"""
Funcs.py

Funcs.py, a member of MiscUtils, holds functions that don't fit in anywhere else.
"""

import md5, os, random, string, time, sys, tempfile
True, False = 1==1, 1==0


def commas(number):
	""" Returns the given number as a string with commas to separate the thousands positions. The number can be a float, int, long or string. Returns None for None. """
	if number is None:
		return None
	if not number:
		return str(number)
	number = list(str(number))
	if '.' in number:
		i = number.index('.')
	else:
		i = len(number)
	while 1:
		i = i-3
		if i<=0 or number[i-1]=='-':
			break
		number[i:i] = [',']
	return string.join(number, '')


def charWrap(s, width, hanging=0):
	""" Returns a new version of the string word wrapped with the given width and hanging indent. The font is assumed to be monospaced.
	This can be useful for including text between <pre> </pre> tags since <pre> will not word wrap and for lengthly lines, will increase the width of a web page.
	It can also be used to help delineate the entries in log-style output by passing hanging=4.
	"""
	import string
	if not s:
		return s
	assert hanging<width
	hanging = ' ' * hanging
	lines = string.split(s, '\n')
	i = 0
	while i<len(lines):
		s = lines[i]
		while len(s)>width:
			t = s[width:]
			s = s[:width]
			lines[i] = s
			i = i + 1
			lines.insert(i, None)
			s = hanging + t
		else:
			lines[i] = s
		i = i + 1
	return string.join(lines, '\n')

# Python 2.3 contains mktemp and mkstemp, both of which accept a
# directory argument.  Earlier versions of Python only contained
# mktemp which didn't accept a directory argument.  So we have to
# implement our own versions here.
if sys.version_info >= (2, 3, None, None):
	# Just use the Python 2.3 built-in versions.
	from tempfile import mktemp, mkstemp
else:
	def mktemp(suffix="", dir=None):
		"""
		User-callable function to return a unique temporary file name.

		Duplicated from Python's own tempfile with the optional "dir"
		argument added. This allows customization of the directory, without
		having to take over the module level variable, tempdir.
		"""
		if not dir: dir = tempfile.gettempdir()
		pre = tempfile.gettempprefix()
		while 1:
			i = tempfile._counter.get_next()
			file = os.path.join(dir, pre + str(i) + suffix)
			if not os.path.exists(file):
				return file

	def mkstemp(suffix="", dir=None):
		"""
		User-callable function to return a tuple containing:
			- a os-level file handle for the temp file, open for read/write
			- the absolute path of that file

		Note that this version of the function is not as secure as the
		version included in Python 2.3.
		"""
		path = mktemp(suffix, dir)
		return os.open(path, os.O_RDWR|os.O_CREAT|os.O_EXCL, 0600), path

def wordWrap(s, width=78):
	"""
	Returns a version of the string word wrapped to the given width.
	Respects existing newlines in the string.

	Taken from:
	http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/148061
	"""
	return reduce(
		lambda line, word, width=width: "%s%s%s" % (
			line,
			' \n'[(len(line[line.rfind('\n')+1:]) + len(word) >= width)],
			word
		),
		s.split(' ')
	)


def dateForEmail(now=None):
	""" Returns a properly formatted date/time string for email messages """
	if now is None:
		now = time.localtime(time.time())
	if now[8]==1:
		offset = -time.altzone / 60
	else:
		offset = -time.timezone / 60
	if offset<0:
		plusminus = '-'
	else:
		plusminus = '+'
	return time.strftime('%a, %d %b %Y %H:%M:%S ', now) + plusminus + '%02d%02d' % (abs(offset/60), abs(offset%60))


def hostName():
	"""
	Returns the host name which is taken first from the os environment and failing that, from the 'hostname' executable. May return None if neither attempt succeeded.
	The environment keys checked are HOST and HOSTNAME both upper and lower case.
	"""
	for name in ['HOST', 'HOSTNAME', 'host', 'hostname']:
		hostName = os.environ.get(name, None)
		if hostName:
			break
	if not hostName:
		hostName = string.strip(os.popen('hostname').read())
	if not hostName:
		hostName = None
	else:
		hostName = string.lower(hostName)
	return hostName


_localIP = None

def localIP(remote=('www.yahoo.com', 80), useCache=1):
	"""
	Gets the "public" address of the local machine, i.e. that address
	which is connected to the general Internet.

	This function connects to a remote HTTP server the first time it is
	invoked (or every time it is invoked with useCache=0). If that is
	not acceptable, pass remote=None, but be warned that the result is
	less likely to be externally visible.

	Getting your local ip is actually quite complex. If this function
	is not serving your needs then you probably need to think deeply
	about what you really want and how your network is really set up.
	Search comp.lang.python for "local ip" for more information.
	http://groups.google.com/groups?q=%22local+ip%22+group:comp.lang.python.*
	"""
	global _localIP
	if useCache and _localIP:
		return _localIP
	import socket
	if remote:
		# code from Donn Cave on comp.lang.python

		# My notes:
		# Q: Why not use this?  socket.gethostbyname(socket.gethostname())
		# A: On some machines, it returns '127.0.0.1' - not what we had in mind.
		#
		# Q: Why not use this?  socket.gethostbyname_ex(socket.gethostname())[2]
		# A: Because some machines have more than one IP (think "VPN", etc.) and
		#    there is no easy way to tell which one is the externally visible IP.

		try:
			s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
			s.connect(remote)
			ip, port = s.getsockname()
			s.close()
			_localIP = ip
			return _localIP
		except socket.error:
			# oh, well. we'll use the local method
			pass

	addresses = socket.gethostbyname_ex(socket.gethostname())[2]
	for address in addresses:
		if address!='127.0.0.1':
			if useCache:
				_localIP = address
			return address
	if useCache:
		_localIP = addresses[0]
	return _localIP


def safeDescription(x, what='what'):
	"""
	Returns the repr() of x and its class (or type) for help in
	debugging. A major benefit here is that exceptions from
	repr() are consumed. This is important in places like
	"assert" where you don't want to lose the assertion
	exception in your attempt to get more information.

	Example use:
	assert isinstance(foo, Foo), safeDescription(foo)
	print "foo:", safeDescription(foo)  # won't raise exceptions

	# better output format:
	assert isinstance(foo, Foo), safeDescription(foo, 'foo')
	print safeDescription(foo, 'foo')
	"""
	try:
		xRepr = repr(x)
	except Exception, e:
		xRepr = _descExc('x', e)
	if hasattr(x, '__class__'):
		try:
			cRepr = repr(x.__class__)
		except Exception, e:
			cRepr = _descExc('x.__class__', e)
		return '%s=%s class=%s' % (what, xRepr, cRepr)
	else:
		try:
			cRepr = repr(type(x))
		except Exception, e:
			cRepr = _descExc('type(x)', e)
		return '%s=%s type=%s' % (what, xRepr, cRepr)

def _descExc(reprOfWhat, e):
	"""
	Returns a description of an exception. This is a private function
	for use by safeDescription().
	"""
	try:
		return '(exception from repr(%s): %s: %s)' % (reprOfWhat, e.__class__, e)
	except:
		return '(exception from repr(%s))' % reprOfWhat

def timestamp(numSecs=None):
	"""
	Returns a dictionary of timestamp versions.

	Returns different versions of the timestamp:
	
		'numSecs': the number of seconds
		'tuple': (year, month, day, hour, min, sec)
		'pretty': 'YYYY-MM-DD HH:MM:SS'
		'condensed': 'YYYYMMDDHHMMSS'
		'dashed': 'YYYY-MM-DD-HH-MM-SS'

	The focus is on the year, month, day, hour and second, with no additional information such as timezone or day of year. This form of timestamp is often ideal for print statements, logs and filenames.

	If the current number of seconds is not passed, then the current time is taken.

	The 'pretty' format is ideal for print statements, while the 'condensed' and 'dashed' formats are generally more appropriate for filenames.
	"""
	if numSecs is None:
		numSecs = time.time()
	tuple     = time.localtime(numSecs)[:6]
	pretty    = '%4i-%02i-%02i %02i:%02i:%02i' % tuple
	condensed = '%4i%02i%02i%02i%02i%02i' % tuple
	dashed    = '%4i-%02i-%02i-%02i-%02i-%02i' % tuple
	return locals()


def uniqueId(forObject=None):
	"""
	Generates an opaque, identifier string that is practically guaranteed to be unique.
	If an object is passed, then its id() is incorporated into the generation.
	Relies on md5 and returns a 32 character long string.
	"""
	r = [time.time(), random.random(), os.times()]
	if forObject is not None:
		r.append(id(forObject))
	md5object = md5.new(str(r))
	try:
		return md5object.hexdigest()
	except AttributeError:
		# Older versions of Python didn't have hexdigest, so we'll do it manually
		hexdigest = []
		for char in md5object.digest():
			hexdigest.append('%02x' % ord(char))
		return string.join(hexdigest, '')


def valueForString(s):
	"""
	For a given string, returns the most appropriate Pythonic value
	such as None, a long, an int, a list, etc. If none of those
	make sense, then returns the string as-is.

	"None", "True" and "False" are case-insensitive because there is
	already too much case sensitivity in computing, damn it!
	"""
	if not s:
		return s
	try:
		return int(s)
	except ValueError:
		pass
	try:
		return long(s)
	except ValueError:
		pass
	try:
		return float(s)
	except ValueError:
		pass
	t = s.lower()
	if t=='none':
		return None
	if t=='true':
		return True
	if t=='false':
		return False
	if s[0] in '[({"\'':
		return eval(s)
	return s


### Deprecated

def Commas(number):
	print 'DEPRECATED: MiscUtils.Funcs.Commas() on 02/23/01 in ver 0.5. Use commas() instead.'
	return commas(number)

def CharWrap(s, width, hanging=0):
	print 'DEPRECATED: MiscUtils.Funcs.CharWrap() on 02/23/01 in ver 0.5. Use charWrap() instead.'
	return charWrap(s, width, hanging)
