#!/usr/bin/python

import pygame
import sys, time
from array import array

PNG = False  # save frames as PNG?
FONT = "/usr/share/fonts/TTF/Courier Prime.ttf" # font path

# power of 2 CARDIAC program
cards = """002
800
005
009
010
100
011
880
012
604
013
105
014
700
015
321
016
605
017
104
018
890
019
880
020
812
021
900
080
686
081
199
082
685
083
586
084
186
090
696
091
199
092
695
093
196
094
296
002
810"""

cards = cards.splitlines()
M = array('i', [0] * 100)   # create memory array
M[0] = 1    # start program by reading the first card
A = 0       # accumulator
PC = 0      # program counter
RES = 700, 500  # window size

INST = "INP", "CLA", "ADD", "TAC", "SFT", "OUT", "STO", "SUB", "JMP", "HRS"

pygame.init()
screen = pygame.display.set_mode(RES)
pygame.display.set_caption('PyCardiac')
font = pygame.font.Font(FONT, 20)
font2 = pygame.font.Font(FONT, 26)
output = ["Output:"]
step = 0

def getop(x):
    "Get opcode"
    if x == 0: quit()
    op = x // 100
    arg = x % 100
    return op, arg

def c(n, x):
    "Clip value x to n digits (also works correctly for negative numbers)"
    if x < 0: s = -1
    else:     s =  1
    return s * (abs(x) % (10**n))

def quit():
    "An error occurred; exit and dump memory"
    for n in range(100):
        print("M", n, M[n])
    sys.exit()

while True:
    step += 1
    op, arg = getop(M[PC])

    screen.fill((0, 0, 0))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
    for y in range(25):
        for x in range(4):
            i = 25 * x + y
            if i == PC: co = 255, 255, 0
            else:       co = 0, 255, 0
            t = "%02u: %+04i" % (i, M[i])
            tr = font.render(t.replace("+", " "), True, co)
            screen.blit(tr, (140*x, 16*y))

    t = "PC: %02u AC: %+05i INST: %s %02u STEP: %5u" % (PC, A, INST[op], arg, step)
    tr = font2.render(t.replace("+", " "), True, (255, 0, 0))
    screen.blit(tr, (0, 450))

    for n, o in enumerate(output):
        tr = font2.render(o.replace("+", " "), True, (255, 255, 255))
        screen.blit(tr, (550, n*40))

    if PNG:
        pygame.image.save(screen, "c%05u.png" % step)
        if op == 9: # HALT
            for i in range(step + 1, step + 9):
                pygame.image.save(screen, "c%05u.png" % i)

    pygame.display.flip()
    PC += 1

    if op == 0:
        x = int(cards.pop(0))
        M[arg] = x
    if op == 1:
        A = M[arg]
    if op == 2:
        A += M[arg]
        A = c(4, A)
    if op == 3:
        if A < 0:
            PC = arg
    if op == 4:
        if A < 0: s = -1
        else:     s =  1
        left, right = arg // 10, arg % 10
        A = abs(A)  # strip sign so it works for negative numbers too
        A *= (10**left) % 10000
        A /= (10**right)
        A = s * int(A) # restore sign
        A = c(4, A)
    if op == 5:
        print(M[arg])
        output.append("%+04i" % M[arg])
    if op == 6:
        M[arg] = c(3, A)
    if op == 7:
        A -= M[arg]
        A = c(4, A)
    if op == 8:
        M[99] = 800 + PC    # save program counter
        PC = arg
    if op == 9:
        PC = arg
        # wait for the user to close the program window when halting
        while True:
            time.sleep(.1)
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    sys.exit()
    time.sleep(.2)

# use this command-line to create the animated GIF with ImageMagick:
# convert -delay 20 c0*.png -loop 0 cardiac_pow2.gif