var vows = require(“vows”),

load = require("../load"),
assert = require("../assert");

var suite = vows.describe(“d3.layout.histogram”);

suite.addBatch({

"histogram": {
  topic: load("layout/histogram").expression("d3.layout.histogram"),
  "defaults to frequencies": function(histogram) {
    var h = histogram();
    assert.deepEqual(h([0,0,0,1,2,2]).map(elements), [[0, 0, 0], [], [1], [2, 2]]);
  },
  "each bin contains the matching source elements": function(histogram) {
    var h = histogram();
    assert.deepEqual(h([0,0,0,1,2,2]).map(elements), [[0, 0, 0], [], [1], [2, 2]]);
  },
  "each bin also has defined x, y and dx properties": function(histogram) {
    var h = histogram();
    assert.deepEqual(h([0,0,0,1,2,2]).map(metadata), [
      {x:   0, y: 3, dx: 0.5},
      {x: 0.5, y: 0, dx: 0.5},
      {x:   1, y: 1, dx: 0.5},
      {x: 1.5, y: 2, dx: 0.5}
    ]);
  },
  "can output frequencies": function(histogram) {
    var h = histogram().frequency(true);
    assert.deepEqual(h([0,0,0,1,2,2]).map(metadata), [
      {x:   0, y: 3, dx: 0.5},
      {x: 0.5, y: 0, dx: 0.5},
      {x:   1, y: 1, dx: 0.5},
      {x: 1.5, y: 2, dx: 0.5}
    ]);
  },
  "can output probabilities": function(histogram) {
    var h = histogram().frequency(false);
    assert.deepEqual(h([0,0,0,1,2,2]).map(metadata), [
      {x:   0, y: 3/6, dx: 0.5},
      {x: 0.5, y:   0, dx: 0.5},
      {x:   1, y: 1/6, dx: 0.5},
      {x: 1.5, y: 2/6, dx: 0.5}
    ]);
  },
  "can specify number of bins": function(histogram) {
    var h = histogram().bins(2);
    assert.deepEqual(h([0,0,0,1,2,2]).map(elements), [
      [0, 0, 0],
      [1, 2, 2]
    ]);
    assert.deepEqual(h([0,0,0,1,2,2]).map(metadata), [
      {x: 0, y: 3, dx: 1},
      {x: 1, y: 3, dx: 1}
    ]);
  },
  "can specify bin thresholds": function(histogram) {
    var h = histogram().bins([0,1,2,3]);
    assert.deepEqual(h([0,0,0,1,2,2]).map(elements), [
      [0, 0, 0],
      [1],
      [2, 2]
    ]);
    assert.deepEqual(h([0,0,0,1,2,2]).map(metadata), [
      {x: 0, y: 3, dx: 1},
      {x: 1, y: 1, dx: 1},
      {x: 2, y: 2, dx: 1}
    ]);
  },
  "returns the empty array with fewer than two bins": function(histogram) {
    var h = histogram().bins([1]);
    assert.deepEqual(h([0]), []);
    var h = histogram().bins([]);
    assert.deepEqual(h([0]), []);
  }
}

});

function elements(bin) {

var array = [], i = -1, n = bin.length;
while (++i < n) array.push(bin[i]);
return array;

}

function metadata(bin) {

var metadata = {};
if ("x" in bin) metadata.x = bin.x;
if ("y" in bin) metadata.y = bin.y;
if ("dx" in bin) metadata.dx = bin.dx;
return metadata;

}

suite.export(module);