#!/usr/bin/env python
import sys
import string

def h2i(rgbOctet):
    """
        Return the Base 10 value for a hex (base 0) octet
    """
    return (int('0x%s' % ( rgbOctet ), 0))

def validate_hex_string( hexString ):
    """
        Loop through a hex string and validate that each character
            in the string is a valid hex character.
    """
    # Set default return status to True
    status = True
    # If the hexString is 4 or 7 characters long, strip off
    # the leading character, as it is going to be a '#'
    if hexString[0] == '#':
        if len( hexString ) in ( 4, 7 ):
            hexString = hexString[1:]
    # If the hexString is not 6 characters long
    if len( hexString ) not in ( 3, 6 ):
        # Print error to stderr
        print >> sys.stderr, 'Error: \n\tArguement should be 6 hexidecimal characters, and may contain a leading # symbol.\n\tAnything else is considered invalid.\n\tExiting.'
        # Exit with non-zero status code
        sys.exit(1)
    # If the length is 3, add padding
    if len( hexString ) == 3:
        hexString = '%s%s%s%s%s%s' % ( hexString[0], hexString[0], hexString[1], hexString[1], hexString[2], hexString[2] )
    # Loop through the string and validate character-by-character
    # Set return value to false if invalid character(s) detected
    for i in hexString:
        # If character is not in string.hexdigits ( a list of valid hex characters )
        if i not in string.hexdigits:
            # Print which character and its placement to stderr
            print >> sys.stderr, 'Error: \n\tCharacter %d (%c) not a valid hex character.' % ( sys.argv[1].index(i), i )
            # Set return status to false
            status = False
    # If status is still true, return hexString
    if status:
        return hexString
    # If status is false, return False
    else:
        return status

# If the validation returns non-False, run the conversion
if validate_hex_string( sys.argv[1] ):
    # Set a to the return status of validator
    a = validate_hex_string( sys.argv[1] )
    # Break up each color's octet
    red     = a[:2]
    green   = a[2:4]
    blue    = a[4:6]
    # Print the original value
    print "Hex value: %s" % ( a )
    # Print the converted value
    print "RGB Value: rgb( %d, %d, %d )" % ( h2i(red), h2i(green), h2i(blue) )
# If errors are detected during validation, Exit
else:
    sys.exit('\nExiting due to invalid H\exidecimal characters being detected.')