#include<stdio.h>
#include<pthread.h>
#include<unistd.h>
#include<fcntl.h>
#include<stdlib.h>

pthread_t notifier_thread_handle;
void (**notifiers)(char*);
size_t notifier_count = 0;
size_t notifier_capacity = 0;
char notifier_shutdown = 0;
int notifier_fd;

void *notifier_thread(void* param){
	notifier_fd = open("/var/log/nginx/access.log", O_RDONLY);
	if(notifier_fd < 1){
		perror("open");
		return 0;
	}
	lseek(notifier_fd, 0, SEEK_END); 	
	char buffer[256];
	while(1){
		// Check to see if a webpage was downloaded
		ssize_t readlen = read(notifier_fd, buffer, 256);
		if(notifier_shutdown)
			return 0;
		if(readlen == 0){
			sleep(1);
			continue;
		}
		if(readlen < 0){
			perror("read");
			return 0;
		}
		for(size_t i = 0; i < notifier_count; i++){
			notifiers[i](buffer);
		}
	}
}

void notifier_clear(){
	notifier_count = 0;
}

void notifier_init(){
	notifiers = malloc(sizeof(void*) * 10);
	notifier_capacity = 10;
	pthread_create(&notifier_thread_handle, 0, notifier_thread, 0);
}

void notifier_add(void (*nn)(char*)){
	if(notifier_count >= notifier_capacity){
		notifiers = realloc(notifiers, sizeof(void*) * (notifier_capacity + 10));
		notifier_capacity += 10;
	}
	notifiers[notifier_count] = nn;
	notifier_count++;
}

void notifier_deinit(){
	notifier_shutdown = 1;
	free(notifiers);
	close(notifier_fd);
	pthread_join(notifier_thread_handle, 0);
}