var DBG = DBG || 0;
var DBG1 = 1;
// var _clientServerTimeDiff = 0;


self.addEventListener('install', onInstall);
self.addEventListener('activate', onActivate);
self.addEventListener('fetch', onFetch);
self.addEventListener('message', onMessage);


// self.importScripts('')

/**
	IAuthStatus {
		type: string "expired" | "logged_in" | "logged_in_again"
		login: string
		expire: int
		time: timestamp (seconds)
	}
 */
var sessionTimerBuffer = (function () {
	// var _timeoutId = null;
	var _lastTimeToExpireSec = null;
	var _responseTimeMs = null;
	var _loggedInUser = null; // login
	var setSessionExpirySec = function (timeToExpire, loggedInUser) {
		DBG && console.log('DBG:sw:sessionTimerBuffer setSessionExpirySec(', { timeToExpire, loggedInUser }, ')');
		_lastTimeToExpireSec = parseInt(timeToExpire);
		_responseTimeMs = (new Date()).getTime();
		if (loggedInUser) _loggedInUser = loggedInUser;
	};
	var getSessionExpirySec = function () {
		var nowMs = (new Date()).getTime();
		return (_lastTimeToExpireSec && _responseTimeMs) ? _lastTimeToExpireSec - Math.floor((nowMs - _responseTimeMs) / 1000) : null;
	};
	var getDiffLastFetchedMs = function () {
		var nowMs = (new Date()).getTime();
		return (_lastTimeToExpireSec && _responseTimeMs) ? (nowMs - _responseTimeMs) : null;
	};
	var getLogin = function () {
		return _loggedInUser;
	};

	return {
		setSessionExpirySec: setSessionExpirySec,
		getSessionExpirySec: getSessionExpirySec,
		getDiffLastFetchedMs: getDiffLastFetchedMs,
		getLogin: getLogin,
	};
})();


function onInstall(event) {
	DBG && console.log("DBG:sw:install", { event })
	if (self.skipWaiting) self.skipWaiting();
}
function onActivate(event) {
	DBG && console.log("DBG:sw:activate", { event })
}
function onFetch(event) { // proxy all client requests
	DBG && console.log("DBG:sw:fetch", { url: event.request.url, clientId: event.clientId, event })
	var url = event.request.url;

	if ('session-expire.php?task=getAuthStatus' === url.substr(url.lastIndexOf('/') + 1)) {
		var lastFetchedMs = sessionTimerBuffer.getDiffLastFetchedMs();
		if (!lastFetchedMs || lastFetchedMs > 2000) {
			event.respondWith(new Promise(function (resolve, reject) {
				// var clientRequestTime = Math.floor(Date.now() / 1000);
				// var clientResponseTime = 0;
				// var serverResponseTime = 0;
				fetch(event.request).then(function (response) {
					// clientResponseTime = Math.floor(Date.now() / 1000);
					return response.text()
				}).then(function (responseText) {
					DBG && console.log("DBG:sw:fetch responseText", { url: event.request.url, clientId: event.clientId, responseText })
					try {
						var json = JSON.parse(responseText);
						return json;
					} catch (e) {
						throw "session_expired"; // resolve(new Response(responseText, { status: 200 }));
					}
				}).then(function (data) { // data: IAuthStatus
					// serverResponseTime = parseInt(data.time);
					// _clientServerTimeDiff = serverResponseTime - (clientResponseTime + clientRequestTime) / 2;
					// DBG && console.log("DBG:sw:getAuthStatus timediff", { clientRequestTime, clientResponseTime, serverResponseTime, _clientServerTimeDiff });
					var expire = parseInt(data.expire);
					sessionTimerBuffer.setSessionExpirySec(expire, data.login);
					resolve(new Response(JSON.stringify(data), { status: 200 }));
				}).catch(function (err) {
					resolve(new Response(err, { status: 200 }));
				})
			}))
		} else {
			var generatedResponseData = {
				expire: sessionTimerBuffer.getSessionExpirySec(),
				login: sessionTimerBuffer.getLogin(),
			}
			event.respondWith(Promise.resolve(new Response(JSON.stringify(generatedResponseData), { status: 202 }))); // 202 - Accepted
		}
	}

	if ('session-expire.php?task=getTimer' === url.substr(url.lastIndexOf('/') + 1)) {
		var lastFetchedMs = sessionTimerBuffer.getDiffLastFetchedMs();
		DBG && console.log("DBG:sw:fetch session-expire getTimer", { lastFetchedMs: lastFetchedMs, sesTimerSec: sessionTimerBuffer.getSessionExpirySec(), url: event.request.url, clientId: event.clientId, event });
		if (!lastFetchedMs || lastFetchedMs > 2000) {
			event.respondWith(new Promise(function (resolve, reject) {
				fetch(event.request).then(function (response) {
					return response.text()
				}).then(function (data) {
					sessionTimerBuffer.setSessionExpirySec(data);
					resolve(new Response("" + data, { status: 200 }));
				}).catch(function (err) {
					reject(new Response("" + err, { status: 200 }));
				})
			}))
		} else {
			event.respondWith(Promise.resolve(new Response("" + sessionTimerBuffer.getSessionExpirySec(), { status: 202 }))); // 202 - Accepted
		}
	}
}
function onMessage(event) {
	DBG && console.log("DBG:sw:Message recieved in service worker:", { data: event.data, clientId: event.source.id, event });
	var data = event.data;
	var clientId = event.source.id;
	var msgType = (data && data.type) ? data.type || '' : '';
	DBG && console.log("DBG:sw:Message type:", { msgType });
	if ('logged_in' === msgType) {
		var lastLogin = sessionTimerBuffer.getLogin();
		var login = data.login || '';
		var isLoggedInAgain = (lastLogin && login && lastLogin === login);
		DBG && console.log("DBG:sw:Message logged_in:", { isLoggedInAgain, lastLogin, login, data: event.data, clientId: event.source.id, event });
		sessionTimerBuffer.setSessionExpirySec(data.expire, data.login);
		sendStateToOtherClients(
			clientId,
			isLoggedInAgain ? Object.assign(data, { type: 'logged_in_again' }) : data
		);
	} else {
		sendStateToAllClients(clientId, data);
	}
}


sendStateToAllClients = function(clientId, data) {
	DBG && console.log("DBG:sw:clients (global)", { clients })
	clients.matchAll().then(function (clients) {
		clients.forEach(function (client) {
			client.postMessage(data);
		})
	})
}
sendStateToOtherClients = function(clientId, data) {
	DBG && console.log("DBG:sw:clients (global)", { clients })
	clients.matchAll().then(function (clients) {
		clients.forEach(function (client) {
			if (client.id !== clientId) {
				client.postMessage(data);
			}
		})
	})
}

// versionCheck();
//
// async function versionCheck() {
// 	const response = await fetch(SW_VERSION_URL);
// 	const version = await response.text();
// 	if (version !== VERSION) {
// 		self.registration.update();
// 	}
// }