/*
 * cash.c
 * Written by D'Arcy J.M. Cain
 *
 * Functions to allow input and output of money normally but store
 * and handle it as longs
 *
 * A slightly modified version of this file and a discussion of the
 * workings can be found in the book "Software Solutions in C" by
 * Dale Schumacher, Academic Press, ISBN: 0-12-632360-7.
 * 
 * $Header: /cvsroot/pgsql/src/backend/utils/adt/cash.c,v 1.4 1997/04/15 17:39:44 scrappy Exp $
 */

#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>
#include <locale.h>

#include "postgres.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/cash.h"

/* when we go to 64 bit values we will have to modify this */
#define CASH_BUFSZ	24

#define TERMINATOR	(CASH_BUFSZ - 1)
#define LAST_PAREN	(TERMINATOR - 1)
#define LAST_DIGIT	(LAST_PAREN - 1)

#ifdef USE_LOCALE
static struct lconv *lconv = NULL;
#endif

/* cash_in()
 * Convert a string to a cash data type.
 * Format is [$]###[,]###[.##]
 * Examples: 123.45 $123.45 $123,456.78
 * 
 * This is currently implemented as a 32-bit integer.
 * XXX HACK It looks as though some of the symbols for
 *  monetary values returned by localeconv() can be multiple
 *  bytes/characters. This code assumes one byte only. - tgl 97/04/14
 */
Cash *
cash_in(const char *str)
{
    Cash *result;

    Cash value = 0;
    Cash dec = 0;
    Cash sgn = 1;
    int seen_dot = 0;
    const char *s = str;
    int fpoint;
    char dsymbol, ssymbol, psymbol, nsymbol, csymbol;

#ifdef USE_LOCALE
    if (lconv == NULL) *lconv = localeconv();

    /* frac_digits in the C locale seems to return CHAR_MAX */
    /* best guess is 2 in this case I think */
    fpoint = ((lconv->frac_digits != CHAR_MAX)? lconv->frac_digits: 2); /* int_frac_digits? */

    dsymbol = *lconv->mon_decimal_point;
    ssymbol = *lconv->mon_thousands_sep;
    csymbol = *lconv->currency_symbol;
    psymbol = *lconv->positive_sign;
    nsymbol = *lconv->negative_sign;
#else
    fpoint = 2;
    dsymbol = '.';
    ssymbol = ',';
    csymbol = '$';
    psymbol = '+';
    nsymbol = '-';
#endif

    /* we need to add all sorts of checking here.  For now just */
    /* strip all leading whitespace and any leading dollar sign */
    while (isspace(*s) || *s == csymbol) s++;

    /* a leading minus or paren signifies a negative number */
    /* again, better heuristics needed */
    if (*s == nsymbol || *s == '(') {
	sgn = -1;
	s++;

    } else if (*s == psymbol) {
	s++;
    }

    while (isspace(*s) || *s == csymbol) s++;

    for (; ; s++) {
	/* we look for digits as long as we have less */
	/* than the required number of decimal places */
	if (isdigit(*s) && dec < fpoint) {
	    value = (value * 10) + *s - '0';

	    if (seen_dot)
		dec++;

	/* decimal point? then start counting fractions... */
	} else if (*s == dsymbol && !seen_dot) {
	    seen_dot = 1;

	/* "thousands" separator? then skip... */
	} else if (*s == ssymbol) {

	} else {
	    /* round off */
	    if (isdigit(*s) && *s >= '5')
		value++;

	    /* adjust for less than required decimal places */
	    for (; dec < fpoint; dec++)
		value *= 10;

	    break;
	}
    }

    while (isspace(*s) || *s == ')') s++;

    if (*s != '\0')
	elog(WARN,"Bad money external representation %s",str);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't input cash '%s'",str);

    *result = (value * sgn);

    return(result);
} /* cash_in() */


/* cash_out()
 * Function to convert cash to a dollars and cents representation.
 * XXX HACK This code appears to assume US conventions for
 *  positive-valued amounts. - tgl 97/04/14
 */
const char *
cash_out(Cash *value)
{
    char *result;
    char buf[CASH_BUFSZ];
    int minus = 0;
    int count = LAST_DIGIT;
    int point_pos;
    int comma_position = 0;
    char mon_group, comma, points;
    char csymbol, dsymbol, *nsymbol;
    char convention;

#ifdef USE_LOCALE
    if (lconv == NULL) *lconv = localeconv();

    mon_group = *lconv->mon_grouping;
    comma = *lconv->mon_thousands_sep;
    csymbol = *lconv->currency_symbol;
    dsymbol = *lconv->mon_decimal_point;
    nsymbol = lconv->negative_sign;
    /* frac_digits in the C locale seems to return CHAR_MAX */
    /* best guess is 2 in this case I think */
    points = ((lconv->frac_digits != CHAR_MAX)? lconv->frac_digits: 2); /* int_frac_digits? */
    convention = lconv->n_sign_posn;
#else
    mon_group = 3;
    comma = ',';
    csymbol = '$';
    dsymbol = '.';
    nsymbol = "-";
    points = 2;
    convention = 0;
#endif

    point_pos = LAST_DIGIT - points;

    /* We're playing a little fast and loose with this.  Shoot me. */
    if (!mon_group || mon_group == CHAR_MAX)
	mon_group = 3;

    /* allow more than three decimal points and separate them */
    if (comma) {
	point_pos -= (points - 1)/mon_group;
	comma_position = point_pos % (mon_group + 1);
    }

    /* we work with positive amounts and add the minus sign at the end */
    if (*value < 0) {
	minus = 1;
	*value *= -1;
    }

    /* allow for trailing negative strings */
    memset(buf, ' ', CASH_BUFSZ);
    buf[TERMINATOR] = buf[LAST_PAREN] = '\0';

    while (*value || count > (point_pos - 2)) {
	if (points && count == point_pos)
	    buf[count--] = dsymbol;
	else if (comma && count % (mon_group + 1) == comma_position)
	    buf[count--] = comma;

	buf[count--] = (*value % 10) + '0';
	*value /= 10;
    }

    buf[count] = csymbol;

    if (buf[LAST_DIGIT] == ',')
	buf[LAST_DIGIT] = buf[LAST_PAREN];

    /* see if we need to signify negative amount */
    if (minus) {
	if (!PointerIsValid(result = PALLOC(CASH_BUFSZ + 2 - count + strlen(nsymbol))))
	    elog(WARN,"Memory allocation failed, can't output cash",NULL);

	/* Position code of 0 means use parens */
	if (convention == 0)
	    sprintf(result, "(%s)", buf + count);
	else if (convention == 2)
	    sprintf(result, "%s%s", buf + count, nsymbol);
	else
	    sprintf(result, "%s%s", nsymbol, buf + count);
    } else {
	if (!PointerIsValid(result = PALLOC(CASH_BUFSZ + 2 - count)))
	    elog(WARN,"Memory allocation failed, can't output cash",NULL);

	strcpy(result, buf + count);
    }

    return(result);
} /* cash_out() */


bool
cash_eq(Cash *c1, Cash *c2)
{
    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(FALSE);

    return(*c1 == *c2);
} /* cash_eq() */

bool
cash_ne(Cash *c1, Cash *c2)
{
    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(FALSE);

    return(*c1 != *c2);
} /* cash_ne() */

bool
cash_lt(Cash *c1, Cash *c2)
{
    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(FALSE);

    return(*c1 < *c2);
} /* cash_lt() */

bool
cash_le(Cash *c1, Cash *c2)
{
    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(FALSE);

    return(*c1 <= *c2);
} /* cash_le() */

bool
cash_gt(Cash *c1, Cash *c2)
{
    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(FALSE);

    return(*c1 > *c2);
} /* cash_gt() */

bool
cash_ge(Cash *c1, Cash *c2)
{
    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(FALSE);

    return(*c1 >= *c2);
} /* cash_ge() */


/* cash_pl()
 * Add two cash values.
 */
Cash *
cash_pl(Cash *c1, Cash *c2)
{
    Cash *result;

    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(NULL);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't add cash",NULL);

    *result = (*c1 + *c2);

    return(result);
} /* cash_pl() */


/* cash_mi()
 * Subtract two cash values.
 */
Cash *
cash_mi(Cash *c1, Cash *c2)
{
    Cash *result;

    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(NULL);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't subtract cash",NULL);

    *result = (*c1 - *c2);

    return(result);
} /* cash_mi() */


/* cash_mul()
 * Multiply cash by floating point number.
 */
Cash *
cash_mul(Cash *c, float8 *f)
{
    Cash *result;

    if (!PointerIsValid(f) || !PointerIsValid(c))
	return(NULL);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't multiply cash",NULL);

    *result = ((*f) * (*c));

    return(result);
} /* cash_mul() */


/* cash_div()
 * Divide cash by floating point number.
 *
 * XXX Don't know if rounding or truncating is correct behavior.
 * Round for now. - tgl 97/04/15
 */
Cash *
cash_div(Cash *c, float8 *f)
{
    Cash *result;

    if (!PointerIsValid(f) || !PointerIsValid(c))
	return(NULL);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't divide cash",NULL);

    *result = rint(*c / *f);

    return(result);
} /* cash_div() */


/* cashlarger()
 * Return larger of two cash values.
 */
Cash *
cashlarger(Cash *c1, Cash *c2)
{
    Cash *result;

    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(NULL);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't return larger cash",NULL);

    *result = ((*c1 > *c2)? *c1: *c2);

    return(result);
} /* cashlarger() */


/* cashsmaller()
 * Return smaller of two cash values.
 */
Cash *
cashsmaller(Cash *c1, Cash *c2)
{
    Cash *result;

    if (!PointerIsValid(c1) || !PointerIsValid(c2))
	return(NULL);

    if (!PointerIsValid(result = PALLOCTYPE(Cash)))
        elog(WARN,"Memory allocation failed, can't return smaller cash",NULL);

    *result = ((*c1 < *c2)? *c1: *c2);

    return(result);
} /* cashsmaller() */


/* cash_words_out()
 * This converts a long as well but to a representation using words
 * Obviously way North American centric - sorry
 */
const char *
cash_words_out(Cash *value)
{
    static char	buf[128];
    char *p = buf;
    Cash m0;
    Cash m1;
    Cash m2;
    Cash m3;

    /* work with positive numbers */
    if (*value < 0) {
	*value *= -1;
	strcpy(buf, "minus ");
	p += 6;
    } else {
	*buf = 0;
    }

    m0 = *value % 100; /* cents */
    m1 = (*value/100) % 1000; /* hundreds */
    m2 = (*value/100000) % 1000; /* thousands */
    m3 = *value/100000000 % 1000; /* millions */

    if (m3) {
	strcat(buf, num_word(m3));
	strcat(buf, " million ");
    }

    if (m2) {
	strcat(buf, num_word(m2));
	strcat(buf, " thousand ");
    }

    if (m1)
	strcat(buf, num_word(m1));

    if (!*p)
	strcat(buf, "zero");

    strcat(buf, (int)(*value/100) == 1 ? " dollar and " : " dollars and ");
    strcat(buf, num_word(m0));
    strcat(buf, m0 == 1 ? " cent" : " cents");
    *buf = toupper(*buf);
    return(buf);
} /* cash_words_out() */


/*************************************************************************
 * Private routines
 ************************************************************************/

static const char *
num_word(Cash value)
{
    static char buf[128];
    static const char *small[] = {
	"zero", "one", "two", "three", "four", "five", "six", "seven",
	"eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen",
	"fifteen", "sixteen", "seventeen", "eighteen", "nineteen", "twenty",
	"thirty", "fourty", "fifty", "sixty", "seventy", "eighty", "ninety"
    };
    const char **big = small + 18;
    int tu = value % 100;

    /* deal with the simple cases first */
    if (value <= 20)
	return(small[value]);

    /* is it an even multiple of 100? */
    if (!tu) {
	sprintf(buf, "%s hundred", small[value/100]);
	return(buf);
    }

    /* more than 99? */
    if (value > 99) {
	/* is it an even multiple of 10 other than 10? */
	if (value % 10 == 0 && tu > 10)
	    sprintf(buf, "%s hundred %s",
	      small[value/100], big[tu/10]);
	else if (tu < 20)
	    sprintf(buf, "%s hundred and %s",
	      small[value/100], small[tu]);
	else
	    sprintf(buf, "%s hundred %s %s",
	      small[value/100], big[tu/10], small[tu % 10]);

    } else {
	/* is it an even multiple of 10 other than 10? */
	if (value % 10 == 0 && tu > 10)
	    sprintf(buf, "%s", big[tu/10]);
	else if (tu < 20)
	    sprintf(buf, "%s", small[tu]);
	else
	    sprintf(buf, "%s %s", big[tu/10], small[tu % 10]);
    }

    return(buf);
} /* num_word() */