// Copyright (C)2018, Philip Munts, President, Munts AM Corp.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

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

#include <expansion_lpc1114.h>
#include <spi-agent.h>

#define DELIMITERS " =\t\r\n"

static FILE *f = NULL;

// Open the configuration file

void spiagent_config_open(int32_t *error)
{
  assert(error != NULL);

  *error = 0;

  // See if the configuration file is already open

  if (f != NULL) return;

  // Open the configuration file

  f = fopen(CONFIGFILE, "r");
  if (f == NULL) *error = errno;
}

// Close the configuration file

void spiagent_config_close(int32_t *error)
{
  assert(error != NULL);

  *error = 0;

  // See if the configuration file is already closed

  if (f == NULL) return;

  // Close the configuration file

  if (fclose(f)) *error = errno;
  f = NULL;
}

// Get the next keyword from the configuration file

void spiagent_config_get_next(char *keyword, int32_t ksize, char *value,
  int32_t vsize, int32_t *error)
{
  assert(error != NULL);

  // Validate parameters

  if (keyword == NULL)
  {
    *error = EINVAL;
    return;
  }

  if (ksize < 32)
  {
    *error = EINVAL;
    return;
  }

  if (value == NULL)
  {
    *error = EINVAL;
    return;
  }

  if (vsize < 256)
  {
    *error = EINVAL;
    return;
  }

  char inbuf[1024];
  char *k;
  char *v;

  // See if the configuration file is open

  if (f == NULL)
  {
    *error = EBADF;
    return;
  }

  // Search for the next keyword/value pair

  memset(keyword, 0, ksize);
  memset(value, 0, vsize);

  while (fgets(inbuf, sizeof(inbuf), f) != NULL)
  {
    k = strtok(inbuf, DELIMITERS);
    if (k == NULL) continue;            // Blank line
    if (k[0] == '#') continue;          // Comment
    if (k[0] == ';') continue;          // Comment

    v = strtok(NULL, DELIMITERS);
    if (v == NULL) continue;            // Malformed

    strncpy(keyword, k, ksize - 1);
    strncpy(value, v, vsize - 1);

    *error = 0;
    return;
  }

  *error = ENODATA;
}

void spiagent_config_get(char *keyword, char *value, int32_t vsize,
  int32_t *error)
{
  assert(error != NULL);

  // Validate parameters

  if (keyword == NULL)
  {
    *error = EINVAL;
    return;
  }

  if (value == NULL)
  {
    *error = EINVAL;
    return;
  }

  if (vsize < 256)
  {
    *error = EINVAL;
    return;
  }

  char k[256];
  char v[256];

  // See if the configuration file is open

  if (f == NULL)
  {
    *error = EBADF;
    return;
  }

  // Rewind the configuration file

  rewind(f);

  // Search for the desired keyword

  for (;;)
  {
    spiagent_config_get_next(k, sizeof(k), v, sizeof(v), error);
    if (*error) return;

    if (!strcasecmp(keyword, k))
    {
      memset(value, 0, vsize);
      strncpy(value, v, vsize - 1);
      *error = 0;
      return;
    }
  }

  *error = ENODATA;
}