#include <bits/types/sig_atomic_t.h>
#include <chrono>
#include <iostream>
#include <string.h>
#include <string>
#include <thread>
#include <readline/readline.h>
#include <readline/history.h>
#include <signal.h>
#include <sys/signalfd.h>
#include <sys/epoll.h>

#include "serial_io.h"

sig_atomic_t stop = false;
constexpr int HISTORY_SIZE = 100;

void intHandler(int dummy)
{
	stop = true;
}

static void printUsage()
{
	std::cout<<"usage mulitplexer [option]\n\
 Available options:\n\
 -h, --help       print this help\n\
 -p, --serialport serial port device to use\n\
 -P, --port       tcp port to use\n\
 -b, --baud       set baud rate with termios id\n\
 -r, --rates      list Available baud rates\n\
 -s, --sinkless   run without serial port\n";
}


struct Config
{
	std::string portFileName = "/dev/ttyUSB0";
	unsigned short port = 6856;
	int baud = B9600;
	bool noSerial = false;
};

static int parseCmdArgs(int argc, char** argv, Config *config)
{
	for (int i = 1; i < argc; i++)
	{
		if (std::string(argv[i]) == "--help" || std::string(argv[i]) == "-h")
		{
			printUsage();
			return -1;
		}
		else if (std::string(argv[i]) == "--serialport" || std::string(argv[i]) == "-p")
		{
			if(argc > i) config->portFileName = argv[i+1];
			else return -1;
		}
		else if (std::string(argv[i]) == "--baud" || std::string(argv[i]) == "-b")
		{
			if(argc > i) config->baud = atoi(argv[i+1]);
			else return -1;
		}
		else if (std::string(argv[i]) == "-r" || std::string(argv[i]) == "--rates")
		{
			printRates();
			return -1;
		}
	}
	return 0;
}

void recvThreadFunction(int serial, int signal)
{
	int pollQue = epoll_create1(0);
	struct epoll_event ev = {};

	ev.events = EPOLLIN;
	ev.data.fd = serial;
	epoll_ctl(pollQue, EPOLL_CTL_ADD, serial, &ev);
	ev.events = EPOLLIN;
	ev.data.fd = signal;
	epoll_ctl(pollQue, EPOLL_CTL_ADD, signal, &ev);

	struct epoll_event event;
	int ret;
	while((ret = epoll_wait(pollQue, &event, 1, -1)) > 0)
	{
		if(event.data.fd == signal)
			break;
		std::this_thread::sleep_for(std::chrono::milliseconds(100));
		char buffer[4096];
		int readlen = sRead(serial, buffer, 4096);
		if(readlen > 0)
		{
			rl_clear_visible_line();
			std::cout<<buffer;
			if(buffer[readlen-1] != '\n')
				std::cout<<'\n';
			rl_on_new_line();
			rl_redisplay();
		}
	}
	if(ret < 0)
		perror("epoll_wait: ");
	close(pollQue);
}

int cb_serial;
static void cb_linehandler(char *line)
{
	if(line != NULL)
	{
		if(*line)
		{
			add_history(line);
			sWrite(cb_serial, line, strlen(line));
		}
		free (line);
	}
}

int main(int argc, char* argv[])
{
	Config config;

	if(parseCmdArgs(argc, argv, &config) != 0)
		return -1;

	std::cout<<"UVOS serial terminal v1.0\n";

	int serial = -1;
	std::cout<<"Using serial port: "<<config.portFileName<<" at "<<config.baud<<" baud\n";
	serial = serialport_init(config.portFileName.c_str(), config.baud);
	if(serial == -1)
		return 1;
	cb_serial = serial;

	tcflush(serial, TCIOFLUSH);

	sigset_t set;
	sigisemptyset(&set);
	sigaddset(&set, SIGINT);
	sigaddset(&set, SIGTERM);
	int sigfd = signalfd(-1, &set, 0);
	signal(SIGINT, intHandler);
	signal(SIGTERM, intHandler);
	signal(SIGPIPE, SIG_IGN);

	std::thread readThread(recvThreadFunction, serial, sigfd);

	rl_catch_signals = 0;
	rl_callback_handler_install ("> ", cb_linehandler);

	int pollQue = epoll_create1(0);
	struct epoll_event ev = {};
	ev.events = EPOLLIN;
	ev.data.fd = fileno(rl_instream);
	epoll_ctl(pollQue, EPOLL_CTL_ADD, fileno(rl_instream), &ev);
	ev.events = EPOLLIN;
	ev.data.fd = sigfd;
	epoll_ctl(pollQue, EPOLL_CTL_ADD, sigfd, &ev);

	struct epoll_event event;
	int ret;
	while((ret = epoll_wait(pollQue, &event, 1, -1)) > 0)
	{
		if(event.data.fd == sigfd)
			break;
		else
			rl_callback_read_char();
	}

	readThread.join();
	close(pollQue);
	close(sigfd);
	rl_callback_handler_remove();
	std::cout<<std::endl;
	return 0;
}