function chatBot() {
	
	// current user input
	this.input;
	
	/**
	 * respondTo
	 * 
	 * return nothing to skip response
	 * return string for one response
	 * return array of strings for multiple responses
	 * 
	 * @param input - input chat string
	 * @return reply of chat-bot
	 */
	this.respondTo = function(input) {
	
		this.input = input.toLowerCase();
		
		if(this.match('(hi|hello|hey|hola|howdy)(\\s|!|\\.|$)'))
			return "Hi..What can I help you with?";
		
		if(this.match('register') || this.match('course') || this.match('courses'))
			return "Which course is this regarding?";
		
		if(this.match('painting') || this.match('cooking') || this.match('knitting'))
			return "Could you provide me with your order number?";
		
		if(this.match('^no+(\\s|!|\\.|$)'))
			return "don't be such a negative nancy :(";
		
		if(this.match('(cya|bye|see ya|ttyl|talk to you later)'))
			return ["alright, see you around", "good teamwork!"];
		
		if(this.match('(dumb|stupid|is that all)'))
			return ["Please call on "];
		
		if(this.input == 'noop')
			return;
		
		return input + " what?";
	}
	
	/**
	 * match
	 * 
	 * @param regex - regex string to match
	 * @return boolean - whether or not the input string matches the regex
	 */
	this.match = function(regex) {
	
		return new RegExp(regex).test(this.input);
	}
}