(function( $ ) {
	jsPsych.samedifferent = (function(){

		var plugin = {};
		
		plugin.create = function(params) {
			sd_stims = params["stimuli"];
			trials = new Array(sd_stims.length);
			for(var i = 0; i < trials.length; i++)
			{
				trials[i] = {};
				trials[i]["type"] = "samedifferent";
				trials[i]["a_path"] = sd_stims[i][0];
				trials[i]["b_path"] = sd_stims[i][1];
				trials[i]["timing"] = params["timing"];
				trials[i]["answer"] = params["answer"][i];
				if(params["prompt"] != undefined){
					trials[i]["prompt"] = params["prompt"];
				}
				if(params["data"]!=undefined){
					trials[i]["data"] = params["data"][i];
				}
			}
			return trials;
		}

		plugin.trial = function($this, block, trial, part)
		{
			switch(part){
				case 1:
					p1_time = (new Date()).getTime();
					$this.append($('<img>', {
						"src": trial.a_path,
						"class": 'sd'
					}));
					setTimeout(function(){plugin.trial($this, block, trial, part + 1);}, trial.timing[0]);
					break;
				case 2:
					p2_time = (new Date()).getTime();
					$('.sd').remove();
					setTimeout(function(){plugin.trial($this, block, trial, part + 1);}, trial.timing[1]);
					break;
				case 3:
					p3_time = (new Date()).getTime();
					$this.append($('<img>', {
						"src": trial.b_path,
						"class": 'sd'
					}));
					if(trial.timing[3]!=undefined){
						setTimeout(function(){plugin.trial($this, block, trial, part + 1);}, trial.timing[3]);
					} else {
						plugin.trial($this, block, trial, part + 1);
					}
					break;
				case 4:
					p4_time = (new Date()).getTime();
					if(trial.timing[3]!=undefined){
						$('.sd').remove();
						$this.html(trial.prompt);
					}
					startTime = (new Date()).getTime();
					var resp_func = function(e) {
						var flag = false;
						var correct = false;
						if(e.which=='80') // 'p' key -- same
						{
							flag = true;
							if(trial.answer == "same") { correct = true; }
						} else if(e.which=='81') // 'q' key -- different
						{
							flag = true;
							if(trial.answer == "different"){ correct = true; }
						}
						if(flag)
						{
							endTime = (new Date()).getTime();
							rt = (endTime-startTime);
							stim1_time = (p2_time-p1_time);
							isi_time = (p3_time-p2_time);
							stim2_time = (p4_time-p3_time);
							var trial_data = {"rt": rt, "correct": correct, "a_path": trial.a_path, "b_path": trial.b_path, "key_press": e.which, "stim1_time": stim1_time, "stim2_time":stim2_time, "isi_time":isi_time}
							block.data[block.trial_idx] = $.extend({},trial_data,trial.data);
							$(document).unbind('keyup',resp_func);
							$('.sd').remove();
							$this.html('');
							setTimeout(function(){block.next();}, trial.timing[2]);
						}
					}
					$(document).keyup(resp_func);
					break;
			}
		}
		
		return plugin;
	})();
}) (jQuery);