import "../arrays/range";

import "../arrays/sum";

import "../math/trigonometry";

import "layout";

d3.layout.pie = function() {

var value = Number,

sort = d3_layout_pieSortByValue,

startAngle = 0,

endAngle = τ,

padAngle = 0;

function pie(data) {

var n = data.length,

values = data.map(function(d, i) { return +value.call(pie, d, i); }),

a = +(typeof startAngle === "function" ? startAngle.apply(this, arguments) : startAngle),

da = (typeof endAngle === "function" ? endAngle.apply(this, arguments) : endAngle) - a,

p = Math.min(Math.abs(da) / n, +(typeof padAngle === "function" ? padAngle.apply(this, arguments) : padAngle)),

pa = p * (da < 0 ? -1 : 1),

k = (da - n * pa) / d3.sum(values),

index = d3.range(n),

arcs = [],

v;

// Optionally sort the data.

if (sort != null) index.sort(sort === d3_layout_pieSortByValue

? function(i, j) { return values[j] - values[i]; }

: function(i, j) { return sort(data[i], data[j]); });

// Compute the arcs! They are stored in the original data's order.

index.forEach(function(i) {

arcs[i] = {

data: data[i],

value: v = values[i],

startAngle: a,

endAngle: a += v * k + pa,

padAngle: p

};

});

return arcs;

}

pie.value = function(_) {

if (!arguments.length) return value;

value = _;

return pie;

};

pie.sort = function(_) {

if (!arguments.length) return sort;

sort = _;

return pie;

};

pie.startAngle = function(_) {

if (!arguments.length) return startAngle;

startAngle = _;

return pie;

};

pie.endAngle = function(_) {

if (!arguments.length) return endAngle;

endAngle = _;

return pie;

};

pie.padAngle = function(_) {

if (!arguments.length) return padAngle;

padAngle = _;

return pie;

};

return pie;

};

var d3_layout_pieSortByValue = {};