Adding a legend to a pie chart in D3js - d3.js

Question

I'm trying to plot a pie chart with a legend inside of it. And I got into troubles to get it plotted, since I get the errors abound undefined variables. I managed to draw the chart itself and the half of the legend, but not in the right colors, what should match the pie chart.
function drawPieChart(d3div, chart_data) {
// chart_data.data is a list of data elements.
// each should contain fields: val, col, name
d3div.html(""); // clear the div
var title = getopt(chart_data, 'title', '');
// desired width and height of chart
var w = getopt(chart_data, 'width', 300);
var h = getopt(chart_data, 'height', 300);
var pad = getopt(chart_data, 'pad', 50);
var textmargin = getopt(chart_data, 'textmargin', 20);
var r = Math.min(w, h) / 2 - pad; // radius of pie chart
var div = d3div.append('div');
if(title !== '') {
div.append('p').attr('class', 'pietitle').text(title);
}
var arc = d3.svg.arc()
.outerRadius(r)
.cornerRadius(20)
.innerRadius(150);
var arcLarge = d3.svg.arc()
.innerRadius(150)
.cornerRadius(20)
.outerRadius(r + 50);
var toggleArc = function(p){
p.state = !p.state;
var dest = p.state ? arcLarge : arc;
d3.select(this).select("path").transition()
.duration(160)
.attr("d", dest);};
var pie = d3.layout.pie()
.padAngle(.03)
.sort(null)
.value(function(d) { return d.val; });
var svg = d3.select("#piechart").append("svg")
.attr("width", w)
.attr("height", h)
.append("g")
.attr("transform", "translate(" + w / 2 + "," + h / 2 + ")");
var g = svg.selectAll(".arc")
.data(pie(chart_data.data))
.enter().append("g")
.attr("class", "arc")
.attr("stroke", "#999")
.attr("id",function(d){return d.data;})
.on("mouseover",toggleArc)
.on("mouseout",toggleArc);
g.append("path")
.attr("d", arc)
.style("fill", function(d) { return d.data.col; });
var color = d3.scale.category20b();
var legendRectSize = 18;
var legendSpacing = 4;
// FROM here the code is not produced the desired result
var legend = svg.selectAll('.legend')
.data(chart_data.data)
.enter()
.append('g')
.attr('class', 'legend')
.attr("id",function(d){return d.data;})
.attr('transform', function(d, i) {
var height = legendRectSize + legendSpacing;
var offset = height * chart_data.data.length / 2;
var horz = -2 * legendRectSize;
var vert = i * height - offset;
return 'translate(' + horz + ',' + vert + ')';
});
legend.append('rect')
.data(chart_data.data)
.attr('width', legendRectSize)
.attr('height', legendRectSize)
.style("fill", function(d) { return d.data.col; });
legend.append("text")
.attr('x', legendRectSize + legendSpacing)
.attr('y', legendRectSize - legendSpacing)
.text(function(d) { return d.data.name; });
}
The code actually works fine untill the line var legend = svg.selectAll('.legend')
Then i start to define the legend, but D3 complains about undefined d.data every time i try to access d.data below the line I written above(also in the last line of the code).
I don't understand where i got on the wrong way.
If instead of defining the whole non working part(var legend...) i write this code:
g.append("text")
.attr("stroke", "none")
.attr("fill", function(d) { return d.data.col; })
.text(function(d) { return d.data.name; });
I'm able to access the d.data.name.
Unfortunately wrong colors of the boxes and not description.
Thanks!