#include <jni.h>
#include <unistd.h>
#include <stdlib.h>

static inline const char **to_string_array(JNIEnv *env, jobjectArray ja) {
	const int len = (*env)->GetArrayLength(env, ja);
	const char **ca = calloc((size_t) len + 1, sizeof(char *));

	for (int i = 0; i < len; ++i) {
		jstring jstr = (jstring) (*env)->GetObjectArrayElement(env, ja, i);
		ca[i] = (*env)->GetStringUTFChars(env, jstr, NULL);
	}

	ca[len] = NULL;
	return ca;
}

static inline void exec(const char **argcv) {
	execv(argcv[0], (char *const *) argcv);
	exit(1);
}

JNIEXPORT jint JNICALL
Java_org_pacien_tincapp_commands_Executor_forkExec(JNIEnv *env, jclass class, jobjectArray argcv) {
	pid_t pid = fork();
	switch (pid) {
		case 0:
			exec(to_string_array(env, argcv));
			return 0;

		default:
			return pid;
	}
}