text: /**
   * jspsych-video-slider-response
   * Josh de Leeuw
   *
   * plugin for playing a video file and getting a slider response
   *
   * documentation: docs.jspsych.org
   *
   **/
  
  jsPsych.plugins["video-slider-response"] = (function() {
  
    var plugin = {};
  
    jsPsych.pluginAPI.registerPreload('video-slider-response', 'stimulus', 'video');
  
    plugin.info = {
      name: 'video-slider-response',
      description: '',
      parameters: {
        sources: {
          type: jsPsych.plugins.parameterType.VIDEO,
          pretty_name: 'Video',
          default: undefined,
          description: 'The video file to play.'
        },
        prompt: {
          type: jsPsych.plugins.parameterType.STRING,
          pretty_name: 'Prompt',
          default: null,
          description: 'Any content here will be displayed below the stimulus.'
        },
        width: {
          type: jsPsych.plugins.parameterType.INT,
          pretty_name: 'Width',
          default: '',
          description: 'The width of the video in pixels.'
        },
        height: {
          type: jsPsych.plugins.parameterType.INT,
          pretty_name: 'Height',
          default: '',
          description: 'The height of the video display in pixels.'
        },
        autoplay: {
          type: jsPsych.plugins.parameterType.BOOL,
          pretty_name: 'Autoplay',
          default: true,
          description: 'If true, the video will begin playing as soon as it has loaded.'
        },
        controls: {
          type: jsPsych.plugins.parameterType.BOOL,
          pretty_name: 'Controls',
          default: false,
          description: 'If true, the subject will be able to pause the video or move the playback to any point in the video.'
        },
        start: {
          type: jsPsych.plugins.parameterType.FLOAT,
          pretty_name: 'Start',
          default: null,
          description: 'Time to start the clip.'
        },
        stop: {
          type: jsPsych.plugins.parameterType.FLOAT,
          pretty_name: 'Stop',
          default: null,
          description: 'Time to stop the clip.'
        },
        rate: {
          type: jsPsych.plugins.parameterType.FLOAT,
          pretty_name: 'Rate',
          default: 1,
          description: 'The playback rate of the video. 1 is normal, <1 is slower, >1 is faster.'
        },
        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.'
        },
        trial_ends_after_video: {
          type: jsPsych.plugins.parameterType.BOOL,
          pretty_name: 'End trial after video finishes',
          default: false,
          description: 'If true, the trial will end immediately after the video finishes playing.'
        },
        trial_duration: {
          type: jsPsych.plugins.parameterType.INT,
          pretty_name: 'Trial duration',
          default: null,
          description: 'How long to show trial before it ends.'
        },
        response_ends_trial: {
          type: jsPsych.plugins.parameterType.BOOL,
          pretty_name: 'Response ends trial',
          default: true,
          description: 'If true, the trial will end when subject makes a response.'
        }
      }
    }
  
    plugin.trial = function(display_element, trial) {
  
      // setup stimulus
      var video_html = '<video id="jspsych-video-slider-response-stimulus"';
  
      if(trial.width) {
        video_html += ' width="'+trial.width+'"';
      }
      if(trial.height) {
        video_html += ' height="'+trial.height+'"';
      }
      if(trial.autoplay){
        video_html += " autoplay ";
      }
      if(trial.controls){
        video_html +=" controls ";
      }
      video_html +=">";
  
      var video_preload_blob = jsPsych.pluginAPI.getVideoBuffer(trial.sources[0]);
      if(!video_preload_blob) {
        for(var i=0; i<trial.sources.length; i++){
          var file_name = trial.sources[i];
          if(file_name.indexOf('?') > -1){
            file_name = file_name.substring(0, file_name.indexOf('?'));
          }
          var type = file_name.substr(file_name.lastIndexOf('.') + 1);
          type = type.toLowerCase();
          video_html+='<source src="' + file_name + '" type="video/'+type+'">';   
        }
      }
      video_html += "</video>";
  
      var html = '<div id="jspsych-video-slider-response-wrapper" style="margin: 100px 0px;">';
      html += '<div id="jspsych-video-slider-response-stimulus">' + video_html + '</div>';
      html += '<div class="jspsych-video-slider-response-container" style="position:relative; margin: 0 auto 3em auto; ';
      if(trial.slider_width !== null){
        html += 'width:'+trial.slider_width+'px;';
      }
      html += '">';
      html += '<input type="range" value="'+trial.start+'" min="'+trial.min+'" max="'+trial.max+'" step="'+trial.step+'" style="width: 100%;" id="jspsych-video-slider-response-response"></input>';
      html += '<div>'
      for(var j=0; j < trial.labels.length; j++){
        var width = 100/(trial.labels.length-1);
        var left_offset = (j * (100 /(trial.labels.length - 1))) - (width/2);
        html += '<div style="display: inline-block; position: absolute; left:'+left_offset+'%; text-align: center; width: '+width+'%;">';
        html += '<span style="text-align: center; font-size: 80%;">'+trial.labels[j]+'</span>';
        html += '</div>'
      }
      html += '</div>';
      html += '</div>';
      html += '</div>';
  
      // add prompt if there is one
      if (trial.prompt !== null) {
        html += '<div>'+trial.prompt+'</div>';
      }
  
      // add submit button
      html += '<button id="jspsych-video-slider-response-next" class="jspsych-btn" '+ (trial.require_movement ? "disabled" : "") + '>'+trial.button_label+'</button>';
  
      display_element.innerHTML = html;
  
      if(video_preload_blob){
        display_element.querySelector('#jspsych-video-slider-response-stimulus').src = video_preload_blob;
      }
  
      display_element.querySelector('#jspsych-video-slider-response-stimulus').onended = function(){
        if(trial.trial_ends_after_video){
          end_trial();
        }
      }
  
      if(trial.start !== null){
        display_element.querySelector('#jspsych-video-slider-response-stimulus').currentTime = trial.start;
      }
  
      if(trial.stop !== null){
        display_element.querySelector('#jspsych-video-slider-response-stimulus').addEventListener('timeupdate', function(e){
          var currenttime = display_element.querySelector('#jspsych-video-slider-response-stimulus').currentTime;
          if(currenttime >= trial.stop){
            display_element.querySelector('#jspsych-video-slider-response-stimulus').pause();
          }
        })
      }
  
      display_element.querySelector('#jspsych-video-slider-response-stimulus').playbackRate = trial.rate;
  
      if(trial.require_movement){
        display_element.querySelector('#jspsych-video-slider-response-response').addEventListener('change', function(){
          display_element.querySelector('#jspsych-video-slider-response-next').disabled = false;
        })
      }
  
      var startTime = performance.now();
  
      // store response
      var response = {
        rt: null,
        response: null
      };
  
      display_element.querySelector('#jspsych-video-slider-response-next').addEventListener('click', function() {
        // measure response time
        var endTime = performance.now();
        response.rt = endTime - startTime;
        response.response = display_element.querySelector('#jspsych-video-slider-response-response').value;
  
        if(trial.response_ends_trial){
          end_trial();
        } else {
          display_element.querySelector('#jspsych-video-slider-response-next').disabled = true;
        }
  
      });
  
      // function to end trial when it is time
      function end_trial() {
  
        // kill any remaining setTimeout handlers
        jsPsych.pluginAPI.clearAllTimeouts();
  
        // gather the data to store for the trial
        var trial_data = {
          "rt": response.rt,
          "stimulus": trial.stimulus,
          "response": response.response
        };
  
        // clear the display
        display_element.innerHTML = '';
  
        // move on to the next trial
        jsPsych.finishTrial(trial_data);
      };
  
      // end trial if time limit is set
      if (trial.trial_duration !== null) {
        jsPsych.pluginAPI.setTimeout(function() {
          end_trial();
        }, trial.trial_duration);
      }
    };
  
    return plugin;
  })();
  