#include <stdio.h>
#include <limits.h>
#include <dlfcn.h>
#include <sys/timerfd.h>
#include <unistd.h>

#include "nfcommander.h"
#include "reader.h"
#include "config.h"

#define MAX_PLUGIN_PATH NAME_MAX
static void* reader_module = NULL;
static reader_plugin_handle reader_backend_handle = NULL;
static reader_plugin_scan reader_backend_scan = NULL;

static int timer_fd = -1;

static int reader_init_backend(){
	char plugin[MAX_PLUGIN_PATH] = "";
	char* reader = config_get("nfc", "reader");

	if(!reader){
		printf("No reader plugin configured\n");
		return -1;
	}

	snprintf(plugin, sizeof(plugin), "./reader_%s.so", reader);
	reader_module = dlopen(plugin, RTLD_NOW);

	if(!reader_module){
		printf("Failed to load reader plugin %s: %s\n", plugin, dlerror());
		return -1;
	}

	reader_backend_handle = dlsym(reader_module, "handle");
	reader_backend_scan = dlsym(reader_module, "scan");

	//call initializer
	reader_plugin_init init = dlsym(reader_module, "init");
	if(!reader_backend_scan || !init || init()){
		printf("Failed to initialize the reader\n");
		return 1;
	}

	return 0;
}

int reader_init(){
	//initialize poll timer
	size_t poll_timeout = 1000;
	struct itimerspec timer_cfg = {
		0
	};

	if(config_get("nfc", "interval")){
		poll_timeout = strtoul(config_get("nfc", "interval"), NULL, 10);
	}

	timer_cfg.it_value.tv_sec = timer_cfg.it_interval.tv_sec = poll_timeout / 1000;
	timer_cfg.it_value.tv_nsec = timer_cfg.it_interval.tv_nsec = (poll_timeout % 1000) * 1e6;

	//create timerfd
	timer_fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
	if(timer_fd < 0){
		printf("Failed to create timer fd\n");
		return 1;
	}

	if(timerfd_settime(timer_fd, 0, &timer_cfg, NULL)){
		printf("Failed to set timer\n");
		return 1;
	}

	core_manage_fd(timer_fd, 1, system_reader);
	return reader_init_backend();
}

int reader_handle(int fd){
	uint8_t buffer[1024];

	if(fd == timer_fd){
		//acknowledge timer
		read(fd, buffer, sizeof(buffer));

		//mark all tags expired
		//TODO

		//scan all tags
		if(reader_backend_scan()){
			return 1;
		}

		//handle changes in active set
		//TODO
	}

	if(reader_backend_handle){
		return reader_backend_handle(fd);
	}
	return 0;
}

void reader_free(){
	if(reader_module){
		dlclose(reader_module);
		reader_backend_handle = NULL;
		reader_backend_scan = NULL;
		reader_module = NULL;
	}

	core_manage_fd(timer_fd, 0, system_reader);
	close(timer_fd);
	timer_fd = -1;
}