window.onload = function() {

  sequencer = ImageSequencer();

  // Load information of all modules (Name, Inputs, Outputs)
  var modulesInfo = sequencer.modulesInfo();

  // Add modules to the addStep dropdown
  for(var m in modulesInfo) {
    $('#addStep select').append(
      '<option value="'+m+'">'+modulesInfo[m].name+'</option>'
    );
  }

  // Initial definitions
  var steps = document.querySelector('#steps');
  var parser = new DOMParser();
  var reader = new FileReader();

  // Set the UI in sequencer. This Will generate HTML based on
  // Image Sequencer events :
  // onSetup : Called every time a step is added
  // onDraw : Called every time a step starts draw
  // onComplete : Called every time a step finishes drawing
  // onRemove : Called everytime a step is removed
  // The variable 'step' stores useful data like input and
  // output values, step information.
  // See documetation for more details.
  sequencer.setUI({

    onSetup: function(step) {

      if (step.options && step.options.description) step.description = step.options.description

      step.ui = '\
      <div class="row step">\
        <div class="col-md-4 details">\
          <h3>'+step.name+'</h3>\
          <p><i>'+(step.description || '')+'</i></p>\
        </div>\
        <div class="col-md-8">\
          <div class="load" style="display:none;"><i class="fa fa-circle-o-notch fa-spin"></i></div>\
          <img alt="" class="img-thumbnail"/>\
        </div>\
      </div>\
      ';

      var tools =
      '<div class="tools btn-group">\
         <button confirm="Are you sure?" class="remove btn btn-xs btn-default">\
           <i class="fa fa-trash"></i>\
         </button>\
      </div>';

      step.ui = parser.parseFromString(step.ui,'text/html');
      step.ui = step.ui.querySelector('div.row');
      step.imgElement = step.ui.querySelector('img');

      if(sequencer.modulesInfo().hasOwnProperty(step.name)) {
        var inputs = sequencer.modulesInfo(step.name).inputs;
        var outputs = sequencer.modulesInfo(step.name).outputs;
        var io = Object.assign(inputs, outputs);
        for (var i in io) {
          var isInput = inputs.hasOwnProperty(i);
          var ioUI = "";
          var inputDesc = (isInput)?inputs[i]:{};
          if (!isInput) {
            ioUI += "<span class=\"output\"></span>";
          }
          else if (inputDesc.type.toLowerCase() == "select") {
            ioUI += "<select class=\"form-control\" name=\""+i+"\">";
            for (var option in inputDesc.values) {
              ioUI += "<option>"+inputDesc.values[option]+"</option>";
            }
            ioUI += "</select>";
          }
          else {
            ioUI = "<input class=\"form-control\" type=\""+inputDesc.type+"\" name=\""+i+"\">";
          }
          var div = document.createElement('div');
          div.className = "row";
          div.setAttribute('name', i);
          div.innerHTML = "<div class='det'>\
                             <label for='" + i + "'>" + i + "</label>\
                             "+ioUI+"\
                           </div>";
          step.ui.querySelector('div.details').appendChild(div);
        }
        $(step.ui.querySelector('div.details')).append("<p><button class='btn btn-default btn-save'>Save</button></p>");

        // on clicking Save in the details pane of the step
        $(step.ui.querySelector('div.details .btn-save')).click(function saveOptions() {
          $(step.ui.querySelector('div.details')).find('input,select').each(function(i, input) {
            step.options[$(input).attr('name')] = input.value;
          });
          sequencer.run();
        });
      }

      if(step.name != "load-image")
        step.ui.querySelector('div.details').appendChild(
          parser.parseFromString(tools,'text/html')
                .querySelector('div')
        );

      steps.appendChild(step.ui);
    },

    onDraw: function(step) {
      $(step.ui.querySelector('.load')).show();
      $(step.ui.querySelector('img')).hide();
    },

    onComplete: function(step) {
      $(step.ui.querySelector('.load')).hide();
      $(step.ui.querySelector('img')).show();

      step.imgElement.src = step.output;
      if(sequencer.modulesInfo().hasOwnProperty(step.name)) {
        var inputs = sequencer.modulesInfo(step.name).inputs;
        var outputs = sequencer.modulesInfo(step.name).outputs;
        for (var i in inputs) {
          if (step.options[i] !== undefined && 
              inputs[i].type.toLowerCase() === "input") step.ui.querySelector('div[name="' + i + '"] input')
                                                               .value = step.options[i];
          if (step.options[i] !== undefined &&
              inputs[i].type.toLowerCase() === "select") step.ui.querySelector('div[name="' + i + '"] select')
                                                                .value = step.options[i];
        }
        for (var i in outputs) {
          if (step[i] !== undefined) step.ui.querySelector('div[name="'+i+'"] input')
                                            .value = step[i];
        }
      }
    },

    onRemove: function(step) {
      step.ui.remove();
    }

  });

  sequencer.loadImage('images/tulips.png', function loadImageUI() {

    // look up needed steps from Url Hash:
    var hash = getUrlHashParameter('steps');

    if (hash) {
      var stepsFromHash = hash.split(',');
      stepsFromHash.forEach(function eachStep(step) {
        sequencer.addSteps(step);
      });
      sequencer.run();
    }

  });


  // File handling

  $('#addStep select').on('change', selectNewStepUI);

  function selectNewStepUI() {
    $('#options').html('');
    var m = $('#addStep select').val();
    for(var input in modulesInfo[m].inputs) {
      var inputUI = "";
      var inputDesc = modulesInfo[m].inputs[input];
      if (inputDesc.type.toLowerCase() == "select") {
        inputUI += "<select class=\"form-control\" name=\""+input+"\">";
        for (var option in inputDesc.values) {
          inputUI += "<option>"+inputDesc.values[option]+"</option>";
        }
        inputUI += "</select>";
      }
      else {
        inputUI = "<input class=\"form-control\" type=\""+inputDesc.type+"\" name=\""+input+"\">";
      }
      $('#options').append(
        '<div class="row">\
           <div class="col-md-5 labels">\
             '+input+':\
           </div>\
           <div class="col-md-5">\
             '+inputUI+'\
           </div>\
         </div>'
      );
    }
  }


  function addStepUI() {
    var options = {};
    var inputs = $('#options input, #options select');
    $.each(inputs, function() {
      options[this.name] = $(this).val();
    });
    if($('#addStep select').val() == "none") return;
    // add to URL hash too
    var hash = getUrlHashParameter('steps') || '';
    if (hash != '') hash += ',';
    setUrlHashParameter('steps', hash + $('#addStep select').val())
    sequencer.addSteps($('#addStep select').val(),options).run();
  }

  $('#addStep button').on('click', addStepUI);


  function removeStepUI(){
    var index = $('button.remove').index(this) + 1;
    sequencer.removeSteps(index).run();
    // remove from URL hash too
    var urlHash = getUrlHashParameter('steps').split(',');
    urlHash.splice(index - 1, 1);
    setUrlHashParameter("steps", urlHash.join(','));
  }

  $('body').on('click','button.remove', removeStepUI);


  // image selection and drag/drop handling from examples/lib/imageSelection.js
  setupFileHandling(sequencer);

}