# Copyright (C) 2005 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 os.path
import re
import time

unknown_version = 'unknown'

def get_version():
    """Return version information if available."""
    try:
        from mercurial.__version__ import version
    except ImportError:
        version = unknown_version
    return version

def write_version(version):
    """Overwrite version file."""
    filename = os.path.join(os.path.dirname(__file__), '__version__.py')
    f = open(filename, 'w')
    f.write("# This file is auto-generated.\n")
    f.write("version = %r\n" % version)
    f.close()

def remember_version():
    """Store version information."""
    f = os.popen("hg identify 2>/dev/null")  # 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')
    else:
        version = unknown_version
    write_version(version)

def forget_version():
    """Remove version information."""
    write_version(unknown_version)