import contextlib
import sys
import termios
import tty

@contextlib.contextmanager
def raw():
    fd = sys.stdin.fileno()
    stash = termios.tcgetattr(fd)
    tty.setraw(fd)
    yield
    termios.tcsetattr(fd, termios.TCSANOW, stash)

def lineify(src):
    merged = ''
    for line in src:
        if line.startswith('\x1b[A'):
            merged += line
        else:
            if merged:
                yield merged
            merged = line
    yield merged.rstrip('\n') + '\n'

with raw():
    HEIGHT = 23
    with open(sys.argv[1], 'rb') as f:
        lines = [line.decode('cp437') for line in lineify(f)]
    top = 0
    while True:
        print('\n'*25)
        print(''.join(lines[top:top+HEIGHT]))
        print('{}-{} of {}'.format(top, top+HEIGHT, len(lines)))
        key = sys.stdin.read(1)
        if key == 'n':
            top += 1
        elif key == 'p':
            top -= 1
        elif key == ' ':
            top += HEIGHT
        elif key == 'q':
            break
        top = max(0, min(len(lines)-HEIGHT, top))