// implementations of all the stuff the Bosch BME280 reference code needs implemented 
// in order to talk to an actual bme280 over i2c on esp32 in idf
// -- github.com/epvuc 12/2017

#include <string.h>
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/i2c.h"
#include "bme280.h"

// pin numbers specific to this TTGO board
#define SCL_PIN 21
#define SDA_PIN 22

int8_t user_i2c_read(uint8_t dev_addr, uint8_t reg_addr, uint8_t *reg_data, uint8_t cnt);
int8_t user_i2c_write(uint8_t dev_addr, uint8_t reg_addr, uint8_t *reg_data, uint8_t cnt);
int8_t stream_sensor_data_forced_mode(struct bme280_dev *dev);
int8_t stream_sensor_data_normal_mode(struct bme280_dev *dev);
void user_delay_ms(uint32_t ms);

struct bme280_dev bme280;

void my_i2c_setup(void)
{
  i2c_config_t conf;
  conf.mode = I2C_MODE_MASTER;
  conf.sda_io_num = SDA_PIN;
  conf.scl_io_num = SCL_PIN;
  conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
  conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
  conf.master.clk_speed = 20000;
  i2c_param_config(I2C_NUM_0, &conf);
  i2c_driver_install(I2C_NUM_0, I2C_MODE_MASTER, 0, 0, 0);
} 

void my_bme280_init(void)
{
  int8_t rslt = BME280_OK;
  uint8_t settings_sel;
  
  bme280.dev_id = BME280_I2C_ADDR_SEC;
  bme280.intf = BME280_I2C_INTF;
  bme280.read = (void *)user_i2c_read;
  bme280.write = (void *)user_i2c_write;
  bme280.delay_ms = (void *)user_delay_ms;
  printf("calling bme280_init\r\n");
  rslt = bme280_init(&bme280);
  printf("bme280 init result %d\r\n", rslt);

  bme280.settings.osr_h = BME280_OVERSAMPLING_1X;
  bme280.settings.osr_p = BME280_OVERSAMPLING_4X;
  bme280.settings.osr_t = BME280_OVERSAMPLING_4X;
  bme280.settings.filter = BME280_FILTER_COEFF_OFF;
  settings_sel = BME280_OSR_PRESS_SEL | BME280_OSR_TEMP_SEL | BME280_OSR_HUM_SEL | BME280_FILTER_SEL;
  rslt = bme280_set_sensor_settings(settings_sel, &bme280);
  printf("bme280 settings config result %d\r\n", rslt);
}

#define SUCCESS 0
#define FAIL -1
#define I2C_MASTER_ACK 0
#define I2C_MASTER_NACK 1

int8_t user_i2c_write(uint8_t dev_addr, uint8_t reg_addr, uint8_t *reg_data, uint8_t cnt)
{
  int32_t iError = 0;

  esp_err_t espRc;
  i2c_cmd_handle_t cmd = i2c_cmd_link_create();

  i2c_master_start(cmd);
  i2c_master_write_byte(cmd, (dev_addr << 1) | I2C_MASTER_WRITE, true);

  i2c_master_write_byte(cmd, reg_addr, true);
  i2c_master_write(cmd, reg_data, cnt, true);
  i2c_master_stop(cmd);

  espRc = i2c_master_cmd_begin(I2C_NUM_0, cmd, 200/portTICK_PERIOD_MS);
  //  printf("in user_i2c_read, i2c_master_cmd_begin returns %d\r\n", espRc);
  if (espRc == ESP_OK) {
    iError = SUCCESS;
  } else {
    iError = FAIL;
  }
  i2c_cmd_link_delete(cmd);

  return (int8_t)iError;
}

int8_t user_i2c_read(uint8_t dev_addr, uint8_t reg_addr, uint8_t *reg_data, uint8_t cnt)
{
  int32_t iError = 0;
  esp_err_t espRc;

  i2c_cmd_handle_t cmd = i2c_cmd_link_create();

  i2c_master_start(cmd);
  i2c_master_write_byte(cmd, (dev_addr << 1) | I2C_MASTER_WRITE, true);
  i2c_master_write_byte(cmd, reg_addr, true);

  i2c_master_start(cmd);
  i2c_master_write_byte(cmd, (dev_addr << 1) | I2C_MASTER_READ, true);

  if (cnt > 1) {
    i2c_master_read(cmd, reg_data, cnt-1, I2C_MASTER_ACK);
  }
  i2c_master_read_byte(cmd, reg_data+cnt-1, I2C_MASTER_NACK);
  i2c_master_stop(cmd);

  espRc = i2c_master_cmd_begin(I2C_NUM_0, cmd, 200/portTICK_PERIOD_MS);
  if (espRc == ESP_OK) {
    iError = SUCCESS;
  } else {
    iError = FAIL;
  }

  i2c_cmd_link_delete(cmd);

  return (int8_t)iError;
}

void user_delay_ms(uint32_t ms)
{
  vTaskDelay(ms/portTICK_PERIOD_MS);
}