# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.


"""I hold HTML generation helpers.
"""

from cgi import escape

from twisted.python import log
from twisted.python.compat import NativeStringIO as StringIO


def PRE(text):
    "Wrap <pre> tags around some text and HTML-escape it."
    return "<pre>"+escape(text)+"</pre>"

def UL(lst):
    io = StringIO()
    io.write("<ul>\n")
    for el in lst:
        io.write("<li> %s</li>\n" % el)
    io.write("</ul>")
    return io.getvalue()

def linkList(lst):
    io = StringIO()
    io.write("<ul>\n")
    for hr, el in lst:
        io.write('<li> <a href="%s">%s</a></li>\n' % (hr, el))
    io.write("</ul>")
    return io.getvalue()

def output(func, *args, **kw):
    """output(func, *args, **kw) -> html string
    Either return the result of a function (which presumably returns an
    HTML-legal string) or a sparse HTMLized error message and a message
    in the server log.
    """
    try:
        return func(*args, **kw)
    except:
        log.msg("Error calling %r:" % (func,))
        log.err()
        return PRE("An error occurred.")