import os, argparse

def solve_task(lines):
    c = CRT()
    signal_strengths = []
    print(c)
    
    for line in lines:
        signal_strengths.extend(c.parse_instruction(line))
    
    total = sum(signal_strengths)
    
    print(signal_strengths)
    print(f"Total signal strength: {total}")
    print(c)

class CRT:
    def __init__(self):
        self.x = 1
        self.cycle = 0
        self.screen = [['.' for x in range(40)] for y in range(6)]
    
    def parse_instruction(self, instruction):
        states_to_return = []
        tokens = instruction.split()
        if tokens[0] == "noop":
            states_to_return.extend(self.tick())
        else:
            xdiff = int(tokens[1])
            states_to_return.extend(self.tick())
            states_to_return.extend(self.tick())
            self.x += xdiff

        return  states_to_return

    def tick(self):
        to_return = []
        self.update_screen()
        self.cycle += 1
        if (self.cycle+20) % 40 == 0:
            to_return = [self.cycle*self.x]
        return to_return
    
    def update_screen(self):
        y = self.cycle // 40
        x = self.cycle % 40
        hit = abs(x-self.x) <= 1
        self.screen[y][x] = '#' if hit else '.'

    def __str__(self):
        to_return = str()
        for line in self.screen:
            to_return += ''.join(line) + "\n"
        return to_return

def read_lines(filename):
    lines = []
    with open(filename) as infile:
        for raw_line in infile:
            line = raw_line.rstrip()
            lines.append(line)
    return lines

def parse_arguments():
    parser = argparse.ArgumentParser(description="Script that solves the case",epilog="Have a nice day!")
    parser.add_argument('filename', nargs='?', default="example.txt", help='Input file')
    args = parser.parse_args()
    return args

def main():
    args = parse_arguments()
    lines = read_lines(args.filename)
    solve_task(lines)

if __name__ == "__main__":
    main()