/*
 * config file:
 * - i2c device
 * - i2c address
 * - email-address
 * - reporting config (when logging / mailing)
 * - thresholds for do shutdown
 *
 * parameters:
 * -d run as daemon
 * -f foreground
 * -v debug
 * -c [idle|charge|test|poweroff] command (not with -d)
 * --config
 * --help
 *
 * in command mode try to use daemon first (via unix-socket)
 * then fallback to i2c
 */
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <linux/i2c.h>
#include <linux/i2c-dev.h>

struct read_data {
	uint8_t sys_state;

	int16_t adc_current;
	int16_t adc_ubat;
	int16_t adc_uin;

	int16_t uin_loss;
	int16_t uin_restore;
	int16_t ubat_full;
	int16_t ubat_low;
	int16_t ubat_critical;
	int16_t ibat_full;
	uint16_t crc16;
} __attribute__((__packed__));

struct write_data {
	uint8_t sys_state;

	int16_t uin_loss;
	int16_t uin_restore;
	int16_t ubat_full;
	int16_t ubat_low;
	int16_t ubat_critical;
	int16_t ibat_full;
	uint16_t crc16;
} __attribute__((__packed__));

enum {
	STATE_IDLE	= 0x01,
	STATE_TEST	= 0x02,
	STATE_CHARGE	= 0x04,
	STATE_DISCHARGE	= 0x08,
	STATE_POWEROFF	= 0x10,
};

static char * state2str(uint8_t state)
{
	switch (state) {
	case STATE_IDLE:
		return "STATE_IDLE";

	case STATE_TEST:
		return "STATE_TEST";

	case STATE_CHARGE:
		return "STATE_CHARGE";

	case STATE_DISCHARGE:
		return "STATE_DISCHARGE";

	case STATE_POWEROFF:
		return "STATE_POWEROFF";

	default:
		return "<UNKNOWN>";
	}
}

static int i2c_open(const char *path)
{
	int fd = open(path, O_RDWR);
	if (fd < 0) {
		perror("open()");
		return -1;
	}

	unsigned long funcs;
	if (ioctl(fd, I2C_FUNCS, &funcs)) {
		perror("ioctl(I2C_FUNCS)");
		close(fd);
		return -1;
	}

	if (!(funcs & I2C_FUNC_I2C)) {
		fprintf(stderr, "I2C_FUNC_I2C not supported!\n");
		close(fd);
		return -1;
	}

	return fd;
}

static int i2c_setaddress(int fd, int address)
{
	if (ioctl(fd, I2C_SLAVE, address) < 0) {
		perror("ioctl(I2C_SLAVE)");
		close(fd);
		return -1;
	}
	return 0;
}

int main(int argc, char *argv[])
{
	int fd = i2c_open("/dev/i2c-0");
	if (fd < 0)
		exit(-1);

	if (i2c_setaddress(fd, 0x10) < 0)
		exit(-1);

	int cnt = 0;

	while (1) {
		struct read_data rdbuf;
		memset(&rdbuf, 0, sizeof(rdbuf));

		int ret = read(fd, &rdbuf, sizeof(rdbuf));
		if (ret <= 0)
			perror("read()");

		printf("state:0x%02x I:%5dmA Ubat:%5dmV Usup:%5dmV (%s) [%5d,%5d,%5d,%5d,%5d,%5d,0x%04x]\n",
			rdbuf.sys_state, rdbuf.adc_current, rdbuf.adc_ubat,
			rdbuf.adc_uin, state2str(rdbuf.sys_state),
			rdbuf.uin_loss, rdbuf.uin_restore, rdbuf.ubat_full,
			rdbuf.ubat_low, rdbuf.ubat_critical, rdbuf.ibat_full,
			rdbuf.crc16);

		sleep(1);
		cnt++;

		if (cnt == 5) {
			struct write_data wrbuf = {
				.sys_state = STATE_CHARGE,
				.uin_loss = 12000,
				.uin_restore = 14000,
				.ubat_full = 13300,
				.ubat_low = 12000,
				.ubat_critical = 10800,
				.ibat_full = 150,
				.crc16 = 0x0000,
			};

//			write (fd, &wrbuf, sizeof(wrbuf));
			write (fd, &wrbuf, 1);
		}
	}
	close(fd);

	return 0;
}