# Simple Snake Game in Python 3 for Beginners
# We love Python as much as you do =)
# LICENSE: GNU/GPL
# DATE: 28.07.2020 (18:41) => Tajikistan Time

"""
How to play?

Using (W, S, D, A) - keywords
    "W" -> UP
    "S" -> DOWN
    "D" -> RIGHT
    "A" -> LEFT

ToDo => [
    1 -> "Teleport snake",
    2 -> "Add arrow shortcuts",
    3 -> "Make an excellent 'Game Over' message",
    ...
]

Have an idea?
Open issue on https://github.com/icoder-new/cpython/issues

Found the bug?
Open issue or pull on https://github.com/icoder-new/cpython/issues
    or https://github.com/icoder-new/cpython/pulls!
    After it you can open another one on python original repo!

"""

__author__ = "Ehsonjon Gadoev <icoder.python.org@gmail.com>"
__credits__ = ["Guido van Rossum, for an excellent programming language.", "Gregor Lingl, for turtle module"]

import turtle
from time import sleep
from random import randint, choice


delay = 0.1

# Score
score = 0
high_score = 0

# Set up the screen
wn = turtle.Screen()
wn.title("Snake Game by Ehsonjon Gadoev")
wn.bgcolor("green")
wn.setup(width=610, height=610)
wn.tracer(0) # Turns off the screen updates

# Snake head
head = turtle.Turtle()
head.speed(0)
head.shape("square")
head.color("black")
head.penup()
head.goto(0,0)
head.direction = "stop" 

# Snake food
food = turtle.Turtle()
food.speed(0)
food.shape("circle")
food.color("red")
food.penup()
food.goto(0,100)

segments = []

# Pen
pen = turtle.Turtle()
pen.speed(0)
pen.shape("square")
pen.color("white")
pen.penup()
pen.hideturtle()
pen.goto(0, 260)
pen.write("Score: 0  High Score: 0", align="center", font=("Courier", 24, "normal"))

# Functions
def go_up():
    if head.direction != "down":
        head.direction = "up"

def go_down():
    if head.direction != "up":
        head.direction = "down"

def go_left():
    if head.direction != "right":
        head.direction = "left"

def go_right():
    if head.direction != "left":
        head.direction = "right"

def move():
    if head.direction == "up":
        y = head.ycor()
        head.sety(y + 20)

    if head.direction == "down":
        y = head.ycor()
        head.sety(y - 20)

    if head.direction == "left":
        x = head.xcor()
        head.setx(x - 20)

    if head.direction == "right":
        x = head.xcor()
        head.setx(x + 20)

# Keyboard bindings
wn.listen()
wn.onkeypress(go_up, "w")
wn.onkeypress(go_down, "s")
wn.onkeypress(go_left, "a")
wn.onkeypress(go_right, "d")

# Main game loop
while True:
    wn.update()

    # Check for a collision with the border
    if head.xcor() > 300 or head.xcor() < -300 or head.ycor() > 300 or head.ycor() < -300:
        sleep(1)
        head.goto(0,0)
        head.direction = "stop"

        # Hide the segments
        for segment in segments:
            segment.goto(1000, 1000)

        # Clear the segments list
        segments.clear()

        # Reset the score
        score = 0

        # Reset the delay
        delay = 0.1

        pen.clear()
        pen.write("Score: {}  High Score: {}".format(score, high_score), align="center", font=("Courier", 24, "normal")) 


    # Check for a collision with the food
    if head.distance(food) < 20:
        # Move the food to a random spot
        x = randint(-290, 290)
        y = randint(-290, 290)
        food.goto(x,y)

        # Add a segment
        new_segment = turtle.Turtle()
        new_segment.speed(0)
        new_segment.shape("square")
        new_segment.color("gold") # body of snake =) 
        new_segment.penup()
        segments.append(new_segment)

        # Shorten the delay
        delay -= 0.001

        # Increase the score
        score += 10

        if score > high_score:
            high_score = score

        pen.clear()
        pen.write("Score: {}  High Score: {}".format(score, high_score), align="center", font=("Courier", 24, "normal"))

    # Move the end segments first in reverse order
    for index in range(len(segments)-1, 0, -1):
        x = segments[index-1].xcor()
        y = segments[index-1].ycor()
        segments[index].goto(x, y)

    # Move segment 0 to where the head is
    if len(segments) > 0:
        x = head.xcor()
        y = head.ycor()
        segments[0].goto(x,y)

    move()

    # Check for head collision with the body segments
    for segment in segments:
        if segment.distance(head) < 20:
            sleep(1)
            head.goto(0,0)
            head.direction = "stop"

            # Hide the segments
            for segment in segments:
                segment.goto(1000, 1000)

            # Clear the segments list
            segments.clear()

            # Reset the score
            score = 0

            # Reset the delay
            delay = 0.1

            # Update the score display
            pen.clear()
            pen.write("Score: {}  High Score: {}".format(score, high_score), align="center", font=("Courier", 24, "normal"))

    sleep(delay)

wn.mainloop()