/*\
title: $:/plugins/tiddlywiki/browser-storage/startup.js
type: application/javascript
module-type: startup

Startup initialisation

\*/
(function(){

/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";

// Export name and synchronous status
exports.name = "browser-storage";
exports.platforms = ["browser"];
exports.after = ["startup"];
exports.synchronous = true;

var ENABLED_TITLE = "$:/config/BrowserStorage/Enabled",
	SAVE_FILTER_TITLE = "$:/config/BrowserStorage/SaveFilter";

var BrowserStorageUtil = require("$:/plugins/tiddlywiki/browser-storage/util.js").BrowserStorageUtil;

exports.startup = function() {
	var self = this;
	
        // If not exists, add ENABLED tiddler with default value "yes"
        if(!$tw.wiki.getTiddler(ENABLED_TITLE)) {
                $tw.wiki.addTiddler({title: ENABLED_TITLE, text: "yes"});
        }
	// Compute our prefix for local storage keys
	var prefix = "tw5#" + window.location.pathname + "#";
	// Make a logger
	var logger = new $tw.utils.Logger("browser-storage",{
			colour: "cyan"
		});
	// Add browserStorage object to $tw
	$tw.browserStorage = new BrowserStorageUtil($tw.wiki,{
		enabledTitle: ENABLED_TITLE,
		prefix: prefix,
		logger: logger
	});
	// Function to compile the filter
	var filterFn,
		compileFilter = function() {
			filterFn = $tw.wiki.compileFilter($tw.wiki.getTiddlerText(SAVE_FILTER_TITLE));
	}
	compileFilter();
	// Listen for tm-clear-browser-storage messages
	$tw.rootWidget.addEventListener("tm-clear-browser-storage",function(event) {
		$tw.wiki.addTiddler({title: ENABLED_TITLE, text: "no"});
		$tw.browserStorage.clearLocalStorage();
	});
	// Track tiddler changes
	$tw.wiki.addEventListener("change",function(changes) {
		// Bail if browser storage is disabled
		if($tw.wiki.getTiddlerText(ENABLED_TITLE) === "no") {
			return;
		}
		// Recompile the filter if it has changed
		if(changes[SAVE_FILTER_TITLE]) {
			compileFilter();
		}
		// Filter the changes
		var filteredChanges = filterFn.call($tw.wiki,function(iterator) {
			$tw.utils.each(changes,function(change,title) {
				var tiddler = $tw.wiki.getTiddler(title);
				iterator(tiddler,title);
			});
		});
		$tw.utils.each(filteredChanges,function(title) {
			// Don't try to save changes to our enabled status
			// (If it were enabled in the file but disabled in local storage then we might not realise that distributing a copy of the file would have local storage enabled for other users)
			if(title === ENABLED_TITLE) {
				return;
			}
			// Save the tiddler
			$tw.browserStorage.saveTiddlerToLocalStorage(title);
		});
	});
};

})();