#include <stdio.h>
#include <signal.h>
#include <sys/epoll.h>
#include <unistd.h>
#include <errno.h>

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

typedef union {
	struct {
		uint32_t system;
		uint32_t fd;
	} components;
	uint64_t u64;
} epoll_private_t;

static volatile sig_atomic_t shutdown_requested = 0;
static volatile sig_atomic_t pid_signaled = 0;
static int epoll_fd = -1;

static void signal_handler(int signum){
	if(signum == SIGCHLD){
		pid_signaled = 1;
	}
	else {
		shutdown_requested = 1;
	}
}

static int usage(char* fn){
	printf("NFCommander %s - trigger actions based on near-field tags\n",
			NFCOMMANDER_VERSION);
	printf("\tUsage: %s <config-file>\n", fn);
	return EXIT_FAILURE;
}

int core_manage_fd(int fd, int manage, notification_target_t system){
	epoll_private_t data = {
		.components.system = system,
		.components.fd = fd
	};

	struct epoll_event event = {
		.events = EPOLLIN,
		.data.u64 = data.u64
	};

	if(fd < 0){
		return 0;
	}

	if(epoll_ctl(epoll_fd, manage ? EPOLL_CTL_ADD : EPOLL_CTL_DEL, fd, &event)){
		perror("core/epoll_mod");
		shutdown_requested = 1;
		return 1;
	}
	return 0;
}

int main(int argc, char** argv){
	size_t n;
	int event_count;
	epoll_private_t polldata;

	if(argc < 2){
		return usage(argv[0]);
	}

	//set up epoll instance
	struct epoll_event events[10];
	epoll_fd = epoll_create1(EPOLL_CLOEXEC);
	if(epoll_fd < 0){
		perror("core/epoll");
		return EXIT_FAILURE;
	}

	//read configuration
	if(config_read(argv[1])){
		//TODO cleanup
		return usage(argv[0]);
	}

	//start reader api
	if(reader_init()){
		//TODO cleanup
		return EXIT_FAILURE;
	}

	//start control api
	if(control_start()){
		printf("Failed to start control interface\n");
		//TODO cleanup
		return EXIT_FAILURE;
	}

	//handle signals
	signal(SIGINT, signal_handler);
	signal(SIGCHLD, signal_handler);
	signal(SIGPIPE, SIG_IGN);

	//handle events
	while(!shutdown_requested){
		event_count = epoll_wait(epoll_fd, events, sizeof(events) / sizeof(struct epoll_event), 1000);
		if(event_count < 0){
			perror("core/poll");
			break;
		}

		for(n = 0; n < event_count; n++){
			polldata.u64 = events[n].data.u64;
			//TODO error checking
			switch(polldata.components.system){
				case system_control:
					control_handle(polldata.components.fd);
					break;
				case system_reader:
					reader_handle(polldata.components.fd);
					break;
				case system_command:
					command_handle(polldata.components.fd);
					break;
				default:
					printf("Unhandled target system for fd %d\n", polldata.components.fd);
					break;
			}
		}

		if(pid_signaled){
			pid_signaled = 0;
			command_reap();
		}
	}
	
	//clean up
	reader_free();
	control_free();
	command_free();
	config_free();
	close(epoll_fd);
	epoll_fd = -1;
}