var data;

d3.csv("data.csv",function(err,d) {
  data = {};
  d.forEach(function(d) {
    var kyn = d.kyn, aldur = +d.aldur;
    Object.keys(d)
    .filter(function(d) { return d != 'kyn' && d != 'aldur';})
    .forEach(function(e,i) {
      var born = +e-aldur;
      var elem =  data[kyn+born] = data[kyn+born] || {kyn:kyn,born:born,domain:[],range:[]};
      // Data is in order, so we can simply push
      elem.domain.push(e);
      elem.range.push(d[e]);
    });
  });

  data = d3.values(data);

  // Create scales for each sex + birth_year
  data.forEach(function(d) {
    d.values = d3.scale.linear()
      .domain(d.domain)
      .range(d.range);
  });

  // Create a rectangle for each group
  bars.selectAll("rect")
    .data(data)
  .enter()
    .append("rect")
    .attr({height:4,x:0})
    .attr("class",function(d) { return d.kyn;});
  redraw(slide.value);
});

var margin = 30,
    height = 450,
    width = 900/2;

var svg = d3.select("svg")
  .attr({width:2*width,height:height});

var title = svg.append("text")
  .attr({class:"title",x:width,y:20})
  .style("text-anchor","middle");
  
var y = d3.scale.linear()
  .domain([0,108])
  .range([height-margin,margin]);

// Define separate scales for both sexes
var scales = {
  kk : d3.scale.linear()
    .domain([0,9000])
    .range([width,margin]),
  kvk : d3.scale.linear()
    .domain([0,9000])
    .range([width,2*width-margin])
};

['kk','kvk'].forEach(function(kyn) {
  svg.append("text")
    .attr({class:"title",x:scales[kyn](9000/2),y:75})
    .text(kyn);
});

var bars = svg.append("svg")
  .attr({x:0,y:0,height:height-margin,width:2*width});

// Y axes

// We draw y-scale twice, first one is a white thick strokes for text labels
svg.append("g").attr("class","y axis white")
  .attr("transform","translate("+(width)+",0)")
  .call(d3.svg.axis().scale(y).orient("left"));

svg.append("g").attr("class","y axis")
  .attr("transform","translate("+(width)+",0)")
  .call(d3.svg.axis().scale(y).orient("left"));

d3.selectAll(".y.axis")
  .call(function(g) { g.selectAll("text").attr("dx",17);})
  .selectAll(".tick.major").selectAll("line").remove();

// X axes

svg.append("g").attr("class","kk axis")
  .attr("transform","translate(0,"+(height-margin)+")")
  .call(d3.svg.axis().scale(scales.kk).orient("bottom").ticks(5));

svg.append("g").attr("class","kvk axis")
  .attr("transform","translate(0,"+(height-margin)+")")
  .call(d3.svg.axis().scale(scales.kvk).orient("bottom").ticks(5));

function redraw(year) {
  if (!data) return;
  title.text("人口ピラミッド(徳島県) ("+Math.round(year)+")");
  bars.selectAll("rect")
    // The scale used is determined by sex (i.e. d.kyn).   We use min and abs to ensure 
    // the left corner and width is correct for both
    .attr("x",function(d) { return Math.min(scales[d.kyn](0),scales[d.kyn](d.values(year))||0 ); })
    .attr("width",function(d) { return Math.abs(scales[d.kyn](0) - scales[d.kyn](d.values(year))||0); })
    .attr("y",function(d) { return y(year-d.born);});
}