import PikaStdLib
import machine 

# hardware init
lcd = machine.LCD()
lcd.init()
lcd.clear('white')
key = machine.KEY()
key.init()
time = machine.Time()
x_max = 120
y_max = 150

# snake init
s = machine.Point()
w = 9
h = 9
s.x = 50
s.y = 10
len = 0
while len < 3:
    b = s
    i = 0
    while i < len:
        b = b.next
        i = i + 1
    b.next = machine.Point()
    b.next.x = b.x - 10
    b.next.y = b.y
    b.next.prev = b
    len = len + 1
# ring link
b.next = s
s.prev = b

i = 0
b = s
while i < len:
    lcd.fill(b.x, b.y, w, h, 'blue')
    b = b.next
    i = i + 1

print('snake lengh')
print(len)

# fruit init
f = machine.Point()
f.x = 30
f.y = 20
lcd.fill(f.x, f.y, w, h, 'green')

# memory check
mem = PikaStdLib.MemChecker()
print('mem used max:')
mem.max()

# main loop
d = 0
isUpdate = 1
isEat = 0
while True:
    time.sleep_ms(50)
    if isUpdate:
        # isUpdate = 0
        # check eat fruit
        if f.x == s.x and f.y == s.y:
            # have eat fruit
            isEat = 1
            f.x = f.x + 30
            if f.x > x_max:
                f.x = f.x - x_max
            f.y = f.y + 30
            if f.y > y_max:
                f.y = f.y - y_max
            lcd.fill(f.x, f.y, w, h, 'green')
        # move snake by the direction
        if d == 0:
            x_new = s.x + 10
            y_new = s.y
            if x_new > x_max:
                x_new = 0
        elif d == 1:
            x_new = s.x
            y_new = s.y - 10
            if y_new < 0:
                y_new = y_max
        elif d == 2:
            x_new = s.x
            y_new = s.y + 10
            if y_new > y_max:
                y_new = 0
        elif d == 3:
            x_new = s.x - 10
            y_new = s.y
            if x_new < 0:
                x_new = x_max
        if isEat:
            isEat = 0
            b_new = machine.Point()
            b_new.x = x_new
            b_new.y = y_new
            b_new.prev = s.prev
            b_new.next = s
            s.prev.next = b_new
            s.prev = b_new
            s = b_new
            len = len + 1
            print('snake lengh')
            print(len)
            print('mem used max:')
            mem.max()
        # drow the snake and fruit
        # clear last body
        lcd.fill(s.prev.x, s.prev.y, w, h, 'white')
        # new body
        s.prev.x = x_new
        s.prev.y = y_new
        # head is last body
        s = s.prev
        lcd.fill(s.x, s.y, w, h, 'blue')
        b = s
        i = 0
    # scan key
    key_val = key.get()
    if key_val == 0:
        d = 0
        isUpdate = 1
    elif key_val == 1:
        d = 1
        isUpdate = 1
    elif key_val == 2:
        d = 2
        isUpdate = 1
    elif key_val == 3:
        d = 3
        isUpdate = 1