#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/types.h>

typedef struct f_comp_data {
	char *f1;
	char *f2;
} f_comp_data;

void *f1_newer(void *arg) {
	f_comp_data *files = (f_comp_data *) arg;
	char *f1 = files->f1;
	char *f2 = files->f2;
	struct stat f1_attr;
	struct stat f2_attr;
	stat(f1, &f1_attr);
	stat(f2, &f2_attr);
	int diff = difftime(f1_attr.st_mtime, f2_attr.st_mtime);
	int ret = 0;
	if (diff <= 0) {
		pthread_exit(&ret);
	}
	ret = 1;
	pthread_exit(&ret);
}

void *create_make() {
	/* Create simple makefile */
	int fd = creat("makefile", 00644);
	FILE *file = fdopen(fd, "w");
	fprintf(file, "debug: main.c\n\tgcc -Wall main.c -o ./bin/debug\nrelease: main.c\n\tgcc -O2 -march=native main.c -o ./bin/release");
	fclose(file);

	return NULL;
}


int main() {
	/* Struct to hold files */
	f_comp_data files;
	files.f1 = "main.c";
	files.f2 = "./bin/debug";

	/* Threads to:
	 * create makefile
	 * check age of source vs. bin
	 */
	pthread_t f_thread, check_thread;
	pthread_create(&f_thread, NULL, create_make, NULL);
	pthread_create(&check_thread, NULL, f1_newer, (void *)&files);

	mkdir("./bin", 0777);

	void *newer;

	pthread_join(f_thread, NULL);
	pthread_join(check_thread, &newer);
	int recomp = *(int *) newer;

	if (recomp) {
		pid_t make_pid;
		if ((make_pid = fork()) == 0) {
			printf("Recompiling...\n");
			execl("/usr/bin/make", "make", "debug", NULL);
		}
		waitpid(make_pid, NULL, 0);
	}

	pid_t x_pid;
	if ((x_pid = fork()) == 0) {
		execl("./bin/debug", "debug", NULL);
	}

	waitpid(x_pid, NULL, 0);

	return 0;
}