From 7393a296dd9f40b028bd7066a436784655eae304 Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@osmosoft.com>
Date: Mon, 21 Oct 2013 22:54:58 +0100
Subject: [PATCH] Add a fieldmangler widget

---
 core/modules/new_widgets/fieldmangler.js | 110 +++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 core/modules/new_widgets/fieldmangler.js

diff --git a/core/modules/new_widgets/fieldmangler.js b/core/modules/new_widgets/fieldmangler.js
new file mode 100644
index 000000000..040404bf5
--- /dev/null
+++ b/core/modules/new_widgets/fieldmangler.js
@@ -0,0 +1,110 @@
+/*\
+title: $:/core/modules/new_widgets/fieldmangler.js
+type: application/javascript
+module-type: new_widget
+
+Field mangler widget
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var Widget = require("$:/core/modules/new_widgets/widget.js").widget;
+
+var FieldManglerWidget = function(parseTreeNode,options) {
+	this.initialise(parseTreeNode,options);
+	this.addEventListeners([
+		{type: "tw-remove-field", handler: "handleRemoveFieldEvent"},
+		{type: "tw-add-field", handler: "handleAddFieldEvent"},
+		{type: "tw-remove-tag", handler: "handleRemoveTagEvent"},
+		{type: "tw-add-tag", handler: "handleAddTagEvent"}
+	]);
+};
+
+/*
+Inherit from the base widget class
+*/
+FieldManglerWidget.prototype = new Widget();
+
+/*
+Render this widget into the DOM
+*/
+FieldManglerWidget.prototype.render = function(parent,nextSibling) {
+	this.parentDomNode = parent;
+	this.computeAttributes();
+	this.execute();
+	this.renderChildren(parent,nextSibling);
+};
+
+/*
+Compute the internal state of the widget
+*/
+FieldManglerWidget.prototype.execute = function() {
+	// Get our parameters
+	this.mangleTitle = this.getAttribute("title",this.getVariable("tiddlerTitle"));
+	// Construct the child widgets
+	this.makeChildWidgets();
+};
+
+/*
+Selectively refreshes the widget if needed. Returns true if the widget or any of its children needed re-rendering
+*/
+FieldManglerWidget.prototype.refresh = function(changedTiddlers) {
+	var changedAttributes = this.computeAttributes();
+	if(changedAttributes.tiddler) {
+		this.refreshSelf();
+		return true;
+	} else {
+		return this.refreshChildren(changedTiddlers);		
+	}
+};
+
+FieldManglerWidget.prototype.handleRemoveFieldEvent = function(event) {
+	var tiddler = this.wiki.getTiddler(this.mangleTitle),
+		deletion = {};
+	deletion[event.param] = undefined;
+	this.wiki.addTiddler(new $tw.Tiddler(tiddler,deletion));
+	return true;
+};
+
+FieldManglerWidget.prototype.handleAddFieldEvent = function(event) {
+	var tiddler = this.wiki.getTiddler(this.mangleTitle);
+	if(tiddler && typeof event.param === "string" && event.param !== "" && !$tw.utils.hop(tiddler.fields,event.param)) {
+		var addition = {};
+		addition[event.param] = "";
+		this.wiki.addTiddler(new $tw.Tiddler(tiddler,addition));
+	}
+	return true;
+};
+
+FieldManglerWidget.prototype.handleRemoveTagEvent = function(event) {
+	var tiddler = this.wiki.getTiddler(this.mangleTitle);
+	if(tiddler && tiddler.fields.tags) {
+		var p = tiddler.fields.tags.indexOf(event.param);
+		if(p !== -1) {
+			var modification = {};
+			modification.tags = (tiddler.fields.tags || []).slice(0);
+			modification.tags.splice(p,1);
+		this.wiki.addTiddler(new $tw.Tiddler(tiddler,modification));
+		}
+	}
+	return true;
+};
+
+FieldManglerWidget.prototype.handleAddTagEvent = function(event) {
+	var tiddler = this.wiki.getTiddler(this.mangleTitle);
+	if(tiddler && typeof event.param === "string" && event.param !== "") {
+		var modification = {};
+		modification.tags = (tiddler.fields.tags || []).slice(0);
+		$tw.utils.pushTop(modification.tags,event.param);
+		this.wiki.addTiddler(new $tw.Tiddler(tiddler,modification));
+	}
+	return true;
+};
+
+exports.fieldmangler = FieldManglerWidget;
+
+})();