)&point,
 *     .length = sizeof(point),
 *   };
 *
 *   return MMR_CAN_Send(&hcan, packet);
 * }
 *
 * int main() {
 *   Point p = {10, 20};
 *   if (send(p) != HAL_OK) {
 *     Error_Handler();
 *   }
 *
 *   // 'p' has been sent.
 * }
 */
typedef struct {
  MmrCanHeader header;
  uint8_t *data;
  uint8_t length;
} MmrCanPacket;


/**
 * @brief
 * A message received over a CAN network.
 *
 * @example
 * typedef struct {
 *   int x;
 *   int y;
 * } Point;
 *
 * HalStatus receive(Point *result) {
 *   MmrCanMessage message = {
 *     .store = result,
 *   };
 *
 *   HalStatus result = MMR_CAN_Receive(&hcan, &message);
 *   bool isAPoint = message.header.messageId == MMR_CAN_EXAMPLES_POINT;
 *   if (!isAPoint) {
 *     return HAL_ERROR;
 *   }
 *
 *   return result;
 * }
 *
 * int main() {
 *   Point p = {};
 *   if (receive(&p) != HAL_OK) {
 *     Error_Handler();
 *   }
 *
 *   // here 'p' has been populated and can
 *   // be used.
 * }
 */
typedef struct {
  MmrCanHeader header;
  void *store;
} MmrCanMessage;


#define MMR_CAN_FilterConfigDefault(phcan) \
  MMR_CAN_FilterConfig(phcan, MMR_CAN_GetDefaultFilterSettings())


/**
 * @brief
 * A function that provides the current tick.
 * Used to track the delay between message
 * and acknowledgment. 
 */
extern MmrCanTickProvider __mmr_can_tickProvider;


/**
 * @brief
 * Sets the tick provider.
 * 
 * @param tickProvider
 *  The function to use when fetching the current tick.
 */
void MMR_CAN_SetTickProvider(MmrCanTickProvider tickProvider);

/**
 * @brief
 * Returns the current tick by calling the
 * configured tick provider.
 */
uint32_t MMR_CAN_GetCurrentTick();

/**
 * @brief
 * Configures the filters with the default configuration
 * and starts the can interface.
 */
HalStatus MMR_CAN_BasicSetupAndStart(CanHandle *hcan);

/**
 * @brief
 * Configures the filters.
 */
HalStatus MMR_CAN_FilterConfig(CanHandle *hcan, MmrCanFilterSettings settings);

/**
 * @brief
 * Provides the default configuration for
 * the filters. 
 */
MmrCanFilterSettings MMR_CAN_GetDefaultFilterSettings();

/**
 * @brief
 * Sends a can packet over the network.
 * Based on the data length, the packet may be split
 * into multiple frames.
 * 
 * It is not recommended to send more than 8 bytes, as the
 * 'multiple frames' feature has not been fully implemented yet.
 */
HalStatus MMR_CAN_Send(CanHandle *hcan, MmrCanPacket packet);

/**
 * @brief
 * Sends a can packet over the network as is, without
 * changing the data that is provided.
 * 
 * This can prevent the sudden change of the header's message type when
 * using MMR_CAN_Send.
 */
HalStatus MMR_CAN_SendNoTamper(CanHandle *hcan, MmrCanPacket packet);

/**
 * @brief
 * Receives a can message from the network.
 */
HalStatus MMR_CAN_Receive(CanHandle *hcan, MmrCanMessage *result);

#endif /* INC_MMR_CAN_H_ */