# Daily Programmer #90
# ---------------------
# A nonstandard black-and-white image format defining the image as a series of
# commands to a "person" with a stamp who can move on a grid stamping black
# pixels.

def parse(text):
    """
    Make text ready for executing.

    Returns each "token" separated by a single space.
    """
    outputText = []
    valid_characters = ['p','n','s','w','e']
    lastCharWasDigit = False

    for char in text:
        char = char.lower()
        if char in valid_characters:
            outputText.append("%s " % char)
            lastCharWasDigit = False
        elif char.isspace():
            if lastCharWasDigit:
                outputText.append(" ")
            lastCharWasDigit = False
        elif char.isdigit():
            outputText.append("%s" % char)
            lastCharWasDigit = True
        else:
            raise ValueError("Invalid character: '%s'" % char)
    return "".join(outputText)

def execute(text):
    """
    Execute 'text'.
    Returns (pixels, width, height)
    """
    text = parse(text).split(' ')

    print("Tokenization:")
    print(text)

    # Obtain the width and height
    (w,h) = (0,0)
    try:
        w = int(text[0])
        h = int(text[1])
    except ValueError:
        raise ValueError("Expected width and height as first tokens in text.")

    grid = [0 for i in range(w*h)]
    currentIndex = 0
    directionToIndexChange = {'n':-h, 's':h, 'w':-1, 'e':1}

    for token in text[2:]:
        if token == 'p':
            grid[currentIndex] = 1
        elif token == '':
            # End!
            break
        else:
            currentIndex += directionToIndexChange[token]
            if currentIndex < 0 or currentIndex >= len(grid):
                print("Execution failed, out of bounds.")

    return (grid, w, h)

def grid_to_ascii(grid, width, height):
    text = []
    for row in range(height):
        for col in range(width):
            index = (row*height)+col
            if grid[index]:
                text.append('#')
            else:
                text.append(' ')
        text.append('\n')
    return "".join(text)

if __name__ == '__main__':
    import sys
    if len(sys.argv) <= 1:
        print("Arguments: file [file2 ... fileN] or <NO_FILE> <TEXT>")
        sys.exit(1)

    executeArgv = False
    if sys.argv[1] == "<NO_FILE>":
        executeArgv = True

    if executeArgv:
        text = " ".join(sys.argv[2:])
        result = execute(text)

        print("Output Data:")
        print(result)

        print("Rasterization:")
        print(grid_to_ascii(*result))
        sys.exit(0)

    for file in [open(filename) for filename in sys.argv[1:]]:
        text = file.read()
        file.close()
        result = execute(text)

        print("Output Data:")
        print(result)

        print("Rasterization:")
        print(grid_to_ascii(*result))