DatabaseHandler.js

var fs = require("fs");
var Promise = require("es6-promise").Promise;
var sqlite3 = require("sqlite3").verbose();

// Can be run in memory!
//var db = new sqlite3.Database(':memory:');

//to run in memory, provide ":memory:" as databaseFile
var DatabaseHandler = function(databaseFile){

	var file = databaseFile;
	var db = new sqlite3.Database(file);

	var _constructor = function(){
		_initializeDBIfEmpty();

	};

	var _initializeDBIfEmpty = function(){
		_createFile();
		_createTables();
	};

	var _createFile = function(){
		var exists = fs.existsSync(file);
		if(!exists) {
			console.log("Creating DB file:"+file);
			fs.openSync(file, "w");
		}	
	};

	var _createTables = function(){
		db.serialize(function() {
			db.run("CREATE TABLE if not exists applicationLog('id' INTEGER primary key AUTOINCREMENT,'userId' varchar(40), 'type' varchar(20), 'message' varchar(2500), 'timestamp' DATETIME DEFAULT CURRENT_TIMESTAMP)");

			db.run("CREATE TABLE if not exists user('id' INTEGER primary key AUTOINCREMENT,'userId' varchar(40), 'name' varchar(40),'participating' varchar(6), 'ovinger' int,'requests' int, 'creation' DATETIME DEFAULT CURRENT_TIMESTAMP)");
		});
	};

	var insertClient = function(userId){
		return new Promise(function(resolve, reject){
		
		var values = {
			$userId:userId,
		};

		//We dont use prepared statements as it will be a long delay between insertions
		var stmt = db.run("INSERT INTO user (userId,ovinger,requests) VALUES ($userId,0,0)",values,function(error){
			if(error !==null){
				reject(error);
				return;
			}
			resolve();
		});
						  

	})
	};

	var setClientName = function(clientId,name){
		return new Promise(function(resolve, reject){
		

		var values = {
			$clientId:clientId,
			$name:name
		};

		console.log("Setting client name for user:",clientId);
		//Check if client exists
		_createClientIfNotExists(clientId).then(function(){

				var stmt = db.run("UPDATE user SET name = $name  WHERE userId= $clientId;",values,function(error){
			if(error == null){
				resolve()
			}else{
				reject(error);
			}
			});

		},function(error){
			reject(error);
		});
		})
	};

	var _createClientIfNotExists = function(clientId){
		return new Promise(function(resolve, reject){
			var values = {
				$clientId: clientId
			}
			var existsStms = db.run("SELECT * FROM user WHERE userId= $clientId;",values,function(error,rows){
				if(error !== null){
					reject(error);
				}

				if(rows === undefined || rows.length < 1){
					insertClient(clientId).then(function(){
						resolve();
					},function(error){reject(error)});

				}else{
					resolve();
				}
		}) 
		})
	}
	
	var setClientParticipating= function(clientId,participating){
		return new Promise(function(resolve, reject){
		

		var values = {
			$clientId:clientId,
			$participating:participating
		};

		var stmt = db.run("UPDATE user SET participating = $participating WHERE userId= $clientId;",values,function(error){
			if(error == null){
				resolve()
			}else{
				reject(error);
			}
			});

		})
	};


	var getIdFromClientName = function(name){
		
		return new Promise(function(resolve,reject){

			console.log("Cheking db for"+name);
			db.get("SELECT userId,name FROM user WHERE name = $name",{$name:name},function(error,rows){
				console.log("Got result",error,rows," for username:",name);
				
				if(rows === undefined || rows.name === undefined || rows.name.length === 0){
						console.log("Rejecting promise")
						reject(error);
				}else{
					resolve(rows.userId);
				}
		});
		});

	};

	var insertApplicationLog = function(userId,type,message){

		var values = {
			$userId:userId,
			$type:type,
			$message: message
		};

		//We dont use prepared statements as it will be a long delay between insertions
		var stmt = db.run("INSERT INTO applicationLog (userId,type,message) VALUES ($userId,$type,$message)",values);

	};

	// Options: {userId:,type:,after:,before:}
	var fetchApplicationLog = function(options){
		return new Promise(function(resolve,reject){
			var wherePart = _generateSQLWherePartFromOptions(options);

			_fetchApplicationLogGivenWhere(wherePart,options).then(
				function(result){
				resolve(result);
			}).catch(function(error){
				reject(error);
			});

		});
	};

	var _fetchApplicationLogGivenWhere = function(whereClause,options){
		return new Promise(function(resolve,reject){
			console.log("SELECT * FROM applicationLog "+whereClause);
			db.all("SELECT * FROM applicationLog "+whereClause+";",{},function(error,rows){

				console.log("got",rows+error)
				if(error!==null){reject(error);}
				resolve(rows);
			});
		});
	};

	var _generateSQLWherePartFromOptions = function(options){
		var conditions = _generateArrayOfConditions(options);
		if(conditions.length === 0){return "";}
		var whereString = _generateStringOfConditions(conditions);

		console.log(whereString);
		return whereString;
	};

	var _generateArrayOfConditions = function(options){
		var conditions = [];

		for(var field in options){
			if(!options.hasOwnProperty(field)){continue;}
			var condition = _optionToCondition(field,options[field]);
			conditions.push(condition);
		}
		return conditions;
	};

	var _optionToCondition = function(option,value){

		if(option == 'before'){
			return "timestamp < "+value;
		}

		if(option == 'after'){
			return "timestamp > "+value;
		}

		return option+ " = '"+value+"'";
	};

	var _generateStringOfConditions = function(conditionsArray){
		var conditionString = " WHERE ";
		for(var i=0;i<conditionsArray.length-1;i++){
			conditionString+=conditionsArray[i] + " AND ";	
		}

		conditionString+=conditionsArray[i] ;	
		return conditionString;
	};

	var _closeConnection = function(){

		db.close();
	};

	_constructor();

	var publicApi = {
		insertClient:insertClient,
		insertApplicationLog:insertApplicationLog,
		setClientName:setClientName,
		setClientParticipating:setClientParticipating,
		getIdFromClientName:getIdFromClientName,
		fetchApplicationLog:fetchApplicationLog
	};

	//TestCode
	publicApi.__forTesting = {_optionToCondition:_optionToCondition,_generateSQLWherePartFromOptions:_generateSQLWherePartFromOptions};

	return publicApi;
};
/*
   var databaseHandler = new DatabaseHandler();
   databaseHandler.insertApplicationLog(12345,"Test","Dette er en lang melding");
   databaseHandler.insertApplicationLog(54321,"Test","Dette er en lang melding");
   databaseHandler.fetchApplicationLog().then(function(result){ console.log("1",result);}).catch(function(error){console.log(error);});
   databaseHandler.fetchApplicationLog({userId:12345}).then(function(result){ console.log(2,result);}).catch(function(error){console.log(error);});

*/
module.exports = DatabaseHandler;