#include "bsp_can.h"
#include "main.h"
#include <stdlib.h>
#include "memory.h"

static can_instance* instance[MX_REGISTER_DEVICE_CNT];

/**
 * @brief add filter to receive mesg with specific ID,called by CANRegister()
 * 
 * @note there are total 28 filter and 2 FIFO in bxCAN of STM32F4 series product.
 *       here, we assign the former 14 to CAN1 and the rest for CAN2
 *       when initializing, module with odd ID will be assigned to FIFO0 while even one to FIFO1
 *       those modules which registered in CAN1 would use Filter0-13, while CAN2 use Filter14-27
 * 
 * @attention you don't have to fully understand what this function done, cause it is basically
 *            for initialization.Enjoy developing without caring about the infrastructure!
 *            if you really want to know what is happeng, contact author.
 * 
 * @param _instance can instance owned by specific module
 */
static void CANAddFilter(can_instance* _instance)
{
    CAN_FilterTypeDef can_filter_conf;
    static uint8_t can1_filter_idx=0,can2_filter_idx=14;

    can_filter_conf.FilterMode = CAN_FILTERMODE_IDLIST;
    can_filter_conf.FilterScale = CAN_FILTERSCALE_16BIT;
    can_filter_conf.FilterFIFOAssignment = (_instance->rx_id & 1) ? CAN_RX_FIFO0 : CAN_RX_FIFO1;
    can_filter_conf.SlaveStartFilterBank = 14;
    can_filter_conf.FilterIdLow = _instance->rx_id << 5;
    can_filter_conf.FilterBank = _instance->can_handle==&hcan1?(can1_filter_idx++):(can2_filter_idx++);
    can_filter_conf.FilterActivation = CAN_FILTER_ENABLE;

    HAL_CAN_ConfigFilter(_instance->can_handle, &can_filter_conf);
}

/**
 * @brief called by CANRegister before the first module being registered
 * 
 * @note this func will handle all these thing automatically
 *       there is no need to worry about hardware initialization, we do these for you!
 * 
 */
static void CANServiceInit()
{
    HAL_CAN_Start(&hcan1);
    HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING);
    HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO1_MSG_PENDING);
    HAL_CAN_Start(&hcan2);
    HAL_CAN_ActivateNotification(&hcan2, CAN_IT_RX_FIFO0_MSG_PENDING);
    HAL_CAN_ActivateNotification(&hcan2, CAN_IT_RX_FIFO1_MSG_PENDING);
}

void CANRegister(can_instance* _instance)
{
    static uint8_t instance_idx;
    if(!instance_idx)
    {
        CANServiceInit();
    }
    _instance->rx_buff=(uint8_t*)malloc(8*sizeof(uint8_t));
    _instance->tx_buff=(uint8_t*)malloc(8*sizeof(uint8_t));
    CANAddFilter(_instance);
    instance[instance_idx++]=_instance;
}

void CANTransmit(can_instance* _instance)
{
    CAN_TxHeaderTypeDef txconf;
    txconf.StdId=_instance->tx_id;
    txconf.IDE=CAN_ID_STD;
    txconf.RTR=CAN_RTR_DATA;
    txconf.DLC=0x08;
    while (HAL_CAN_GetTxMailboxesFreeLevel(_instance->can_handle) == 0);
    HAL_CAN_AddTxMessage(_instance->can_handle, &txconf, _instance->tx_buff, &_instance->tx_mailbox);
}

/**
 * @brief this func will recv data from @param:fifox to a tmp can_rx_buff
 *        then, all the instances will be polling to check which should recv this pack of data
 * 
 * @param _hcan 
 * @param fifox passed to HAL_CAN_GetRxMessage() to get mesg from a specific fifo
 */
static void CANFIFOxCallback(CAN_HandleTypeDef* _hcan,uint32_t fifox)
{
    uint8_t can_rx_buff[8];
    CAN_RxHeaderTypeDef rxconf;
    HAL_CAN_GetRxMessage(_hcan,fifox,&rxconf,can_rx_buff);
    for (size_t i = 0; i < DEVICE_CAN_CNT; i++)
    {
        if(_hcan==instance[i]->can_handle && rxconf.StdId==instance[i]->rx_id)
        {
            memcpy(instance[i]->rx_buff,can_rx_buff,8);
            instance[i]->can_module_callback(instance[i]);
            break;
        }
    }   
}

/* ATTENTION: two CAN device in STM32 share two FIFO */
/* functions below will call CANFIFOxCallback() to further process message from a specific CAN device */
/**
 * @brief rx fifo callback. Once FIFO_0 is full,this func would be called
 * 
 * @param hcan CAN handle indicate which device the oddest mesg in FIFO_0 comes from
 */
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan) 
{
    CANFIFOxCallback(hcan, CAN_RX_FIFO0);
}

/**
 * @brief rx fifo callback. Once FIFO_1 is full,this func would be called
 * 
 * @param hcan CAN handle indicate which device the oddest mesg in FIFO_1 comes from
 */
void HAL_CAN_RxFifo1MsgPendingCallback(CAN_HandleTypeDef *hcan) 
{
    CANFIFOxCallback(hcan, CAN_RX_FIFO1);
}