var dashboardView = Backbone.View.extend({
  el: '#content',
  updateInterval: 1000, // 1 second, constant
  updateFrequency: 5, // the actual update rate (5 s)
  updateCounter: 0,
  arraySize: 99, // how many values will we keep per figure?
  seriesData: {},
  charts: {},
  units: [],

  initialize: function () {
    var self = this;

    this.initUnits();

    this.collection.fetch({
      success: function() {
        self.calculateSeries();
        self.renderCharts();

        window.setInterval(function() {
          self.updateCounter++;

          if (self.updateCounter < self.updateFrequency) {
            return false;
          }

          self.updateCounter = 0;
          self.collection.fetch({
            success: function() {
              self.calculateSeries();
              self.renderCharts();
            },
            error: function() {
              // need to flush previous values
              self.calculateSeries(true);
              self.renderCharts();
            }
          });

        }, self.updateInterval);
      }
    });
  },

  events: {
    "click .dashboard-dropdown li" : "checkEnabled",
    "click .interval-dropdown li" : "checkInterval"
  },

  template: new EJS({url: 'js/templates/dashboardView.ejs'}),

  render: function() {
    var self = this;
    $(this.el).html(this.template.text);

    $.each(this.options.description.models[0].attributes.groups, function () {
      $('.thumbnails').append(
        '<ul class="statGroups" id="' + this.group + '">' +
        '<h4 class="statsHeader">' + this.name + '</h4>' +
        '</ul>');
      $('#menuGroups').append(
        '<li class="nav-header">' + this.name + '</li>' + 
        '<li class="divider" id="' + this.group + 'Divider"></li>'
      );
    });

    $.each(this.options.description.models[0].attributes.figures, function () {
      self.renderFigure(this);
    });

    $('input[name=every'+self.updateInterval/1000 +']').attr('checked', true);

    if (this.collection.models[0] === undefined) {
      this.collection.fetch({
        success: function() {
          self.calculateSeries();
          self.renderCharts();
        },
        error: function() {
          self.calculateSeries();
          self.renderCharts(flush);
        }
      });
    }
    else {
      self.calculateSeries();
      self.renderCharts();
    }
    return this;
  },

  checkInterval: function (a) {
    this.updateFrequency = a.target.value;
  },

  checkEnabled: function (a) {
    var myId = a.target.id;
    var position = myId.search('Checkbox');
    var preparedId = myId.substring(0, position);
    var toCheck = $(a.target).is(':checked');
    if (toCheck === false) {
      $("#" + preparedId).hide();
    }
    else if (toCheck === true) {
      $("#" + preparedId).show();
    }
  },

  initUnits : function () {
    this.units = [ ];
    var i;
    var scale = 0.0001;

    for (i = 0; i < 12; ++i) {
      this.units.push(scale * 1);
      this.units.push(scale * 2);
      this.units.push(scale * 2.5);
      this.units.push(scale * 4);
      this.units.push(scale * 5);
      scale *= 10;
    }
  },

  getMaxValue : function (identifier) {
    var max = this.seriesData[identifier].max || 1;

    var i = 0, n = this.units.length;
    while (i < n) {
      var unit = this.units[i++];
      if (max > unit) {
        continue;
      }
      if (max == unit) {
        break;
      }
      return unit;
    }

    return max;
  },

  renderCharts: function () {
    var self = this;

    $.each(self.options.description.models[0].attributes.figures, function () {
      var figure = this;
      var identifier = figure.identifier;
      var chart;

      if (self.charts[identifier] === undefined) {
        chart = self.charts[identifier] = nv.models.lineChart();
        chart.xAxis.axisLabel('').tickFormat(function (d) {
          if (isNaN(d)) {
            return '';
          }

          function pad (value) {
            return (value < 10 ? "0" + String(value) : String(value));
          }

          var date = new Date(d / 10);

          return pad(date.getHours()) + ":" + pad(date.getMinutes()) + ":" + pad(date.getSeconds());
        });

        var label = figure.units;

        if (figure.units === 'bytes') {
          label = "megabytes";
        }
        chart.yAxis.axisLabel(label);

        nv.addGraph (function () {
          nv.utils.windowResize(function () {
            d3.select('#' + identifier + 'Chart svg').call(chart);
          });

          return chart;
        });
      }
      else {
        chart = self.charts[identifier];
      }

      chart.yDomain([ 0, self.getMaxValue(identifier) ]);

      d3.select("#" + identifier + "Chart svg")
        .call(chart)
        .datum([ { values: self.seriesData[identifier].values, key: identifier, color: "#8AA051" } ])
        .transition().duration(500);
    });
  },

  calculateSeries: function (flush) {
    var self = this;
    var timeStamp = Math.round(new Date() * 10);

    $.each(self.options.description.models[0].attributes.figures, function () {
      var figure = this;
      var identifier = figure.identifier;

      if (self.seriesData[identifier] === undefined) {
        self.seriesData[identifier] = { max: 0, values: [ ] };
      }

      while (self.seriesData[identifier].values.length > self.arraySize) {
        self.seriesData[identifier].values.shift();
      }

      if (flush) {
        self.seriesData[identifier].values.push({ x: timeStamp, y: undefined, value: undefined });
        return;
      }

      var responseValue = self.collection.models[0].attributes[figure.group][identifier];

      if (responseValue !== undefined && responseValue !== null) {
        if (responseValue.sum !== undefined) {
          responseValue = responseValue.sum;
        }
      }

      function sanitize (value, figure) {
        if (value < 0) {
          value = 0;
        }
        else {
          if (figure.units === 'bytes') {
            value /= (1024 * 1024);
          }
          value = Math.round(value * 100) / 100;
        }

        return value;
      }

      var newValue = 0;

      if (figure.type === 'current') {
        newValue = responseValue;
      }
      else {
        var n = self.seriesData[identifier].values.length;

        if (responseValue !== undefined && n > 0) {
          var previous = self.seriesData[identifier].values[n - 1];
          if (previous.value !== undefined) {
            newValue = responseValue - previous.value;
          }
        }
      }

      newValue = sanitize(newValue, figure);
      if (newValue > self.seriesData[identifier].max) {
        self.seriesData[identifier].max = newValue;
      }

      self.seriesData[identifier].values.push({ x: timeStamp, y: newValue, value: responseValue });
    });
  },

  renderFigure: function (figure) {
    $('#' + figure.group).append(
      '<li class="statClient" id="' + figure.identifier + '">' +
      '<div class="boxHeader"><h6 class="dashboardH6">' + figure.name + '</h6></div>' +
      '<div class="statChart" id="' + figure.identifier + 'Chart"><svg class="svgClass"/></div>' +
      '</li>'
    );

    $('#' + figure.group + 'Divider').before(
      '<li><a><label class="checkbox">'+
      '<input type="checkbox" id=' + figure.identifier + 'Checkbox checked>' + figure.name + '</label></a></li>'
    );
  }

});