# Copyright (C) 2005-2010 Aaron Bentley and Panometrics, Inc.
#                         Gianluca Montecchi <gian@grys.it>
#                         W. Trevor King <wking@drexel.edu>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""
Assorted utility functions that don't fit in anywhere else.
"""

import calendar
import codecs
import os
import shutil
import tempfile
import time
import types

import libbe
if libbe.TESTING == True:
    import doctest

class InvalidXML(ValueError):
    """
    Invalid XML while parsing for a *.from_xml() method.
    type    - string identifying *, e.g. "bug", "comment", ...
    element - ElementTree.Element instance which caused the error
    error   - string describing the error
    """
    def __init__(self, type, element, error):
        msg = 'Invalid %s xml: %s\n  %s\n' \
            % (type, error, ElementTree.tostring(element))
        ValueError.__init__(self, msg)
        self.type = type
        self.element = element
        self.error = error

def search_parent_directories(path, filename):
    """
    Find the file (or directory) named filename in path or in any
    of path's parents.

    e.g.
    search_parent_directories("/a/b/c", ".be")
    will return the path to the first existing file from
    /a/b/c/.be
    /a/b/.be
    /a/.be
    /.be
    or None if none of those files exist.
    """
    path = os.path.realpath(path)
    assert os.path.exists(path)
    old_path = None
    while True:
        check_path = os.path.join(path, filename)
        if os.path.exists(check_path):
            return check_path
        if path == old_path:
            return None
        old_path = path
        path = os.path.dirname(path)

class Dir (object):
    "A temporary directory for testing use"
    def __init__(self):
        self.path = tempfile.mkdtemp(prefix="BEtest")
        self.removed = False
    def cleanup(self):
        if self.removed == False:
            shutil.rmtree(self.path)
            self.removed = True
    def __call__(self):
        return self.path

RFC_2822_TIME_FMT = "%a, %d %b %Y %H:%M:%S +0000"


def time_to_str(time_val):
    """Convert a time value into an RFC 2822-formatted string.  This format
    lacks sub-second data.
    >>> time_to_str(0)
    'Thu, 01 Jan 1970 00:00:00 +0000'
    """
    return time.strftime(RFC_2822_TIME_FMT, time.gmtime(time_val))

def str_to_time(str_time):
    """Convert an RFC 2822-fomatted string into a time value.
    >>> str_to_time("Thu, 01 Jan 1970 00:00:00 +0000")
    0
    >>> q = time.time()
    >>> str_to_time(time_to_str(q)) == int(q)
    True
    >>> str_to_time("Thu, 01 Jan 1970 00:00:00 -1000")
    36000
    """
    timezone_str = str_time[-5:]
    if timezone_str != "+0000":
        str_time = str_time.replace(timezone_str, "+0000")
    time_val = calendar.timegm(time.strptime(str_time, RFC_2822_TIME_FMT))
    timesign = -int(timezone_str[0]+"1") # "+" -> time_val ahead of GMT
    timezone_tuple = time.strptime(timezone_str[1:], "%H%M")
    timezone = timezone_tuple.tm_hour*3600 + timezone_tuple.tm_min*60
    return time_val + timesign*timezone

def handy_time(time_val):
    return time.strftime("%a, %d %b %Y %H:%M", time.localtime(time_val))

def time_to_gmtime(str_time):
    """Convert an RFC 2822-fomatted string to a GMT string.
    >>> time_to_gmtime("Thu, 01 Jan 1970 00:00:00 -1000")
    'Thu, 01 Jan 1970 10:00:00 +0000'
    """
    time_val = str_to_time(str_time)
    return time_to_str(time_val)

def iterable_full_of_strings(value, alternative=None):
    """
    Require an iterable full of strings.
    >>> iterable_full_of_strings([])
    True
    >>> iterable_full_of_strings(["abc", "def", u"hij"])
    True
    >>> iterable_full_of_strings(["abc", None, u"hij"])
    False
    >>> iterable_full_of_strings(None, alternative=None)
    True
    """
    if value == alternative:
        return True
    elif not hasattr(value, "__iter__"):
        return False
    for x in value:
        if type(x) not in types.StringTypes:
            return False
    return True

def underlined(instring):
    """Produces a version of a string that is underlined with '='

    >>> underlined("Underlined String")
    'Underlined String\\n================='
    """

    return "%s\n%s" % (instring, "="*len(instring))

if libbe.TESTING == True:
    suite = doctest.DocTestSuite()