snake.py

# adapted from https://gist.github.com/sanchitgangwar/2158084
from random import randint
from time import sleep
import sys, vim
from threading import Thread, Lock
sys.excepthook = lambda *args: sys.stderr.write('error %s, %s, %s\n' % args) and sys.stderr.flush()


buf = vim.current.buffer

key = 'right'
prevKey = 'right'
score = 0
snake = [[4,10], [4,9], [4,8]]                                     # Initial snake co-ordinates
food = [10,20]                                                     # First food co-ordinates
lock = Lock()
     
def run_game():
    global key, prevKey, score, snake, food

    timeout = None
     
    addstr(food[0], food[1], '*')                                      # Prints the food
    while key != 'esc':
        lock.acquire() 
	if key == 'space':                                             # If SPACE BAR is pressed, wait for another
	    key = None
	    while key != 'space':
                lock.release() 
		sleep(timeout)
                lock.acquire() 
	    key = prevKey
            lock.release() 
	    continue
     
	# Calculates the new coordinates of the head of the snake. NOTE: len(snake) increases.
	# This is taken care of later at [1].
	snake.insert(0, [snake[0][0] + (key == 'down' and 1) + (key == 'up' and -1), snake[0][1] + (key == 'left' and -1) + (key == 'right' and 1)])
     
	# If snake crosses the boundaries, make it enter from the other side
	if snake[0][0] == 0: snake[0][0] = 18
	if snake[0][1] == 0: snake[0][1] = 58
	if snake[0][0] == 19: snake[0][0] = 1
	if snake[0][1] == 59: snake[0][1] = 1
     
	# Exit if snake crosses the boundaries (Uncomment to enable)
	#if snake[0][0] == 0 or snake[0][0] == 19 or snake[0][1] == 0 or snake[0][1] == 59: break
     
        l = len(snake)
	# If snake runs over itself
        trail = snake[1:]
	if snake[0] in trail:
            lock.release()
            break

	timeout = 0.001 * (150 - (l / 5 + l /10) % 120)   # Increases the speed of Snake as its length increases
        prevKey = key                                                  # Previous key pressed
        vim.trigger('update-screen')
        lock.release()
	sleep(timeout)

    lock.acquire()
    vim.trigger('end-game')
    lock.release()



def addstr(lnum, cnum, string):
    line = buf[lnum]
    line = line[0:cnum] + string + line[cnum + len(string):]
    buf[lnum] = line


def update():
    global key, prevKey, score, snake, food
    lock.acquire()
    if snake[0] == food:                                            # When snake eats the food
        food = []
        score += 1
        while food == []:
            food = [randint(1, 18), randint(1, 58)]                 # Calculating next food's coordinates
            if food in snake: food = []
        addstr(food[0], food[1], '*')
    else:    
        last = snake.pop()                                          # [1] If it does not eat the food, length decreases
        addstr(last[0], last[1], ' ')
    addstr(snake[0][0], snake[0][1], '#')
    addstr(0, 2, 'Score : ' + str(score) + ' ')                    # Printing 'Score' and
    addstr(0, 27, ' SNAKE / MOVEMENTs(hjkl) EXIT(i) PAUSE(space) ')
    lock.release()


def end():
    lock.acquire()
    buf[:] = None
    buf.append("Score - " + str(score))
    buf.append("http://bitemelater.in")
    lock.release()


def keypress(k):
    global key
    lock.acquire()
    key = k
    lock.release()


def start():
    game = Thread(target=run_game)
    game.daemon = True
    game.start()