#include <strformat.h>

#define HAVE_DOUBLE

#define HAVE_LONGLONG
#ifndef LARGEST_SIGNED
#ifdef HAVE_LONGLONG
#define LARGEST_SIGNED long long int
#else
#define LARGEST_UNSIGNED long int
#endif
#endif

#ifndef LARGEST_UNSIGNED
#ifdef HAVE_LONGLONG
#define LARGEST_UNSIGNED unsigned long long int
#else
#define LARGEST_UNSIGNED unsigned long int
#endif
#endif

#ifndef POINTER_INT
#define POINTER_INT unsigned long
#endif

typedef unsigned int FormatFlags;

#define MAKE_MASK(shift,size) (((1 << size) - 1) << (shift))

#define JUSTIFY_SHIFT	0
#define JUSTIFY_SIZE	1
#define JUSTIFY_RIGHT	0x0000
#define JUSTIFY_LEFT	0x0001
#define JUSTIFY_MASK	MAKE_MASK(JUSTIFY_SHIFT,JUSTIFY_SIZE)


/* How a positive number is prefixed */
#define POSITIVE_SHIFT	(JUSTIFY_SHIFT + JUSTIFY_SIZE)
#define POSITIVE_NONE	(0x0000 << POSITIVE_SHIFT)
#define POSITIVE_SPACE	(0x0001 << POSITIVE_SHIFT)
#define POSITIVE_PLUS	(0x0003 << POSITIVE_SHIFT)
#define POSITIVE_MASK	MAKE_MASK(POSITIVE_SHIFT, POSITIVE_SIZE)

#define POSITIVE_SIZE	2

#define ALTERNATE_FORM_SHIFT (POSITIVE_SHIFT + POSITIVE_SIZE)
#define ALTERNATE_FORM_SIZE 1
#define ALTERNATE_FORM  (0x0001 << ALTERNATE_FORM_SHIFT)


#define PAD_SHIFT	(ALTERNATE_FORM_SHIFT + ALTERNATE_FORM_SIZE)
#define PAD_SIZE	1
#define PAD_SPACE	(0x0000 << PAD_SHIFT)
#define PAD_ZERO	(0x0001 << PAD_SHIFT)

#define SIZE_SHIFT	(PAD_SHIFT + PAD_SIZE)
#define SIZE_SIZE	3
#define SIZE_CHAR	(0x0001 << SIZE_SHIFT)
#define SIZE_SHORT	(0x0002 << SIZE_SHIFT)
#define SIZE_INT	(0x0000 << SIZE_SHIFT)
#define SIZE_LONG	(0x0003 << SIZE_SHIFT)
#define SIZE_LONGLONG	(0x0004 << SIZE_SHIFT)
#define SIZE_MASK	MAKE_MASK(SIZE_SHIFT,SIZE_SIZE)

#define CONV_SHIFT	(SIZE_SHIFT + SIZE_SIZE)
#define CONV_SIZE	3
#define CONV_INTEGER	(0x0001 << CONV_SHIFT)
#define CONV_FLOAT	(0x0002 << CONV_SHIFT)
#define CONV_POINTER	(0x0003 << CONV_SHIFT)
#define CONV_STRING	(0x0004 << CONV_SHIFT)
#define CONV_CHAR	(0x0005 << CONV_SHIFT)
#define CONV_PERCENT	(0x0006 << CONV_SHIFT)
#define CONV_WRITTEN	(0x0007 << CONV_SHIFT)
#define CONV_MASK	MAKE_MASK(CONV_SHIFT, CONV_SIZE)

#define RADIX_SHIFT	(CONV_SHIFT + CONV_SIZE)
#define RADIX_SIZE	2
#define RADIX_DECIMAL	(0x0001 << RADIX_SHIFT)
#define RADIX_OCTAL	(0x0002 << RADIX_SHIFT)
#define RADIX_HEX	(0x0003 << RADIX_SHIFT)
#define RADIX_MASK	MAKE_MASK(RADIX_SHIFT,RADIX_SIZE)

#define SIGNED_SHIFT	(RADIX_SHIFT + RADIX_SIZE)
#define SIGNED_SIZE	1
#define SIGNED_NO	(0x0000 << SIGNED_SHIFT)
#define SIGNED_YES	(0x0001 << SIGNED_SHIFT)
#define SIGNED_MASK	MAKE_MASK(SIGNED_SHIFT,SIGNED_SIZE)

#define CAPS_SHIFT	(SIGNED_SHIFT + SIGNED_SIZE)
#define CAPS_SIZE	1
#define CAPS_NO		(0x0000 << CAPS_SHIFT)
#define CAPS_YES	(0x0001 << CAPS_SHIFT)
#define CAPS_MASK	MAKE_MASK(CAPS_SHIFT,CAPS_SIZE)

#define FLOAT_SHIFT	(CAPS_SHIFT + CAPS_SIZE)
#define FLOAT_SIZE	2
#define FLOAT_NORMAL	(0x0000 << FLOAT_SHIFT)
#define FLOAT_EXPONENT	(0x0001 << FLOAT_SHIFT)
#define FLOAT_DEPENDANT	(0x0002 << FLOAT_SHIFT)
#define FLOAT_HEX	(0x0003 << FLOAT_SHIFT)
#define FLOAT_MASK	MAKE_MASK(FLOAT_SHIFT, FLOAT_SIZE)

static FormatFlags
parse_flags(const char **posp)
{
  FormatFlags flags = 0;
  const char *pos = *posp;
  while (1) {
    switch(*pos) {
    case '-':
      flags |= JUSTIFY_LEFT;
      break;
    case '+':
      flags |= POSITIVE_PLUS;
      break;
    case ' ':
      flags |= POSITIVE_SPACE;
      break;
    case '#':
      flags |= ALTERNATE_FORM;
      break;
    case '0':
      flags |= PAD_ZERO;
      break;
    default:
      *posp = pos;
      return flags;
    }
    pos++;
  }
      
}

static unsigned int
parse_uint(const char **posp)
{
  unsigned v = 0;
  const char *pos = *posp;
  char ch;
  while((ch = *pos) >= '0' && ch <= '9') {
    v = v * 10 + (ch - '0');
    pos++;
  }
  *posp = pos;
  return v;
}

#define MAXCHARS_HEX ((sizeof(LARGEST_UNSIGNED) * 8) / 4 )

/* Largest number of characters needed for converting an unsigned integer.
 */
#define MAXCHARS ((sizeof(LARGEST_UNSIGNED) * 8  + 2) / 3 )

static unsigned int
output_uint_decimal(char **posp, LARGEST_UNSIGNED v)
{
  unsigned int len;
  char *pos = *posp;
  while (v > 0) {
    *--pos = (v % 10) + '0';
    v /= 10;
  }
  len = *posp - pos;
  *posp = pos;
  return len;
}

static unsigned int
output_uint_hex(char **posp, LARGEST_UNSIGNED v, unsigned int flags)
{
  unsigned int len;
  const char *hex = (flags & CAPS_YES) ?"0123456789ABCDEF":"0123456789abcdef";
  char *pos = *posp;
  while (v > 0) {
    *--pos = hex[(v % 16)];
    v /= 16;
  }
  len = *posp - pos;
  *posp = pos;
  return len;
}

static unsigned int
output_uint_octal(char **posp, LARGEST_UNSIGNED v)
{
  unsigned int len;
  char *pos = *posp;
  while (v > 0) {
    *--pos = (v % 8) + '0';
    v /= 8;
  }
  len = *posp - pos;
  *posp = pos;
  return len;
}

static StrFormatResult
fill_space(const StrFormatContext *ctxt, unsigned int len)
{
  StrFormatResult res;
  static const char buffer[16] = "                ";
  while(len > 16) {
    res = ctxt->write_str(ctxt->user_data, buffer, 16);
    if (res != STRFORMAT_OK) return res;
    len -= 16;
  }
  if (len == 0) return STRFORMAT_OK;
  return ctxt->write_str(ctxt->user_data, buffer, len);
}

static StrFormatResult
fill_zero(const StrFormatContext *ctxt, unsigned int len)
{
  StrFormatResult res;
  static const char buffer[16] = "0000000000000000";
  while(len > 16) {
    res = ctxt->write_str(ctxt->user_data, buffer, 16);
    if (res != STRFORMAT_OK) return res;
    len -= 16;
  }
  if (len == 0) return STRFORMAT_OK;
  return ctxt->write_str(ctxt->user_data, buffer, len);
}

#define CHECKCB(res) {if ((res) != STRFORMAT_OK) {va_end(ap); return -1;}}

int
format_str(const StrFormatContext *ctxt, const char *format, ...)
{
  int ret;
  va_list ap;
  va_start(ap, format);
  ret = format_str_v(ctxt, format, ap);
  va_end(ap);
  return ret;
}

int
format_str_v(const StrFormatContext *ctxt, const char *format, va_list ap)
{
  unsigned int written = 0;
  const char *pos = format;
  while(*pos != '\0') {
    FormatFlags flags;
    unsigned int minwidth = 0;
    int precision = -1; /* Negative means no precision */
    char ch;
    const char *start = pos;
    while( (ch = *pos) != '\0' && ch != '%') pos++;
    if (pos != start) {
      CHECKCB(ctxt->write_str(ctxt->user_data, start, pos - start));
      written += pos - start;
    }
    if (*pos == '\0') {
      va_end(ap);
      return written;
    }
    pos++;
    if (*pos == '\0') {
      va_end(ap);
      return written;
    }
    flags = parse_flags(&pos);

    /* parse width */
    if (*pos >= '1' && *pos <= '9') {
      minwidth = parse_uint(&pos);
    } else if (*pos == '*') {
      int w = va_arg(ap,int);
      if (w < 0) {
	flags |= JUSTIFY_LEFT;
	minwidth = w;
      } else {
	minwidth = w;
      }
      pos ++;
    }

    /* parse precision */
    if (*pos == '.') {
      pos++;
      if (*pos >= '0' && *pos <= '9') {
	precision = parse_uint(&pos);
      } else if (*pos == '*') {
	pos++;
	precision = va_arg(ap,int);
      }
    }
    if (*pos == 'l') {
      pos++;
      if (*pos == 'l') {
	flags |= SIZE_LONGLONG;
	pos++;
      } else {
	flags |= SIZE_LONG;
      }
    } else if (*pos == 'h') {
      pos++;
      if (*pos == 'h') {
	flags |= SIZE_CHAR;
	pos++;
      } else {
	flags |= SIZE_SHORT;
      }
    }

    /* parse conversion specifier */
    switch(*pos) {
    case 'd':
    case 'i':
      flags |= CONV_INTEGER | RADIX_DECIMAL | SIGNED_YES;
      break;
    case 'u':
      flags |= CONV_INTEGER | RADIX_DECIMAL | SIGNED_NO;
      break;
    case 'o':
      flags |= CONV_INTEGER | RADIX_OCTAL | SIGNED_NO;
      break;
    case 'x':
      flags |= CONV_INTEGER | RADIX_HEX | SIGNED_NO;
      break;
    case 'X':
      flags |= CONV_INTEGER | RADIX_HEX | SIGNED_NO | CAPS_YES;
      break;
#ifdef HAVE_DOUBLE
    case 'f':
      flags |= CONV_FLOAT | FLOAT_NORMAL;
      break;
    case 'F':
      flags |= CONV_FLOAT | FLOAT_NORMAL | CAPS_YES;
      break;
    case 'e':
      flags |= CONV_FLOAT | FLOAT_EXPONENT;
      break;
    case 'E':
      flags |= CONV_FLOAT | FLOAT_EXPONENT | CAPS_YES;
      break;
    case 'g':
      flags |= CONV_FLOAT | FLOAT_DEPENDANT;
      break;
    case 'G':
      flags |= CONV_FLOAT | FLOAT_DEPENDANT | CAPS_YES;
      break;
    case 'a':
      flags |= CONV_FLOAT | FLOAT_HEX;
      break;
    case 'A':
      flags |= CONV_FLOAT | FLOAT_HEX | CAPS_YES;
      break;
#endif
    case 'c':
      flags |= CONV_CHAR;
      break;
    case 's':
      flags |= CONV_STRING;
      break;
    case 'p':
      flags |= CONV_POINTER;
      break;
    case 'n':
      flags |= CONV_WRITTEN;
      break;
    case '%':
      flags |= CONV_PERCENT;
      break;
    case '\0':
      va_end(ap);
      return written;
    }
    pos++;
    switch(flags & CONV_MASK) {
    case CONV_PERCENT:
      CHECKCB(ctxt->write_str(ctxt->user_data, "%", 1));
      written++;
      break;
    case CONV_INTEGER:
      {
	/* unsigned integers */
	char *prefix = 0; /* sign, "0x" or "0X" */
	unsigned int prefix_len = 0;
	char buffer[MAXCHARS];
	char *conv_pos = buffer + MAXCHARS;
	unsigned int conv_len = 0;
	unsigned int width = 0;
	unsigned int precision_fill;
	unsigned int field_fill;
	LARGEST_UNSIGNED uvalue = 0;
	int negative = 0;
      
	if (precision < 0) precision = 1;
	else flags &= ~PAD_ZERO;
      
	if (flags & SIGNED_YES) {
	  /* signed integers */
	  LARGEST_SIGNED value = 0;
	  switch(flags & SIZE_MASK) {
	  case SIZE_CHAR:
	    value = (signed char)va_arg(ap, int);
	    break;
	  case SIZE_SHORT:
	    value = (short)va_arg(ap, int);
	    break;
	  case SIZE_INT:
	    value = va_arg(ap, int);
	    break;
#ifndef HAVE_LONGLONG
	  case SIZE_LONGLONG:	/* Treat long long the same as long */
#endif
	  case SIZE_LONG:
	    value = va_arg(ap, long);
	    break;
#ifdef HAVE_LONGLONG
	  case SIZE_LONGLONG:
	    value = va_arg(ap, long long);
	    break;
#endif
	  }
	  if (value < 0) {
	    uvalue = -value;
	    negative = 1;
	  } else {
	    uvalue = value;
	  }
	} else {
	
	  switch(flags & SIZE_MASK) {
	  case SIZE_CHAR:
	    uvalue = (unsigned char)va_arg(ap,unsigned int);
	    break;
	  case SIZE_SHORT:
	    uvalue = (unsigned short)va_arg(ap,unsigned int);
	    break;
	  case SIZE_INT:
	    uvalue = va_arg(ap,unsigned int);
	    break;
#ifndef HAVE_LONGLONG
	  case SIZE_LONGLONG:	/* Treat long long the same as long */
#endif
	  case SIZE_LONG:
	    uvalue = va_arg(ap,unsigned long);
	    break;
#ifdef HAVE_LONGLONG
	  case SIZE_LONGLONG:
	    uvalue = va_arg(ap,unsigned long long);
	    break;
#endif
	  }
	}
	
	switch(flags & (RADIX_MASK)) {
	case RADIX_DECIMAL:
	  conv_len = output_uint_decimal(&conv_pos,uvalue);
	  break;
	case RADIX_OCTAL:
	  conv_len = output_uint_octal(&conv_pos,uvalue);
	  break;
	case RADIX_HEX:
	  conv_len = output_uint_hex(&conv_pos,uvalue, flags);
	  break;
	}

	width += conv_len;
	precision_fill = (precision > conv_len) ? precision - conv_len : 0;
	if ((flags & (RADIX_MASK | ALTERNATE_FORM))
	    == (RADIX_OCTAL | ALTERNATE_FORM)) {
	  if (precision_fill < 1) precision_fill = 1;
	}

	width += precision_fill;
	
	if ((flags & (RADIX_MASK | ALTERNATE_FORM))
	    == (RADIX_HEX | ALTERNATE_FORM) && uvalue != 0) {
	  prefix_len = 2;
	  if (flags & CAPS_YES) {
	    prefix = "0X";
	  } else {
	    prefix = "0x";
	  }
	}

	if (flags & SIGNED_YES) {
	  if (negative) {
	    prefix = "-";
	    prefix_len = 1;
	  } else {
	    switch(flags & POSITIVE_MASK) {
	    case POSITIVE_SPACE:
	      prefix = " ";
	      prefix_len = 1;
	      break;
	    case POSITIVE_PLUS:
	      prefix = "+";
	      prefix_len = 1;
	      break;
	    }
	  }
	}

	width += prefix_len;

	field_fill = (minwidth > width) ? minwidth - width : 0;

	if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
	  if (flags & PAD_ZERO) {
	    precision_fill += field_fill;
        field_fill = 0;  /* Do not double count padding */
	  } else {
	    CHECKCB(fill_space(ctxt,field_fill));
	  }
	}

	if (prefix_len > 0)
	  CHECKCB(ctxt->write_str(ctxt->user_data, prefix, prefix_len));
	written += prefix_len;
	
	CHECKCB(fill_zero(ctxt,precision_fill));
	written += precision_fill;
	
	CHECKCB(ctxt->write_str(ctxt->user_data, conv_pos,conv_len));
	written += conv_len;
	
	if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	}
	written += field_fill;
      }
      break;
    case CONV_STRING:
      {
	unsigned int field_fill;
	unsigned int len;
	char *str = va_arg(ap,char *);
	if (str) {
	  char *pos = str;
	  while(*pos != '\0') pos++;
	  len = pos - str;
	} else {
	  str = "(null)";
	  len = 6;
	}
	if (precision >= 0 && precision < len) len = precision;
	field_fill = (minwidth > len) ? minwidth - len : 0;
	if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	}
	CHECKCB(ctxt->write_str(ctxt->user_data, str,len));
	written += len;
	if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	}
	written += field_fill;
      }
      break;
    case CONV_POINTER:
      {
	LARGEST_UNSIGNED uvalue =
	  (LARGEST_UNSIGNED)(POINTER_INT)va_arg(ap,void *);
	char buffer[MAXCHARS_HEX + 3];
	char *conv_pos = buffer + MAXCHARS_HEX+3;
	unsigned int conv_len;
	unsigned int field_fill;
	
	conv_len = output_uint_hex(&conv_pos,uvalue,flags);
	if (conv_len == 0) {
	  *--conv_pos = '0';
	  conv_len++;
	}
	*--conv_pos = 'x';
	*--conv_pos = '0';
	*--conv_pos = '#';
	conv_len += 3;

	field_fill = (minwidth > conv_len) ? minwidth - conv_len : 0;
	
	if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	}
	
	CHECKCB(ctxt->write_str(ctxt->user_data, conv_pos,conv_len));
	written += conv_len;
	
	if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	}
	written += field_fill;
      }
      break;
    case CONV_CHAR:
      {
	char ch = va_arg(ap,int);
	unsigned int field_fill = (minwidth > 1) ? minwidth - 1 : 0;
	if ((flags & JUSTIFY_MASK) == JUSTIFY_RIGHT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	  written += field_fill;
	}
	
	CHECKCB(ctxt->write_str(ctxt->user_data, &ch, 1));
	written++;
	
	if ((flags & JUSTIFY_MASK) == JUSTIFY_LEFT) {
	  CHECKCB(fill_space(ctxt,field_fill));
	}
	written+= field_fill;
      }
      break;
    case CONV_WRITTEN:
      {
	int *p = va_arg(ap,int*);
	*p = written;
      }
      break;

    }
  }
  
  return written;
}