add lua module for sending a message on a certain day of the week

lua/dailies.lua

@@ -0,0 +1,43 @@
+target_time = {hour=hour, min=minute, sec=second}
+
+function get_total_day_seconds (time_table)
+    return (((time_table.hour * 60) + (time_table.min)) * 60) + time_table.sec
+end
+
+SECONDS_PER_DAY = get_total_day_seconds({hour=24, min=0, sec=0})
+
+function get_sleep_duration_sec ()
+    current_time = os.time()
+    current_time_table = os.date("*t", current_time)
+    current_day_seconds = get_total_day_seconds(current_time_table)
+    target_day_seconds = get_total_day_seconds(target_time)
+    difference = target_day_seconds - current_day_seconds
+    if difference > 0 then
+        return difference
+    else
+        return SECONDS_PER_DAY + difference
+    end
+end
+
+function get_weekday ()
+    return os.date("%a", current_time)
+end
+
+function sleep (sec)
+    return os.execute("sleep " .. tonumber(sec))
+end
+
+while true do
+    sleep_duration = get_sleep_duration_sec()
+    print("sleep for " .. sleep_duration)
+
+    if not sleep(sleep_duration) then
+        print("sleep exited abnormally - break")
+        break
+    end
+
+    if get_weekday() == weekday then
+        print("send message " .. message)
+        sender:send({type = "message", channel = channel, message = message})
+    end
+end