relu-core/modules/rp/lib/variable.js

Core for bot

var base = require("./base");
var ActionsList = require("./ActionsList");

module.exports = function rpVariable(value) {
	var p = base();
	p.constructor = rpVariable;

	var valueContainer = [value];

	var actionsList = new ActionsList();

	actionsList.onChange = function() {
		base.atAtomicEnd(applyChangesWithEvents);
	};
	
	p._get = function() {
		p.depend();
		return valueContainer[0];
	};
	
	p._getUndependend = function() {
		return valueContainer[0];
	};
	
	p._actionsList = function() {
		 return actionsList;
	};
	
	p._actionsTarget = function() {
		 return this;
	};

	p._forgetUpdate = function() {
		applyChanges(false);
	};
	
	function applyChangesWithEvents() {
		applyChanges(true);
	}

	function applyChanges(events) {
		function Applier(path, obj, property) {
			this.currentPath = path;
			this.currentObject = obj;
			this.currentProperty = property;
			this.changed = false;
		}
		Applier.prototype.enter = function(i, apply) {
			var obj = this.currentObject[this.currentProperty];
			if(typeof i === "number") {
				if(!Array.isArray(obj))
					throw new Error("Cannot access item " + i + " of " + obj + " at " + this.currentPath.join("."));
			} else {
				if(Array.isArray(obj)) {
					obj.forEach(function(_, idx) {
						this.currentPath.push(idx);
						var applier = new Applier(this.currentPath, obj, idx);
						applier.enter(i, apply);
						applier.done();
						this.currentPath.pop();
						this.changed |= applier.changed;
					}, this);
					return;
				} else if(typeof obj !== "object" || obj === null) {
					// need to create the object first
					var old = obj;
					obj = this.currentObject[this.currentProperty] = {};
					if(events) fireUpdatedForPath(this.currentPath, obj, old);
				}
			}
			this.currentPath.push(i);
			var applier = new Applier(this.currentPath, obj, i);
			apply(applier);
			this.currentPath.pop();
			this.changed |= applier.changed;
		}
		Applier.prototype.update = function(v) {
			var o = this.currentObject[this.currentProperty];
			if(v === undefined)
				delete this.currentObject[this.currentProperty];
			else
				this.currentObject[this.currentProperty] = v;
			if(isDifferent(o, v)) this.changed = true;
			if(events) fireUpdatedForPath(this.currentPath, v, o);
		};
		Applier.prototype.modify = function(fns) {
			var o = this.currentObject[this.currentProperty];
			var v = o;
			fns.forEach(function(fn) { v = fn(v); });
			this.currentObject[this.currentProperty] = v;
			if(isDifferent(o, v)) this.changed = true;
			if(events) fireUpdatedForPath(this.currentPath, v, o);
		};
		Applier.prototype.remove = function(i) {
			if(i === Infinity)
				i = this.currentObject[this.currentProperty].length - 1;
			else if(i >= this.currentObject[this.currentProperty].length)
				throw new Error("Cannot remove out of range value from array");
			var v = this.currentObject[this.currentProperty][i];
			this.currentObject[this.currentProperty].splice(i, 1);
			this.changed = true;
			if(events) fireRemovedForPath(this.currentPath, i, v);
		};
		Applier.prototype.add = function(i, v) {
			if(i === Infinity)
				i = this.currentObject[this.currentProperty].length;
			this.currentObject[this.currentProperty].splice(i, 0, v);
			this.changed = true;
			if(events) fireAddedForPath(this.currentPath, i, v);
		};
		Applier.prototype.done = function() {
			if(events && this.changed) {
				fireChangedForPath(this.currentPath);
			}
		};
		actionsList.apply(new Applier([], valueContainer, 0));
	}

	function fireChangedForPath(path) {
		if(path.length === 0) {
			p._changed();
		} else {
			p._nested("changed", path.slice());
		}
	}

	function fireUpdatedForPath(path, v, o) {
		if(path.length === 0) {
			p._updated(v, o);
		} else {
			p._nested("updated", path.slice(), v, o);
		}
	}

	function fireAddedForPath(path, i, v) {
		if(path.length === 0) {
			p._added(i, v);
		} else {
			p._nested("added", path.slice(), i, v);
		}
	}

	function fireRemovedForPath(path, i, v) {
		if(path.length === 0) {
			p._removed(i, v);
		} else {
			p._nested("removed", path.slice(), i, v);
		}
	}

	p._writable = true;

	return p;
};

function isDifferent(a, b) {
	if(a === b) return false;
	if(typeof a === "number" && typeof b === "number" && isNaN(a) && isNaN(b)) return false;
	return true;
}