#!/usr/bin/env python

"""Update the rcsparse library from ViewVC."""

import sys
import os
import subprocess
import re
import optparse


VIEWVC_REPOS = 'http://viewvc.tigris.org/svn/viewvc'
BRANCH = 'trunk'
RCSPARSE_URL = '/'.join([VIEWVC_REPOS, BRANCH, 'lib/vclib/ccvs/rcsparse'])
LICENSE_URL = '/'.join([VIEWVC_REPOS, BRANCH, 'LICENSE.html'])

DEST = os.path.dirname(__file__)

INIT_TEXT = """\
# This file causes Python to treat its containing directory it as a
# package.  Please note that the contents of this file differ from
# those of the __init__.py file distributed with ViewVC.

"""


def get_current_revision():
    revision_re = re.compile(r'^Revision\:\s*(?P<revision>\d+)$')

    cmd = ['svn', 'info', VIEWVC_REPOS]
    sys.stderr.write('%s\n' % (' '.join(cmd),))
    p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
    (out, err) = p.communicate()
    for line in out.splitlines():
        m = revision_re.match(line)
        if m:
            return int(m.group('revision'))

    sys.exit(
        'Could not determine the current revision of the ViewVC repository!'
        )

def export(url, revision, dest):
    cmd = ['svn', 'export', '-r', str(revision), '--force', url, dest]
    sys.stderr.write('%s\n' % (' '.join(cmd),))
    retcode = subprocess.call(cmd)

    if retcode:
        sys.exit('Export failed!')


def main(args):
    parser = optparse.OptionParser(
        description=__doc__,
        )

    parser.add_option(
        '--revision', '-r', metavar='REV',
        action='store', type='int', default=None,
        help='download the specific revision REV',
        )

    (options, args) = parser.parse_args(args)

    if args:
        parser.error('Unexpected arguments: %s' % (' '.join(args),))

    if options.revision is None:
        options.revision = get_current_revision()

    export(RCSPARSE_URL, options.revision, DEST)
    export(LICENSE_URL, options.revision, os.path.join(DEST, 'LICENSE.html'))

    # Record which version of the upstream source was downloaded:
    open(os.path.join(DEST, 'UPSTREAM_SOURCE'), 'w').write(
        '%s@%d\n' % (RCSPARSE_URL, options.revision,)
        )

    # Replace the upstream __init__.py file, which does some stuff that we
    # don't want:
    open(os.path.join(DEST, '__init__.py'), 'w').write(INIT_TEXT)


main(sys.argv[1:])