--Shane and Ben
--PC300/319 combined project
--Control unit for a parking lot management system

library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;

entity carlot is
port(carin,carout,clk,reset					:in std_logic;  --inputs from system
	full, gatein, gateout					:out std_logic;	--outputs to system
	count							:out std_logic_vector(6 downto 0));--7 segment display
end carlot;

architecture manager of carlot is

signal gatetempin,gatetempout			:std_logic;			--temporary variables to tell if gate is open
signal timein,timeout				:std_logic_vector(3 downto 0);	--timing variables
signal statechange,statechange2			:std_logic;						--changestates
signal state					:std_logic_vector(3 downto 0);	--current state in binary	




begin

controlgatein: gatetempin<= (timein(0) or timein(1) or timein(2) or timein(3));  --controls the in gate
controlgateout: gatetempout<=(timeout(0) or timeout(1) or timeout(2) or timeout(3));	--controls the out gate
statein: statechange<= not state(3) and carin and not gatetempin;				--controls state change in
stateout: statechange2<=carout and not gatetempout and (state(0) or state(1) or state(2) or state(3)); --controls state change out
controlcount0: count(0)<=not((state(0) and not state(1) and not state(2) and not state(3)) or (not state(0) and not state(1) and state(2) and not state(3)) or (state(0) and state(1) and state(2) and not state(3)));		--change the value of state to output to 7 segment display
controlcount1: count(1)<=not(not state(0) and state(1) and not state(2));
controlcount2: count(2)<=not ((state(0)) or (not state(0) and not state(1) and state(2) and not state(3)));
controlcount3: count(3)<=not((not state(0)and not state(1) and not state(2) and not state(3)) or (state(0) and not state(1) and not state(2) and not state(3)) or (state(0) and state(1) and state(2) and not state(3))); 
controlcount4: count(4)<=not((state(0) and not state(1) and state(2) and not state(3)) or (not state(0) and state(1) and state(2) and not state(3))); 
controlcount5: count(5)<= (not state(0) and not state(1) and not state(2)) or (not state(0) and not state(1) and state(2) and not state(3)) or (state(0) and not state(1) and state(2) and not state(3)) or (not state(0) and state(1) and state(2) and not state(3));
controlcount6: count(6)<=not((state(0) and not state(1) and not state(2) and not state(3)) or (not state(0) and not state(1) and state(2) and not state(3)));
controlfull: Full<=state(3);	--controls full lot light

	process(clk)
		begin
			if clk'Event and clk='1' then
				--if timer						--side program

				if reset='1' then 				--reset parking lot
					state<="0000";				
					gatein<='0';			--turn off gates program
					gateout<='0';
					timein<="0000";
					timeout<="0000";
				elsif statechange='1' then			--does not deal with two state changes at once
					state<=state+'1';				--this is the car in case
					gatein<='1';
					timein<="0001";
						if timeout >"0000" and timeout <"1000" then		--continue to count time out
							timeout<=timeout+'1';
							gateout<='1';
						else
							timeout<="0000";
							gateout<='0';
						end if;

				elsif statechange2='1' then				--car out case
					state<=state - '1';
					gateout<='1';
					timeout<= "0001";
						if timein>"0000" and timein <"1000" then	--continue to count time in
							timein<=timein + '1';
							gatein<='1';
						else
							timein<="0000";
							gatein<='0';
						end if;
						
					
				else												--if not state change
					if timein>"0000" and timein <"1000" then		--if timein is counting
							timein<=timein + '1';					--gate is open
							gatein<='1';
					else			
							timein<="0000";							--reset timein if not counting or count is done
							gatein<='0';
					end if;

					if timeout >"0000" and timeout <"1000" then			--same as above but with timeout
							timeout<=timeout+'1';
							gateout<='1';
						else
							timeout<="0000";
							gateout<='0';
					end if;
		
			
			end if;
		end if;
	end process;
end manager;						--end program.