var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var formatPercent = d3.format(".0%"),
    tooltipPercent = d3.format(".2%");

var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1, 1);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left")
    .tickFormat(formatPercent);

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

d3.tsv("letter.tsv", function(error, data) {

  data.forEach(function(d) {
    d.frequency = +d.frequency;
  });

  x.domain(data.map(function(d) { return d.letter; }));
  y.domain([0, d3.max(data, function(d) { return d.frequency; })]);

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")
      .text("Frequency");

  var bars = svg.selectAll(".bar")
      .data(data),
      barsEnter = bars.enter().append("g")
                        .classed('bar', true)
                        .attr({
                          transform: function(d) { return 'translate(' + x(d.letter) + ',' + 0 + ')'; },
                        }),
      displayEnter = barsEnter.append('rect')
                                  .classed('display', true)
                                  .attr({
                                    width: x.rangeBand(),
                                    height: function(d) { return height - y(d.frequency); },
                                    y: function(d) { return y(d.frequency); }
                                  }),
      interactEnter = barsEnter.append('rect')
                                  .classed('interact', true)
                                  .attr({
                                    width: x.rangeBand(),
                                    height: height,
                                    'fill-opacity': 0.0,
                                  })
                                  .call(d3.helper.tooltip().attr({class: "d3-helper-tooltip" })
                                                            .html(function(d, i) { return '<h5>' + d.letter + '</h5><p>' + tooltipPercent(d.frequency) + '</p>'; }));

  d3.select("input").on("change", change);

  var sortTimeout = setTimeout(function() {
    d3.select("input").property("checked", true).each(change);
  }, 2000);

  function change() {
    clearTimeout(sortTimeout);

    // Copy-on-write since tweens are evaluated after a delay.
    var x0 = x.domain(data.sort(this.checked
        ? function(a, b) { return b.frequency - a.frequency; }
        : function(a, b) { return d3.ascending(a.letter, b.letter); })
        .map(function(d) { return d.letter; }))
        .copy();

    var transition = svg.transition().duration(750),
        delay = function(d, i) { return i * 50; };

    transition.selectAll(".bar")
        .delay(delay)
        .attr({
          transform: function(d) { return 'translate(' + x0(d.letter) + ',' + 0 + ')'; },
        });

    transition.select(".x.axis")
        .call(xAxis)
      .selectAll("g")
        .delay(delay);
  }
});

d3.helper = {};

d3.helper.tooltip = function() {
  var tooltipDiv;
  var bodyNode = d3.select('body').node();
  var attrs = {};
  var html = d3.functor('');
  var styles = {};

  function tooltip(selection) {
    selection.on('mouseenter.tooltip', function(pD, pI) {
      d3.select(this).classed('selected-tooltip', true);
      var name, value;
      // Clean up lost tooltips
      d3.select('body').selectAll('div.tooltip').remove();
      // Append tooltip
      tooltipDiv = d3.select('body').append('div');
      tooltipDiv.attr(attrs);
      tooltipDiv.style(styles);
      var absoluteMousePos = d3.mouse(bodyNode);
      tooltipDiv.style({
        left: (absoluteMousePos[0] + 15)+'px',
        top: (absoluteMousePos[1] - 10)+'px',
        position: 'absolute',
        'z-index': 1001
      });
      // Add text using the accessor function, Crop text arbitrarily
      tooltipDiv.style('width', function(d, i) { return (html(pD, pI).length > 80) ? '300px' : null; })
            .html(function(d, i) {return html(pD, pI);});
    })
    .on('mousemove.tooltip', function(pD, pI) {
      d3.select(this).classed('selected-tooltip', true);
      // Move tooltip
      var absoluteMousePos = d3.mouse(bodyNode);
      if (!tooltipDiv) {
        tooltipDiv = d3.select('body').append('div');
        tooltipDiv.attr(attrs);
        tooltipDiv.style(styles);
      }
      tooltipDiv.style({
        left: (absoluteMousePos[0] + 15)+'px',
        top: (absoluteMousePos[1] - 10)+'px'
      });
      // Keep updating the text, it could change according to position
      tooltipDiv.html(function(d, i) { return html(pD, pI); });
    })
    .on('mouseleave.tooltip', function(pD, pI) {
      d3.select(this).classed('selected-tooltip', false);
      // Remove tooltip
      tooltipDiv.remove();
    });
  }

  tooltip.attr = function(_x) {
    if (!arguments.length) return attrs;
    attrs = _x;
    return this;
  };

  tooltip.style = function(_x) {
    if (!arguments.length) return styles;
    styles = _x;
    return this;
  };

  tooltip.html = function(_x) {
    if (!arguments.length) return html;
    html = d3.functor(_x);
    return this;
  };

  return tooltip;
};