var StairsViewModel = function()
{
  var self = this;

  self.mode = ko.observable('Static');
  self.static =
  {
    brightness: ko.observable(0)
  };

  self.custom =
  {
    brightness: ko.observableArray([])
  };

  self.alternate =
  {
    interval: ko.observable(500),
    brightness: ko.observable(0)
  }

  self.slide =
  {
    interval: ko.observable(500),
    brightness: ko.observable(4096),
    direction: ko.observable(0),
    fadeOutTime: ko.observable(0)
  }


  self.loading = ko.observable(true);
  self.updatingFromServer = false;

  self.autoSetTimeout = null;
  self.autoSetMode = ko.computed(function()
  {
    if (self.loading()) return;

    var url = '/setMode/' + encodeURIComponent(self.mode());
    switch (self.mode())
    {
      case 'Static':
        url += '?brightness=' + encodeURIComponent(self.static.brightness());
        break;

      case 'Custom':
        var values = self.custom.brightness().map(function(item) { return item.value(); });
        values.reverse();
        url += '?brightness=' + encodeURIComponent(values.join());
        break;

      case 'Alternate':
        url += '?interval=' + encodeURIComponent(self.alternate.interval()) +
               '&brightness=' + encodeURIComponent(self.alternate.brightness());
        break;

      case 'Slide':
        url += '?interval=' + encodeURIComponent(self.slide.interval()) +
               '&brightness=' + encodeURIComponent(self.slide.brightness()) +
               '&direction=' + encodeURIComponent(self.slide.direction()) +
               '&fadeOutTime=' + encodeURIComponent(self.slide.fadeOutTime());
        break;
    }


    // Exit after checking all the parameters, so the observers
    // are properly subscribed
    if (self.updatingFromServer) return;


    if (self.autoSetTimeout !== null)
    {
      clearTimeout(self.autoSetTimeout);
      self.autoSetTimeout = null;
    }

    self.autoSetTimeout = setTimeout(function()
    {
      // TODO retry on failure
      $.ajax(
      {
        url: url,
        dataType: 'json',
        cache: false
      });

      clearTimeout(self.autoSetTimeout);
      self.autoSetTimeout = null;
    }, 200);

    return true;
  });


  self.ping = function()
  {
    self.loading(true);

    $.ajax(
    {
      url: '/ping',
      dataType: 'json',
      cache: false
    })
      .done(function(data)
      {
        self.updatingFromServer = true;

        // Initialize the 'Custom' values based on the step count.
        // Each item is an object containing an observable; we can't
        // add the observable directly otherwise the foreach template
        // will unwrap it before we can attach it to the range input.
        var values = [];
        for (var index = 0; index < data.stepCount; index++)
          values.push({ value: ko.observable(0) });

        self.custom.brightness(values);

        // TODO get current mode
        // TODO get range settings
        // TODO allow tweaking of range settings

        self.loading(false);

        self.updatingFromServer = false;
      })
      .fail(function()
      {
        setTimeout(self.ping, 1000);
      });
  };
};



$(function()
{
  var viewModel = new StairsViewModel();
  ko.applyBindings(viewModel);

  viewModel.ping();
});