import { Logger } from '../common/Logger';
import { IConfiguration, ILogger, IAppDelegate, IBPMNServer, IDataStore, ICacheManager, IScriptHandler, IModelsDatastore } from '../';
import { Engine } from './Engine';
import { Cron } from './Cron';
import { EventEmitter } from 'eventemitter3';

/**
 *	The main class of Server Layer
 *	provides the full functionalities:
 *	
 *		at start of the app:
 *			new BPMNServer(configuration,options);
 *			
 *		after that point:
 *		
 *			BPMNServer.engine.start(...)
 *			BPMNServer.engine.invoke(...)
 *			BPMNServer.dataStore.findInstances(...)
 *			BPMNServer.dataStore.findItems(...)
 */

 /* removing the following block causes :#222
	restored in release 2.2.11
 */

 process.on('uncaughtException', function (err) {
	console.log('***************BPMNServer UNCAUGHT ERROR***********');
	try {
		BPMNServer.getInstance().error = err;
		BPMNServer.getInstance().logger.reportError(err);
	}
	catch (exc) {
		console.log(err);
    }
	return;
}); 

class BPMNServer implements IBPMNServer {

	engine: Engine;
	listener: EventEmitter;
	configuration: IConfiguration;
	logger: ILogger;
	definitions;
	appDelegate: IAppDelegate;
	dataStore: IDataStore;
	cache: ICacheManager;
	scriptHandler: IScriptHandler;
	cron: Cron;
	error;

	private static instance: BPMNServer;

	/**
	 * Server Constructor
	 * 
	 * @param configuration	see 
	 * @param logger
	 */

	constructor(configuration: IConfiguration, logger?: ILogger, options = {}) {

		if (logger == null) {
			logger = new Logger({});
		}
		this.listener = new EventEmitter();
		this.logger = logger;
		this.configuration = configuration;
		this.cron = new Cron(this);
		this.engine = new Engine(this);

		this.cache = configuration.cacheManager(this);
		this.dataStore = configuration.dataStore(this);
		this.definitions = configuration.definitions(this);
		this.appDelegate = configuration.appDelegate(this);
		this.scriptHandler = configuration.scriptHandler(this);
	
		//this.acl = new ACL(this);
		//this.iam = new IAM(this);
		console.log("bpmn-server version " + BPMNServer.getVersion());
		BPMNServer.instance=this;

		this.appDelegate.startUp(options);

		if (options['cron'] == false) {
			return;
		}
		else {
			this.cron.start();
		}
	}
	status() {
		return {
			version: BPMNServer.getVersion(),
			cache: this.cache.list,
			engineRunning: this.engine.runningCounter,
			engineCalls: this.engine.callsCounter,
			memoryUsage: typeof __dirname === 'undefined' ? require('node:process').memoryUsage() : null,
		};
	}
	static getVersion() {
		if (typeof __dirname === 'undefined') return 'unknown';
		const configPath = __dirname+'/../../package.json';
		const fs = require('fs');

		if (fs.existsSync(configPath)) {

			var configuration = JSON.parse(fs.readFileSync(configPath, 'utf8'));
			var _version = configuration['version'];
			return _version;
		}
		else
			return 'cannot locate package.json current: ' + __dirname+' path '+configPath;
    }
	public static get engine() {
		return BPMNServer.getInstance().engine;
    }
	public static getInstance(): BPMNServer {
		if (!BPMNServer.instance) {
			throw Error("BPMN Server Not initialized");
		}

		return BPMNServer.instance;
	}
}


export { BPMNServer};