diff --git a/Makefile b/Makefile
index 858dbd8..8407c7b 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,8 @@
 
 include config.mk
 
-SRC = main.c
+SRC = datetime.c main.c
+HDR = datetime.h
 OBJ = $(SRC:.c=.o)
 
 all: options polytree-session
@@ -16,7 +17,7 @@ options:
 %.o: %.c
 	$(CC) -c $< -o $@ $(CFLAGS)
 
-OBJ: config.mk
+OBJ: config.mk $(HDR)
 
 polytree-session: $(OBJ)
 	$(CC) -o $@ $(OBJ) $(LDFLAGS)
diff --git a/datetime.c b/datetime.c
new file mode 100644
index 0000000..9ba3888
--- /dev/null
+++ b/datetime.c
@@ -0,0 +1,61 @@
+#include "datetime.h"
+
+#include <pthread.h>
+#include <unistd.h>
+#include <X11/Xlib.h>
+
+static bool running = false;
+static Display *display = NULL;
+static pthread_t thread;
+static bool thread_created = false;
+
+static void *run(void *arg);
+
+bool datetime_start()
+{
+	// TODO: maybe we should assert
+	if (running) return false;
+	running = true;
+
+	if ((display = XOpenDisplay(NULL)) == NULL) {
+		datetime_stop();
+		return false;
+	}
+
+	if (!(thread_created = pthread_create(&thread, NULL, run, NULL) == 0)) {
+		datetime_stop();
+		return false;
+	}
+
+	return true;
+}
+
+void datetime_stop()
+{
+	// TODO: maybe we should assert
+	if (!running) return;
+	running = false;
+
+	if (thread_created) pthread_join(thread, NULL);
+	if (display) XCloseDisplay(display);
+}
+
+void *run(__attribute__((unused)) void *const arg)
+{
+	while (running) {
+		time_t curr_time;
+		time(&curr_time);
+
+		const struct tm *const curr_tm = localtime(&curr_time);
+
+		char buffer[256];
+		strftime(buffer, sizeof(buffer), "%a, %e %b %Y, %H:%M:%S", curr_tm);
+
+		XStoreName(display, DefaultRootWindow(display), buffer);
+		XSync(display, False);
+
+		sleep(1);
+	}
+
+	return NULL;
+}
diff --git a/datetime.h b/datetime.h
new file mode 100644
index 0000000..86e35e9
--- /dev/null
+++ b/datetime.h
@@ -0,0 +1,9 @@
+#ifndef _DATETIME_H
+#define _DATETIME_H
+
+#include <stdbool.h>
+
+bool datetime_start();
+void datetime_stop();
+
+#endif // _DATETIME_H
diff --git a/main.c b/main.c
index b0d353b..98da2b6 100644
--- a/main.c
+++ b/main.c
@@ -1,4 +1,5 @@
-#include <pthread.h>
+#include "datetime.h"
+
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -6,16 +7,6 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
-#include <X11/Xlib.h>
-
-static bool datetime_running = false;
-static Display *datetime_display = NULL;
-static pthread_t datetime_thread;
-static bool datetime_thread_created = false;
-
-static bool datetime_start();
-static void datetime_stop();
-static void *datetime_run(void *arg);
 
 int main()
 {
@@ -42,56 +33,3 @@ int main()
 
 	exit(WEXITSTATUS(wm_status));
 }
-
-bool datetime_start()
-{
-	// TODO: maybe we should assert
-	if (datetime_running) return false;
-	datetime_running = true;
-
-	if ((datetime_display = XOpenDisplay(NULL)) == NULL) {
-		datetime_stop();
-		return false;
-	}
-
-	if (!(datetime_thread_created =
-			pthread_create(&datetime_thread, NULL, datetime_run, NULL) == 0))
-	{
-		datetime_stop();
-		return false;
-	}
-
-	return true;
-}
-
-void datetime_stop()
-{
-	// TODO: maybe we should assert
-	if (!datetime_running) return;
-	datetime_running = false;
-
-	if (datetime_thread_created) pthread_join(datetime_thread, NULL);
-	if (datetime_display) XCloseDisplay(datetime_display);
-}
-
-void *datetime_run(__attribute__((unused)) void *const arg)
-{
-	while (datetime_running) {
-		time_t curr_time;
-		time(&curr_time);
-
-		const struct tm *const curr_tm = localtime(&curr_time);
-
-		char buffer[256];
-		strftime(buffer, sizeof(buffer), "%a, %e %b %Y, %H:%M:%S", curr_tm);
-
-		XStoreName(datetime_display,
-					DefaultRootWindow(datetime_display),
-					buffer);
-		XSync(datetime_display, False);
-
-		sleep(1);
-	}
-
-	return NULL;
-}