#define L2_JNI__NO_DEFINE_PROXIES

#include "config.h"
#include "jniwrap.h"
#include "macros.h"
#include "command.h"

#include <stddef.h>
#include <dlfcn.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

/* this isn't even a little bit thread safe but it is what it is */

jint JNICALL l2_JNI__GetDefaultJavaVMInitArgs_load(void *args);
jint JNICALL l2_JNI__CreateJavaVM_load(JavaVM **pvm, void **penv, void *args);

l2_JNI__GetDefaultJavaVMInitArgs_t *l2_JNI__GetDefaultJavaVMInitArgs_call = &l2_JNI__GetDefaultJavaVMInitArgs_load;
l2_JNI__CreateJavaVM_t *l2_JNI__CreateJavaVM_call = &l2_JNI__CreateJavaVM_load;

void *volatile l2_JNI__jnimod = NULL;

int l2_jni__try_load(const char *path)
{
  struct stat st;
  if (stat(path, &st) < 0) {
    CMD_ERROR("Could not stat %s: %s", path, strerror(errno));
    return -1;
  }

  void *thelib = dlopen(path, RTLD_LAZY);
  if (!thelib) {
    CMD_ERROR("Failed to load JVM library %s: %s", path, dlerror());
    return -1;
  }

  l2_JNI__jnimod = thelib;
  return 0;
}

int l2_jni_init(const char *modpath)
{
  if (l2_JNI__jnimod) return 0;

  if (l2_jni__try_load(modpath) < 0) {
    CMD_ERROR0("Could not load JVM library.");
    return -1;
  }

  return 0;
}

typedef void (l2_jni__fsym_unspec)(void);

l2_jni__fsym_unspec *l2_jni__try_load_sym(const char *sym)
{
  void *themod = l2_JNI__jnimod;
  if (!themod) {
    CMD_MSG("bug", "JNI function %s called before l2_jni_init!", sym);
    abort();
  }

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
  l2_jni__fsym_unspec *thesym = dlsym(themod, sym);
#pragma GCC diagnostic pop

  if (!thesym) {
    CMD_ERROR("Could not load JNI symbol %s: %s", sym, dlerror());
    abort();
  }

  return thesym;
}

jint JNICALL l2_JNI__GetDefaultJavaVMInitArgs_load(void *args)
{
  l2_JNI__GetDefaultJavaVMInitArgs_t *thesym = (l2_JNI__GetDefaultJavaVMInitArgs_t *)l2_jni__try_load_sym("JNI_GetDefaultJavaVMInitArgs");
  l2_JNI__GetDefaultJavaVMInitArgs_call = thesym;

  return (*thesym)(args);
}

jint JNICALL l2_JNI__CreateJavaVM_load(JavaVM **pvm, void **penv, void *args)
{
  l2_JNI__CreateJavaVM_t *thesym = (l2_JNI__CreateJavaVM_t *)l2_jni__try_load_sym("JNI_CreateJavaVM");
  l2_JNI__CreateJavaVM_call = thesym;

  return (*thesym)(pvm, penv, args);
}