mpdnotify: Add host/port options

To support connecting to MPD instances on other hosts, or if the socket
is in a different location, the host and/or port can be specified using
either command-line arguments or environment variables. The behavior is
similar to that of `mpc` in that the password can be specified in the
host value using `password@host` syntax. The command-line arguments
override the environment variables. If neither are specified, the
default of `localhost:6600` is used.

src/mpdnotify.vala

@@ -1,14 +1,67 @@
 namespace MpdNotify {
+    public static const string DEFAULT_HOST = "localhost";
+    public static const int DEFAULT_PORT = 6600;
+
+    private static string host;
+    private static int port;
+
+    private const OptionEntry[] options = {
+        {"host", 'h', 0, OptionArg.STRING, ref host,
+            "MPD server hostname/address", "HOST" },
+        {"port", 'p', 0, OptionArg.INT, ref port,
+            "MPD server port", "PORT" },
+        { null }
+    };
+
+    private static void parse_args(string[] args) throws OptionError {
+        host = Environment.get_variable("MPD_HOST");
+        if (host == null) {
+            host = DEFAULT_HOST;
+        }
+        string port_s = Environment.get_variable("MPD_PORT");
+        if (port_s == null) {
+            port = DEFAULT_PORT;
+        } else {
+            int p;
+            port_s.scanf("%d", out p);
+            port = p;
+        }
+
+        var ctx = new OptionContext(
+            "- Send desktop notifications for MPD events");
+        ctx.set_help_enabled(true);
+        ctx.add_main_entries(options, null);
+        ctx.parse(ref args);
+    }
+
+    int main(string[] args) {
+        try {
+            parse_args(args);
+        } catch (OptionError e) {
+            stderr.printf("Error: %s\n", e.message);
+            return 2;
+        }
 
-    void main() {
         var loop = new MainLoop();
         Unix.signal_add(2, () => {
             loop.quit();
             return false;
         });
-        var notifier = new Notifier("/run/mpd/socket", 0);
+
+        string _host;
+        string _password;
+        var split_host = host.split("@", 2);
+        if (split_host.length == 2) {
+            _host = split_host[1];
+            _password = split_host[0];
+        } else {
+            _host = split_host[0];
+            _password = null;
+        }
+        var notifier = new Notifier(_host, port, _password);
         notifier.start();
         loop.run();
+        return 0;
     }
 
 }