// i2c_linux.c
#include "i2c_linux.h"
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/i2c-dev.h>

/* Open the I2C bus node for read/write :contentReference[oaicite:0]{index=0} */
int i2c_open_bus(const char *bus)
{
    int fd = open(bus, O_RDWR);
    if (fd < 0) {
        perror("I2C open failed");
    }
    return fd;
}

void i2c_close_bus(int fd)
{
    close(fd);
}

/* Read: write register address, then read back data :contentReference[oaicite:1]{index=1} */
BME68X_INTF_RET_TYPE bme68x_i2c_read(uint8_t  reg_addr,
                                     uint8_t *reg_data,
                                     uint32_t  len,
                                     void     *intf_ptr)
{
    int fd = *(int *)intf_ptr;
    if (write(fd, &reg_addr, 1) != 1) {
        return BME68X_E_COM_FAIL;
    }
    if (read(fd, reg_data, len) != (ssize_t)len) {
        return BME68X_E_COM_FAIL;
    }
    return BME68X_OK;
}

/* Write: prepend register address to payload */
BME68X_INTF_RET_TYPE bme68x_i2c_write(uint8_t        reg_addr,
                                      const uint8_t *reg_data,
                                      uint32_t       len,
                                      void          *intf_ptr)
{
    int fd = *(int *)intf_ptr;
    uint8_t buf[len + 1];
    buf[0] = reg_addr;
    memcpy(&buf[1], reg_data, len);
    if (write(fd, buf, len + 1) != (ssize_t)(len + 1)) {
        return BME68X_E_COM_FAIL;
    }
    return BME68X_OK;
}

void bme68x_delay_us(uint32_t period, void *intf_ptr)
{
    (void)intf_ptr;
    usleep(period);
}