//Set up environmental variables, pulled from ~/.env file used as process.env.DB_HOST
const os = require('os') //Used to get path of home directory
const result = require('dotenv').config({ path:(os.homedir()+'/.env') })

const ports = {
	express: 3000,
	socketIo: 3001
}

//Allow user of @ in in require calls. Config in package.json
require('module-alias/register')

//Auth helper, used for decoding users web token
let Auth = require('@helpers/Auth')

//Helmet adds additional security to express server
const helmet = require('helmet')

//Setup express server
const express = require('express')
const app = express()
app.use( helmet() )
// allow for the parsing of url encoded forms
app.use(express.urlencoded({ extended: true }));


//
// Request Rate Limiter 
//
const rateLimit = require('express-rate-limit')
//Limiter for the entire app
const limiter = rateLimit({
	windowMs: 10 * 60 * 1000, // 10 minutes
	max: 1000 // limit each IP to 1000 requests per windowMs
})
 
// apply to all requests
app.use(limiter);


var http = require('http').createServer(app);
var io = require('socket.io')(http, {
	path:'/socket'
});

//Set socket IO as a global in the app
global.SocketIo = io

let noteDiffs = {}

io.on('connection', function(socket){

	//When a user connects, add them to their own room
	// This allows the server to emit events to that specific user
	// access socket.io in the controller with SocketIo global
	socket.on('user_connect', token => {
		Auth.decodeToken(token)
		.then(userData => {
			socket.join(userData.userId)

			//Track active logged in user accounts
			const usersInRoom = io.sockets.adapter.rooms[userData.userId]
			io.to(userData.userId).emit('update_active_user_count', usersInRoom.length)

		}).catch(error => {
			//Don't add user to room if they are not logged in
			// console.log(error)
		})
	})

	socket.on('get_active_user_count', token => {
		Auth.decodeToken(token)
		.then(userData => {
			socket.join(userData.userId)

			//Track active logged in user accounts
			const usersInRoom = io.sockets.adapter.rooms[userData.userId]
			io.to(userData.userId).emit('update_active_user_count', usersInRoom.length)

		}).catch(error => {
			// console.log(error)
		})
	})

	//Renew Session tokens when users request a new one
	socket.on('renew_session_token', token => {

		//Decode the token they currently have
		Auth.decodeToken(token)
		.then(userData => {

			if(userData.active == 1){
				//Create a new one using credentials and session keys from current
				Auth.createToken(userData.userId, userData.masterKey, userData.sessionId, userData.created)
				.then(newToken => {

					//Emit new token only to user on socket
					socket.emit('recievend_new_token', newToken)
				})
			} else {
				//Attempting to reactivate disabled session, kills it all
				Auth.terminateSession(userData.sessionId)
			}
		})
	})

	socket.on('join_room', rawTextId => {
		// Join user to rawtextid room when they enter
		socket.join(rawTextId)

		//If there are past diffs for this note, send them to the user
		if(noteDiffs[rawTextId] != undefined){
			
			//Sort all note diffs by when they were created.
			noteDiffs[rawTextId].sort((a,b) => { return a.time - b.time })

			//Emit all sorted diffs to user
			socket.emit('past_diffs', noteDiffs[rawTextId])
		}

		const usersInRoom = io.sockets.adapter.rooms[rawTextId]
		if(usersInRoom){
			//Update users in room count
			io.to(rawTextId).emit('update_user_count', usersInRoom.length)
		}
	})

	socket.on('leave_room', roomId => {
		socket.leave(roomId)
		// console.log('User Left room')

		const usersInRoom = io.sockets.adapter.rooms[roomId]
		if(usersInRoom){
			// console.log('Users in room', usersInRoom.length)
			io.to(roomId).emit('update_user_count', usersInRoom.length)
		}
		
	})

	socket.on('note_diff', data => {

		//Log each diff for note
		const noteId = data.id
		delete data.id
		if(noteDiffs[noteId] == undefined){ noteDiffs[noteId] = [] }
		data.time = +new Date
		
		noteDiffs[noteId].push(data)

		// Go over each user in this note-room
		io.in(noteId).clients((error, clients) => {
			if (error) throw error;

			//Go through each client in note-room and send them the diff
			clients.forEach(socketId => {
				// only send off diff if user
				if(socketId != socket.id){
					io.to(socketId).emit('incoming_diff', data)
				}
			})

		});

	})

	socket.on('truncate_diffs_at_save', checkpoint => {

		let diffSet = noteDiffs[checkpoint.rawTextId]
		if(diffSet && diffSet.length > 0){

			//Make sure all diffs are sorted before cleaning
			noteDiffs[checkpoint.rawTextId].sort((a,b) => { return a.time - b.time })

			// Remove all diffs until it reaches the current hash
			let sliceTo = 0
			for (var i = 0; i < diffSet.length; i++) {
				if(diffSet[i].hash == checkpoint){
					sliceTo = i
					break
				}
			}

			noteDiffs[checkpoint.rawTextId] = diffSet.slice(0, sliceTo)

			if(noteDiffs[checkpoint.rawTextId].length == 0){
				delete noteDiffs[checkpoint.rawTextId]
			} 
			//Debugging
			else {
				console.log('Diffset after save')
				console.log(noteDiffs[checkpoint.rawTextId])
			}

		}
	})

	socket.on('disconnect', function(socket){
		// console.log('user disconnected');
	});
});


http.listen(ports.socketIo, function(){
	console.log(`Socke.io: Listening on port ${ports.socketIo}`)
});

//Enable json body parsing in requests. Allows me to post data in ajax calls
app.use(express.json({limit: '5mb'}))

//App Auth, all requests will come in with a token, decode the token and set global var
app.use(function(req, res, next){

	//Always null out master key, never allow it set from outside
	req.headers.userId = null
	req.headers.masterKey = null
	req.headers.sessionId = null

	//auth token set by axios in headers
	let token = req.headers.authorizationtoken
	if(token !== undefined && token.length > 0){
		Auth.decodeToken(token, req)
		.then(userData => {

			//Update headers for the rest of the application
			req.headers.userId = userData.userId
			req.headers.masterKey = userData.masterKey
			req.headers.sessionId = userData.sessionId

			//Tell front end remaining uses on current token
			res.set('remainingUses', userData.remainingUses)

			next()
		})
		.catch(error => {

			next('Unauthorized')
		})
	} else {
		next() //No token. Move along.
	}
})


// Test Area
// const printResults = true
// let UserTest = require('@models/User')
// let NoteTest = require('@models/Note')
// let AuthTest = require('@helpers/Auth')
// Auth.test()
// UserTest.keyPairTest('genMan30', '1', printResults)
// .then( ({testUserId, masterKey}) => 
// 	NoteTest.test(testUserId, masterKey, printResults))
// .then( message => { 
// 	if(printResults) console.log(message) 
// 	Auth.testTwoFactor()
// })
// .catch((error) => {
// 	console.log(error)
// })

//Test 
app.get('/api', (req, res) => res.send('Solidscribe /API is up and running'))

//Serve up uploaded files
app.use('/api/static', express.static( __dirname+'/../staticFiles' ))

//Public routes
var public = require('@routes/publicController')
app.use('/api/public', public)

//user endpoint
var user = require('@routes/userController')
app.use('/api/user', user)

//notes endpoint
var notes = require('@routes/noteController')
app.use('/api/note', notes)

//tags endpoint
var tags = require('@routes/tagController')
app.use('/api/tag', tags)

//notes endpoint
var attachment = require('@routes/attachmentController')
app.use('/api/attachment', attachment)

//quick notes endpoint
var quickNote = require('@routes/quicknoteController')
app.use('/api/quick-note', quickNote)

//cycle tracking endpoint
var metricTracking = require('@routes/metrictrackingController')
app.use('/api/metric-tracking', metricTracking)

//Output running status
app.listen(ports.express, () => { 
	console.log(`Express: Listening on port ${ports.express}!`)
})

//
//Error handlers
//
//Default error handler just say unauthorized for everything
app.use(function (err, req, res, next) {
	if (err) {
		res.status(401).send('Unauthorized')
		return
	}
	next()
})