#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <setjmp.h>
#include <strings.h>

extern const char *__progname;

#include "currlib.h"

static CURR *currencies = 0;
static void (*errfn)(int, const char *);
static jmp_buf err_jmp;
static char errbuf[10240];
static int fmt_neg;
static unsigned long int fmt_i;
static int fmt_fplaces;
static unsigned long int fmt_f;
static CURR unk_curr;

static void init_unk_curr(void)
{
 unk_curr.name = "?";
 unk_curr.places = 0;
 unk_curr.divisor = 1;
 unk_curr.fmt = "?¤%?--%.%i";
}

static unsigned long int tentothe(unsigned int n)
{
 unsigned int i;
 unsigned long int p;

 p = 1;
 for (i=1;i&&(i<=n);i<<=1) ;
 if (! i) return(~0UL);
 for (i>>=1;i>=1;i>>=1)
  { p *= p;
    if (n & i) p *= 10;
  }
 return(p);
}

static volatile void err(const char *fmt, ...)
{
 va_list ap;

 va_start(ap,fmt);
 vsprintf(&errbuf[0],fmt,ap);
 va_end(ap);
 (*errfn)(1,&errbuf[0]);
 longjmp(err_jmp,1);
}

static void warn(const char *fmt, ...)
{
 va_list ap;

 va_start(ap,fmt);
 vsprintf(&errbuf[0],fmt,ap);
 va_end(ap);
 (*errfn)(0,&errbuf[0]);
}

static void default_errf(int fatal, const char *msg)
{
 fprintf(stderr,"%s: %s\n",__progname,msg);
 if (fatal) exit(1);
}

void load_currencies(const char *fn, void (*errf)(int, const char *))
{
 FILE *f;
 char *line;
 int have;
 int len;
 int ch;
 CURR *c;
 char *c1;
 char *c2;

 errfn = errf ? errf : default_errf;
 if (setjmp(err_jmp)) return;
 f = fopen(fn,"r");
 if (f == 0)
  { err("can't open currencies file %s",fn);
  }
 currencies = 0;
 while (1)
  { have = 8;
    len = 0;
    line = malloc(8+1);
    while (1)
     { ch = getc(f);
       if (ch == EOF)
	{ if (len > 0)
	   { warn("partial line at end of currencies file %s ignored\n",fn);
	   }
	  goto out; /* break 2 */
	}
       if (ch == '\n')
	{ line[len] = '\0';
	  break;
	}
       while (have <= len) line = realloc(line,(have+=8)+1);
       line[len++] = ch;
     }
    if (0)
     {
badcurr:;
       warn("bad line in currencies file %s: %s",fn,line);
       continue;
     }
    c1 = index(line,':');
    if (c1 == 0) goto badcurr;
    c2 = index(c1+1,':');
    if (c2 == 0) goto badcurr;
    *c1  = '\0';
    c = malloc(sizeof(CURR));
    c->name = line;
    c->places = atoi(c1+1);
    c->divisor = tentothe(c->places);
    c->fmt = c2 + 1;
    c->link = currencies;
    currencies = c;
  }
out:;
 fclose(f);
}

void fake_currencies(void)
{
 currencies = malloc(sizeof(CURR));
 currencies->link = 0;
 currencies->name = "";
 currencies->places = 0;
 currencies->divisor = 1;
 currencies->fmt = "¤%?--%.%i";
}

CURR *find_currency(const char *name)
{
 CURR *c;

 for (c=currencies;c;c=c->link)
  { if (!strcmp(name,c->name)) return(c);
  }
 return(0);
}

CURR *walk_currencies(int (*fn)(CURR *))
{
 CURR *c;

 for (c=currencies;c;c=c->link)
  { if ((*fn)(c)) return(c);
  }
 return(0);
}

static int do_format(char *buf, const char *fmt, int (*ifn)(char *), int (*ffn)(char *))
{
 typedef struct istack ISTACK;
 struct istack { ISTACK *link; unsigned int true:1; };
 static ISTACK *istack = 0;
 ISTACK *it;
 int cond;
 int n;
 int d;
#define INTRUEIF() (!istack || istack->true)

 while (istack)
  { it = istack;
    istack = it->link;
    free(it);
  }
 n = 0;
 for (;*fmt;fmt++)
  { if (*fmt != '%')
     { if (INTRUEIF())
	{ if (buf) *buf++ = *fmt;
	  n ++;
	}
       continue;
     }
    fmt ++;
    switch (*fmt)
     { case '\0':
	  if (buf)
	   { bcopy("%EOS",buf,4);
	     buf += 4;
	   }
	  n += 4;
	  goto out; /* break 2 */
	  break;
       default:
	  if (buf)
	   { *buf++ = '%';
	     *buf++ = '<';
	     *buf++ = '?';
	     *buf++ = *fmt;
	     *buf++ = '>';
	   }
	  n += 5;
	  continue;
	  break;
       case 'i':
	  if (INTRUEIF())
	   { d = (*ifn)(buf);
	     if (buf) buf += d;
	     n += d;
	   }
	  break;
       case 'f':
	  if (INTRUEIF())
	   { d = (*ffn)(buf);
	     if (buf) buf += d;
	     n += d;
	   }
	  break;
       case '?':
	  fmt ++;
	  switch (*fmt)
	   { case '\0':
		if (buf)
		 { bcopy("%?EOS",buf,5);
		   buf += 5;
		 }
		n += 5;
		goto out; /* break 2 */
		break;
	     default:
		if (buf)
		 { *buf++ = '%';
		   *buf++ = '?';
		   *buf++ = '<';
		   *buf++ = '?';
		   *buf++ = *fmt;
		   *buf++ = '>';
		 }
		n += 6;
		continue;
		break;
	     case '-':
		cond = fmt_neg;
		break;
	     case '+':
		cond = ! fmt_neg;
		break;
	   }
	  it = malloc(sizeof(ISTACK));
	  it->link = istack;
	  istack = it;
	  it->true = cond;
	  break;
       case ':':
	  if (istack)
	   { istack->true = ! istack->true;
	   }
	  else
	   { if (buf)
	      { *buf++ = '%';
		*buf++ = '?';
		*buf++ = '<';
		*buf++ = ':';
		*buf++ = '>';
	      }
	     n += 5;
	     continue;
	   }
	  break;
       case '.':
	  if (istack)
	   { it = istack->link;
	     istack = it;
	     free(it);
	   }
	  else
	   { if (buf)
	      { *buf++ = '%';
		*buf++ = '?';
		*buf++ = '<';
		*buf++ = '.';
		*buf++ = '>';
	      }
	     n += 5;
	     continue;
	   }
	  break;
     }
  }
out:;
#undef INTRUEIF
 if (buf) *buf = '\0';
 return(n);
}

static int fmt_amt_i(char *buf)
{
 char tmp[64];

 if (! buf) buf = &tmp[0];
 sprintf(buf,"%lu",fmt_i);
 return(strlen(buf));
}

static int fmt_amt_f(char *buf)
{
 if (buf) sprintf(buf,"%0*lu",fmt_fplaces,fmt_f);
 return(fmt_fplaces);
}

int format_amount(char *buf, int neg, unsigned long int amt, const char *curr)
{
 CURR *c;

 c = find_currency(curr);
 if (! c)
  { if (! unk_curr.name) init_unk_curr();
    c = &unk_curr;
  }
 fmt_neg = neg;
 fmt_i = amt / c->divisor;
 fmt_fplaces = c->places;
 fmt_f = amt % c->divisor;
 return(do_format(buf,c->fmt,fmt_amt_i,fmt_amt_f));
}

static int fmt_unk_i(char *buf)
{
 if (buf) *buf++ = '?';
 return(1);
}

static int fmt_unk_f(char *buf)
{
 int i;

 if (buf) for (i=0;i<fmt_fplaces;i++) *buf++ = '?';
 return(fmt_fplaces);
}

int format_unknown_amount(char *buf, const char *curr)
{
 CURR *c;

 c = find_currency(curr);
 if (! c)
  { if (! unk_curr.name) init_unk_curr();
    c = &unk_curr;
  }
 fmt_neg = 0;
 fmt_fplaces = c->places;
 return(do_format(buf,c->fmt,fmt_unk_i,fmt_unk_f));
}