function renderBuildCounts(container, data) {
	var valueLabelWidth = 40; // space reserved for value labels (right)
	var barHeight = 20; // height of one bar
	var barLabelWidth = 160; // space reserved for bar labels
	var barLabelPadding = 5; // padding between bar and bar labels (left)
	var gridLabelHeight = 18; // space reserved for gridline labels
	var gridChartOffset = 3; // space between start of grid and first bar
	var maxBarWidth = 420; // width of the bar with the max value

	// accessor functions 
	var barValue = function(d) { return d.value; };

	// scales
	var yScale = d3.scale.ordinal().domain(d3.range(0, data.length)).rangeBands([0, data.length * barHeight]);
	var y = function(d, i) { return yScale(i); };
	var yText = function(d, i) { return y(d, i) + yScale.rangeBand() / 2; };
	var x = d3.scale.linear().domain([0, d3.max(data, barValue)]).range([0, maxBarWidth]);

	// svg container element
	var chart = d3.select(container).html('').append("svg")
		.attr('width', maxBarWidth + barLabelWidth + valueLabelWidth)
		.attr('height', gridLabelHeight + gridChartOffset + data.length * barHeight);

	// grid line labels
	var gridContainer = chart.append('g')
		.attr('transform', 'translate(' + barLabelWidth + ',' + gridLabelHeight + ')'); 
	gridContainer.selectAll("text").data(x.ticks(10)).enter().append("text")
		.attr("x", x)
		.attr("dy", -3)
		.attr("text-anchor", "middle")
		.text(String);

	// vertical grid lines
	gridContainer.selectAll("line").data(x.ticks(10)).enter().append("line")
		.attr("x1", x)
		.attr("x2", x)
		.attr("y1", 0)
		.attr("y2", yScale.rangeExtent()[1] + gridChartOffset)
		.style("stroke", "#ccc");

	// bar labels
	var labelsContainer = chart.append('g')
		.attr('transform', 'translate(' + (barLabelWidth - barLabelPadding) + ',' + (gridLabelHeight + gridChartOffset) + ')'); 
		labelsContainer.selectAll('text').data(data).enter().append('text')
		.attr('y', yText)
		.attr("dy", ".35em") // vertical-align: middle
		.attr('text-anchor', 'end')
		.text(function(d) { return d.key; });

	// bars
	var barsContainer = chart.append('g')
		.attr('transform', 'translate(' + barLabelWidth + ',' + (gridLabelHeight + gridChartOffset) + ')'); 
	barsContainer.selectAll("rect").data(data).enter().append("rect")
		.attr('y', y)
		.attr('height', yScale.rangeBand())
		.attr('width', function(d) { return x(barValue(d)); })
		.attr('stroke', 'white')
		.attr('fill', 'steelblue');

	// bar value labels
	barsContainer.selectAll("text").data(data).enter().append("text")
		.attr("x", function(d) { return x(barValue(d)); })
		.attr("y", yText)
		.attr("dx", 3) // padding-left
		.attr("dy", ".35em") // vertical-align: middle
		.attr("text-anchor", "start") // text-align: right
		.attr("fill", "black")
		.attr("stroke", "none")
		.text(function(d) { return d3.round(barValue(d), 2); });

	// start line
	barsContainer.append("line")
		.attr("y1", -gridChartOffset)
		.attr("y2", yScale.rangeExtent()[1] + gridChartOffset)
		.style("stroke", "#000");
}

function renderBuildTimes(container, barValue, data, baseUrl) {
	var paddingLeft = 5; // space to the left of the bars
	var paddingRight = 10; // space to the right of the bars
	var barHeight = 5; // height of one bar
	var barPaddingV = 1; // vertical padding between bars
	var gridLabelHeight = 18; // space reserved for gridline labels
	var gridChartOffset = 3; // space between start of grid and first bar
	var maxBarWidth = 450; // width of the bar with the max value

	// scales
	var yScale = d3.scale.ordinal()
		.domain(d3.range(0, data.length))
		.rangeBands([0, data.length * (barHeight+barPaddingV)]);
	var y = function(d, i) { return yScale(i) + barPaddingV*i; };
	var yText = function(d, i) { return y(d, i) + yScale.rangeBand() / 2; };
	var x = d3.scale.linear()
		.domain([0, d3.max(data, barValue)])
		.range([0, maxBarWidth]);

	// svg container element
	var chart = d3.select(container).html('').append("svg")
		.attr('width', maxBarWidth + paddingLeft + paddingRight)
		.attr('height', gridLabelHeight + gridChartOffset + data.length * (barHeight+barPaddingV*2));

	// grid line labels
	var gridContainer = chart.append('g')
		.attr('transform', 'translate(' + paddingLeft + ',' + gridLabelHeight + ')'); 
	gridContainer.selectAll("text").data(x.ticks(10)).enter().append("text")
		.attr("x", x)
		.attr("dy", -3)
		.attr("text-anchor", "middle")
		.text(String);

	// vertical grid lines
	gridContainer.selectAll("line").data(x.ticks(10)).enter().append("line")
		.attr("x1", x)
		.attr("x2", x)
		.attr("y1", 0)
		.attr("y2", yScale.rangeExtent()[1] + gridChartOffset + barPaddingV*data.length)
		.style("stroke", "#ccc");

	// bars
	var barsContainer = chart.append('g')
		.attr('transform', 'translate(' + paddingLeft + ',' + (gridLabelHeight + gridChartOffset) + ')'); 
	barsContainer.selectAll("rect").data(data).enter().append("rect")
		.attr('y', y)
		.attr('height', yScale.rangeBand())
		.attr('width', function(d) { return x(barValue(d)); })
		.attr('stroke', 'white')
		.attr('class', 'build-time-bar')
		.attr('fill', function(d) {
			return d.state === 'passed' ? '#038035' : '#CC0000';
		})
		.on('click', function(d) {
			window.open(baseUrl + d.id);
		});
}

function getBuildDate(build) {
	var dt = new Date(Date.parse(build.started_at));
	return dt.toDateString();
}

function getJSON(url, callback) {
    return d3.xhr(
	url,
	"application/vnd.travis-ci.2+json",
	function(xhr) {
	    if (xhr.readyState==4 && xhr.status==200) {
		callback(JSON.parse(xhr.responseText));
	    }
	}
    );
    // With d3 4.0:
    //return d3.request(url)
    //    //.mimeType("application/json")
    //    .header("Accept", "application/vnd.travis-ci.2+json")
    //    .response(function(xhr) { return JSON.parse(xhr.responseText); })
    //    .get(callback);
}

function updateChart() {
	var repoName = document.getElementById('repo-name').value;
	var includeFailed = document.getElementById('include-failed').checked;
	var onlyMaster = document.getElementById('only-master').checked;

	// need at least "a/a"
	if (repoName.length < 3) {
		return;
	}

	var baseUrl = 'https://travis-ci.org/' + repoName + '/builds/';

	var buildsUrl = 'https://api.travis-ci.org/repos/' + repoName + '/builds?'; // event_type=push';

	var builds = [];

	var oldestBuild = Infinity;
	var i=0, n=20;

	var buildCounts = {};

	function updateCount(build) {
		var buildDate = getBuildDate(build);

		if (!buildCounts[buildDate]) {
			buildCounts[buildDate] = 1;
		} else {
			buildCounts[buildDate] += 1;
		}
	}

	function filterBuilds(json) {
		if (typeof json.builds.length === 'undefined') {
			alert('invalid repository: ' + repoName);
			return;
		}

		var curOldestBuild = oldestBuild;

		json.builds.forEach(function(build, idx) {
			var buildNr = Number(build.number);
			if (buildNr < curOldestBuild) {
				curOldestBuild = buildNr;
			}

			if ((onlyMaster && json.commits[idx].branch !== 'master')
			    || (build.finished_at == null)
			    || (!includeFailed && build.state !== 'passed')
			    || (build.event_type != "push" && build.event_type != "cron")) {
				return;
			}

			updateCount(build);
			builds.push(build);
		});

		function getDuration(build) {
			return build.duration/60;
		}

		function getClockTime(build) {
			var started_at = Date.parse(build.started_at);
			var finished_at = Date.parse(build.finished_at);

			return (finished_at - started_at) / 60000;
		}

		renderBuildTimes('#build-times-duration', getDuration, builds, baseUrl);
		renderBuildTimes('#build-times', getClockTime, builds, baseUrl);
		// renderBuildTimes('#build-shortest-job', getShortest, builds, baseUrl);
		// renderBuildTimes('#build-longest-job', getLongest, builds, baseUrl);
		renderBuildCounts('#build-counts', d3.entries(buildCounts), baseUrl);

		if (++i < n && curOldestBuild < oldestBuild) {
			oldestBuild = curOldestBuild;
			getJSON(buildsUrl + '&after_number=' + oldestBuild, filterBuilds);
		}
	}

	getJSON(buildsUrl, filterBuilds);
}

function updateInputViaHash() {
	document.getElementById('repo-name').value = window.location.hash.substr(1);
}

function updateHashViaInput() {
	window.location.hash = '#' + document.getElementById('repo-name').value;
}

d3.select(window).on('hashchange', updateInputViaHash);

d3.select('form').on('submit', function() {
	d3.event.preventDefault();

	updateHashViaInput();
	updateChart();
});

updateInputViaHash();
updateChart();