Implement notification uri keyword expansion

Resolves #198.  Four keywords are supported: context, nick, datetime,
and unixtime.

README.md

@@ -202,7 +202,18 @@ Configuration
 *   `message_url = ""`
 
     URI that will be sent with the notification to Notifo.  This could be a web address or a
-    local scheme to access a mobile application.
+    local scheme to access a mobile application.  Keyword expansion is performed on this
+    value each time a notification is sent; the following keywords will be replaced with
+    the appropriate value:
+
+    *   `{context}`: the channel or query window context
+    *   `{nick}`: the nick that sent the message
+    *   `{datetime}`: [ISO 8601][] date string, in server-local time
+    *   `{unixtime}`: unix-style integer timestamp
+
+    As an example, a value of "http://domain/{context}/{datetime}" would be expanded to
+    something similar to "http://domain/#channel/2011-03-09 14:25:09", or
+    "http://domain/{nick}/{unixtime}" to "http://domain/somenick/1299685136".
 
 ### Advanced
 
@@ -256,5 +267,6 @@ This project is licensed under the MIT license.  See the `LICENSE` file for deta
 [mantis]: http://leetcode.net/mantis
 [Notifo]: http://notifo.com "Notifo, Mobile Notifications for Everything"
 [ZNC]: http://en.znc.in "ZNC, an advanced IRC bouncer"
+[ISO 8601]: http://en.wikipedia.org/wiki/ISO_8601 "ISO 8601 Date Format"
 
 <!-- vim:set ft= expandtab tabstop=4 shiftwidth=4: -->

notifo.cpp

@@ -167,7 +167,7 @@ class CNotifoMod : public CModule
 		 * @param title Message title to use
 		 * @param context Channel or nick context
 		 */
-		void send_message(const CString& message, const CString& title="New Message", const CString& context="")
+		void send_message(const CString& message, const CString& title="New Message", const CString& context="*notifo", const CNick& nick=CString("*notifo"))
 		{
 			// Set the last notification time
 			last_notification_time[context] = time(NULL);
@@ -180,12 +180,28 @@ class CNotifoMod : public CModule
 				short_message = message.Ellipsize(message_length);
 			}
 
+			// Generate an ISO8601 date string
+			time_t rawtime;
+			struct tm * timeinfo;
+			time(&rawtime);
+			timeinfo = localtime(&rawtime);
+			char iso8601 [20];
+			strftime(iso8601, 20, "%Y-%m-%d %H:%M:%S", timeinfo);
+
+			// URI string replacements
+			MCString replace;
+			replace["{context}"] = context;
+			replace["{nick}"] = nick.GetNick();
+			replace["{datetime}"] = CString(iso8601);
+			replace["{unixtime}"] = CString(time(NULL));
+			CString uri = expand(options["message_uri"], replace);
+
 			// POST body parameters for the request
 			CString post = "to=" + urlencode(options["username"]);
 			post += "&msg=" + urlencode(short_message);
 			post += "&label=" + urlencode(app);
 			post += "&title=" + urlencode(title);
-			post += "&uri=" + urlencode(options["message_uri"]);
+			post += "&uri=" + urlencode(uri);
 
 			// Request headers and POST body
 			CString request = "POST " + notifo_url + " HTTP/1.1" + crlf;