export function uniq(xs) {
	var seen = {};
	return xs.filter(x => seen.hasOwnProperty(x) ? false : (seen[x] = true));
}

export function groupBy(xs, key) {
	return xs.reduce(function(rv, x) {
		var v = key instanceof Function ? key(x) : x[key];
		(rv[v] = rv[v] || []).push(x);
		return rv;
	}, {});
}

export function groupByArray(xs, key) {
	var mapping = {};
	return xs.reduce(function(rv, x) {
		var v = key instanceof Function ? key(x) : x[key];
		var el = mapping[v];
		if(el) el.values.push(x);
		else rv.push(mapping[v] = { key: v, values: [x] });
		return rv;
	}, []);
}

export function pivotByArray(xs, key, reducer) {
	var groups = groupByArray(xs, key);
	groups.forEach(function(group) {
		group.aggregate = group.values.reduce(reducer, {});
	});
	return groups;
}

export function quantile_sorted(arr_sorted, quantile) {
	var pos = (arr_sorted.length - 1) * quantile, base = Math.floor(pos), rest = pos - base;
	return arr_sorted[base + 1] !== undefined ? arr_sorted[base] + rest * (arr_sorted[base + 1] - arr_sorted[base]) : arr_sorted[base];
}

export function strHashCode(str) {
	var hash = 0;
	for(var i = 0; i < str.length; ++i) hash = str.charCodeAt(i) + ((hash << 5) - hash);
	return hash & hash;	// convert to 32 bit
}

export function strHashJenkins(str) {
	for(var hash = 0, i = str.length; i--;) hash += str.charCodeAt(i), hash += hash << 10, hash ^= hash >> 6;
	hash += hash << 3;
	hash ^= hash >> 11;
	return (hash + (hash << 15) & 4294967295) >>> 0
}

export function strHashHex(str) {
	var hash = strHashJenkins(str), color = '#';
	for(var i = 0; i < 3; ++i) color += ('00' + ((hash >> (i * 8)) & 0xFF).toString(16)).slice(-2);
	return color;
}

export function strHashHSL(str, lightness='50%') {
	var hash = strHashJenkins(str);
	return 'hsl(' + (hash%360) + ',' + (hash%100) + '%,' + lightness + ')';
}

export function strftime_vista(date) {
	return 10000*(date.getFullYear() - 1700) + 100*(date.getMonth() + 1) + date.getDate() + date.getHours()/100 + date.getMinutes()/10000 + date.getSeconds()/1000000 + date.getMilliseconds()/1000000000;
}

export function strptime_vista(s) {
	s = +s;
	var date = Math.floor(s), time = s - date;
	return new Date(Math.floor(date/10000) + 1700, (Math.floor(date/100) + '').slice(-2) - 1, (date + '').slice(-2), Math.floor(time*100), (Math.floor(time*10000) + '').slice(-2), (Math.floor(time*1000000) + '').slice(-2), (Math.floor(time*1000000000) + '').slice(-3));
}

export function debounce(fn, delay) {
	var clock = null;
	return function() {
		clearTimeout(clock);
		var self = this, args = arguments;
		clock = setTimeout(function() { fn.apply(self, args) }, delay);
	}
}