import std.conv;
import std.datetime;
import std.experimental.logger;
import std.stdio;
import std.string;

import vibe.core.core;
import vibe.core.net;
import vibe.core.process;

import ddbus;
import ddbus.c_lib;
import msgpackrpc;

string appName = "Automatisch In- en Uitschakelen Ober";

extern (C) void close(int fileNo);

/**
 * Represententeerd de toepassing
 */
struct Toep {
public:
	immutable ushort PORT = 18_002;
	immutable int m_waitingTime;
	immutable string m_clientAddress;
	immutable int CHECK_COUNT = 2;
	Connection m_dbusCon;
	bool m_keepRunning = true;
	version(WithRPC) Client m_client;
	
	this(int waitingTime, string clientAddress) {
		this.m_waitingTime = waitingTime;
		this.m_clientAddress = clientAddress;
		this.m_dbusCon = connectToBus(DBusBusType.DBUS_BUS_SYSTEM);
	}
	
	int exec() {
		info ("Can shut down: ", canShutdown());
		version(WithRPC) {
			TCPConnection conn = connectTCP(m_clientAddress, PORT);
			Duration sleepTime = 500.msecs;
			while(!conn) {
				infof("Not connected, trying again in %s", sleepTime);
				sleep(sleepTime);
				conn = connectTCP(m_clientAddress, PORT);
			}
			info("Connected!");
			m_client = new Client(conn);
			writeln("Receive response: '", m_client.call!(string)("GetBootReason"), "'");
		}
		
		runTask({
			import vibe.core.core : yield;
			while(m_dbusCon.tick() && m_keepRunning) {
				yield();
			}
		});
		
		runTask({
			FileDescriptor inhibitLock = FileDescriptor.none;
			version(WithRPC) {
				FileDescriptor sleepLock = FileDescriptor.none;
				FileDescriptor shutdownLock = FileDescriptor.none;
			}
			
			// Get interfaces
			BusName loginBus = busName("org.freedesktop.login1");
			ObjectPath loginPath = ObjectPath("/org/freedesktop/login1");
			InterfaceName loginIFace = interfaceName("org.freedesktop.login1.Manager");
			PathIface loginManager = new PathIface(m_dbusCon, loginBus, loginPath, loginIFace);
			PathIface loginManagerProps = new PathIface(m_dbusCon, loginBus, loginPath, interfaceName("org.freedesktop.DBus.Properties"));
			
			void releaseLock(ref FileDescriptor fd) {
				if (fd != FileDescriptor.none) {
					close(cast(int) fd);
					fd = FileDescriptor.none;
				}
			}
			
			version(WithRPC) {
				// Register signal listeners
				// FIXME: this does not work yet.
				MessageRouter router = new MessageRouter();
				MessagePattern sleepPattern = MessagePattern(loginPath, loginIFace, "PrepareForSleep", true);
				MessagePattern shutdownPattern = MessagePattern(loginPath, loginIFace, "PrepareForShutdown", true);
				router.setHandler!(void, bool)(sleepPattern, (bool active) {
					logf("Preparing for sleep: %b", active);
					if (active) {
						m_client.notify("NotifySleep");
						releaseLock(sleepLock);
					} else {
						m_client.notify("NotifyWakeup");
						sleepLock = loginManager.Inhibit("sleep", appName, "Systeem op de hoogte brengen dat de ober gaat slapen", "delay").to!FileDescriptor;
					}
				});
				router.setHandler!(void, bool)(shutdownPattern, (bool active) {
					logf("Preparing for shutdown: %b", active);
					if (active) {
						m_client.notify("NotifyShutdown");
						releaseLock(shutdownLock);
					}
				});
				registerRouter(m_dbusCon, router);
				
				// Take the sleep lock
				sleepLock = loginManager.Inhibit("sleep", appName, "Systeem op de hoogte brengen dat de ober gaat slapen", 
					"delay").to!FileDescriptor;
				shutdownLock = loginManager.Inhibit("shutdown", appName, "Systeem op de hoogte brengen dat de ober gaat sluiten", 
					"delay").to!FileDescriptor;
			}
			
				
			void block() {
				if (inhibitLock != FileDescriptor.none) return;
				Message mesg = loginManager.Inhibit("shutdown:sleep:idle:handle-suspend-key:handle-power-key", appName, "Er zijn spelers op de server", "block");
				inhibitLock = mesg.to!FileDescriptor;
			}
		
			
			scope (exit) {
				// Als we om een of andere redenen deze functie verlaten, laat het slot los!
				releaseLock(inhibitLock);
				releaseLock(sleepLock);
				releaseLock(shutdownLock);
			}
			
			int checkCount = CHECK_COUNT;
			while(m_keepRunning) {
				// Check if we are already preventing shutdown
				if (inhibitLock != FileDescriptor.none) {
					// We are. Check if we can shutdown (as in, no players are on the server)
					if (canShutdown()) {
						
						if (checkCount == 1) {
							// Release the lock
							releaseLock(inhibitLock);
							info("Stop preventing shutdown");
						} else {
							// Check 1? more time
							checkCount--;
							tracef("Checking %d more time(s)", checkCount);
						}
					} else {
						// We cannot shut down. Reset the check counter.
						checkCount = CHECK_COUNT;
						tracef("Still players out there. Keeping lock");
					}
				} else if (!canShutdown()) {
					try {
						block();
					} catch(DBusException e) {
						warning("Could not take lock and prevent sleep/shutdown: ", e);
					}
					info("Start preventing shutdown");
				} else {
					trace("Nothing to do");
				}
				sleep(seconds(m_waitingTime));
			}
		});
		
		int exitCode = runEventLoop();
		// cleanup
		info("Cleanup");
		return exitCode;
	}
	
	/**
	 * Checks if the system can shut down.
	 */
	bool canShutdown() {
		auto result = execute(["ss", "-H", "--query=tcp", "state", "established", "sport", "=", ":minecraft"]);
		return result.output.splitLines().length == 0;
	}
}


int main(string[] args) {
	scope(failure) stderr.writefln("GEBRUIK: %s WACHTTIJD KLANTADRES", args[0]);
	if (args.length < 3) {
		stderr.writefln("GEBRUIK: %s WACHTTIJD KLANTADRES", args[0]);
		return -1;
	}
	int waitingTime = to!int(args[1]);
	return Toep(waitingTime, args[2]).exec();
}