/*!
 * \file error.c
 * 
 * \brief GIS Library: Error messages functions
 *
 * (C) 1999-2011 by the GRASS Development Team
 *
 * This program is free software under the GNU General Public
 * License (>=v2). Read the file COPYING that comes with GRASS
 * for details.
 *
 * \author USACERL and many others
 */

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <stdarg.h>
#include <sys/types.h>
#include <grass/glocale.h>
#include <grass/gis.h>

/*!
 * \def MSG
 *
 * \brief A message
 */
#define MSG  0
/*!
 * \def WARN
 *
 * \brief A warning message
 */
#define WARN 1
/*!
 * \def ERR
 *
 * \brief A fatal error message
 */
#define ERR  2


/* static int (*error)() = 0; */
static int (*ext_error) (const char *, int);	/* Roger Bivand 17 June 2000 */
static int no_warn = 0;
static int no_sleep = 1;
static int message_id = 1;

static int print_word(FILE *, char **, int *, const int);
static void print_sentence(FILE *, const int, const char *);
static int print_error(const char *, const int);
static int mail_msg(const char *, int);
static int write_error(const char *, int, time_t, const char *);
static int log_error(const char *, int);

static int vfprint_error(int type, const char *template, va_list ap)
{
    char buffer[2000];		/* G_asprintf does not work */

    vsprintf(buffer, template, ap);

    /* . */
    return print_error(buffer, type);
}

/*!
 * \brief Print a message to stderr
 *
 * The output format depends on environment variable GRASS_MESSAGE_FORMAT
 *
 * \param msg string (cannot be NULL)
 */
void G_message(const char *msg, ...)
{
    if (G_verbose() >= G_verbose_std()) {
	va_list ap;

	va_start(ap, msg);
	vfprint_error(MSG, msg, ap);
	va_end(ap);
    }

    return;
}

/*!
 * \brief Print a message to stderr but only if module is in verbose mode
 *
 * The output format depends on environment variables
 *  GRASS_MESSAGE_FORMAT and GRASS_VERBOSE
 *
 * \param msg string (cannot be NULL)
 */
void G_verbose_message(const char *msg, ...)
{
    if (G_verbose() > G_verbose_std()) {
	va_list ap;

	va_start(ap, msg);
	vfprint_error(MSG, msg, ap);
	va_end(ap);
    }

    return;
}

/*!
 * \brief Print a message to stderr even in brief mode (verbosity=1)
 *
 * Ususally just G_percent()/G_clicker() would be shown at this level.
 * This allows important non-error/warning messages to display as well.
 *
 * The output format depends on environment variables
 *  GRASS_MESSAGE_FORMAT and GRASS_VERBOSE
 *
 * \param msg string (cannot be NULL)
 */
void G_important_message(const char *msg, ...)
{
    if (G_verbose() > G_verbose_min()) {
	va_list ap;

	va_start(ap, msg);
	vfprint_error(MSG, msg, ap);
	va_end(ap);
    }

    return;
}

/*!
 * \brief Print a fatal error message to stderr
 * 
 * The output format depends on environment variable
 * GRASS_MESSAGE_FORMAT
 *
 * By default, the message is handled by an internal routine which
 * prints the message to the screen. Using G_set_error_routine() the
 * programmer can have the message handled by another routine. This is
 * especially useful if the message should go to a particular location
 * on the screen when using curses or to a location on a graphics
 * device (monitor).
 *
 * \param msg string (cannot be NULL)

 * \return Terminates with an exit status of EXIT_FAILURE if no external
 * routine is specified by G_set_error_routine()
 */
int G_fatal_error(const char *msg, ...)
{
    static int busy;
    va_list ap;

    if (busy)
	exit(EXIT_FAILURE);
    busy = 1;

    va_start(ap, msg);
    vfprint_error(ERR, msg, ap);
    va_end(ap);

    exit(EXIT_FAILURE);
}

/*!
 * \brief Print a warning message to stderr
 * 
 * The output format depends on environment variable
 * GRASS_MESSAGE_FORMAT
 *
 * A warning message can be suppressed by G_suppress_warnings()
 *
 * \param msg string (cannot be NULL)
 *
 * \return 0
 */
int G_warning(const char *msg, ...)
{
    va_list ap;

    if (no_warn)
	return 0;

    va_start(ap, msg);
    vfprint_error(WARN, msg, ap);
    va_end(ap);

    return 0;
}

/*!
 * \brief Suppress printing a warning message to stderr
 * 
 * \param flag a warning message will be suppressed if non-zero value is given
 *
 * \return previous flag
 */
int G_suppress_warnings(int flag)
{
    int prev;

    prev = no_warn;
    no_warn = flag;
    return prev;
}

/*!
 * \brief Turn on/off no_sleep flag
 * 
 * \param flag if non-zero/zero value is given G_sleep() will be activated/deactivated
 *
 * \return previous flag
 */
int G_sleep_on_error(int flag)
{
    int prev;

    prev = !no_sleep;
    no_sleep = !flag;
    return prev;
}

/*!
 * \brief Establishes error_routine as the routine that will handle
 * the printing of subsequent error messages.
 * 
 * \param error_routine routine will be called like this: error_routine(msg,
 * fatal)
 *
 * \return 0
 */
int G_set_error_routine(int (*error_routine) (const char *, int))
{
    ext_error = error_routine;	/* Roger Bivand 17 June 2000 */
    return 0;
}

/*!
 * \brief After this call subsequent error messages will be handled in the
 * default method.
 * 
 * Error messages are printed directly to the screen: ERROR: message or WARNING: message
 *
 * \return 0
 */
int G_unset_error_routine(void)
{
    ext_error = 0;		/* Roger Bivand 17 June 2000 */

    return 0;
}

/* Print info to stderr and optionally to log file and optionally send mail */
static int print_error(const char *msg, const int type)
{
    static char *prefix_std[3];
    int fatal, format;

    if (!prefix_std[0]) {	/* First time: set prefixes  */
	prefix_std[0] = "";
	prefix_std[1] = _("WARNING: ");
	prefix_std[2] = _("ERROR: ");
    }

    if (type == ERR)
	fatal = TRUE;
    else			/* WARN */
	fatal = FALSE;

    if ((type == WARN || type == ERR) && ext_error) {	/* Function defined by application */
	ext_error(msg, fatal);
    }
    else {
	char *w;
	int len, lead;

	format = G_info_format();

	if (format != G_INFO_FORMAT_GUI) {
	    if (type == WARN || type == ERR) {
		log_error(msg, fatal);
	    }

	    fprintf(stderr, "%s", prefix_std[type]);
	    len = lead = strlen(prefix_std[type]);
	    w = (char *)msg;

	    while (print_word(stderr, &w, &len, lead)) ;

	    if ((type != MSG) && isatty(fileno(stderr))
		&& (G_info_format() == G_INFO_FORMAT_STANDARD)) {	/* Bell */
		fprintf(stderr, "\7");
		fflush(stderr);
		if (!no_sleep)
		    G_sleep(5);
	    }
	    else if ((type == WARN || type == ERR) && getenv("GRASS_ERROR_MAIL")) {	/* Mail */
		mail_msg(msg, fatal);
	    }
	}
	else {	/* GUI */
	    print_sentence(stderr, type, msg);
	}
    }

    return 0;
}

static int log_error(const char *msg, int fatal)
{
    char cwd[GPATH_MAX];
    time_t clock;
    char *gisbase;

    /* get time */
    clock = time(NULL);

    /* get current working directory */
    getcwd(cwd, sizeof(cwd));

    /* write the error log file */
    if ((gisbase = G_gisbase()))
	write_error(msg, fatal, clock, cwd);

    return 0;
}

/* Write a message to the log file */
static int write_error(const char *msg, int fatal,
		       time_t clock, const char *cwd)
{
    static char *logfile;
    FILE *log;

    if (!logfile) {
	logfile = getenv("GIS_ERROR_LOG");
	if (!logfile) {
	    char buf[GPATH_MAX];

	    sprintf(buf, "%s/GIS_ERROR_LOG", G__home());
	    logfile = G_store(buf);
	}
    }

    log = fopen(logfile, "r");
    if (!log)
	/* GIS_ERROR_LOG file is not readable or does not exist */
	return 1;

    log = freopen(logfile, "a", log);
    if (!log)
	/* the user doesn't have write permission */
	return 1;

    fprintf(log, "-------------------------------------\n");
    fprintf(log, "%-10s %s\n", "program:", G_program_name());
    fprintf(log, "%-10s %s\n", "user:", G_whoami());
    fprintf(log, "%-10s %s\n", "cwd:", cwd);
    fprintf(log, "%-10s %s\n", "date:", ctime(&clock));
    fprintf(log, "%-10s %s\n", fatal ? "error:" : "warning:", msg);
    fprintf(log, "-------------------------------------\n");

    fclose(log);

    return 0;
}

/* Mail a message */
static int mail_msg(const char *msg, int fatal)
{
    FILE *mail;
    char command[64];
    char *user;

    user = G_whoami();
    if (user == 0 || *user == 0)
	return 1;

    sprintf(command, "mail '%s'", G_whoami());
    if ((mail = popen(command, "w"))) {
	fprintf(mail, "GIS %s: %s\n", fatal ? "ERROR" : "WARNING", msg);
	G_pclose(mail);
    }

    return 0;
}

/* Print one word, new line if necessary */
static int print_word(FILE * fd, char **word, int *len, const int lead)
{
    int wlen, start, totlen;
    int nl;
    char *w, *b;

    start = *len;
    w = *word;

    nl = 0;
    while (*w == ' ' || *w == '\t' || *w == '\n')
	if (*w++ == '\n')
	    nl++;

    wlen = 0;
    for (b = w; *b != 0 && *b != ' ' && *b != '\t' && *b != '\n'; b++)
	wlen++;

    if (wlen == 0) {
	fprintf(fd, "\n");
	return 0;
    }

    if (start > lead) {		/* add space */
	totlen = start + wlen + 1;
    }
    else {
	totlen = start + wlen;
    }

    if (nl != 0 || totlen > 75) {
	while (--nl > 0)
	    fprintf(fd, "\n");
	fprintf(fd, "\n%*s", lead, "");
	start = lead;
    }

    if (start > lead) {
	fprintf(fd, " ");
	start++;
    }

    *len = start + wlen;

    fwrite(w, 1, wlen, fd);
    w += wlen;

    *word = w;

    return 1;
}

/* Print one message, prefix inserted before each new line */
static void print_sentence(FILE * fd, const int type, const char *msg)
{
    char prefix[100];
    const char *start;

    switch (type) {
    case MSG:
	sprintf(prefix, "GRASS_INFO_MESSAGE(%d,%d): ", getpid(), message_id);
	break;
    case WARN:
	sprintf(prefix, "GRASS_INFO_WARNING(%d,%d): ", getpid(), message_id);
	break;
    case ERR:
	sprintf(prefix, "GRASS_INFO_ERROR(%d,%d): ", getpid(), message_id);
	break;
    }

    start = msg;

    fprintf(stderr, "\n");
    while (*start != '\0') {
	const char *next = start;

	fprintf(fd, "%s", prefix);

	while (*next != '\0') {
	    next++;

	    if (*next == '\n') {
		next++;
		break;
	    }
	}

	fwrite(start, 1, next - start, fd);
	fprintf(fd, "\n");
	start = next;
    }
    fprintf(stderr, "GRASS_INFO_END(%d,%d)\n", getpid(), message_id);
    message_id++;
}

/*!
 * \brief Get current message format
 * 
 * Maybe set to either "standard" or "gui" (normally GRASS takes care)
 *
 * \return grass_info_format value
 */
int G_info_format(void)
{
    static int grass_info_format = -1;
    char *fstr;

    if (grass_info_format < 0) {
	fstr = getenv("GRASS_MESSAGE_FORMAT");

	if (fstr && G_strcasecmp(fstr, "gui") == 0)
	    grass_info_format = G_INFO_FORMAT_GUI;
	else if (fstr && G_strcasecmp(fstr, "silent") == 0)
	    grass_info_format = G_INFO_FORMAT_SILENT;
	else if (fstr && G_strcasecmp(fstr, "plain") == 0)
	    grass_info_format = G_INFO_FORMAT_PLAIN;
	else
	    grass_info_format = G_INFO_FORMAT_STANDARD;
    }

    return grass_info_format;
}