# Copyright (C) 2005, 2006, 2008 by Intevation GmbH

# Author(s):

# Thomas Arendsen Hein <thomas@intevation.de>

#

# This program is free software under the GNU GPL (>=v2)

# Read the file COPYING coming with the software for details.

"""

Mercurial version

"""

import os

import re

import time

unknown_version = 'unknown'

remembered_version = False

def get_version(doreload=False):

    """Return version information if available."""

    try:

        import mercurial.__version__

        if doreload:

            reload(mercurial.__version__)

        version = mercurial.__version__.version

    except ImportError:

        version = unknown_version

    return version

def write_version(version):

    """Overwrite version file."""

    if version == get_version():

        return

    directory = os.path.dirname(__file__)

    for suffix in ['py', 'pyc', 'pyo']:

        try:

            os.unlink(os.path.join(directory, '__version__.%s' % suffix))

        except OSError:

            pass

    f = open(os.path.join(directory, '__version__.py'), 'w')

    f.write("# This file is auto-generated.\n")

    f.write("version = %r\n" % version)

    f.close()

    # reload the file we've just written

    get_version(True)

def remember_version(version=None):

    """Store version information."""

    global remembered_version

    if not version and os.path.isdir(".hg"):

        f = os.popen("hg identify")  # use real hg installation

        ident = f.read()[:-1]

        if not f.close() and ident:

            ids = ident.split(' ', 1)

            version = ids.pop(0)

            if version[-1] == '+':

                version = version[:-1]

                modified = True

            else:

                modified = False

            if version.isalnum() and ids:

                for tag in ids[0].split('/'):

                    # is a tag is suitable as a version number?

                    if re.match(r'^(\d+\.)+[\w.-]+$', tag):

                        version = tag

                        break

            if modified:

                version += time.strftime('+%Y%m%d')

    if version:

        remembered_version = True

        write_version(version)

def forget_version():

    """Remove version information."""

    if remembered_version:

        write_version(unknown_version)