#include "main.h"
#include "bcmxcp.h"
#include "bcmxcp_io.h"
#include "bcmxcp_ser.h"
#include "serial.h"
#include "nut_stdint.h"

#define SUBDRIVER_NAME    "RS-232 communication subdriver"
#define SUBDRIVER_VERSION "0.21"

/* communication driver description structure */
upsdrv_info_t comm_upsdrv_info = {
	SUBDRIVER_NAME,
	SUBDRIVER_VERSION,
	NULL,
	0,
	{ NULL }
};

#define PW_MAX_BAUD 5

/* NOT static: also used from nut-scanner, so extern'ed via bcmxcp_ser.h */
pw_baud_rate_t pw_baud_rates[] = {
	{ B19200, 19200 },
	{ B9600,  9600 },
	{ B4800,  4800 },
	{ B2400,  2400 },
	{ B1200,  1200 },
	/* end of structure. */
	{ 0,  0 }
};

/* NOT static: also used from nut-scanner, so extern'ed via bcmxcp_ser.h */
unsigned char BCMXCP_AUTHCMD[4] = {0xCF, 0x69, 0xE8, 0xD5}; /* Authorisation command */

static void send_command(unsigned char *command, size_t command_length)
{
	int retry = 0;
	ssize_t sent;
	unsigned char sbuf[1024];

	if (command_length > UCHAR_MAX) {
		upsdebugx (3, "%s: ERROR: command_length too long for the character protocol", __func__);
		return;
	}

	/* Prepare the send buffer */
	sbuf[0] = PW_COMMAND_START_BYTE;
	sbuf[1] = (unsigned char)(command_length);
	memcpy(sbuf+2, command, command_length);
	command_length += 2;

	/* Add checksum */
	sbuf[command_length] = calc_checksum(sbuf);
	command_length += 1;

	upsdebug_hex (3, "send_command", sbuf, command_length);

	while (retry++ < PW_MAX_TRY) {

		if (retry == PW_MAX_TRY) {
			ser_send_char(upsfd, 0x1d); /* last retry is preceded by a ESC.*/
			usleep(250000);
		}

		sent = ser_send_buf(upsfd, sbuf, command_length);

		if (sent < 0) {
			upslogx(LOG_ERR, "%s(): error reading from ser_send_buf()", __func__);
			return;
		}

		if ((size_t)sent == command_length) {
			return;
		}
	}
}

void send_read_command(unsigned char command)
{
	send_command(&command, 1);
}

void send_write_command(unsigned char *command, size_t command_length)
{
	send_command(command, command_length);
}

/* get the answer of a command from the ups. And check that the answer is for this command */
ssize_t get_answer(unsigned char *data, unsigned char command)
{
	unsigned char	my_buf[128]; /* packet has a maximum length of 121+5 bytes */
	ssize_t		res;
	size_t	length, end_length = 0, endblock = 0, start = 0;
	unsigned char	block_number, sequence, pre_sequence = 0;

	while (endblock != 1) {

		do {
			/* Read PW_COMMAND_START_BYTE byte */
			res = ser_get_char(upsfd, my_buf, 1, 0);

			if (res != 1) {
				upsdebugx(1,
					"Receive error (PW_COMMAND_START_BYTE): %zd, cmd=%x!!!\n",
					res, command);
				return -1;
			}

			start++;

		} while ((my_buf[0] != PW_COMMAND_START_BYTE) && (start < 128));

		if (start == 128) {
			ser_comm_fail("Receive error (PW_COMMAND_START_BYTE): packet not on start!!%x\n", my_buf[0]);
			return -1;
		}

		/* Read block number byte */
		res = ser_get_char(upsfd, my_buf + 1, 1, 0);

		if (res != 1) {
			ser_comm_fail("Receive error (Block number): %zd!!!\n", res);
			return -1;
		}

		block_number = (unsigned char)my_buf[1];

		if (command <= 0x43) {
			if ((command - 0x30) != block_number) {
				ser_comm_fail("Receive error (Request command): %x!!!\n", block_number);
				return -1;
			}
		}

		if (command >= 0x89) {
			if ((command == 0xA0) && (block_number != 0x01)) {
				ser_comm_fail("Receive error (Requested only mode command): %x!!!\n", block_number);
				return -1;
			}

			if ((command != 0xA0) && (block_number != 0x09)) {
				ser_comm_fail("Receive error (Control command): %x!!!\n", block_number);
				return -1;
			}
		}

		/* Read data length byte */
		res = ser_get_char(upsfd, my_buf + 2, 1, 0);

		if (res != 1) {
			ser_comm_fail("Receive error (length): %zd!!!\n", res);
			return -1;
		}

		length = (unsigned char)my_buf[2];

		if (length < 1) {
			ser_comm_fail("Receive error (length): packet length %zx!!!\n", length);
			return -1;
		}

		/* Read sequence byte */
		res = ser_get_char(upsfd, my_buf + 3, 1, 0);

		if (res != 1) {
			ser_comm_fail("Receive error (sequence): %zd!!!\n", res);
			return -1;
		}

		sequence = (unsigned char)my_buf[3];

		if ((sequence & 0x80) == 0x80) {
			endblock = 1;
		}

		if ((sequence & 0x07) != (pre_sequence + 1)) {
			ser_comm_fail("Not the right sequence received %x!!!\n", sequence);
			return -1;
		}

		pre_sequence = sequence;

		/* Try to read all the remaining bytes */
		res = ser_get_buf_len(upsfd, my_buf + 4, length, 1, 0);
		if (res < 0) {
			ser_comm_fail("%s(): ser_get_buf_len() returned error code %zd", __func__, res);
			return res;
		}

		if ((size_t)res != length) {
			ser_comm_fail("Receive error (data): got %zd bytes instead of %zu!!!\n", res, length);
			return -1;
		}

		/* Get the checksum byte */
		res = ser_get_char(upsfd, my_buf + (4 + length), 1, 0);

		if (res != 1) {
			ser_comm_fail("Receive error (checksum): %zx!!!\n", res);
			return -1;
		}

		/* now we have the whole answer from the ups, we can checksum it */
		if (!checksum_test(my_buf)) {
			ser_comm_fail("checksum error! ");
			return -1;
		}

		memcpy(data+end_length, my_buf + 4, length);
		end_length += length;

	}

	upsdebug_hex (5, "get_answer", data, end_length);
	ser_comm_good();

	assert(end_length < SSIZE_MAX);
	return (ssize_t)end_length;
}

static ssize_t command_sequence(unsigned char *command, size_t command_length, unsigned char *answer)
{
	ssize_t	bytes_read;
	int	retry = 0;

	while (retry++ < PW_MAX_TRY) {

		if (retry == PW_MAX_TRY) {
			ser_flush_in(upsfd, "", 0);
		}

		send_write_command(command, command_length);

		bytes_read = get_answer(answer, *command);

		if (bytes_read > 0) {
			return bytes_read;
		}
	}

	return -1;
}

/* Sends a single command (length=1). and get the answer */
ssize_t command_read_sequence(unsigned char command, unsigned char *answer)
{
	ssize_t bytes_read;

	bytes_read = command_sequence(&command, 1, answer);

	if (bytes_read < 1) {
		ser_comm_fail("Error executing command");
	}

	return bytes_read;
}

/* Sends a setup command (length > 1) */
ssize_t command_write_sequence(unsigned char *command, size_t command_length, unsigned	char *answer)
{
	ssize_t bytes_read;

	bytes_read = command_sequence(command, command_length, answer);

	if (bytes_read < 1) {
		ser_comm_fail("Error executing command");
	}

	return bytes_read;
}

void upsdrv_comm_good()
{
	ser_comm_good();
}

#if (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP_BESIDEFUNC) && (!defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP_INSIDEFUNC) && ( (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TYPE_LIMITS_BESIDEFUNC) || (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TAUTOLOGICAL_CONSTANT_OUT_OF_RANGE_COMPARE_BESIDEFUNC) )
# pragma GCC diagnostic push
#endif

#if (!defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP_INSIDEFUNC) && (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TYPE_LIMITS_BESIDEFUNC)
# pragma GCC diagnostic ignored "-Wtype-limits"
#endif
#if (!defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP_INSIDEFUNC) && (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TAUTOLOGICAL_CONSTANT_OUT_OF_RANGE_COMPARE_BESIDEFUNC)
# pragma GCC diagnostic ignored "-Wtautological-constant-out-of-range-compare"
#endif
static void pw_comm_setup(const char *port)
{
	unsigned char command = PW_SET_REQ_ONLY_MODE;
	unsigned char id_command = PW_ID_BLOCK_REQ;
	unsigned char answer[256];
	int i = 0;
	ssize_t ret = -1;
	speed_t mybaud = 0, baud;

	if (getval("baud_rate") != NULL)
	{
		int br = atoi(getval("baud_rate"));
		/* Note that atoi() behavior on erroneous input is undefined */
		if (br < 0) {
			upslogx(LOG_ERR, "baud_rate option is invalid");
			return;
		}

		/* FIXME: speed_t does not define a SPEED_MAX value nor
		 * guarantee that it is an int (just a typedef from
		 * termios.h happens to say that on some systems)...
		 * But since we convert this setting from int, we assume...
		 */
#if (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP) && ( (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TYPE_LIMITS) || (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TAUTOLOGICAL_CONSTANT_OUT_OF_RANGE_COMPARE) || (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_UNREACHABLE_CODE) )
/* Note for gating macros above: unsuffixed HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP
 * means support of contexts both inside and outside function body, so the push
 * above and pop below (outside this finction) are not used.
 */
# pragma GCC diagnostic push
#endif
#ifdef HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TYPE_LIMITS
/* Note that the individual warning pragmas for use inside function bodies
 * are named without a _INSIDEFUNC suffix, for simplicity and legacy reasons
 */
# pragma GCC diagnostic ignored "-Wtype-limits"
#endif
#ifdef HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_UNREACHABLE_CODE
#pragma GCC diagnostic ignored "-Wunreachable-code"
#endif
#ifdef HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TAUTOLOGICAL_CONSTANT_OUT_OF_RANGE_COMPARE
# pragma GCC diagnostic ignored "-Wtautological-constant-out-of-range-compare"
#endif
/* Older CLANG (e.g. clang-3.4) seems to not support the GCC pragmas above */
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
#pragma clang diagnostic ignored "-Wtautological-compare"
#pragma clang diagnostic ignored "-Wtautological-constant-out-of-range-compare"
#endif
		switch(sizeof(speed_t)) {
			case 8:	assert (br < INT64_MAX); break;
			case 4:	assert (br < INT32_MAX); break;
			case 2:	assert (br < INT16_MAX); break;
			default:	assert (br < INT_MAX);
		}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
#if (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP) && ( (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TYPE_LIMITS) || (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TAUTOLOGICAL_CONSTANT_OUT_OF_RANGE_COMPARE) || (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_UNREACHABLE_CODE) )
# pragma GCC diagnostic pop
#endif
		baud = (speed_t)br;

		for (i = 0; i < PW_MAX_BAUD; i++) {
			if (baud == pw_baud_rates[i].name) {
				mybaud = pw_baud_rates[i].rate;
				break;
			}
		}

		if (mybaud == 0) {
			fatalx(EXIT_FAILURE, "Specified baudrate \"%s\" is invalid!", getval("baud_rate"));
		}

		ser_set_speed(upsfd, device_path, mybaud);
		ser_send_char(upsfd, 0x1d); /* send ESC to take it out of menu */
		usleep(90000);
		send_write_command(BCMXCP_AUTHCMD, 4);
		usleep(500000);
		ret = command_sequence(&command, 1, answer);
		if (ret <= 0) {
			usleep(500000);
			ret = command_sequence(&id_command, 1, answer);
		}

		if (ret > 0) {
			/* Cast baud into max length unsigned, despite the POSIX
			 * standard some systems vary in definition of this type
			 */
			upslogx(LOG_INFO, "Connected to UPS on %s with baudrate %llu", port, (unsigned long long int)baud);
			return;
		}

		upslogx(LOG_ERR, "No response from UPS on %s with baudrate %llu", port, (unsigned long long int)baud);
	}

	upslogx(LOG_INFO, "Attempting to autodect baudrate");

	for (i=0; i<PW_MAX_BAUD; i++) {

		ser_set_speed(upsfd, device_path, pw_baud_rates[i].rate);
		ser_send_char(upsfd, 0x1d); /* send ESC to take it out of menu */
		usleep(90000);
		send_write_command(BCMXCP_AUTHCMD, 4);
		usleep(500000);
		ret = command_sequence(&command, 1, answer);
		if (ret <= 0) {
			usleep(500000);
			ret = command_sequence(&id_command, 1, answer);
		}

		if (ret > 0) {
			upslogx(LOG_INFO, "Connected to UPS on %s with baudrate %zu", port, pw_baud_rates[i].name);
			return;
		}

		upsdebugx(2, "No response from UPS on %s with baudrate %zu", port, pw_baud_rates[i].name);
	}

	fatalx(EXIT_FAILURE, "Can't connect to the UPS on port %s!\n", port);
}
#if (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP_BESIDEFUNC) && (!defined HAVE_PRAGMA_GCC_DIAGNOSTIC_PUSH_POP_INSIDEFUNC) && ( (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TYPE_LIMITS_BESIDEFUNC) || (defined HAVE_PRAGMA_GCC_DIAGNOSTIC_IGNORED_TAUTOLOGICAL_CONSTANT_OUT_OF_RANGE_COMPARE_BESIDEFUNC) )
# pragma GCC diagnostic pop
#endif

void upsdrv_initups(void)
{
	upsfd = ser_open(device_path);
	pw_comm_setup(device_path);
}

void upsdrv_cleanup(void)
{
	/* free(dynamic_mem); */
	ser_close(upsfd, device_path);
}

void upsdrv_reconnect(void)
{
}