#include "stream.h"

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

struct _internal_foug_stream
{
  void* cookie;
  foug_stream_manip_t manip;
};

foug_stream_t* foug_stream_create(foug_malloc_func_t func, void* data, foug_stream_manip_t manip)
{
  foug_stream_t* stream;

  if (func == NULL)
    return NULL;
  stream = (*func)(sizeof(struct _internal_foug_stream));
  if (stream != NULL) {
    stream->cookie = data;
    stream->manip = manip;
  }
  return stream;
}

/*!
 * \brief Create a null stream manipulator
 */
foug_stream_manip_t foug_stream_manip_null()
{
  foug_stream_manip_t manip;
  memset(&manip, 0, sizeof(foug_stream_manip_t));
  return manip;
}

static foug_bool_t foug_stream_stdio_at_end(foug_stream_t* stream)
{
  return feof((FILE*) stream->cookie);
}

static int32_t foug_stream_stdio_error(foug_stream_t* stream)
{
  return ferror((FILE*) stream->cookie);
}

static size_t foug_stream_stdio_read(foug_stream_t* stream,
                                     void* ptr,
                                     size_t item_size,
                                     size_t item_count)
{
  return fread(ptr, item_size, item_count, (FILE*) stream->cookie);
}

static size_t foug_stream_stdio_write(foug_stream_t* stream,
                                      const void* ptr,
                                      size_t item_size,
                                      size_t item_count)
{
  return fwrite(ptr, item_size, item_count, (FILE*) stream->cookie);
}

/*!
 * \brief Create a stream manipulator for standard FILE*
 */
foug_stream_manip_t foug_stream_manip_stdio()
{
  foug_stream_manip_t manip;
  manip.at_end_func = foug_stream_stdio_at_end;
  manip.error_func = foug_stream_stdio_error;
  manip.read_func = foug_stream_stdio_read;
  manip.write_func = foug_stream_stdio_write;
  return manip;
}

foug_bool_t foug_stream_at_end(foug_stream_t* stream)
{
  if (stream != NULL && stream->manip.at_end_func != NULL)
    return stream->manip.at_end_func(stream);
  return 0;
}

/*!
 * \brief Check error indicator
 *
 * Checks if the error indicator associated with \p stream is set, returning a value different from
 * zero if it is.
 *
 * This indicator is generally set by a previous operation on the \p stream that failed.
 */
int foug_stream_error(foug_stream_t* stream)
{
  if (stream != NULL && stream->manip.error_func != NULL)
    return stream->manip.error_func(stream);
  return 0;
}

/*!
 * \brief Read block of data from stream
 *
 * Reads an array of \p item_count elements, each one with a \p item_size of size bytes, from the
 * \p stream and stores them in the block of memory specified by \p ptr.
 *
 * The total amount of bytes read if successful is (item_size * item_count).
 *
 * \return The total number of elements successfully read is returned.
 *         If this number differs from the \p item_count argument, either a reading error occurred
 *         or the end-of-file was reached while reading. In both cases, the proper indicator is set,
 *         which can be checked with foug_stream_error() and foug_stream_at_end(), respectively.
 *         If either \p item_size or \p item_count is zero, the function returns zero and both the
 *         stream state and the content pointed by \p ptr remain unchanged.
 */
size_t foug_stream_read(foug_stream_t* stream, void *ptr, size_t item_size, size_t item_count)
{
  if (stream != NULL && stream->manip.read_func != NULL)
    return stream->manip.read_func(stream, ptr, item_size, item_count);
  return 0;
}

/*!
 * \brief Write block of data to stream
 *
 *  Writes an array of \p item_count elements, each one with a \p item_size of size bytes, from the
 *  block of memory pointed by \p ptr to the current position in the \p stream.
 *
 *  The total amount of bytes written is (item_size * item_count).
 */
size_t foug_stream_write(foug_stream_t* stream, const void *ptr, size_t item_size, size_t item_count)
{
  if (stream != NULL && stream->manip.write_func != NULL)
    return stream->manip.write_func(stream, ptr, item_size, item_count);
  return 0;
}

void* foug_stream_get_cookie(const foug_stream_t* stream)
{
  return stream != NULL ? stream->cookie : NULL;
}

void foug_stream_set_cookie(foug_stream_t* stream, void* data)
{
  if (stream != NULL)
    stream->cookie = data;
}