help! .FPGA based led lighting where d lights come on at night and goes off at day

LIBRARY IEEE;

USE IEEE.std_logic _1164.all;

ENTITY streetlight IS

PORT (D, resetn,clock: IN STD_LOGIC;

Q :OUT STD_LOGIC);

END flipflop;

ARCHITECTURE Behaviour of streetlight IS

BEGIN

PROCESS (Clock,resetn)

BEGIN

IF Clock 'EVENT AND CLOCK='1' THEN

IF resetn='0' THEN

Q<='0';

ELSE

Q<=D;

END IF;

END IF;

END PROCESS;

END BEHAVIOR;

I have done this and I have assigned pin to produce d output on an led on d de2 board.when i push d switch down d led comes on when i push it up d led goes off.but now I want to use an external ldr to generate analog input that will b converted into digital form whose output will turn on an external led.that is when it is dark d ldr will generate input signal that will turn on d led and when if is day d ldr will generate signal to turn off d led.

Pls put me through