snake/snake.py

import curses
import random
import time

def main(stdscr, start_length, speed):
    # Setup curses
    curses.curs_set(0) # Hide cursor
    stdscr.nodelay(1)  # Non-blocking getch

    w = 100
    if speed == 1: w = 250
    if speed == 2: w = 225
    if speed == 3: w = 200
    if speed == 4: w = 175
    if speed == 5: w = 150
    if speed == 6: w = 125
    if speed == 7: w = 100
    if speed == 8: w = 75
    if speed == 9: w = 50
    if speed == 10: w = 25

    stdscr.timeout(w) # Wait 100ms for input
    # if speed = 50 then timeout = 100
    # if speed = 100 then timeout = 50
    # if speed = 0 then timeout = 1000

    # Snake and food characters
    head_char = '█'
    #head_char = '■'
    #head_char = '0'
    #head_char_up = '▄'
    #head_char_down = '▀'
    head_char_up = head_char_down = head_char
    body_char = '▓'
    #body_char = 'Φ'
    #body_char = '■'
    #body_char = 'O'
    #body_char = '░'
    #body_char = '■'
    #food_char = '💗'
    food_char = '█'
    #food_char = '▓'
    #food_char = '▒'

    # Setup colors
    curses.start_color()
    curses.init_pair(1, curses.COLOR_GREEN, curses.COLOR_BLACK) # Snake
    curses.init_pair(2, curses.COLOR_RED, curses.COLOR_BLACK)   # Food
    curses.init_pair(3, curses.COLOR_WHITE, curses.COLOR_BLACK) # Score/Text
    stdscr.bkgd(' ', curses.color_pair(3))

    # Game constants
    h, w = stdscr.getmaxyx()
    # Ensure window is large enough
    if h < 10 or w < 20:
        stdscr.addstr(0, 0, "Terminal window too small!")
        stdscr.refresh()
        time.sleep(2)
        return

    # Initial snake: list of [y, x]
    # Check if snake fits horizontally
    if start_length > w - 2:
        stdscr.addstr(h // 2, (w - len(f"Length {start_length} too long for width {w}!")) // 2, f"Length {start_length} too long for width {w}!", curses.color_pair(3))
        stdscr.refresh()
        time.sleep(2)
        return

    # Start the head at x=start_length so the tail ends at x=1
    snake = [[h // 2, start_length - i] for i in range(start_length)]

    # Initial food
    def get_new_food():
        while True:
            nf = [random.randint(1, h - 2), random.randint(1, w - 2)]
            if nf not in snake:
                return nf
    
    food = get_new_food()
    
    # Initial direction
    key = curses.KEY_RIGHT
    score = start_len

    hc = head_char

    while True:

        next_key = stdscr.getch()
        # If no key is pressed, next_key is -1
        # Update direction if it's a valid arrow key and not opposite to current
        if next_key != -1:
            if next_key == curses.KEY_DOWN and key != curses.KEY_UP:
                key = next_key
                hc = head_char_down
            elif next_key == curses.KEY_UP and key != curses.KEY_DOWN:
                key = next_key
                hc = head_char_up
            elif next_key == curses.KEY_LEFT and key != curses.KEY_RIGHT:
                key = next_key
                hc = head_char
            elif next_key == curses.KEY_RIGHT and key != curses.KEY_LEFT:
                key = next_key
                hc = head_char
            elif next_key == ord('q'): # Allow quit
                break

        # Calculate new head
        head = snake[0]
        if key == curses.KEY_DOWN:
            new_head = [head[0] + 1, head[1]]
        elif key == curses.KEY_UP:
            new_head = [head[0] - 1, head[1]]
        elif key == curses.KEY_LEFT:
            new_head = [head[0], head[1] - 1]
        elif key == curses.KEY_RIGHT:
            new_head = [head[0], head[1] + 1]
        else:
            # Should not happen
            new_head = head

        # Check collisions
        if (new_head[0] in [0, h - 1] or 
            new_head[1] in [0, w - 1] or 
            new_head in snake):
            key = stdscr.getch()
            break

        snake.insert(0, new_head)

        # Check if snake ate food
        if snake[0] == food:
            score += 1
            food = get_new_food()
        else:
            snake.pop() # Remove tail

        # Draw everything
        stdscr.clear()
        stdscr.attron(curses.color_pair(3))
        stdscr.border(0)
        stdscr.attroff(curses.color_pair(3))
        
        # Draw snake
        for i, (y, x) in enumerate(snake):
            char = hc if i == 0 else body_char
            stdscr.addch(y, x, char, curses.color_pair(1))
            
        # Draw food
        stdscr.addch(food[0], food[1], food_char, curses.color_pair(2))
        
        # Draw score
        stdscr.addstr(0, 2, f' Length: {score} @ {speed}MPH ({w}x{h}) ', curses.color_pair(3))
        
        stdscr.refresh()

    # Game Over screen
    #stdscr.clear()
    msg = f"GAME OVER! SCORE: {score}"
    stdscr.addstr(h // 2, (w - len(msg)) // 2, msg, curses.color_pair(3))
    stdscr.addstr(h // 2 + 1, (w - 18) // 2, "Press Q to exit", curses.color_pair(3))
    stdscr.nodelay(0)
    key = stdscr.getch()
    while key != ord('q'):
        key = stdscr.getch()
    exit('bye')

if __name__ == "__main__":
    try:
        start_len = input("Enter starting snake length (default 3): ")
        start_len = int(start_len) if start_len.strip() else 3
        if start_len < 1:
            start_len = 3
    except ValueError:
        start_len = 3

    try:
        speed = input("Enter snake speed (1 to 10, default 7): ")
        speed = int(speed) if speed.strip() else 7
        if speed > 10: speed = 10
        if speed < 1: speed = 1
    except ValueError:
        speed = 7
        
    curses.wrapper(main, start_len, speed)