snake.py

class Snake(object):
    """ Snake """
    def __init__(self ,board, position=(0, 0),
                 slength=1, sdirection='6'):
        # board
        self.board = board
        # board limit
        self.board_limit = board.size
        # start position
        self.positions = [ position ]
        # start direction is right by default
        self.direction = sdirection
        # start length snake
        self.start_length = slength
        # length snake
        self.length = 0
        # score snake
        self.score = 0
        # snake died
        self.died = False
        # Allowed Directions
        #       8:UP
        #4:LEFT       6:RIGHT
        #      2:DOWN
        self.directions = "2468"

    # eat food by snake
    def check_food(self, food):
        # collision detection food and snake
        if food.position == self.positions[0]:
            # find new random loaction for food
            # add length snake
            food.randomize()
            self.add_length()
            # add score
            self.score += 1
            # if food eated return true
            return True

    # add length snake
    def add_length(self):
        # add snake body
        # add a new length at last tail
        new_position = self.positions[self.length]
        self.positions.append(new_position)
        self.length += 1

    # draw snake in board
    def draw(self, is_draw):
        # check direction is allow
        if self.direction in self.directions:
            #show and hide by is_draw
            self.board.draw(self.positions, is_draw)

    # move snake in board
    def move(self):
        # possible_direciton
        pos_dir = self.possible_direcitons()
        self.directions = pos_dir if pos_dir else self.directions
        # check direction is allow
        if self.direction in self.directions:
            # increase length each move and decrease start length
            if self.start_length > 0:
                self.start_length -= 1
                self.add_length()
            # next position
            new_position = self.next_position(self.positions[0], self.direction)
            # - limit movement inside board(game) false is limited movement
            limit_check = self.point_in_rectangle(new_position, self.board_limit)
            # collision detection body snake with head snake or board:
            # - self.positions : old locations of snake
            # - moved_position : new location head snake at now
            # if moved_position not in self.positions
            if new_position not in self.positions and limit_check:
                # add new location of head to shited locations
                self.positions.insert(0, new_position)
                # delete last tail for shift all locations
                # and new location will be added after checks
                self.positions.pop()
            else:
                # just a log ...
                print("\033[31mGAME OVER \033[m")
                self.died = True


    def next_position(self, position, direction):
        # next directions
        y,x = position
        if  (direction == '8'): y -= 1 # move up
        elif(direction == '2'): y += 1 # move down
        elif(direction == '4'): x -= 1 # move left
        elif(direction == '6'): x += 1 # move right
        return (y,x)

    # you cant move reverse inside youself( limit movement )
    def possible_direcitons(self):
        # prevent snake colliding with second body
        ch = self.direction
        if ch in "46":
            return ch + "82"
        elif ch in "82":
            return ch + "46"
        else:
            return ""

   # point_in_rectangle
    def point_in_rectangle(self, pos, rectangle):
        if  rectangle[0][0] <= pos[0] and \
            rectangle[0][1] <= pos[1] and \
            rectangle[1][0] >  pos[0] and \
            rectangle[1][1] >  pos[1] :
            return True
        else:
            return False