export const comp = (...fs) => x0 => fs.reduceRight((x, f) => f(x), x0);
export const flow = (...fs) => x0 => fs.reduce((x, f) => f(x), x0);
export const pipe = (x0, ...fs) => fs.reduce((x, f) => f(x), x0);
export const aflow = (f0, ...fs) => async (...args) => fs.reduce((x, f) => f(x), await f0(...args));

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 strtr(s, a, b) {
	var res = '';
	for(var i = 0; i < s.length; ++i) {
		var j = a.indexOf(s.charAt(i));
		res += j >= 0 ? b.charAt(j) : s.charAt(i);
	}
	return res;
}

export function strtr_unscramble(name) {
	return name.length > 0 ? (name.charAt(0) + strtr(name.substring(1), 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'LKJIHGFEDCBAZYXWVUTSRQPONM')) : name;
}

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 datetime_datestr(dt) {
	return dt ? dt.toLocaleDateString('sv-SE') : undefined;
}

export function datetime_timestr(dt) {
	if(dt) {
		const res = dt.toLocaleTimeString('en-GB');
		return res.endsWith(':00') ? res.substring(0, 5) : res;
	}
}

export function datetime_dtstr(dt) {
	if(dt) {
		const res = dt.toLocaleTimeString('en-GB');
		return dt.toLocaleDateString('sv-SE') + ' ' + (res.endsWith(':00') ? res.substring(0, 5) : res);
	}
}

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 strfdate_vista(date) {
	return 10000*(date.getFullYear() - 1700) + 100*(date.getMonth() + 1) + date.getDate();
}

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 escapeHTML(unsafe) {
	return unsafe.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#039;');
}

export function escapeRegExp(unsafe) {
	return unsafe.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

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

export function isInViewport(el, entirely = false) {
	const rect = el.getBoundingClientRect();
	return entirely ? (
		(rect.top >= 0) &&
		(rect.left >= 0) &&
		(rect.bottom <= (window.innerHeight || document.documentElement.clientHeight)) &&
		(rect.right <= (window.innerWidth || document.documentElement.clientWidth))
	) : (
		(rect.bottom >= 0) &&
		(rect.right >= 0) &&
		(rect.top <= (window.innerHeight || document.documentElement.clientHeight)) &&
		(rect.left <= (window.innerWidth || document.documentElement.clientWidth))
	);
}

export function filter_pattern(query, between, flags) {
	if((query = query.replace(/^\s+|\s+$/g, '')).length > 0) {
		if(query.startsWith('/')) {
			if(query.length > 1) {
				var m = /^\/(.*)\/([a-z]*)$/.exec(query);
				return m ? new RegExp(m[1], m[2]) : new RegExp(query.substring(1), flags || 'gims');
			}
		} else {
			query = query.split('|').map(x => filter_part(x, between || 5)).filter(x => x);
			if(query.length > 0) return new RegExp(query.join('|'), flags || 'gims');
		}
	}
}

function filter_part(query, between) {
	if((query = query.replace(/^\s+|\s+$/g, '')).length > 0) {
		if(query.startsWith('"')) {
			query = query.substring(1, query.length - ((query.length > 1) && (query.endsWith('"')) ? 1 : 0));
			if(query.length > 0) return query.split(/\s+/).map(x => x.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')).join('\\s*');
		} else return '(?:' + query.split(/\s+/).map(x => '(?<!\\w)' + x.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')).join('\\S*\\s+(?:\\S+\\s+){0,' + (+(between || 5)) + '}?') + ')';
	}
}

export function filter_test(pattern, haystack) {
	pattern.lastIndex = 0;
	return pattern.test(haystack);
}

export function filter_mark(pattern, haystack, mark) {
	return haystack.replace(pattern, mark || '<mark>$&</mark>');
}

export function filter_snippets(pattern, haystack, mark, before, after) {
	var res = [], context = new RegExp('(?:\\S+[ \t\v\xa0\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u202f\u205f\u3000\ufeff]+){0,' + (+(before || 3)) + '}\\S*(' + pattern.source + ')\\S*(?:[ \t\v\xa0\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u202f\u205f\u3000\ufeff]+\\S+){0,' + (+(after || before || 3)) + '}', pattern.flags), match;
	if(context.global) while((match = context.exec(haystack)) !== null) res.push(match[0].replace(pattern, mark || '<mark>$&</mark>').replace(/\s+/g, ' ').replace(/([\W_])\1{2,}/g, '$1$1'));
	else if((match = context.exec(haystack)) !== null) res.push(match[0].replace(pattern, mark || '<mark>$&</mark>').replace(/\s+/g, ' ').replace(/([\W_])\1{2,}/g, '$1$1'));
	return uniq(res);
}

export function filter_snippets_lines(pattern, haystack, mark) {
	var res = [], context = new RegExp('[^\r\n]*(' + pattern.source + ')[^\r\n]*', pattern.flags), match;
	if(context.global) while((match = context.exec(haystack)) !== null) res.push(match[0].replace(pattern, mark || '<mark>$&</mark>').replace(/[\r\n]/g, ' '));
	else if((match = context.exec(haystack)) !== null) res.push(match[0].replace(pattern, mark || '<mark>$&</mark>').replace(/[\r\n]/g, ' '));
	return uniq(res);
}

function Descendant() {}
export function inherit(obj) {
	Descendant.prototype = obj;
	return new Descendant();
}