Components.utils.import("chrome://redirector/content/js/xpcom.js");
Components.utils.import("chrome://redirector/content/js/redirect.js");
Components.utils.import("chrome://redirector/content/js/redirectorprefs.js");
Components.utils.import("resource://gre/modules/Services.jsm");
Components.utils.import('resource://gre/modules/AddonManager.jsm');

var EXPORTED_SYMBOLS = ['Redirector'];

Redirector = {

	get enabled() {
		return this._prefs && this._prefs.enabled;
	},

	set enabled(value) {
		if (this._prefs) {
			this._prefs.enabled = value;
		}
	},

	get redirectCount() {
		return this._list.length;
	},

	toString : function() {
		return "Redirector";
	},

	addRedirect : function(redirect) {
		this._list.push(redirect);
		this.save();
	},

	debug : function(msg) {
		if (this._prefs.debugEnabled) {
			Services.console.logStringMessage('REDIRECTOR: ' + msg);
		}
	},

	deleteRedirect : function(redirect) {
		this._list.splice(this._list.indexOf(redirect), 1);
		this.save();
	},

	exportRedirects : function(file) {
		const PR_WRONLY		 = 0x02;
		const PR_CREATE_FILE = 0x08;
		const PR_TRUNCATE	 = 0x20;

		var fileStream = new FileOutputStream(file, PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0644, 0);
		var stream = new ConverterOutputStream(fileStream, "UTF-8", 16384, Ci.nsIConverterInputStream.DEFAULT_REPLACEMENT_CHARACTER);
		var rjson = { createdBy : 'Redirector v' + this._prefs.version, createdAt : new Date(), redirects :[]};
		for each (var re in this._list) {
			rjson.redirects.push(re.toObject());
		}
		stream.writeString(JSON.stringify(rjson, null, 4));
		stream.close();
	},

	getRedirectAt : function(index) {
		return this._list[index];
	},

	//Get the redirect url for the given url. This will not check if we are enabled, and
	//not do any verification on the url, just assume that it is a good string url that is for http/s
	getRedirectUrl : function(url) {
		this.debug("Checking " + url);

		for each (var redirect in this._list) {
			var result = redirect.getMatch(url);
			if (result.isExcludeMatch) {
				this.debug(url + ' matched exclude pattern ' + redirect.excludePattern + ' so the redirect ' + redirect.includePattern + ' will not be used');
			} else if (result.isDisabledMatch) {
				this.debug(url + ' matched pattern ' + redirect.includePattern + ' but the redirect is disabled');
			} else if (result.isMatch) {
				redirectUrl = this._makeAbsoluteUrl(url, result.redirectTo);

				//check for loops...
				result = redirect.getMatch(redirectUrl);
				if (result.isMatch) {
					var msg = this._getFormattedString('invalidRedirectText', [redirect.includePattern, url, redirectUrl]);
					this.debug(msg);
					redirect.disabled = true;
					this.save();
					ConsoleService.logStringMessage('Redirector: ' + msg);
				} else {
					this.debug('Redirecting ' + url + ' to ' + redirectUrl);
					return redirectUrl;
				}
			}
		}
		return null;
	},

	QueryInterface: function(iid) {
		if (iid.equals(Ci.nsISupports) || iid.equals(Ci.nsIContentPolicy) || iid.equals(Ci.nsIChannelEventSink)) {
			return this;
		}
		throw Cr.NS_ERROR_NO_INTERFACE;
	},

	_getRedirectsFile : function() {
		var file = DirectoryService.get("ProfD", Ci.nsIFile);
		file.append('redirector.rjson');
		return file;
	},

	// Return a list of Redirects read from a string.
	//
	// The string is expected to be in the format redirector used in
	// older versions where it was stored as a user pref.
	parseRedirectsString : function(data) {
		let list = [];
		for each (redirectString in data.split(':::')) {
			if (!redirectString || !redirectString.split) {
				this.debug('Invalid old redirect: ' + redirectString);
				continue;
			}
			let parts = redirectString.split(',,,');
			if (parts.length < 5) {
				throw Error("Invalid serialized redirect, too few fields: " + redirectString);
			}
			let redirect = new Redirect();
			redirect._init.apply(redirect, parts);
			list.push(redirect);
		}
		return list;
	},

	handleUpgrades : function() {
		let branch, data;
		try {
			branch = PrefService.getBranch("extensions.redirector.");
		 	data = branch.getCharPref("redirects");
		} catch (e) {
			this.debug("No legacy redirect string preference found");
			return;
		}
		this.debug("Legacy redirect string preference found, migrating");
		oldRedirects = this.parseRedirectsString(data);
		if (!oldRedirects) {
			throw Error("Failed to migrate redirects, this shouldn't happen, send hatemail to papush@deepzero.net");
		}
		let redirectsFile = this._getRedirectsFile();
		if (redirectsFile.exists()) {
			this.importRedirects(redirectsFile);
		}
		this._list = this._list.concat(oldRedirects);
		this.save();
		branch.deleteBranch('redirects');
	},

	importRedirects : function(file) {
		var fileStream = new FileInputStream(file, 0x01, 0444, 0);
		var stream = new ConverterInputStream(fileStream, "UTF-8", 16384, Ci.nsIConverterInputStream.DEFAULT_REPLACEMENT_CHARACTER);
		var str = {};
		var rjson = '';
		while (stream.readString(4096, str) != 0) {
			rjson += str.value;
		}
		stream.close();
		var importCount = 0, existsCount = 0;
		rjson = JSON.parse(rjson);
		for each (var rd in rjson.redirects) {
			var redirect = new Redirect();
			redirect.fromObject(rd);
			if (this._containsRedirect(redirect)) {
				existsCount++;
			} else {
				this._list.push(redirect);
				importCount++;
			}
		}
		this.save();
		return importCount | (existsCount << 16);
	},

	save : function() {
		var file = this._getRedirectsFile();
		this.exportRedirects(file);
	},

	sortRedirects : function(sortFunc) {
		this._list.sort(sortFunc);
		this.save();
	},

	// nsIContentPolicy implementation
	shouldLoad: function(contentType, contentLocation, requestOrigin, aContext, mimeTypeGuess, extra) {
		this.debug('REDIRECTOR: inside shouldLoad');
		if (contentLocation.scheme != "http" && contentLocation.scheme != "https") {
			return Ci.nsIContentPolicy.ACCEPT;
		} //Immediately, otherwise we will log all sorts of crap

		this.debug('nsIContentPolicy::ShouldLoad ' + contentLocation.spec);
		try {
			//This is also done in getRedirectUrl, but we want to exit as quickly as possible for performance
			if (!this._prefs.enabled) {
				this.debug('REDIRECTOR: not enabled');
				return Ci.nsIContentPolicy.ACCEPT;
			}

			if (contentType != Ci.nsIContentPolicy.TYPE_DOCUMENT) {
				this.debug('REDIRECTOR: TYPE DOCUMENT');
				return Ci.nsIContentPolicy.ACCEPT;
			}

			if (contentLocation.scheme != "http" && contentLocation.scheme != "https") {
				this.debug('REDIRECTOR: not http or https');
				return Ci.nsIContentPolicy.ACCEPT;
			}

			if (!aContext || !aContext.loadURI) {
				this.debug('REDIRECTOR: no context or context.loadURI');
				return Ci.nsIContentPolicy.ACCEPT;
			}

			var redirectUrl = this.getRedirectUrl(contentLocation.spec);

			if (!redirectUrl) {
				this.debug('REDIRECTOR: invalid redirect url');
				return Ci.nsIContentPolicy.ACCEPT;
			}

			this.debug('REDIRECTOR: redirecting');
			aContext.loadURI(redirectUrl, requestOrigin, null);
			return Ci.nsIContentPolicy.REJECT_REQUEST;
		} catch(e) {
			this.debug(e);
		}

	},

	shouldProcess: function(contentType, contentLocation, requestOrigin, insecNode, mimeType, extra) {
		return Ci.nsIContentPolicy.ACCEPT;
	},
	//end nsIContentPolicy

	//nsIChannelEventSink implementation

	//For FF4.0. Got this from a thread about adblock plus, https://adblockplus.org/forum/viewtopic.php?t=5895
	asyncOnChannelRedirect: function(oldChannel, newChannel, flags, redirectCallback) {
		this.onChannelRedirect(oldChannel, newChannel, flags);
		redirectCallback.onRedirectVerifyCallback(0);
	},

	onChannelRedirect: function(oldChannel, newChannel, flags)
	{
		try {
			let newLocation = newChannel.URI.spec;
			this.debug('nsIChannelEventSink::onChannelRedirect ' + newLocation);

			if (!(newChannel.loadFlags & Ci.nsIChannel.LOAD_DOCUMENT_URI)) {
				//We only redirect documents...
				return;
			}

			if (!this._prefs.enabled) {
				return;
			}

			if (!newLocation) {
				return;
			}
			let callbacks = [];
			if (newChannel.notificationCallbacks) {
				callbacks.push(newChannel.notificationCallbacks);
			}
			if (newChannel.loadGroup && newChannel.loadGroup.notificationCallbacks) {
				callbacks.push(newChannel.loadGroup.notificationCallbacks);
			}
			var win;
			var webNav;
			for each (let callback in callbacks)
			{
				try {
					win = callback.getInterface(Ci.nsILoadContext).associatedWindow;
					webNav = win.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation);
					break;
				} catch(e) {}
			}
			if (!webNav) {
				return;
			}
			var redirectUrl = this.getRedirectUrl(newLocation);

			if (redirectUrl) {
				webNav.loadURI(redirectUrl,null,null,null,null);
				throw Cr.NS_BASE_STREAM_WOULD_BLOCK; //Throw this because the real error we should throw shows up in console...
			}

		} catch (e if (e != Cr.NS_BASE_STREAM_WOULD_BLOCK)) {
			// We shouldn't throw exceptions here - this will prevent the redirect.
			this.debug("Redirector: Unexpected error in onChannelRedirect: " + e + "\n");
		}
	},
	//end nsIChannelEventSink

	//Private members and methods

	_prefs : null,
	_list : null,
	_strings : null,

	init : function() {
		if (this._prefs) {
			this._prefs.dispose();
		}
		this._prefs = new RedirectorPrefs();
		this.debug('REDIRECTOR CREATED');
		//Check if we need to update existing redirects
		var data = this._prefs.redirects;
		var version = this._prefs.version;
		this._loadStrings();
		this._list = [];
		this.handleUpgrades();
		var redirectsFile = this._getRedirectsFile();
		if (redirectsFile.exists()) {
			this.importRedirects(redirectsFile);
		}
	},

	_loadStrings : function() {
		var src = 'chrome://redirector/locale/redirector.properties';
		var appLocale = Services.locale.getApplicationLocale();
		this._strings = StringBundleService.createBundle(src, appLocale);
	},

	_containsRedirect : function(redirect) {
		for each (var existing in this._list) {
			if (existing.equals(redirect)) {
				return true;
			}
		}
		return false;
	},

	_getString : function(name) {
		return this._strings.GetStringFromName(name);
	},

	_getFormattedString : function(name, params) {
		return this._strings.formatStringFromName(name, params, params.length);
	},

	_makeAbsoluteUrl : function(currentUrl, relativeUrl) {

		if (relativeUrl.match(/https?:/)) {
			return relativeUrl;
		}

		var uri = IOService.newURI(currentUrl, null, null);
		return uri.resolve(relativeUrl);
	}
};

Redirector.init();