#include <stdio.h>

#include <dlfcn.h>

typedef void* dllib_t;

typedef void* opqst_t;

dllib_t open_library(const char* library, int* err)
{
  dllib_t lib = dlopen(library, RTLD_LAZY);

  if (!lib) {
    fprintf(stderr, "Error opening shared library: %s\n", dlerror());
    *err = 1;
  }
  *err = 0;
  return lib;
}

void* getsym(dllib_t handle, char* sym, int* err)
{
  void* ret = dlsym(handle, sym);
  if (!ret) {
    fprintf(stderr, "Unable to read symbol '%s'\n", sym);
    *err |= 1;
    return NULL;
  }
  return ret;
}

void use_library(int argc, char** argv, dllib_t lib, int* err)
{
  *err = 0;

  opqst_t (*init)(int* argc, char*** argv) = getsym(lib, "plugin_init", err);
  void (*teardown)() = getsym(lib, "plugin_teardown", err);
  opqst_t (*sym)(opqst_t) = getsym(lib, "handle_thing", err);

  if (*err) {
    fprintf(stderr, "Unable to find symbol call_in.\n");
    return;
  }

  opqst_t st = init(&argc, &argv);
  for (int i = 0; i < 100000; ++ i) {
    st = sym(st);
    printf("stable_ptr: %p\n", st);
  }
  teardown();
}

int main(int argc, char** argv)
{
  if (!argv[0] && !argv[1]) {
    fprintf(stderr, "Missing argument.\n");
    return 1;
  }

  int err = 0;
  dllib_t lib = open_library(argv[1], &err);

  if (err) {
    return err;
  }

  use_library(argc, argv, lib, &err);
  return 0;
}