----------------------------------------------------------------------------------
-- Company: 
-- Engineer: 
-- 
-- Create Date: 30.11.2021 10:35:30
-- Design Name: 
-- Module Name: Gene_Snake - Behavioral
-- Project Name: 
-- Target Devices: 
-- Tool Versions: 
-- Description: 
-- 
-- Dependencies: 
-- 
-- Revision:
-- Revision 0.01 - File Created
-- Additional Comments:
-- 
----------------------------------------------------------------------------------
-- a faire:
--  - faire bouger le snake
--  - ajouter une clk

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating
-- any Xilinx leaf cells in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity Gene_Snake is
Port ( X : in unsigned (9 downto 0);
       Y : in unsigned (8 downto 0);
       up : in std_logic;
       down : in std_logic;
       left : in std_logic;
       right : in std_logic;
       reset: in std_logic;
       snakePresent : out std_logic);
end Gene_Snake;

architecture Behavioral of Gene_Snake is
type coord is array(0 to 39, 0 to 29) of unsigned(10 downto 0);
type direction is (haut, bas, gauche, droite);
type pos is record
    X: unsigned(9 downto 0);
    Y: unsigned(8 downto 0);
    dir: direction;
    isDefined: std_logic;
end record;
type listSnake is array(0 to 1200) of pos;

signal mat: coord;
signal snake: listSnake;
signal snakeHere: std_logic;
begin

process(X,Y,mat,reset, snake)
variable ref : unsigned(10 downto 0);
variable position : pos;
begin
    if(reset='0')
    then
--        snake <= (others=>(to_unsigned(1023,10),to_unsigned(511,10)));
        for i in 0 to snake'length-1 loop
            if(i<100)
            then
                snake(i).X <= to_unsigned(0,10);
                snake(i).Y <= to_unsigned(0,9);
                snake(i).isDefined <= '1';
            else
                snake(i).X <= to_unsigned(1023,10);
                snake(i).Y <= to_unsigned(511,9);
                snake(i).isDefined <= '0';
            end if;
        end loop;
        for x in 0 to 39 loop
            for y in 0 to 29 loop
                mat(x,y) <= to_unsigned(y*40+x,11);
            end loop;
        end loop;
    end if;
    ref := mat(to_integer(X/16),to_integer(Y/16));
    position := snake(to_integer(ref));
    if(position.isDefined = '0')
    then
        snakeHere <= '0';
    else
        snakeHere <= '1';
    end if;
end process;
snakePresent <= snakeHere;
end Behavioral;