// construct keys, start and end time; currently using 1 hour as baseline
var keys = ["a", "b", "c", "d", "e"]
	, now = new Date().valueOf()
	, duration = 1000 * 60 * 60
	, start = now - duration
	, end = now
	, min = 1
	, max = 100
	, sample_count = 20
	;

// generate some data
var data = generateData(keys, sample_count, start, end, min, max);

// need the time range for the slider
var t = d3.scale.linear().domain([0, 1]).rangeRound([start, end]);

// start with the last known values
var cursor = R.map(R.last, data);

// draw the table
var $table = d3.select("#data-table");

$table.selectAll("tr")
		.data(cursor)
	.enter().append("tr").selectAll("td")
		.data(function(d) { return [d.series, d.value, d.iso_time]; })
		.enter().append("td")
			.text(function(d) { return d; });

// setup the range slider; update when the value changes
$slider = d3.select("#time-slider").on("input", function() {
	updateTable($table, select(t(this.value), data));
});

// debugging table
var $debugging = d3.selectAll("div.series")
	.data(data)
	.enter().append("div").classed("series", true);

$debugging.append("h3").text(function(d) { return d[0].series; });
$debugging.append("table")
		.selectAll("tr")
			.data(function(d) { return d; })
			.enter().append("tr")
				.selectAll("td")
					.data(function(d) { return [d.series, d.step, d.value, d.time, d.iso_time]; })
					.enter().append("td")
					.text(function(d) { return d; });


// update the table values
function updateTable($target, data) {
	$target.selectAll("tr")
			.data(data)
		.selectAll("td")
			.data(function(d) { return [d.series, d.value, d.iso_time]; })
			.text(function(d) { return d; });
}


function select(time, data) {
//	var predicate = R.compose(R.gte(time), R.prop("time"));
	// return R.map(R.find(predicate), data);

	// ugh
	return R.map(function(d) {
		return R.findLast(function(v) {
			return v.time <= time;
		})(d) || R.head(d);
	})(data);
}


/**
 * data generation
 *
 */
function generateData(keys, count, start, end, min, max) {
	var generateFn = R.curry(generateDataForKey)(R.__, count, start, end, min, max);
	return R.map(generateFn, keys);
}


/**
 * generate data for a single key
 */
function generateDataForKey(key, count, start, end, min, max) {
	// setup ranges
	var timeRange = d3.scale.linear().domain([0, 1]).rangeRound([start, end])
		, valueRange = d3.scale.linear().domain([0, 1]).rangeRound([min, max])
		;

	// sample function
	var sampleFn = R.curry(makeSample)(timeRange, valueRange, key);

	// generate samples
	return R.sortBy(
		R.prop("time"),
		R.map(sampleFn, R.range(0, count))
	);
}


/**
 * generate a single random sample
 */
function makeSample(timeRange, valueRange, key, step) {
	var t = timeRange(Math.random())
		, isoTime = new Date(t).toISOString()
		;

	return {
		series: key
		, step: step
		, time: t
		, iso_time: isoTime
		, value: valueRange(Math.random())
	};
}