let g_emojis;

function get_emojis() {
	if (g_emojis) {
		return Promise.resolve(g_emojis);
	}
	return fetch('emojis.json').then(function(result) {
		g_emojis = result.json();
		return g_emojis;
	});
}

export function picker(callback, anchor) {
	get_emojis().then(function(json) {
		let existing = document.getElementById('emoji_picker');
		if (existing) {
			existing.parentElement.removeChild(existing);
			return;
		}
		let div = document.createElement('div');
		div.id = 'emoji_picker';
		div.style.color = '#000';
		div.style.background = '#fff';
		div.style.border = '1px solid #000';
		div.style.display = 'block';
		div.style.position = 'absolute';
		div.style.maxWidth = '16em';
		div.style.maxHeight = '16em';
		div.style.overflow = 'scroll';
		div.style.fontWeight = 'bold';
		div.style.cursor = 'pointer';
		Object.entries(json).forEach(function(row) {
			let header = document.createElement('div');
			header.appendChild(document.createTextNode(row[0]));
			div.appendChild(header);
			for (let entry of row[1]) {
				let emoji = document.createElement('span');
				const k_size = '1.25em';
				emoji.style.width = k_size;
				emoji.style.maxWidth = k_size;
				emoji.style.minWidth = k_size;
				emoji.style.height = k_size;
				emoji.style.maxHeight = k_size;
				emoji.style.minHeight = k_size;
				emoji.style.display = 'inline-block';
				emoji.style.overflow = 'hidden';
				emoji.onclick = function() {
					callback(entry);
					div.parentElement.removeChild(div);
				}
				emoji.appendChild(document.createTextNode(entry.emoji));
				div.appendChild(emoji);
			}
		});
		document.body.appendChild(div);
		if (anchor) {
			let rect = anchor.getBoundingClientRect();
			if (rect.top < window.clientHeight / 2) {
				div.style.top = rect.bottom + 'px';
			} else {
				div.style.top = (rect.top - div.clientHeight) + 'px';
			}
			if (rect.left < window.clientWidth / 2) {
				div.style.left = rect.left + 'px';
			} else {
				div.style.left = (rect.left - div.clientWidth) + 'px';
			}
		}
	});
}