#include <evapp/util.h>

bool set_xsrf_token(evapp_ctx *ctx, HDF *hdf) {
  struct evkeyvalq cookie;
  struct timeval tv;
  uint64_t id = 0;
  char token[21];
  bool secure = true;

  TAILQ_INIT(&cookie);
  gettimeofday(&tv, NULL);
  if (!hdf)
    return false;
  // We just use high-res time and some pseudo randomness.
  id = (tv.tv_sec - random());
  id <<= 31;
  id |= (tv.tv_usec - random());
  snprintf(token, sizeof(token), "%llu", id);
  evhttp_add_header(&cookie, "token", token);

  /* Disable secure cookies when in debug mode */
  secure = !evapp_get_debug_mode(ctx);

  /* Set this at the top level and give it a day. Since this
   * has to be paired with the post data, I could care less how
   * long it lives.
   */
  // XXX: maybe we can do better?
  //      if everything was per object likst
  //      /vuln/view instead, we could!
  if (!set_cookie(ctx, &cookie, "/", NULL, 86400, secure)) {
    evhttp_clear_headers(&cookie);
    return false;
  }
  evhttp_clear_headers(&cookie);
  hdf_set_value(hdf, "token", token);
  response_cacheable(ctx, CACHE_NONE, 0);
  return true;
}

bool check_xsrf(evapp_ctx *ctx, char *token) {
  struct app_settings *settings;
  struct evkeyvalq cookie;
  const char *ctoken = NULL;

  assert(ctx && token);

  settings = evapp_get_state(ctx);
  if (!evapp_get_xsrf_protection(ctx))
    return true;

  TAILQ_INIT(&cookie);

  // XXX: we should avoid double parsing this cookie...
  if (!token || !parse_cookie(ctx, &cookie)) {
    return false;
  }
  ctoken = evhttp_find_header(&cookie, "token");
  if (!ctoken) {
    evhttp_clear_headers(&cookie);
    return false;
  }
  /* Check against the length of the cookie token as that shouldn't
   * be tampered with.  If we checked against the query, a token of
   * length 1 could be supplied meaning an easy brute force.
   */
  if (strncmp(ctoken, token, strlen(ctoken))) {
    evhttp_clear_headers(&cookie);
    return false;
  }
  evhttp_clear_headers(&cookie);
  return true;
}