#include <stdio.h>
#include <string.h>

int kputchar(int c) {
  terminal_putchar(c);
  return (unsigned char)c;
}

int kputs(const char *s) {
  int i = 0;
  while(s[i] != '\0') {
    kputchar(s[i]);
    i++;
  }
  kputchar('\n');
  return 1; // FIXME
}

int kvsnprintf(char *restrict s, size_t n, const char *restrict format, va_list ap) {
  char *str;
  int value;
  size_t size = 0;
  for (size_t i = 0; i < strlen(format) && size < n-1; i++) {
    if (format[i] == '%') {
      i++;
      switch(format[i]) {
      case 'c':
	s[size] = (char) va_arg(ap, int);
	size++;
	break;
      case 's':
	str = va_arg(ap, char *);
	for (size_t j = 0; j < strlen(str); j++) {
	  s[size] = str[j];
	  size++;
	}
	break;
      case 'd':
	value = va_arg(ap, int);
	if (value == 0) {
	  s[size] = '0';
	  size++;
	} if (value < 0) {
	  s[size] = '-';
	  value *= (-1);
	  size++;
	}
	
	long long power = 1;
	
	while (value > power)
	  power *= 10;
	
	if (power >= 10)
	  power /= 10;
	
	while (value != 0) {
	  int digit = (int)(value / power);
	  s[size] = '0' + digit;
	  size++;
	  if (digit != 0)
	    value = value - digit * power;
	  if (power != 1)
	    power /= 10;
	}
	break;
      case 'x':
	value = va_arg(ap, int);
	if (value == 0) {
	  s[size] = '0';
	  size++;
	}
	
	power = 1;
	
	while (value > power)
	  power *= 16;
	
	if (power >= 16)
	  power /= 16;
	
	while (value != 0) {
	  int digit = (int)(value / power);
	  if (digit < 10)
	    s[size] = '0' + digit;
	  else if (digit == 10)
	    s[size] = 'a';
	  else if (digit == 11)
	    s[size] = 'b';
	  else if (digit == 12)
	    s[size] = 'c';
	  else if (digit == 13)
	    s[size] = 'd';
	  else if (digit == 14)
	    s[size] = 'e';
  	  else if (digit == 15)
	    s[size] = 'f';	      
	  size++;
	  if (digit != 0)
	    value = value - digit * power;
	  if (power != 1)
	    power /= 16;
	}
	break;
      }
    } else {
      s[size] = format[i];
      size++;
    }
  }
  s[size] = '\0';
  return size;
}

int ksnprintf(char *restrict s, size_t n, const char *restrict format, ...) {
  int size;
  va_list ap;
  va_start(ap, format);
  size = kvsnprintf(s, n, format, ap);
  va_end(ap);
  return size;
}

int kvsprintf(char *restrict s, const char *restrict format, va_list ap) {
  size_t n = strlen(s);
  return kvsnprintf(s, n, format, ap);
}

int ksprintf(char *restrict s, const char *restrict format, ...) {
  int size;
  va_list ap;
  va_start(ap, format);
  size = kvsprintf(s, format, ap);
  va_end(ap);
  return size;
}

int kvprintf(const char *restrict format, va_list ap) {
  char s[1024] = ""; // FIXME
  int size = kvsprintf(s, format, ap);
  int i = 0;
  while (i < size) {
    kputchar(s[i]);
    i++;
  }
  return size;
}

int kprintf(const char *restrict format, ...) {
  int size;
  va_list ap;
  va_start(ap, format);
  size = kvprintf(format, ap);
  va_end(ap);
  return size;
}