#!/usr/bin/env python2.6 -tt
# -*- coding: utf-8 -*-

from __future__ import print_function

__version__   = 'version 0.3'
__author__    = 'Marcin ``MySZ`` Sztolcman <marcin@urzenia.net>'
__copyright__ = '(r) 2009-2009'
__program__   = 'rdiff - show differences in local or remote files'
__date__      = '2009-02-21'
__license__   = 'GPL v.2'

__desc__      = '''%(desc)s
%(author)s %(copyright)s
license: %(license)s
%(version)s (%(date)s)''' % {
  'desc': __program__,
  'author': __author__,
  'copyright': __copyright__,
  'license': __license__,
  'version': __version__,
  'date': __date__
}

import contextlib
import netrc
import os, os.path
import sys
import urlparse
import urllib2
import warnings

usage = '''{0} [-i|--interactive] [-n|--normal] [-c|--context] [-h|--help] [-v|--version]
-i|--interactive    - use interactive mode if username or password is needed
-n|--normal         - normal diff instead of unified
-c|--context        - number of context lines
-v|--version        - show version info
-h|--help           - this help
'''.format (os.path.basename (sys.argv[0]))

def download_file (url):
    ## we just need some tmpname, and assume that it's used in secure environment (desktop or sth like this)
    with warnings.catch_warnings ():
        warnings.simplefilter ('ignore', Warning)
        tmpfile = os.tmpnam ()

    opener = urllib2.build_opener () #urllib2.OpenerDirector ()
    opener.addheaders = [
        ('User-Agent', 'rdiff/' + __version__.split (None, 1)[1] + ' http://useless-scripts.googlecode.com'),
    ]

    with contextlib.closing (opener.open (url)) as uh:
        with open (tmpfile, 'w') as fh:
            for line in uh:
                fh.write (line)

    return tmpfile

def url_auth_data (netloc, interactive):
    user = password = None
    if '@' in netloc:
        user, netloc = netloc.split ('@', 1)
        if ':' in user:
            user, password = user.split (':', 1)

    if not user or not password:
        try:
            _netrc = netrc.netrc (os.path.expanduser ('~/.netrc')).authenticators (netloc)
            if _netrc:
                if not user:
                    user = _netrc[0].strip ('"')
                if not password:
                    password = _netrc[2].strip ('"')
        except netrc.NetrcParseError as e:
            pass

    if (not user or not password) and interactive:
        import getpass
        if not user:
            user = raw_input ('Username for {0}: '.format (netloc))
        if not password:
            password = getpass.getpass ('Password for {0}: '.format (netloc))

    if user and password:
        netloc = '{0}:{1}@{2}'.format (user, password, netloc)

    return netloc

def normalize_url (url, interactive):
    anonymous = False
    url_data = list (urlparse.urlparse (url))
    if (url_data[0] == 'ftp' or url_data[0] == 'ftps') and not anonymous:
        url_data[1] = url_auth_data (url_data[1], interactive)

    elif url_data[0] == 'file' or not url_data[0]:
        if not url_data[0]:
            url_data[0] = 'file'
        url_data[2] = os.path.expanduser (url_data[2])
        if not os.path.isabs (url_data[2]):
            url_data[2] = os.path.join (os.getcwd (), url_data[2])

    return urlparse.urlunparse (url_data)

def main ():
    import getopt

    try:
        opts, args = getopt.gnu_getopt (sys.argv[1:], 'inc:hv', ('interactive', 'normal', 'context=', 'help', 'version', ))
    except getopt.GetoptError as e:
        print (e, file=sys.stderr)
        raise SystemExit (1)

    interactive     = False
    context         = 3
    unified         = True
    for o, a in opts:
        if o in ('-i', '--interactive'):
            interactive = True
        elif o in ('-n', '--normal'):
            unified = False
        elif o in ('-c', '--context'):
            context = int (a)
        elif o in ('-h', '--help'):
            print (usage)
            raise SystemExit (0)
        elif o in ('-v', '--version'):
            print (__version__)
            raise SystemExit (0)

    cmd = 'diff -s ' + ('-U' if unified else '-C') + str (context)
    while args:
        try:
            url1, url2 = args.pop (0), args.pop (0)
        except IndexError:
            if url1:
                print ('Need even number of arguments.', file=sys.stderr)
            break

        url1 = normalize_url (url1, interactive)
        url2 = normalize_url (url2, interactive)

        try:
            f1 = download_file (url1)
            f2 = download_file (url2)
        except Exception as e:
            print (e, file=sys.stderr)
            continue
        else:
            os.system ('{0} {1} {2}'.format (cmd, f1, f2))
            try:
                os.remove (f1)
                os.remove (f2)
            except:
                pass
            print ()

if __name__ == '__main__':
    main ()