#!/usr/bin/env node

'use strict';

var os = require('os');
var path = require('path');
var dotenv = require("dotenv");
var fs = require('fs');

var configPaths = [ path.join(os.homedir(), '.config', 'btc-rpc-explorer.env'), path.join(process.cwd(), '.env') ];
configPaths.filter(fs.existsSync).forEach(path => {
	console.log('Loading env file:', path);
	dotenv.config({ path });
});

// debug module is already loaded by the time we do dotenv.config
// so refresh the status of DEBUG env var
var debug = require("debug");
debug.enable(process.env.DEBUG || "btcexp:app,btcexp:error");

var debugLog = debug("btcexp:app");
var debugPerfLog = debug("btcexp:actionPerformace");

var express = require('express');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require("express-session");
var csurf = require("csurf");
var config = require("./app/config.js");
var simpleGit = require('simple-git');
var utils = require("./app/utils.js");
var moment = require("moment");
var Decimal = require('decimal.js');
var bitcoinCore = require("bitcoin-core");
var pug = require("pug");
var momentDurationFormat = require("moment-duration-format");
var coreApi = require("./app/api/coreApi.js");
var coins = require("./app/coins.js");
var request = require("request");
var qrcode = require("qrcode");
var addressApi = require("./app/api/addressApi.js");
var electrumAddressApi = require("./app/api/electrumAddressApi.js");
var coreApi = require("./app/api/coreApi.js");
var auth = require('./app/auth.js');

var package_json = require('./package.json');
global.appVersion = package_json.version;

var crawlerBotUserAgentStrings = [ "Googlebot", "Bingbot", "Slurp", "DuckDuckBot", "Baiduspider", "YandexBot", "Sogou", "Exabot", "facebot", "ia_archiver" ];

var baseActionsRouter = require('./routes/baseActionsRouter');
var apiActionsRouter = require('./routes/api');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));

// ref: https://blog.stigok.com/post/disable-pug-debug-output-with-expressjs-web-app
app.engine('pug', (path, options, fn) => {
	options.debug = false;
	return pug.__express.call(null, path, options, fn);
});

app.set('view engine', 'pug');

// basic http authentication
if (process.env.BTCEXP_BASIC_AUTH_PASSWORD) {
	app.disable('x-powered-by');
	app.use(auth(process.env.BTCEXP_BASIC_AUTH_PASSWORD));
}

// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
//app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(session({
	secret: config.cookieSecret,
	resave: false,
	saveUninitialized: false
}));

app.use(express.static(path.join(__dirname, 'public')));

process.on("unhandledRejection", (reason, p) => {
	debugLog("Unhandled Rejection at: Promise", p, "reason:", reason, "stack:", (reason != null ? reason.stack : "null"));
});

function loadMiningPoolConfigs() {
	global.miningPoolsConfigs = [];

	var miningPoolsConfigDir = path.join(__dirname, "public", "txt", "mining-pools-configs", global.coinConfig.ticker);

	fs.readdir(miningPoolsConfigDir, function(err, files) {
		if (err) {
			utils.logError("3ufhwehe", err, {configDir:miningPoolsConfigDir, desc:"Unable to scan directory"});

			return;
		}

		files.forEach(function(file) {
			var filepath = path.join(miningPoolsConfigDir, file);

			var contents = fs.readFileSync(filepath, 'utf8');

			global.miningPoolsConfigs.push(JSON.parse(contents));
		});
	});

	for (var i = 0; i < global.miningPoolsConfigs.length; i++) {
		for (var x in global.miningPoolsConfigs[i].payout_addresses) {
			if (global.miningPoolsConfigs[i].payout_addresses.hasOwnProperty(x)) {
				global.specialAddresses[x] = {type:"minerPayout", minerInfo:global.miningPoolsConfigs[i].payout_addresses[x]};
			}
		}
	}
}

function getSourcecodeProjectMetadata() {
	var options = {
		url: "https://api.github.com/repos/janoside/btc-rpc-explorer",
		headers: {
			'User-Agent': 'request'
		}
	};

	request(options, function(error, response, body) {
		if (error == null && response && response.statusCode && response.statusCode == 200) {
			var responseBody = JSON.parse(body);

			global.sourcecodeProjectMetadata = responseBody;

		} else {
			utils.logError("3208fh3ew7eghfg", {error:error, response:response, body:body});
		}
	});
}

function loadChangelog() {
	var filename = "CHANGELOG.md";
	
	fs.readFile(path.join(__dirname, filename), 'utf8', function(err, data) {
		if (err) {
			utils.logError("2379gsd7sgd334", err);

		} else {
			global.changelogMarkdown = data;
		}
	});
}

function loadHistoricalDataForChain(chain) {
	global.specialTransactions = {};
	global.specialBlocks = {};
	global.specialAddresses = {};

	if (global.coinConfig.historicalData) {
		global.coinConfig.historicalData.forEach(function(item) {
			if (item.chain == chain) {
				if (item.type == "blockheight") {
					global.specialBlocks[item.blockHash] = item;

				} else if (item.type == "tx") {
					global.specialTransactions[item.txid] = item;

				} else if (item.type == "address") {
					global.specialAddresses[item.address] = {type:"fun", addressInfo:item};
				}
			}
		});
	}
}

function verifyRpcConnection() {
	if (!global.activeBlockchain) {
		debugLog(`Trying to verify RPC connection...`);

		coreApi.getNetworkInfo().then(function(getnetworkinfo) {
			coreApi.getBlockchainInfo().then(function(getblockchaininfo) {
				global.activeBlockchain = getblockchaininfo.chain;

				// we've verified rpc connection, no need to keep trying
				clearInterval(global.verifyRpcConnectionIntervalId);

				onRpcConnectionVerified(getnetworkinfo, getblockchaininfo);

			}).catch(function(err) {
				utils.logError("329u0wsdgewg6ed", err);
			});
		}).catch(function(err) {
			utils.logError("32ugegdfsde", err);
		});
	}
}

function onRpcConnectionVerified(getnetworkinfo, getblockchaininfo) {
	// localservicenames introduced in 0.19
	var services = getnetworkinfo.localservicesnames ? ("[" + getnetworkinfo.localservicesnames.join(", ") + "]") : getnetworkinfo.localservices;

	global.getnetworkinfo = getnetworkinfo;

	debugLog(`RPC Connected: version=${getnetworkinfo.version} (${getnetworkinfo.subversion}), protocolversion=${getnetworkinfo.protocolversion}, chain=${getblockchaininfo.chain}, services=${services}`);

	// load historical/fun items for this chain
	loadHistoricalDataForChain(global.activeBlockchain);

	if (global.activeBlockchain == "main") {
		if (global.exchangeRates == null) {
			utils.refreshExchangeRates();
		}

		// refresh exchange rate periodically
		setInterval(utils.refreshExchangeRates, 1800000);
	}
}

function refreshUtxoSetSummary() {
	if (config.slowDeviceMode) {
		global.utxoSetSummary = null;
		global.utxoSetSummaryPending = false;

		debugLog("Skipping performance-intensive task: fetch UTXO set summary. This is skipped due to the flag 'slowDeviceMode' which defaults to 'true' to protect slow nodes. Set this flag to 'false' to enjoy UTXO set summary details.");

		return;
	}

	// flag that we're working on calculating UTXO details (to differentiate cases where we don't have the details and we're not going to try computing them)
	global.utxoSetSummaryPending = true;

	coreApi.getUtxoSetSummary().then(function(result) {
		global.utxoSetSummary = result;

		result.lastUpdated = Date.now();

		debugLog("Refreshed utxo summary: " + JSON.stringify(result));
	});
}


app.onStartup = function() {
	global.config = config;
	global.coinConfig = coins[config.coin];
	global.coinConfigs = coins;

	loadChangelog();

	if (global.sourcecodeVersion == null && fs.existsSync('.git')) {
		simpleGit(".").log(["-n 1"], function(err, log) {
			if (err) {
				utils.logError("3fehge9ee", err, {desc:"Error accessing git repo"});

				debugLog(`Starting ${global.coinConfig.ticker} RPC Explorer, v${global.appVersion} (code: unknown commit)`);

			} else {
				global.sourcecodeVersion = log.all[0].hash.substring(0, 10);
				global.sourcecodeDate = log.all[0].date.substring(0, "0000-00-00".length);

				debugLog(`Starting ${global.coinConfig.ticker} RPC Explorer, v${global.appVersion} (commit: '${global.sourcecodeVersion}', date: ${global.sourcecodeDate})`);
			}

			app.continueStartup();
		});

	} else {
		debugLog(`Starting ${global.coinConfig.ticker} RPC Explorer, v${global.appVersion}`);

		app.continueStartup();
	}
}

app.continueStartup = function() {
	var rpcCred = config.credentials.rpc;
	debugLog(`Connecting to RPC node at ${rpcCred.host}:${rpcCred.port}`);

	var rpcClientProperties = {
		host: rpcCred.host,
		port: rpcCred.port,
		username: rpcCred.username,
		password: rpcCred.password,
		timeout: rpcCred.timeout
	};

	global.rpcClient = new bitcoinCore(rpcClientProperties);

	var rpcClientNoTimeoutProperties = {
		host: rpcCred.host,
		port: rpcCred.port,
		username: rpcCred.username,
		password: rpcCred.password,
		timeout: 0
	};

	global.rpcClientNoTimeout = new bitcoinCore(rpcClientNoTimeoutProperties);


	// keep trying to verify rpc connection until we succeed
	// note: see verifyRpcConnection() for associated clearInterval() after success
	verifyRpcConnection();
	global.verifyRpcConnectionIntervalId = setInterval(verifyRpcConnection, 30000);


	if (config.addressApi) {
		var supportedAddressApis = addressApi.getSupportedAddressApis();
		if (!supportedAddressApis.includes(config.addressApi)) {
			utils.logError("32907ghsd0ge", `Unrecognized value for BTCEXP_ADDRESS_API: '${config.addressApi}'. Valid options are: ${supportedAddressApis}`);
		}

		if (config.addressApi == "electrumx") {
			if (config.electrumXServers && config.electrumXServers.length > 0) {
				electrumAddressApi.connectToServers().then(function() {
					global.electrumAddressApi = electrumAddressApi;
					
				}).catch(function(err) {
					utils.logError("31207ugf4e0fed", err, {electrumXServers:config.electrumXServers});
				});
			} else {
				utils.logError("327hs0gde", "You must set the 'BTCEXP_ELECTRUMX_SERVERS' environment variable when BTCEXP_ADDRESS_API=electrumx.");
			}
		}
	}


	loadMiningPoolConfigs();


	if (config.demoSite) {
		getSourcecodeProjectMetadata();
		setInterval(getSourcecodeProjectMetadata, 3600000);
	}


	utils.logMemoryUsage();
	setInterval(utils.logMemoryUsage, 5000);


	refreshUtxoSetSummary();
	setInterval(refreshUtxoSetSummary, 30 * 60 * 1000);
};

app.use(function(req, res, next) {
	req.startTime = Date.now();
	req.startMem = process.memoryUsage().heapUsed;

	next();
});

app.use(function(req, res, next) {
	// make session available in templates
	res.locals.session = req.session;

	if (config.credentials.rpc && req.session.host == null) {
		req.session.host = config.credentials.rpc.host;
		req.session.port = config.credentials.rpc.port;
		req.session.username = config.credentials.rpc.username;
	}

	var userAgent = req.headers['user-agent'];
	for (var i = 0; i < crawlerBotUserAgentStrings.length; i++) {
		if (userAgent.indexOf(crawlerBotUserAgentStrings[i]) != -1) {
			res.locals.crawlerBot = true;
		}
	}

	res.locals.config = global.config;
	res.locals.coinConfig = global.coinConfig;
	res.locals.exchangeRates = global.exchangeRates;
	res.locals.utxoSetSummary = global.utxoSetSummary;
	res.locals.utxoSetSummaryPending = global.utxoSetSummaryPending;
	
	res.locals.host = req.session.host;
	res.locals.port = req.session.port;

	res.locals.genesisBlockHash = coreApi.getGenesisBlockHash();
	res.locals.genesisCoinbaseTransactionId = coreApi.getGenesisCoinbaseTransactionId();

	res.locals.pageErrors = [];


	// currency format type
	if (!req.session.currencyFormatType) {
		var cookieValue = req.cookies['user-setting-currencyFormatType'];

		if (cookieValue) {
			req.session.currencyFormatType = cookieValue;

		} else {
			req.session.currencyFormatType = "";
		}
	}

	// theme
	if (!req.session.uiTheme) {
		var cookieValue = req.cookies['user-setting-uiTheme'];

		if (cookieValue) {
			req.session.uiTheme = cookieValue;

		} else {
			req.session.uiTheme = "";
		}
	}

	// homepage banner
	if (!req.session.hideHomepageBanner) {
		var cookieValue = req.cookies['user-setting-hideHomepageBanner'];

		if (cookieValue) {
			req.session.hideHomepageBanner = cookieValue;

		} else {
			req.session.hideHomepageBanner = "false";
		}
	}

	res.locals.currencyFormatType = req.session.currencyFormatType;
	global.currencyFormatType = req.session.currencyFormatType;


	if (!["/", "/connect"].includes(req.originalUrl)) {
		if (utils.redirectToConnectPageIfNeeded(req, res)) {
			return;
		}
	}

	if (req.session.userMessage) {
		res.locals.userMessage = req.session.userMessage;
		
		if (req.session.userMessageType) {
			res.locals.userMessageType = req.session.userMessageType;
			
		} else {
			res.locals.userMessageType = "warning";
		}

		req.session.userMessage = null;
		req.session.userMessageType = null;
	}

	if (req.session.query) {
		res.locals.query = req.session.query;

		req.session.query = null;
	}

	// make some var available to all request
	// ex: req.cheeseStr = "cheese";

	next();
});

app.use(csurf(), (req, res, next) => {
	res.locals.csrfToken = req.csrfToken();
	next();
});

app.use('/', baseActionsRouter);
app.use('/api/', apiActionsRouter);

app.use(function(req, res, next) {
	var time = Date.now() - req.startTime;
	var memdiff = process.memoryUsage().heapUsed - req.startMem;

	debugPerfLog("Finished action '%s' in %d ms", req.path, time);
});

/// catch 404 and forwarding to error handler
app.use(function(req, res, next) {
	var err = new Error('Not Found');
	err.status = 404;
	next(err);
});

/// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
	app.use(function(err, req, res, next) {
		res.status(err.status || 500);
		res.render('error', {
			message: err.message,
			error: err
		});
	});
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
	res.status(err.status || 500);
	res.render('error', {
		message: err.message,
		error: {}
	});
});

app.locals.moment = moment;
app.locals.Decimal = Decimal;
app.locals.utils = utils;



module.exports = app;