jsPsych.plugins['audio-slider-response'] = (function() {
	var plugin = {};

	jsPsych.pluginAPI.registerPreload('audio-slider-response', 'stimulus', 'audio');

	plugin.info = {
		name: 'audio-slider-response',
		description: '',
    parameters: {
      stimulus: {
        type: jsPsych.plugins.parameterType.AUDIO,
        pretty_name: 'Stimulus',
        default: undefined,
        description: 'The image to be displayed'
      },
      min: {
        type: jsPsych.plugins.parameterType.INT,
        pretty_name: 'Min slider',
        default: 0,
        description: 'Sets the minimum value of the slider.'
      },
      max: {
        type: jsPsych.plugins.parameterType.INT,
        pretty_name: 'Max slider',
        default: 100,
        description: 'Sets the maximum value of the slider',
      },
			slider_start: {
				type: jsPsych.plugins.parameterType.INT,
				pretty_name: 'Slider starting value',
				default: 50,
				description: 'Sets the starting value of the slider',
			},
      step: {
        type: jsPsych.plugins.parameterType.INT,
        pretty_name: 'Step',
        default: 1,
        description: 'Sets the step of the slider'
      },
      labels: {
        type: jsPsych.plugins.parameterType.HTML_STRING,
        pretty_name:'Labels',
        default: [],
        array: true,
        description: 'Labels of the slider.',
      },
      slider_width: {
        type: jsPsych.plugins.parameterType.INT,
        pretty_name:'Slider width',
        default: null,
        description: 'Width of the slider in pixels.'
      },
      button_label: {
        type: jsPsych.plugins.parameterType.STRING,
        pretty_name: 'Button label',
        default: 'Continue',
        array: false,
        description: 'Label of the button to advance.'
      },
      require_movement: {
        type: jsPsych.plugins.parameterType.BOOL,
        pretty_name: 'Require movement',
        default: false,
        description: 'If true, the participant will have to move the slider before continuing.'
      },
      prompt: {
        type: jsPsych.plugins.parameterType.STRING,
        pretty_name: 'Prompt',
        default: null,
        description: 'Any content here will be displayed below the slider.'
      },
      trial_duration: {
        type: jsPsych.plugins.parameterType.INT,
        pretty_name: 'Trial duration',
        default: null,
        description: 'How long to show the trial.'
      },
      response_ends_trial: {
        type: jsPsych.plugins.parameterType.BOOL,
        pretty_name: 'Response ends trial',
        default: true,
        description: 'If true, trial will end when user makes a response.'
      },
      response_allowed_while_playing: {
        type: jsPsych.plugins.parameterType.BOOL,
        pretty_name: 'Response allowed while playing',
        default: true,
        description: 'If true, then responses are allowed while the audio is playing. '+
          'If false, then the audio must finish playing before a response is accepted.'
      }
    }
  }

  plugin.trial = function(display_element, trial) {

    // half of the thumb width value from jspsych.css, used to adjust the label positions
    var half_thumb_width = 7.5; 

    // setup stimulus
    var context = jsPsych.pluginAPI.audioContext();
    if(context !== null){
      var source = context.createBufferSource();
      source.buffer = jsPsych.pluginAPI.getAudioBuffer(trial.stimulus);
      source.connect(context.destination);
    } else {
      var audio = jsPsych.pluginAPI.getAudioBuffer(trial.stimulus);
      audio.currentTime = 0;
    }

    // set up end event if trial needs it
    if(trial.trial_ends_after_audio){
      if(context !== null){
        source.addEventListener('ended', end_trial);
      } else {
        audio.addEventListener('ended', end_trial);
      }
    }

    // enable slider after audio ends if necessary
    if ((!trial.response_allowed_while_playing) & (!trial.trial_ends_after_audio)) {
      if (context !== null) {
        source.addEventListener('ended', enable_slider);
      } else {
        audio.addEventListener('ended', enable_slider);
      }
    }

    var html = '<div id="jspsych-audio-slider-response-wrapper" style="margin: 100px 0px;">';
  	html += '<div class="jspsych-audio-slider-response-container" style="position:relative; margin: 0 auto 3em auto; width:';
    if(trial.slider_width !== null){
      html += trial.slider_width+'px;';
    } else {
      html += 'auto;';
    }
    html += '">';
    html += '<input type="range" class="jspsych-slider" value="'+trial.slider_start+'" min="'+trial.min+'" max="'+trial.max+'" step="'+trial.step+'" id="jspsych-audio-slider-response-response"';
    if (!trial.response_allowed_while_playing) {
      html += ' disabled';
    }
    html += '></input><div>'
    for(var j=0; j < trial.labels.length; j++){
      var label_width_perc = 100/(trial.labels.length-1);
      var percent_of_range = j * (100/(trial.labels.length - 1));
      var percent_dist_from_center = ((percent_of_range-50)/50)*100;
      var offset = (percent_dist_from_center * half_thumb_width)/100;
      html += '<div style="border: 1px solid transparent; display: inline-block; position: absolute; '+
      'left:calc('+percent_of_range+'% - ('+label_width_perc+'% / 2) - '+offset+'px); text-align: center; width: '+label_width_perc+'%;">';
      html += '<span style="text-align: center; font-size: 80%;">'+trial.labels[j]+'</span>';
      html += '</div>'
    }
    html += '</div>';
    html += '</div>';
    html += '</div>';

		if (trial.prompt !== null){
	    html += trial.prompt;
		}

    // add submit button
    var next_disabled_attribute = "";
    if (trial.require_movement | !trial.response_allowed_while_playing) {
      next_disabled_attribute = "disabled";
    }
    html += '<button id="jspsych-audio-slider-response-next" class="jspsych-btn" '+ next_disabled_attribute + '>'+trial.button_label+'</button>';

    display_element.innerHTML = html;

    var response = {
      rt: null,
      response: null
    };

    if (!trial.response_allowed_while_playing) {
      display_element.querySelector('#jspsych-audio-slider-response-response').disabled = true;
      display_element.querySelector('#jspsych-audio-slider-response-next').disabled = true;
    }

    if(trial.require_movement){
      display_element.querySelector('#jspsych-audio-slider-response-response').addEventListener('click', function(){
        display_element.querySelector('#jspsych-audio-slider-response-next').disabled = false;
      });
    }

    display_element.querySelector('#jspsych-audio-slider-response-next').addEventListener('click', function() {
      // measure response time
      var endTime = performance.now();
			var rt = endTime - startTime;
			if(context !== null){
				endTime = context.currentTime;
				rt = Math.round((endTime - startTime) * 1000);
			}
      response.rt = rt;
      response.response = display_element.querySelector('#jspsych-audio-slider-response-response').valueAsNumber;

      if(trial.response_ends_trial){
        end_trial();
      } else {
        display_element.querySelector('#jspsych-audio-slider-response-next').disabled = true;
      }

    });

    function end_trial(){

      // kill any remaining setTimeout handlers
      jsPsych.pluginAPI.clearAllTimeouts();

      // stop the audio file if it is playing
			// remove end event listeners if they exist
			if(context !== null){
        source.stop();
        source.removeEventListener('ended', end_trial);
        source.removeEventListener('ended', enable_slider);
      } else {
        audio.pause();
        audio.removeEventListener('ended', end_trial);
        audio.removeEventListener('ended', enable_slider);
      }

      // save data
      var trialdata = {
        "rt": response.rt,
        "stimulus": trial.stimulus,
        "slider_start": trial.slider_start,
        "response": response.response
      };

      display_element.innerHTML = '';

      // next trial
      jsPsych.finishTrial(trialdata);
    }

    // function to enable slider after audio ends
    function enable_slider() {
      document.querySelector('#jspsych-audio-slider-response-response').disabled = false;
      if (!trial.require_movement) {
        document.querySelector('#jspsych-audio-slider-response-next').disabled = false;
      }
    }

		var startTime = performance.now();
		// start audio
    if(context !== null){
      startTime = context.currentTime;
      source.start(startTime);
    } else {
      audio.play();
    }

    // end trial if trial_duration is set
    if (trial.trial_duration !== null) {
      jsPsych.pluginAPI.setTimeout(function() {
        end_trial();
      }, trial.trial_duration);
    }


  };

  return plugin;
})();