// select svg canvas
var m = [30, 10, 10, 10],      // margins
    w = 500-m[1]-m[3],         // width
    h = 400-m[0]-m[2],         // height
    xcol = 0,                  // active x column
    ycol = 1;                  // active y column

// create svg element, adjusted by margins
svg = d3.select('#chart')
  .append("g")
  .attr("transform", "translate(" + m[1] + "," + m[0] + ")");

// load data from csv file
d3.csv('nutrients.csv', function(data) {

  // get columns of csv, mark excluded columns
  var columns = d3.keys(data[0]),
      excluded = ['name', 'group', 'id'];

  // get quantitative dimensions
  var dimensions = _(columns)
    .difference(excluded);

  // extents for each dimension
  var extents = _(dimensions)
    .map(function(col) {
      return [0, d3.max(data, function(d) { return parseFloat(d[col]) })]
    });

  // create scales
  var x = d3.scale.linear().domain(extents[xcol]).range([0, w]),
      y = d3.scale.linear().domain(extents[ycol]).range([h, 0]);

  // color scale
  var color = {
    "Baby Foods"                        : '#555555',
    "Baked Products"                    : '#7f7f7f',
    "Beverages"                         : '#c49c94',
    "Breakfast Cereals"                 : '#9467bd',
    "Cereal Grains and Pasta"           : '#bcbd22',
    "Dairy and Egg Products"            : '#ff7f0e',
    "Ethnic Foods"                      : '#e7ba52',
    "Fast Foods"                        : '#dbdb8d',
    "Fats and Oils"                     : '#ffbb78',
    "Finfish and Shellfish Products"    : '#e377c2',
    "Fruits and Fruit Juices"           : '#c5b0d5',
    "Legumes and Legume Products"       : '#f7b6d2',
    "Meals, Entrees, and Sidedishes"    : '#17becf',
    "Nut and Seed Products"             : '#8c564b',
    "Pork Products"                     : "#00ee99",
    "Poultry Products"                  : '#d62728',
    "Restaurant Foods"                  : '#1f77b4',
    "Sausages and Luncheon Meats"       : '#ff9896',
    "Snacks"                            : '#9edae5',
    "Soups, Sauces, and Gravies"        : '#98df8a',
    "Spices and Herbs"                  : '#aec7e8',
    "Sweets"                            : '#c7c7c7',
    "Vegetables and Vegetable Products" : '#2ca02c'
  };

  // bind data to chart
  svg.selectAll('circle')
     .data(data)
   .enter().append('circle')
     .attr("fill", function(d) { return color[d.group]; })
     .attr("cx", function(d) { return x(d[dimensions[xcol]]) || 0; })
     .attr("cy", function(d) { return y(d[dimensions[ycol]]) || h; })
     .attr("r", 2.5);

  // change x axis
  function xaxis(i) {
    x.domain(extents[i]);
    svg.selectAll('circle')
      .transition()
      .duration(1500)
      .attr("cx", function(d) { return x(d[dimensions[i]]) || 0; });
  };

  // change y axis
  function yaxis(i) {
    y.domain(extents[i]);
    svg.selectAll('circle')
      .transition()
      .duration(1500)
      .attr("cy", function(d) { return y(d[dimensions[i]]) || h; })
  };

  // create dropdowns to change axes
  d3.select("#xaxis")
    .selectAll("option")
    .data(dimensions)
    .enter().append("option")
      .attr("value", function(d,i) { return i; })
      .text(function(d) { return d; })
      .each(function(d,i) {
        if (i == xcol) d3.select(this).attr("selected", "yes");
      });

  d3.select("#xaxis")
      .on("change", function() { xaxis(this.selectedIndex) });

  d3.select("#yaxis")
    .selectAll("option")
    .data(dimensions)
    .enter().append("option")
      .attr("value", function(d,i) { return i; })
      .text(function(d) { return d; })
      .each(function(d,i) {
        if (i == ycol) d3.select(this).attr("selected", "yes");
      });

  d3.select("#yaxis")
      .on("change", function() { yaxis(this.selectedIndex) });

  window.data = data;
});