/*
 * serial.c -- Serial port routines.
 *
 * Copyright (C) 2008 Hugo Villeneuve <hugo@hugovil.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "config.h"

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>   /* Standard input/output definitions */
#include <string.h>  /* String function definitions */
#include <unistd.h>  /* UNIX standard function definitions */
#include <fcntl.h>   /* File control definitions */
#include <errno.h>   /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */
#include <ctype.h>   /* For isdigit() and friends... */
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/ioctl.h>

#include "common.h"
#include "serial.h"

#define _POSIX_SOURCE	1 /* POSIX compliant source */

#define CHAR_BUF_MAX	256
#define MAX_LINE_CHAR	768

const char *baud_rate_ascii[] = {
	"2400",
	"4800",
	"9600",
	"19200",
	"38400",
	"57600",
	"115200"
};

#define BAUD_RATE_VALUES_COUNT \
	(sizeof(baud_rate_ascii)/sizeof(baud_rate_ascii[0]))

const speed_t baud_rate_termios[] = {
	B2400,
	B4800,
	B9600,
	B19200,
	B38400,
	B57600,
	B115200
};

struct serial_port_t {
	int fd; /* Serial port file descriptor.*/
	struct termios oldtio; /* To save serial port original settings. */
	struct termios newtio;
};

static struct serial_port_t serial_port;

/*
 * Validates baud rate entered on the command line as an ASCII string, and
 * returns an index corresponding to this speed inside an array (see above).
 */
int
validate_baudrate(char *baud_rate_string)
{
	int i;

	for (i = 0; i < BAUD_RATE_VALUES_COUNT; i++) {
		if (STREQ(baud_rate_ascii[i], baud_rate_string))
			return i; /* Found it! */
	}

	return -1;
}

static int
serial_port_configure(int baud_rate_index)
{
	int status;
	speed_t speed = baud_rate_termios[baud_rate_index];

	/* Save current port settings. */
	tcgetattr(serial_port.fd, &serial_port.oldtio);

	/* Clear struct for new port settings. */
	bzero(&serial_port.newtio, sizeof(serial_port.newtio));

	/*
	 * speed   : Set bps rate.
	 * CRTSCTS : output hardware flow control (only used if the cable has
	 *           all necessary lines. See sect. 7 of Serial-HOWTO)
	 * CS8     : 8n1 (8bit,no parity,1 stopbit)
	 * CLOCAL  : local connection, no modem contol
	 * CREAD   : enable receiving characters
	 */
	serial_port.newtio.c_cflag = speed | CS8 | CLOCAL | CREAD;

	/*
	 * IGNPAR  : ignore bytes with parity errors
	 * ICRNL   : map CR to NL (otherwise a CR input on the other computer
	 *           will not terminate input)
	 *           otherwise make device raw (no other input processing)
	 */
	serial_port.newtio.c_iflag = IGNPAR;

	/* Raw output. */
	serial_port.newtio.c_oflag = 0;

	/* Set input mode (non-canonical, no echo,...) */
	serial_port.newtio.c_lflag = 0;

	/* Inter-character timer unused */
	serial_port.newtio.c_cc[VTIME] = 0;

	/* Blocking read until 1 chars received */
	serial_port.newtio.c_cc[VMIN] = 1;

	/* Now clean the modem line and activate the settings for the port. */
	tcflush(serial_port.fd, TCIFLUSH);
	status = tcsetattr(serial_port.fd, TCSANOW, &serial_port.newtio);
	if (status < 0) {
		log_fail("tcsetattr() failed");
		return status;
	}

	return 0;
}

int
serial_port_open(const char *port, const int baud_rate_index)
{
	int status;

	log_debug2("baud_rate_index = %d", baud_rate_index);

	/*
	 * The O_NOCTTY flag tells UNIX that this program doesn't want to be the
	 * "controlling terminal" for that port. If you don't specify this then
	 * any input (such as keyboard abort signals and so forth) will affect
	 * your process.
	 *
	 * The O_NDELAY flag tells UNIX that this program doesn't care what
	 * state the DCD signal line is in - whether the other end of the port
	 * is up and running. If you do not specify this flag, your process will
	 * be put to sleep until the DCD signal line is the space voltage.
	 *
	 * Timeouts are ignored in canonical input mode or when the O_NDELAY
	 * option is set on the file via open or fcntl. */
	serial_port.fd = open(port, O_RDWR | O_NOCTTY);
	if (serial_port.fd < 0) {
		/* Could not open the port. */
		log_fail("Error opening serial port %s", port);
		perror(PACKAGE_NAME);
		status = EXIT_FAILURE;
	} else
		status = serial_port_configure(baud_rate_index);

	/* Flush unread data. */
	status = tcflush(serial_port.fd, TCIFLUSH);
	if (status != 0)
		log_fail("Failure calling ioctl with TCFLSH argument");

	return status;
}

void
serial_port_close(void)
{
	if (serial_port.fd != 0) {
		log_debug2("Closing Serial Port");

		/* Restoring original port settings. */
		tcsetattr(serial_port.fd, TCSANOW, &serial_port.oldtio);

		close(serial_port.fd);
		serial_port.fd = 0;
	}
}

int
set_dtr(int dtr)
{
	int status;

	ioctl(serial_port.fd, TIOCMGET, &status);
	if (dtr) status &= ~TIOCM_DTR;
	else     status |=  TIOCM_DTR; 
	ioctl(serial_port.fd, TIOCMSET, &status);
	return EXIT_SUCCESS;
}	

int
set_rts(int rts)
{
	int status;
	
	ioctl(serial_port.fd, TIOCMGET, &status);
	if (rts) status &= ~TIOCM_RTS;
	else     status |=  TIOCM_RTS; 
	ioctl(serial_port.fd, TIOCMSET, &status);
	return EXIT_SUCCESS;
}
	
int
send_message(const char *msg)
{
	int status;
	ssize_t len;
	int size = strlen(msg);
	int k;
	char buf[CHAR_BUF_MAX];

	log_debug2("Sending size = %d", size);

	strncpy(buf, msg, sizeof(buf));

	for (k = 0; k < size; k++) {
		/* Replace CR/LF by \0 */
		if (buf[k] == '\n')
			buf[k] = 0x00;

		log_debug3("  [%02d] 0x%02X", k, (u_int8_t) buf[k]);
	}

	len = write(serial_port.fd, buf, size);
	if (len < 0) {
		perror(PACKAGE_NAME);
		log_fail("  Error writing message to serial port.");
		status = EXIT_FAILURE;
	} else
		status = EXIT_SUCCESS;

	log_debug2("  Written %d characters", len);

	return status;
}

int
send_number(u_int32_t number, int digits)
{
	char buf[CHAR_BUF_MAX];
	int index = 0;

	sprintf(buf, "%08X", number);
	index = 8 - digits;

	return send_message(&buf[index]);
}

int
send_buffer(u_int8_t *data, ssize_t size_in_bytes)
{
	int k;
	u_int32_t *data32 = (u_int32_t *) data;

	if ((size_in_bytes % 4) != 0) {
		log_fail("Data must be 32-bits aligned");
		return 1;
	}

	for (k = 0; k < (size_in_bytes / 4); k++)
		send_number(data32[k], 8);

	return 0;
}

int
send_buffer_bin(u_int8_t *data, ssize_t size_in_bytes)
{
	for (; size_in_bytes > 0; size_in_bytes--, data++)
		write(serial_port.fd, data, 1);

	return 0;
}

int
send_ascii_data(u_int8_t *data, ssize_t size)
{
	int status;
	ssize_t len;

	log_debug2("Sending size = %d", size);

	len = write(serial_port.fd, data, size);
	if (len < 0) {
		perror(PACKAGE_NAME);
		log_fail("  Error writing ADCII data to serial port.");
		status = EXIT_FAILURE;
	} else
		status = EXIT_SUCCESS;

	log_debug2("  Written %d characters", len);

	return status;
}

/*
 * Compare received characters with str1, str2 and str3.
 * The function returns when either str1, str2 or str3 is found,
 * or after a timeout.
 *
 * Return value:
 *  -1 = Error
 *   0 = no strings found
 *   1 = str1 found
 *   2 = str2 found
 *   3 = str3 found
 */
int
wait_for_message(const char *str1, const char *str2, const char *str3)
{
	int str_found = 0;
	char input[CHAR_BUF_MAX];
	char *message;
	const char *received_string = NULL;
	int i;
	ssize_t len;

	i = 0;
	input[0] = '\0';

	if (!str1) {
		log_fail("str1 search string not specified");
		return -1;
	}

	len = sprintf(input, "[%s]", str1);
	if (str2)
		len += sprintf(&input[len], " [%s]", str2);
	if (str3)
		len += sprintf(&input[len], " [%s]", str3);

	log_info("Expecting messages: %s", input);

	while (!str_found) {
		do {
			/* read() returns after 1 char have been input */
			len = read(serial_port.fd, &input[i], 1);
			if (len != 0) {
				log_debug3("[%d] 0x%02X", i,
					   (u_int8_t) input[i]);
				i++;
			} else
				log_debug2("LEN == 0");
		} while ((input[i - 1] != 0) &&
			 (i < (CHAR_BUF_MAX - 1)) &&
			 (input[i - 1] != 0x0A) &&
			 (input[i - 1] != 0x0D));

		/* Remove trailing CR or LF */
		if ((input[i-1] == 0x0A) || (input[i-1] == 0x0D))
			input[i-1] = '\0';

		i = 0;
		/* Remove space before string */
		while (input[i] == ' ')
			i++;

		message = &input[i];

		if (strlen(message) == 0)
			continue;

		log_debug1("  Reading: [%s]", message);

		if (strstr(message, str1)) {
			str_found = 1;
			received_string = str1;
		}

		if (str2 != NULL) {
			if (strstr(message, str2)) {
				str_found = 2;
				received_string = str2;
			}
		}

		if (str3 != NULL) {
			if (strstr(message, str3)) {
				str_found = 3;
				received_string = str3;
			}
		}

		i = 0;
	}

	if (received_string)
		log_info("  [%s] received", received_string);

	return str_found;
}