from __future__ import unicode_literals
import six


def csv_format(data):
    """
    Encapsulate any data which contains a comma within double quotes.
    """
    csv = []
    for value in data:

        # Represent None or False with empty string
        if value in [None, False]:
            csv.append('')
            continue

        # Force conversion to string first so we can check for any commas
        if not isinstance(value, six.string_types):
            value = '{}'.format(value)

        # Double-quote the value if it contains a comma
        if ',' in value:
            csv.append('"{}"'.format(value))
        else:
            csv.append('{}'.format(value))

    return ','.join(csv)


def foreground_color(bg_color):
    """
    Return the ideal foreground color (black or white) for a given background color in hexadecimal RGB format.
    """
    bg_color = bg_color.strip('#')
    r, g, b = [int(bg_color[c:c + 2], 16) for c in (0, 2, 4)]
    if r * 0.299 + g * 0.587 + b * 0.114 > 186:
        return '000000'
    else:
        return 'ffffff'