#include <llarp/buffer.h>
#include <stdarg.h>
#include <stdio.h>

extern "C" {

size_t llarp_buffer_size_left(llarp_buffer_t* buff) {
  size_t diff = buff->cur - buff->base;
  if (diff > buff->sz)
    return 0;
  else
    return buff->sz - diff;
}

bool llarp_buffer_writef(llarp_buffer_t* buff, const char* fmt, ...) {
  int written;
  size_t sz = llarp_buffer_size_left(buff);
  va_list args;
  va_start(args, fmt);
  written = vsnprintf(buff->cur, sz, fmt, args);
  va_end(args);
  if (written == -1) return false;
  buff->cur += written;
  return true;
}

bool llarp_buffer_write(llarp_buffer_t* buff, const void* data, size_t sz) {
  size_t left = llarp_buffer_size_left(buff);
  if (left >= sz) {
    memcpy(buff->cur, data, sz);
    buff->cur += sz;
    return true;
  }
  return false;
}

bool llarp_buffer_readfile(llarp_buffer_t* buff, FILE* f, llarp_alloc* mem) {
  ssize_t len;
  fseek(f, 0, SEEK_END);
  len = ftell(f);
  rewind(f);
  if (len > 0) {
    buff->base = static_cast<char*>(mem->alloc(mem, len, 8));
    buff->cur = buff->base;
    buff->sz = len;
    ssize_t sz = fread(buff->base, len, 1, f);
    rewind(f);
    return sz == len;
  }
  return false;
}

size_t llarp_buffer_read_until(llarp_buffer_t * buff, char delim, char * result, size_t resultsize)
{
  size_t read = 0;
  
  while(*buff->cur != delim && resultsize && (buff->cur != buff->base + buff->sz))
  {
    *result = *buff->cur;
    buff->cur ++;
    result ++;
    resultsize --;
    read ++;
  }

  if(llarp_buffer_size_left(buff))
    return read;
  else  
    return 0;
}

bool llarp_buffer_eq(llarp_buffer_t buf, const char * str)
{
  while(*str && buf.cur != (buf.base + buf.sz))
  {
    if(*buf.cur != *str) return false;
    buf.cur ++;
    str++;
  }
  return *str == 0;
}

}