Constellations/js/Mode.js

var mode;
var modes;
var mouseEvents = ['onClick', 'onMousedown', 'onMouseup', 'onMouseenter'];
var currentMode = 'play';

return {
	init: init,
	dispatch: dispatch,
	set: set,
	setEnabled: setEnabled
}

function init(chosenModes, elementId) {
	mode = document.getElementById(elementId || 'mode');
	mode.addEventListener('change', onChange);
	modes = chosenModes;
}

function setEnabled(enabled, targets) {
	if(!Array.isArray(targets)) {
		targets = [targets];
	}
	for(var i = 0; i < mode.options.length; i++) {
		var option = mode.options[i];
		if(targets.indexOf(option.value) >= 0) {
			option.disabled = !enabled;
		}
	}
}

function runEvent(eventName) {
	var handler = modes[currentMode].events[eventName];
	if(typeof handler == 'function') {
		handler.apply(null, Array.prototype.slice.call(arguments, 1));
	}
}

function onChange() {
	runEvent('onLeave');
	currentMode = mode.value;
	runEvent('onEnter');
}

function set(newMode) {
	if(modes[newMode]) {
		mode.value = newMode;
		onChange();
	}
}

function dispatch(cell) {
	var handler = {};
	mouseEvents.forEach(function(eventName) {
		handler[eventName] = function(e) {runEvent(eventName, e, cell);};
	});
	return handler;
}