/* 
 * D3-Centraliser - A REST API based database management script 
 * Licence: GPL-3
 * Copyright: Jesper Bergman (jesperbe@dsv.su.se)
 * 
 */

/* Make sure the CORS support works. */ 

const corsMiddleware = require('restify-cors-middleware');
const errs = require('restify-errors');
const restify = require("restify");
const sqlite3 = require('sqlite3').verbose();
const os = require('os');
const crypto = require('crypto');
const performance = require('performance-now');
const { spawn } = require('child_process');
const fs = require('fs');

/*  Server config.   */
const server = restify.createServer();
server.use(restify.plugins.acceptParser(server.acceptable));
server.use(restify.plugins.queryParser());
server.use(restify.plugins.bodyParser());

/* Ugly hack: allow request from everywhere. */ 
const cors = corsMiddleware({
	  preflightMaxAge: 5, 
	  origins: ['*'],
	  allowHeaders: ['*'],
	  exposeHeaders: ['*', 'Content-Type: text/html; charset=UTF-8']
	  
});

/* Activate CORS settings */
server.pre(cors.preflight);
server.use(cors.actual);

/* Allow CORS from everywhere. Does not work... 
restify.defaultResponseHeaders = data => {
	this.header('Access-Control-Allow-Origin', '*');
	this.header('Access-Control-Allowed-Methods', 'GET, POST, OPTIONS, DELETE');
	this.header('Access-Control-Allowed-Headers', '*');
}*/

/* Database connection. */
const databaseConnection = new sqlite3.Database("annotations.db", (err) => {
	if(err){console.error( "nej nej", err.message);}
});

/* Receive POST for adding stuff to the database. */
server.post('/api/:command', function (req, res, next){
	res.setHeader('Access-Control-Allow-Origin', '*');
	let feedback = req.body;
	/* Try - catch after database insertion success/failure */
	console.log("Client REQ data: ", req.getQuery(), " . And other than that: ", feedback);
	let verr_hash = addToDatabase(feedback, req.getQuery());
    res.send(200, verr_hash);
    verr_hash = null;
	return next();
});


/* REST API get() stuff from the database. */
server.get('/api/:categories', function (req, res, next){
	res.setHeader('Access-Control-Allow-Origin', '*');
	let feedback = req.body;
    let categories = databaseConnection.all("SELECT DISTINCT category FROM categories;", function(err,rows){res.send(200, rows)});
    //res.send(200, categories);
    console.log("Received category")
	return next();
});

/* Main attraction: insert new categories and other data into the DB. Change name to addCategoriesToDatabase*/
function addToDatabase(input, uid){
	let inputType = null;
	let uuid = uid.split("=");
	uuid = uuid[1];
	let sqlUUID = "SELECT uuid FROM users WHERE uuid=\'" + uuid + "\'"; 

    /* Verify message intergrity. */
    let verification_hashsum = calculateSHA256(input);
	console.log("UUID: ", sqlUUID, " Message verification hash sum: ", verification_hashsum);

    /* Prepare insertion. */
    databaseConnection.serialize(function(){
		databaseConnection.prepare(sqlUUID);
	});

	for(var i in input){
		inputType = i;
        try{
            let com = JSON.parse(inputType)
    		console.log("Command: " , inputType, com.username, com.fullname);
        }
        catch{
            console.log("This is not a username.")
        }
	}
    	
    if(JSON.parse(inputType).username){
        console.log("NOW WE TALK");

	    /* Insert username and UUID into DB. 
	    databaseConnection.serialize(function(){
            let query = databaseConnection.prepare("INSERT OR IGNORE INTO users (username) VALUES(?,?)");
            query.run("Andersson", uuid);
            query.finalize(); 
        });*/
    }

	if(inputType == "webpage"){
		/* Open up a connection. */
		databaseConnection.serialize(function(){
		/* Prepare queries for each table. */
		let webpageQuery = databaseConnection.prepare("REPLACE INTO webpage (url, domain, sha256, md5, timestamp, uuid) VALUES(?,?,?,?,?,?)");
		let categoryQuery = databaseConnection.prepare("REPLACE INTO categories (category, sha256, uuid) VALUES(?,?,?)");
		let noteQuery = databaseConnection.prepare("REPLACE INTO notes (note, sha256, uuid) VALUES(?,?,?)");
		let highlightedTextQuery = databaseConnection.prepare("REPLACE INTO highlightedText(highlightedText, sha256, uuid) VALUES(?,?,?)");

		/* Extract key/values from receivd JSON objects.*/
		let firstKey = Object.keys(input);
		let firstValue = Object.values(input);
		let secondKey = Object.keys(firstValue[0]);
		let secondValue = Object.values(firstValue[0]);
		let webpage = secondValue[0];
        let url = webpage.url;
		webpageQuery.run(
			webpage.url,
			webpage.domain,
			webpage.sha256,
			webpage.md5,
			webpage.timestamp,
			uuid,
		);
        
        /* Call D3-Collector and time*/
        let date = new Date();
        let t1 = performance();
        let t2 = null;
        let h = date.getHours();
        let m = "0" + date.getMinutes();
        let s = "0" + date.getSeconds();
        let ss = "0" + date.getMilliseconds();
        let formattedTime = h + ':' + m.substr(-2) + ':' + s.substr(-2) + '.' + ss.substr(-2);
        
        let ok = archive_webpage(webpage.url);

        if(ok != null){
            t2 = performance();
        }

        let sync_time = t2-t1;
        console.log("Fetched .onion page in: ", sync_time, " At: ", formattedTime)
        log(("Fetched .onion page " + webpage.url + " in: " + sync_time + " At: " + formattedTime+"\n\n"))
        
        /* Reset */
        t1 = null;
        t1 = null;
        sync_time = null;

		/* Parse arrays and refer to the correct SHA256. */
		if(webpage.category != "N/A"){
			for(var cat in webpage.category){
				categoryQuery.run(webpage.category[cat], webpage.sha256, uuid);
			}
		}
		for(var note in webpage.notes){
			console.log("|- looping through notes: ", webpage.notes[note]);
			noteQuery.run(webpage.notes[note], webpage.sha256, uuid);
		}
		for(var hlt in webpage.text){
			highlightedTextQuery.run(webpage.text[hlt], webpage.sha256, uuid);
		}

		/* Write to database. */
		
        t1 = performance();
        webpageQuery.finalize();
        t2 = performance();
        sync_time = t2 - t1;
            //t1 = performance();
            //webpageQuery.finalize();
            //2 = performance();
            //sync_time = t2 - t1;
        console.log("DB web page insert time: ", sync_time);
        t1 = performance();
        categoryQuery.finalize();
        t2 = performance();
        sync_time = t2-t1;
        console.log("DB category insert time: ", sync_time);
        t1 = performance();
		noteQuery.finalize();
        t2 = performance();
        sync_time = t2-t1;
        console.log("DB note insert time: ", sync_time);
        t1 = performance();
		highlightedTextQuery.finalize();
        t2 = performance();
        sync_time = t2-t1;
        console.log("DB highlightedText page insert time: ", sync_time);
		});
	}
	if(inputType == "category"){
		databaseConnection.serialize(function(){
			let query = databaseConnection.prepare("INSERT INTO categories (category,sha256, uuid) VALUES(?,?,?)");
			let stKey = Object.keys(input);
			let stValue = Object.values(input);
			let ndValue = Object.values(stValue[0]);
			console.log("Only categories being added: ", ndValue[0].category);
			let categories = ndValue[0].category;
			let sha256 = ndValue[0].sha256;

			if(categories != "N/A"){
				for(var y in categories){ 
					console.log("|-- ", categories[y]);
					query.run(categories[y], sha256, uuid);
				}
			}
			query.finalize();
		});
	}
    
    return verification_hashsum;
    verification_hashsum = null;
}

/* Invoke D3-Collector to archive the web page the URLs are pointing to. */
function archive_webpage(url){
    let success = false;
    const spawn = require("child_process").spawn;
    const spawnedShell = spawn('sh',["../D3-Collector/start-d3-collector.sh"]);
    console.log("Spawning .sh to get .onion sites.", url);
    // Success or not?
    spawnedShell.stdout.on('data', (data) => {
        console.log("Data back from D3-Collector: ", data)
        if(data != null){
            success = true;
        }
    });

    return success;
}

/* Close connection */
function closeDatabaseConnection(){
	databaseConnection.close((err) =>{
		if(err){
			console.error(err.message);
		}
	});
}
/* Calculate SHA256 of any input. */ 
function calculateSHA256(json_candidate){
    const hash = crypto.createHash('sha256');
    let str = JSON.stringify(json_candidate);
    hash.update(str);

    return hash.copy().digest('hex');
    hash.update("");
    str = "";
    console.log("Calculating hash sums...")
}

function log(log_item){
    fs.writeFile('d3-centraliser.log', log_item, function (err) {
          if (err) return console.log(err);
    });
}

/* Start up the server */
server.listen(8080, "10.1.100.17" , function (){
	console.log('%s listening at %s', server.name, server.url);
    console.log("And other sufttt.");
});