#include <stdio.h>
#include <stdint.h>
#include "esp_system.h"
#include "esp_err.h"
#include "driver/i2c.h"
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"

// The DS1307 Address on I2C BUS
#define DS1307_ADDRESS  0x68

// Internal Registers Address
#define DS1307_SECOND   0x00  // the address of SECOND register in DS1307
#define DS1307_MINUTE   0x01  // the address of MINUTE register in DS1307
#define DS1307_HOUR     0x02  // the address of HOUR register in DS1307
#define DS1307_DAY      0x03  // the address of DAY register in DS1307
#define DS1307_DATE     0x04  // the address of DATE register in DS1307
#define DS1307_MONTH    0x05  // the address of MONTH register in DS1307
#define DS1307_YEAR     0x06  // the address of YEAR register in DS1307
#define DS1307_CONTROL  0x07  // the address of CONTROL register in DS1307

// Non-volatile RAM Address
#define DS1307_RAM      0x08  // the address of first byte of Non-volatile RAM
#define DS1307_RAM_SIZE 56    // size of Non-volatile

// CONTROL register bits
#define DS1307_OUT      7
#define DS1307_SQWE     4
#define DS1307_RS0      0
#define DS1307_RS1      1

/* Private Macro ----------------------------------------------------------------*/
#ifndef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif

#define DS1307_I2C_NUM   I2C_NUM_1
#define DS1307_I2C_RATE  100000
#define DS1307_SCL_GPIO  GPIO_NUM_22
#define DS1307_SDA_GPIO  GPIO_NUM_21

typedef enum DS1307_Result_e
{
  DS1307_OK             = 0,
  DS1307_FAIL           = 1,
  DS1307_INVALID_PARAM  = 2,
} DS1307_Result_t;

/**
   @brief  Function type for Initialize/Deinitialize the platform dependent layer.
   @retval
           -  0: The operation was successful.
           - -1: The operation failed.
*/
typedef int8_t (*DS1307_PlatformInitDeinit_t)(void);

/**
   @brief  Function type for Send/Receive data to/from the slave.
   @param  Address: Address of slave (0 <= Address <= 127)
   @param  Data: Pointer to data
   @param  Len: data len in Bytes
   @retval
           -  0: The operation was successful.
           - -1: Failed to send/receive.
           - -2: Bus is busy.
           - -3: Slave doesn't ACK the transfer.
*/
typedef int8_t (*DS1307_PlatformSendReceive_t)(uint8_t Address, uint8_t *Data, uint8_t Len);

/**
   @brief  Handler
   @note   This handler must be initialize before using library functions
*/
typedef struct DS1307_Handler_s
{
  // Initializes platform dependent layer
  DS1307_PlatformInitDeinit_t PlatformInit;
  // De-initializes platform dependent layer
  DS1307_PlatformInitDeinit_t PlatformDeInit;
  // Send Data to the DS1307
  DS1307_PlatformSendReceive_t PlatformSend;
  // Receive Data from the DS1307
  DS1307_PlatformSendReceive_t PlatformReceive;
} DS1307_Handler_t;

/**
   @brief  Date and time data type
*/
typedef struct DS1307_DateTime_s
{
  uint8_t   Second;
  uint8_t   Minute;
  uint8_t   Hour;
  uint8_t   WeekDay;
  uint8_t   Day;
  uint8_t   Month;
  uint8_t   Year;
} DS1307_DateTime_t;

/**
   @brief  squarewave output signal options
*/
typedef enum DS1307_OutWave_e
{
  DS1307_OutWave_Low    = 0,  // Logic level 0 on the SQW/OUT pin
  DS1307_OutWave_High   = 1,  // Logic level 1 on the SQW/OUT pin
  DS1307_OutWave_1Hz    = 2,  // Output wave frequency = 1Hz
  DS1307_OutWave_4KHz   = 3,  // Output wave frequency = 4.096KHz
  DS1307_OutWave_8KHz   = 4,  // Output wave frequency = 8.192KHz
  DS1307_OutWave_32KHz  = 5   // Output wave frequency = 32.768KHz
} DS1307_OutWave_t;


/* Functionality Options --------------------------------------------------------*/
/**
   @brief  Specify Send buffer size.
   @note   larger buffer size => better performance
   @note   The DS1307_SEND_BUFFER_SIZE must be set larger than 1 (9 or more is
           suggested)
*/
#define DS1307_SEND_BUFFER_SIZE   9



/**
  ==================================================================================
                           ##### Common Functions #####
  ==================================================================================
*/

/**
   @brief  Initialize DS1307
   @param  Handler: Pointer to handler
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: One of parameters is invalid.
*/
DS1307_Result_t
DS1307_Init(DS1307_Handler_t *Handler);


/**
   @brief  Uninitialize DS1307
   @param  Handler: Pointer to handler
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
*/
DS1307_Result_t
DS1307_DeInit(DS1307_Handler_t *Handler);



/**
  ==================================================================================
                             ##### RTC Functions #####
  ==================================================================================
*/

/**
   @brief  Set date and time on DS1307 real time chip
   @param  Handler: Pointer to handler
   @param  DateTime: pointer to date and time value structure
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: One of parameters is invalid.
*/
DS1307_Result_t
DS1307_SetDateTime(DS1307_Handler_t *Handler, DS1307_DateTime_t *DateTime);


/**
   @brief  Get date and time from DS1307 real time chip
   @param  Handler: Pointer to handler
   @param  DateTime: pointer to date and time value structure
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
*/
DS1307_Result_t
DS1307_GetDateTime(DS1307_Handler_t *Handler, DS1307_DateTime_t *DateTime);



/**
  ==================================================================================
                           ##### Memory Functions #####
  ==================================================================================
*/

/**
   @brief  Write data on DS1307 data Non-volatile RAM
   @param  Handler: Pointer to handler
   @param  Address: address of block beginning (0 to 55)
   @param  Data: pointer to data array
   @param  Size: data size (1 to 56)
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: Requested area is out of range.
*/
DS1307_Result_t
DS1307_WriteRAM(DS1307_Handler_t *Handler,
                uint8_t Address, uint8_t *Data, uint8_t Size);


/**
   @brief  Read data from DS1307 data Non-volatile RAM
   @param  Handler: Pointer to handler
   @param  Address: address of block beginning (0 to 55)
   @param  Data: pointer to data array
   @param  Size: data size (1 to 56)
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: Requested area is out of range.
*/
DS1307_Result_t
DS1307_ReadRAM(DS1307_Handler_t *Handler,
               uint8_t Address, uint8_t *Data, uint8_t Size);



/**
  ==================================================================================
                          ##### Out Wave Functions #####
  ==================================================================================
*/

/**
   @brief  Set output Wave on SQW/Out pin of DS1307
   @param  Handler: Pointer to handler
   @param  OutWave: where OutWave Shows different output wave states
           - DS1307_OutWave_Low:    Logic level 0 on the SQW/OUT pin
           - DS1307_OutWave_High:   Logic level 1 on the SQW/OUT pin
           - DS1307_OutWave_1Hz:    Output wave frequency = 1Hz
           - DS1307_OutWave_4KHz:   Output wave frequency = 4.096KHz
           - DS1307_OutWave_8KHz:   Output wave frequency = 8.192KHz
           - DS1307_OutWave_32KHz:  Output wave frequency = 32.768KHz

   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: One of parameters is invalid.
*/
DS1307_Result_t
DS1307_SetOutWave(DS1307_Handler_t *Handler, DS1307_OutWave_t OutWave);


/**
  ==================================================================================
                           ##### Private Functions #####
  ==================================================================================
*/

static uint8_t
DS1307_DECtoBCD(uint8_t DEC)
{
  uint8_t Buff2 = DEC % 10;
  uint8_t Buff1 = (DEC / 10) % 10;
  uint8_t BCD   = (Buff1 << 4) | Buff2;

  return BCD;
}

static uint8_t
DS1307_BCDtoDEC(uint8_t BCD)
{
  uint8_t Buff1 = BCD >> 4;
  uint8_t Buff2 = BCD & 0x0f;
  uint8_t DEC   = (Buff1 * 10) + Buff2;

  return DEC;
}

static int8_t
DS1307_WriteRegs(DS1307_Handler_t *Handler,
                 uint8_t StartReg, uint8_t *Data, uint8_t BytesCount)
{
  uint8_t Buffer[DS1307_SEND_BUFFER_SIZE];
  uint8_t Len = 0;

  Buffer[0] = StartReg; // send register address to set RTC pointer
  while (BytesCount)
  {
    Len = MIN(BytesCount, sizeof(Buffer) - 1);
    memcpy((void*)(Buffer + 1), (const void*)Data, Len);

    if (Handler->PlatformSend(DS1307_ADDRESS, Buffer, Len + 1) < 0)
      return -1;

    Data += Len;
    Buffer[0] += Len;
    BytesCount -= Len;
  }

  return 0;
}

static int8_t
DS1307_ReadRegs(DS1307_Handler_t *Handler,
                uint8_t StartReg, uint8_t *Data, uint8_t BytesCount)
{
  if (Handler->PlatformSend(DS1307_ADDRESS, &StartReg, 1) < 0)
    return -1;

  if (Handler->PlatformReceive(DS1307_ADDRESS, Data, BytesCount) < 0)
    return -1;

  return 0;
}



/**
  ==================================================================================
                       ##### Public Common Functions #####
  ==================================================================================
*/

/**
   @brief  Initialize DS1307
   @param  Handler: Pointer to handler
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: One of parameters is invalid.
*/
DS1307_Result_t
DS1307_Init(DS1307_Handler_t *Handler)
{
  if (!Handler->PlatformSend ||
      !Handler->PlatformReceive)
    return DS1307_INVALID_PARAM;

  if (Handler->PlatformInit)
    if (Handler->PlatformInit() < 0)
      return DS1307_FAIL;

  return DS1307_OK;
}

/**
   @brief  Uninitialize DS1307
   @param  Handler: Pointer to handler
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
*/
DS1307_Result_t
DS1307_DeInit(DS1307_Handler_t *Handler)
{
  if (Handler->PlatformDeInit)
    if (Handler->PlatformDeInit() < 0)
      return DS1307_FAIL;

  return DS1307_OK;
}



/**
  ==================================================================================
                         ##### Public RTC Functions #####
  ==================================================================================
*/

/**
   @brief  Set date and time on DS1307 real time chip
   @param  Handler: Pointer to handler
   @param  DateTime: pointer to date and time value structure
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: One of parameters is invalid.
*/
DS1307_Result_t
DS1307_SetDateTime(DS1307_Handler_t *Handler, DS1307_DateTime_t *DateTime)
{
  uint8_t Buffer[7] = {0};

  if (DateTime->Second > 59 ||
      DateTime->Minute > 59 ||
      DateTime->Hour > 23 ||
      DateTime->WeekDay > 7 || DateTime->WeekDay == 0 ||
      DateTime->Day > 31 || DateTime->Day == 0 ||
      DateTime->Month > 12 || DateTime->Month == 0 ||
      DateTime->Year > 99)
    return DS1307_INVALID_PARAM;

  // convert value of parameter to BCD
  Buffer[0] = DS1307_DECtoBCD(DateTime->Second) & 0x7F;
  Buffer[1] = DS1307_DECtoBCD(DateTime->Minute);
  Buffer[2] = DS1307_DECtoBCD(DateTime->Hour);
  Buffer[3] = DS1307_DECtoBCD(DateTime->WeekDay);
  Buffer[4] = DS1307_DECtoBCD(DateTime->Day);
  Buffer[5] = DS1307_DECtoBCD(DateTime->Month);
  Buffer[6] = DS1307_DECtoBCD(DateTime->Year);

  if (DS1307_WriteRegs(Handler, DS1307_SECOND, Buffer, 7) < 0)
    return DS1307_FAIL;

  return DS1307_OK;
}


/**
   @brief  Get date and time from DS1307 real time chip
   @param  Handler: Pointer to handler
   @param  DateTime: pointer to date and time value structure
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
*/
DS1307_Result_t
DS1307_GetDateTime(DS1307_Handler_t *Handler, DS1307_DateTime_t *DateTime)
{
  uint8_t Buffer[7] = {0};

  if (DS1307_ReadRegs(Handler, DS1307_SECOND, Buffer, 7) < 0)
    return DS1307_FAIL;

  // convert BCD value to decimal
  DateTime->Second  = DS1307_BCDtoDEC(Buffer[0] & 0x7F);
  DateTime->Minute  = DS1307_BCDtoDEC(Buffer[1]);
  DateTime->Hour    = DS1307_BCDtoDEC(Buffer[2]);
  DateTime->WeekDay = DS1307_BCDtoDEC(Buffer[3]);
  DateTime->Day     = DS1307_BCDtoDEC(Buffer[4]);
  DateTime->Month   = DS1307_BCDtoDEC(Buffer[5]);
  DateTime->Year    = DS1307_BCDtoDEC(Buffer[6]);

  return DS1307_OK;
}



/**
  ==================================================================================
                       ##### Public Memory Functions #####
  ==================================================================================
*/

/**
   @brief  Write data on DS1307 data Non-volatile RAM
   @param  Handler: Pointer to handler
   @param  Address: address of block beginning (0 to 55)
   @param  Data: pointer to data array
   @param  Size: data size (1 to 56)
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: Requested area is out of range.
*/
DS1307_Result_t
DS1307_WriteRAM(DS1307_Handler_t *Handler,
                uint8_t Address, uint8_t *Data, uint8_t Size)
{
  Address += 8;

  if ((Address + Size) > 0x3f)
    return DS1307_INVALID_PARAM;

  if (DS1307_WriteRegs(Handler, Address, Data, Size) < 0)
    return DS1307_FAIL;

  return DS1307_OK;
}


/**
   @brief  Read data from DS1307 data Non-volatile RAM
   @param  Handler: Pointer to handler
   @param  Address: address of block beginning (0 to 55)
   @param  Data: pointer to data array
   @param  Size: data size (1 to 56)
   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: Requested area is out of range.
*/
DS1307_Result_t
DS1307_ReadRAM(DS1307_Handler_t *Handler,
               uint8_t Address, uint8_t *Data, uint8_t Size)
{
  Address += 8;

  if ((Address + Size) > 0x3f)
    return DS1307_INVALID_PARAM;

  if (DS1307_ReadRegs(Handler, Address, Data, Size) < 0)
    return DS1307_FAIL;

  return DS1307_OK;
}



/**
  ==================================================================================
                     ##### Public Out Wave Functions #####
  ==================================================================================
*/

/**
   @brief  Set output Wave on SQW/Out pin of DS1307
   @param  Handler: Pointer to handler
   @param  OutWave: where OutWave Shows different output wave states
           - DS1307_OutWave_Low:    Logic level 0 on the SQW/OUT pin
           - DS1307_OutWave_High:   Logic level 1 on the SQW/OUT pin
           - DS1307_OutWave_1Hz:    Output wave frequency = 1Hz
           - DS1307_OutWave_4KHz:   Output wave frequency = 4.096KHz
           - DS1307_OutWave_8KHz:   Output wave frequency = 8.192KHz
           - DS1307_OutWave_32KHz:  Output wave frequency = 32.768KHz

   @retval DS1307_Result_t
           - DS1307_OK: Operation was successful.
           - DS1307_FAIL: Failed to send or receive data.
           - DS1307_INVALID_PARAM: One of parameters is invalid.
*/
DS1307_Result_t
DS1307_SetOutWave(DS1307_Handler_t *Handler, DS1307_OutWave_t OutWave)
{
  uint8_t ControlReg;

  switch (OutWave)
  {
    case DS1307_OutWave_Low:
      ControlReg = 0;
      break;

    case DS1307_OutWave_High:
      ControlReg = (1 << DS1307_OUT);
      break;

    case DS1307_OutWave_1Hz:
      ControlReg = (1 << DS1307_SQWE);
      break;

    case DS1307_OutWave_4KHz:
      ControlReg = (1 << DS1307_SQWE) | (1 << DS1307_RS0);
      break;

    case DS1307_OutWave_8KHz:
      ControlReg = (1 << DS1307_SQWE) | (1 << DS1307_RS1);
      break;

    case DS1307_OutWave_32KHz:
      ControlReg = (1 << DS1307_SQWE) | (3 << DS1307_RS0);
      break;

    default:
      return DS1307_INVALID_PARAM;
  }

  if (DS1307_WriteRegs(Handler, DS1307_CONTROL, &ControlReg, 1) < 0)
    return DS1307_FAIL;

  return DS1307_OK;
}

int8_t
DS1307_Platform_Init(void)
{
  i2c_config_t conf;
  conf.mode = I2C_MODE_MASTER;
  conf.sda_io_num = DS1307_SDA_GPIO;
  conf.sda_pullup_en = GPIO_PULLUP_DISABLE;
  conf.scl_io_num = DS1307_SCL_GPIO;
  conf.scl_pullup_en = GPIO_PULLUP_DISABLE;
  conf.master.clk_speed = DS1307_I2C_RATE;
  if (i2c_param_config(DS1307_I2C_NUM, &conf) != ESP_OK)
    return -1;
  if (i2c_driver_install(DS1307_I2C_NUM, conf.mode, 0, 0, 0) != ESP_OK)
    return -1;
  return 0;
}

int8_t
DS1307_Platform_DeInit(void)
{
  i2c_driver_delete(DS1307_I2C_NUM);
  gpio_reset_pin(DS1307_SDA_GPIO);
  gpio_reset_pin(DS1307_SCL_GPIO);
  return 0;
}

int8_t
DS1307_Platform_Send(uint8_t Address, uint8_t *Data, uint8_t DataLen)
{
  i2c_cmd_handle_t DS1307_i2c_cmd_handle = 0;
  Address <<= 1;
  Address &= 0xFE;

  DS1307_i2c_cmd_handle = i2c_cmd_link_create();
  i2c_master_start(DS1307_i2c_cmd_handle);
  i2c_master_write(DS1307_i2c_cmd_handle, &Address, 1, 1);
  i2c_master_write(DS1307_i2c_cmd_handle, Data, DataLen, 1);
  i2c_master_stop(DS1307_i2c_cmd_handle);
  if (i2c_master_cmd_begin(DS1307_I2C_NUM, DS1307_i2c_cmd_handle, 1000 / portTICK_RATE_MS) != ESP_OK)
  {
    i2c_cmd_link_delete(DS1307_i2c_cmd_handle);
    return -1;
  }
  i2c_cmd_link_delete(DS1307_i2c_cmd_handle);
  return 0;
}

int8_t
DS1307_Platform_Receive(uint8_t Address, uint8_t *Data, uint8_t DataLen)
{
  i2c_cmd_handle_t DS1307_i2c_cmd_handle = 0;
  Address <<= 1;
  Address |= 0x01;

  DS1307_i2c_cmd_handle = i2c_cmd_link_create();
  i2c_master_start(DS1307_i2c_cmd_handle);
  i2c_master_write(DS1307_i2c_cmd_handle, &Address, 1, 1);
  i2c_master_read(DS1307_i2c_cmd_handle, Data, DataLen, I2C_MASTER_LAST_NACK);
  i2c_master_stop(DS1307_i2c_cmd_handle);
  if (i2c_master_cmd_begin(DS1307_I2C_NUM, DS1307_i2c_cmd_handle, 1000 / portTICK_RATE_MS) != ESP_OK)
  {
    i2c_cmd_link_delete(DS1307_i2c_cmd_handle);
    return -1;
  }
  i2c_cmd_link_delete(DS1307_i2c_cmd_handle);
  return 0;
}

int app_main(void)
{
  DS1307_Handler_t Handler;
  DS1307_DateTime_t DateTime =
  {
    .Second   = 0,
    .Minute   = 20,
    .Hour     = 10,
    .WeekDay  = 6,
    .Day      = 17,
    .Month    = 4,
    .Year     = 22
  };

  Handler.PlatformInit    = DS1307_Platform_Init;
  Handler.PlatformDeInit  = DS1307_Platform_DeInit;
  Handler.PlatformSend    = DS1307_Platform_Send;
  Handler.PlatformReceive = DS1307_Platform_Receive;

  DS1307_Init(&Handler);
  DS1307_SetDateTime(&Handler, &DateTime);
  DS1307_SetOutWave(&Handler, DS1307_OutWave_1Hz);

  while (1)
  {
    DS1307_GetDateTime(&Handler, &DateTime);
    printf("Fecha: %02u-%02u-20%02u\r\n", DateTime.Day, DateTime.Month, DateTime.Year);
    printf("Hora: %02u:%02u:%02u\r\n", DateTime.Hour, DateTime.Minute, DateTime.Second);
    vTaskDelay(1000 / portTICK_PERIOD_MS);
  }

  DS1307_DeInit(&Handler);
    
  return 0;
}