// Based on http://vis.stanford.edu/protovis/ex/clock.html

// Based on http://blog.pixelbreaker.com/polarclock

var w = 960,

    h = 700,

    r = Math.min(w, h) / 1.8,

    s = .09,

    fsec = d3.time.format("%S s"),

    fmin = d3.time.format("%M m"),

    fhou = d3.time.format("%H h"),

    fwee = d3.time.format("%a"),

    fdat = d3.time.format("%d d"),

    fmon = d3.time.format("%b");

var fill = d3.scale.linear()

    .range(["hsl(-180, 50%, 50%)", "hsl(180, 50%, 50%)"])

    .interpolate(d3.interpolateHsl);

var arc = d3.svg.arc()

    .startAngle(0)

    .endAngle(function(d) { return d.value * 2 * Math.PI; })

    .innerRadius(function(d) { return d.index * r; })

    .outerRadius(function(d) { return (d.index + s) * r; });

var vis = d3.select("#clock").append("svg:svg")

    .attr("width", w)

    .attr("height", h)

  .append("svg:g")

    .attr("transform", "translate(" + w / 2 + "," + h / 2 + ")");

var g = vis.selectAll("g")

    .data(fields)

  .enter().append("svg:g");

g.append("svg:path")

    .style("fill", function(d) { return fill(d.value); })

    .attr("d", arc);

g.append("svg:text")

    .attr("text-anchor", "middle")

    .attr("dy", "1em")

    .text(function(d) { return d.text; });

// Update arcs.

d3.timer(function() {

  var g = vis.selectAll("g")

      .data(fields);

  g.select("path")

      .style("fill", function(d) { return fill(d.value); })

      .attr("d", arc);

  g.select("text")

      .attr("dy", function(d) { return d.value < .5 ? "-.5em" : "1em"; })

      .attr("transform", function(d) {

        return "rotate(" + 360 * d.value + ")"

            + "translate(0," + -(d.index + s / 2) * r + ")"

            + "rotate(" + (d.value < .5 ? -90 : 90) + ")"

      })

      .text(function(d) { return d.text; });

});

// Generate the fields for the current date/time.

function fields() {

  var d = new Date;

  function days() {

    return 32 - new Date(d.getYear(), d.getMonth(), 32).getDate();

  }

  var second = (d.getSeconds() + d.getMilliseconds() / 1000) / 60,

      minute = (d.getMinutes() + second) / 60,

      hour = (d.getHours() + minute) / 24,

      weekday = (d.getDay() + hour) / 7,

      date = (d.getDate() - 1 + hour) / days(),

      month = (d.getMonth() + date) / 12;

  return [

    {value: second,  index: .7, text: fsec(d)},

    {value: minute,  index: .6, text: fmin(d)},

    {value: hour,    index: .5, text: fhou(d)},

    {value: weekday, index: .3, text: fwee(d)},

    {value: date,    index: .2, text: fdat(d)},

    {value: month,   index: .1, text: fmon(d)},

  ];

}