library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;

entity elevator is
	port(up1,up2,up3,up4:in std_logic;--上樓信號
		down2,down3,down4,down5:in std_logic;--下樓信號
		b1,b2,b3,b4,b5:in std_logic;--電梯內目的樓層信號
		opendoor,closedoor:in std_logic;--電梯內開關門信號
		clk:in std_logic;--時鐘信號
		mode:out std_logic_vector(1 downto 0);--模式
		floor:out std_logic_vector(4 downto 0);--所在樓層
		up,down:out std_logic;--給電機的上升或下降信號
		door:out std_logic;--給電機的開或關門信號
		q:out std_logic);--發音信號
end elevator;

architecture behave of elevator is
	type state_type is(upward,downward,dullA,dullB);--dullA是由上升模式而來，dullB由下降模式而來
	signal WLA,WLB:std_logic_vector(5 downto 1);--WLA,WLB是正在執行的工作表
	variable state:state_type;
	variable countA,countB:integer:=0;
	signal ceng:std_logic_vector(5 downto 1);
	variable x,y:std_logic;
	begin
		
			    WLA(1)<='1' when up1='1' ;
				
				WLA(2)<='1' when up2='1';
				
				WLA(3)<='1' when up3='1';
				
				WLA(4)<='1' when up4='1';
				
				WLB(5)<='1' when down5='1';
				
				WLB(4)<='1' when down4='1';
				
				WLB(3)<='1' when down3='1';
				
				WLB(2)<='1' when down2='1';
				
				
				if b1='1' then
					if ceng>"00001" then WLA(1)<='1';
					else WLB(1)<='1';
					end if;
				end if;
				if b2='1' then 
					if ceng>"00010" then WLA(2)<='1';
					else WLB(2)<='1';
					end if;
				end if;
				if b3='1' then 
					if ceng>"00100" then WLA(3)<='1';
					else WLB(3)<='1';
					end if;
				end if;
				if b4='1' then 
					if ceng>"01000" then WLA(4)<='1';
					else WLB(4)<='1';
					end if;
				end if;
				if b5='1' then 
					if ceng>"10000" then WLA(5)<='1';
					else WLB(5)<='1';
					end if;
				end if;	
	process(clk)
			begin			
			if clk'event and clk='1' then
				case state is
					when upward=>
						if ((WLA and ceng)=ceng or WLA="00000") then--判斷是否要在當前層停
							state:=dullA;
							else state:=upward;
						end if
						if y='1' then
							if ceng>0 then--底層有無上樓請求
								down<='1';
								if countA<2E6 then countA:=countA+1;
									else countA:=0;ceng<=ceng-1;
								end if;
								else down<='0';
								y:='0';		
							end if;
							else	
							mode<="01";--顯示上升模式
							up<='1';
							floor<=ceng;
							if countA<2E6 then --每1秒樓層數加一
								countA:=countA+1;
								else ceng<=ceng+1;
								countA:=0;
							end if;
						end if;
						
						
					
					when downward =>
						if (WLB and ceng)=ceng or WLB="00000" then
							state:=dullB;
						else state:=downward;
						end if
						if x='1' then 
							if WLA>(ceng+ceng) then--高層有無下樓請求
								up<='1';
								if countA<2E6 then countA:=countA+1;
									else countA:=0;ceng<=ceng+1;
								end if;
							else up<='0';--高層無請求，直接轉到下降模式
									x:='0';
							end if;
						else
							mode <="10";--顯示下降模式
							down<='1';
							if countA<2E6 then 
								countA:=countA+1;
							else ceng<=ceng-1;
								countA:=0;
							end if;
						end if;
						floor<=ceng;
						
				
					when dullA =>--由上升模式到停 
						if (WLA and ceng)=ceng then
							mode <="00";
							up<='0';
							down<='0';
							door<='1';
								
							if countB<8E6 then--開門時間為四秒
								countB:=countB+1;
							else door<='0';
								countB:=0;
							end if;
							if closedoor='1' then
								door<='0';
							end if;
							if opendoor='1' then
								door<='1';
								countB:=0;
							end if;
						else
							WLA<=WLA and (not ceng);--清除當前層的記錄
							if WLA>=(ceng+ceng) then state:=upward;--高層有無上樓請求
							else state:=downward;x:='1';
							end if;	
						end if;	
								
					
					when dullB => --由下降模式到停
						if(WLB and ceng)=ceng then
							mode <="00";
							up<='0';
							down<='0';
							door<='1';	
							if countB<8E6 then
								countB:=countA+1;
							else door<='0';
								countB:=0;
							end if;
							if closedoor='1' then
								door<='0';
							end if;
							if opendoor='1' then
								door<='1';
								countB:=0;
							end if;
						else
							WLB<=WLB and (not ceng);
							if ceng>0 then state:=downward;--底層有無下樓請求
							else state:=upward;y:='1';
							end if;
						end if;
					
			end case;
		end if;
	end process;
end behave;