/*
 * utils.c -- various utility routines
 *
 * This code is Copyright (c) 2006, by the authors of nmh.  See the
 * COPYRIGHT file in the root directory of the nmh distribution for
 * complete copyright information.
 */

#include <h/mh.h>
#include <h/utils.h>
#include <fcntl.h>

/* sbr/signals.c */
extern int setup_signal_handlers();

/* sbr/m_mktemp.c */
extern void remove_registered_files_atexit();


/*
 * We allocate space for messages (msgs array)
 * this number of elements at a time.
 */
#define MAXMSGS 256

/*
 * Safely call malloc
 */
void *
mh_xmalloc(size_t size)
{
    void *memory;

    if (size == 0)
        adios(NULL, "Tried to malloc 0 bytes");

    memory = malloc(size);
    if (!memory)
        adios(NULL, "Malloc failed");

    return memory;
}

/*
 * Safely call realloc
 */
void *
mh_xrealloc(void *ptr, size_t size)
{
    void *memory;

    /* Some non-POSIX realloc()s don't cope with realloc(NULL,sz) */
    if (!ptr)
        return mh_xmalloc(size);

    if (size == 0)
        adios(NULL, "Tried to realloc 0bytes");

    memory = realloc(ptr, size);
    if (!memory)
        adios(NULL, "Realloc failed");

    return memory;
}

/*
 * Return the present working directory, if the current directory does not
 * exist, or is too long, make / the pwd.
 */
char *
pwd(void)
{
    register char *cp;
    static char curwd[PATH_MAX];

    if (!getcwd (curwd, PATH_MAX)) {
        admonish (NULL, "unable to determine working directory");
        if (!mypath || !*mypath
                || (strcpy (curwd, mypath), chdir (curwd)) == -1) {
            strcpy (curwd, "/");
            chdir (curwd);
        }
        return curwd;
    }

    if ((cp = curwd + strlen (curwd) - 1) > curwd && *cp == '/')
        *cp = '\0';

    return curwd;
}

/*
 * add   -- If "s1" is NULL, this routine just creates a
 *       -- copy of "s2" into newly malloc'ed memory.
 *       --
 *       -- If "s1" is not NULL, then copy the concatenation
 *       -- of "s1" and "s2" (note the order) into newly
 *       -- malloc'ed memory.  Then free "s1".
 */
char *
add (const char *s2, char *s1)
{
    char *cp;
    size_t len1 = 0, len2 = 0;

    if (s1)
        len1 = strlen (s1);
    if (s2)
        len2 = strlen (s2);

    cp = mh_xmalloc (len1 + len2 + 1);

    /* Copy s1 and free it */
    if (s1) {
        memcpy (cp, s1, len1);
        free (s1);
    }

    /* Copy s2 */
    if (s2)
        memcpy (cp + len1, s2, len2);

    /* Now NULL terminate the string */
    cp[len1 + len2] = '\0';

    return cp;
}

/*
 * addlist
 *	Append an item to a comma separated list
 */
char *
addlist (char *list, const char *item)
{
    if (list)
    	list = add (", ", list);

    return add (item, list);
}

/*
 * folder_exists
 *      Check to see if a folder exists.
 */
int folder_exists(const char *folder)
{
    struct stat st;
    int exists = 0;

    if (stat (folder, &st) == -1) {
        /* The folder either doesn't exist, or we hit an error.  Either way
         * return a failure.
         */
        exists = 0;
    } else {
        /* We can see a folder with the right name */
        exists = 1;
    }

    return exists;
}


/*
 * create_folder
 *      Check to see if a folder exists, if not, prompt the user to create
 *      it.
 */
void create_folder(char *folder, int autocreate, void (*done_callback)(int))
{
    struct stat st;
    extern int errno;
    char *cp;

    if (stat (folder, &st) == -1) {
        if (errno != ENOENT)
            adios (folder, "error on folder");
        if (autocreate == 0) {
            /* ask before creating folder */
            cp = concat ("Create folder \"", folder, "\"? ", NULL);
            if (!getanswer (cp))
                done_callback (1);
            free (cp);
        } else if (autocreate == -1) {
            /* do not create, so exit */
            done_callback (1);
        }
        if (!makedir (folder))
            adios (NULL, "unable to create folder %s", folder);
    }
}

/*
 * num_digits
 *      Return the number of digits in a nonnegative integer.
 */
int
num_digits (int n)
{
    int ndigits = 0;

    /* Sanity check */
    if (n < 0)
        adios (NULL, "oops, num_digits called with negative value");

    if (n == 0)
        return 1;

    while (n) {
        n /= 10;
        ndigits++;
    }

    return ndigits;
}

/*
 * Append a message arg to an array of them, resizing it if necessary.
 * Really a simple vector-of-(char *) maintenance routine.
 */
void
app_msgarg(struct msgs_array *msgs, char *cp)
{
	if(msgs->size >= msgs->max) {
		msgs->max += MAXMSGS;
		msgs->msgs = mh_xrealloc(msgs->msgs,
			msgs->max * sizeof(*msgs->msgs));
	}
	msgs->msgs[msgs->size++] = cp;
}

/*
 * Append a message number to an array of them, resizing it if necessary.
 * Like app_msgarg, but with a vector-of-ints instead.
 */

void
app_msgnum(struct msgnum_array *msgs, int msgnum)
{
	if (msgs->size >= msgs->max) {
		msgs->max += MAXMSGS;
		msgs->msgnums = mh_xrealloc(msgs->msgnums,
			msgs->max * sizeof(*msgs->msgnums));
	}
	msgs->msgnums[msgs->size++] = msgnum;
}

/* Open a form or components file */
int
open_form(char **form, char *def)
{
	int in;
	if (*form) {
		if ((in = open (etcpath (*form), O_RDONLY)) == NOTOK)
			adios (*form, "unable to open form file");
	} else {
		if ((in = open (etcpath (def), O_RDONLY)) == NOTOK)
			adios (def, "unable to open default components file");
		*form = def;
	}
	return in;
}


/*
 * Finds first occurrence of str in buf.  buf is not a C string but a
 * byte array of length buflen.  str is a null-terminated C string.
 * find_str() does not modify buf but passes back a non-const char *
 * pointer so that the caller can modify it.
 */
char *
find_str (const char buf[], size_t buflen, const char *str) {
    const size_t len = strlen (str);
    size_t i;

    for (i = 0; i + len <= buflen; ++i, ++buf) {
        if (! memcmp (buf, str, len)) return (char *) buf;
    }

    return NULL;
}


/*
 * Finds last occurrence of str in buf.  buf is not a C string but a
 * byte array of length buflen.  str is a null-terminated C string.
 * find_str() does not modify buf but passes back a non-const char *
 * pointer so that the caller can modify it.
 */
char *
rfind_str (const char buf[], size_t buflen, const char *str) {
    const size_t len = strlen (str);
    size_t i;

    for (i = 0, buf += buflen - len; i + len <= buflen; ++i, --buf) {
        if (! memcmp (buf, str, len)) return (char *) buf;
    }

    return NULL;
}


/* POSIX doesn't have strcasestr() so emulate it. */
char *
nmh_strcasestr (const char *s1, const char *s2) {
    const size_t len = strlen (s2);

    if (isupper ((unsigned char) s2[0])  ||  islower ((unsigned char)s2[0])) {
        char first[3];
        first[0] = (char) toupper ((unsigned char) s2[0]);
        first[1] = (char) tolower ((unsigned char) s2[0]);
        first[2] = '\0';

        for (s1 = strpbrk (s1, first); s1; s1 = strpbrk (++s1, first)) {
            if (! strncasecmp (s1, s2, len)) return (char *) s1;
        }
    } else {
        for (s1 = strchr (s1, s2[0]); s1; s1 = strchr (++s1, s2[0])) {
            if (! strncasecmp (s1, s2, len)) return (char *) s1;
        }
    }

    return NULL;
}


int
nmh_init(const char *argv0, int read_context) {
    setlocale(LC_ALL, "");

    invo_name = r1bindex ((char *) argv0, '/');

    if (setup_signal_handlers()) {
        admonish("sigaction", "unable to set up signal handlers");
    }

    /* POSIX atexit() does not define any error conditions. */
    if (atexit(remove_registered_files_atexit)) {
        admonish("atexit", "unable to register atexit function");
    }

    if (read_context) {
        context_read();
        return OK;
    } else {
        int status = context_foil(NULL);
        if (status != OK) {
            advise("", "failed to create minimal profile/conext");
        }
        return status;
    }
}


/* Returns copy of argument str with all characters converted to upper
   case, and trimmed whitespace (see cpytrim()) . */
char *
upcase (const char *str) {
    char *up = cpytrim (str);
    char *cp;

    for (cp = up; *cp; ++cp) { *cp = toupper ((unsigned char) *cp); }

    return up;
}


/*
 * Scan for any 8-bit characters.  Return 1 if they exist.
 *
 * Scan up until the given endpoint (but not the actual endpoint itself).
 * If the endpoint is NULL, scan until a '\0' is reached.
 */

int
contains8bit(const char *start, const char *end)
{
    if (! start)
	return 0;

    while (*start != '\0' && (!end || (start < end)))
	if (! isascii((unsigned char) *start++))
	    return 1;

    return 0;
}