import { Key } from "stb-key";
import { Focus } from "stb-shadow";
import { diffNode } from "../util";

export function focus(target) {

	// Saves a reference to the primitive constructor
	var original = target;
	const _subscribeToEvents = original.prototype.subscribeToEvents || function () { };
	const _autoFocus = original.prototype.autoFocus || function () { };
	const _componentFocusDidUpdate = original.prototype.componentFocusDidUpdate || function () { };
	const _render = original.prototype.render || function () { };

	// Utility method used to generate an instance of a class
	function construct(constructor, args) {

		var c: any = function () {
			return constructor.apply(this, args);
		}
		c.prototype = constructor.prototype;

		return new c();
	}

	// New constructor behavior
	var f: any = function (...args) {
		// console.log('new:' + original.name);

		original.prototype.render = function (...args) {

			let vnode = _render.apply(this, args);

			vnode = diffNode.apply(this, [vnode]);

			return vnode;
		}

		original.prototype.subscribeToEvents = function (subs) {

			let r = _subscribeToEvents.apply(this, [subs]);

			if (false !== r && undefined !== this.identCode) {

				subs.onkeydown((e) => {
					if (Key.Left === e.keyCode || Key.Up === e.keyCode || Key.Right === e.keyCode || Key.Down === e.keyCode) {
						this.autoFocus(e.keyCode);
					}
					else if (Key.Enter === e.keyCode) {
						if (this.onEnter) this.onEnter(e.data || {});
					}
					else if (Key.Backspace === e.keyCode) {
						if (this.onBackspace) this.onBackspace();
					}
				});
			}
		}
		original.prototype.autoFocus = function (keyCode) {

			let r = _autoFocus.apply(this, [keyCode]);

			if (r !== false) {

				let f = Focus.center(this.tags.getAll(), this.index, keyCode);
				if (f) {
					this.setFocus(f.index);

					if (this.onChange) this.onChange(true, keyCode);
				} else {
					if (this.onChange) this.onChange(false, keyCode);
				}
			}

		}
		original.prototype.componentFocusDidUpdate = function ({ from }) {

			let r = _componentFocusDidUpdate.apply(this, [{ from }]);

			if (r !== false) {

				if (!this.tags || !this.tags.length || this.tags.length <= this.index) {
					return;
				}

				this.tags.removeClass("active").removeClass("focus");

				if (this.identCode !== this.event.getTargetIdentCode() || 'blur' === from) {
					this.tags.eq(this.index).addClass("active");

				} else if ('blur' !== from) {
					this.tags.eq(this.index).addClass("focus");
				}

			}
		}

		return construct(original, args);
	}

	// Duplicate the prototype so that the instanceof operation works
	f.prototype = original.prototype;

	// Returns the new constructor
	return f;
}