#!/usr/bin/python
#
# skel -- keep your basic configuration files in sync on remote machines
#
# installation instructions:

# 1. download yamlconfig.py from
#    http://trevor.caira.com/scripts/yamlconfig.py and put it on your
#    python path in a package called trevor.
# 2. create a configuration file ~/.config/skel/config.yml containing
#    ``files:`` and ``pull from:`` entries. an example config.yml is
#    available at http://trevor.caira.com/scripts/config.yml.
# 3. copy skel to your path and make it executable

import os, sys

from trevor.yamlconfig import ConfigurationError, YamlConfig

DEFAULTS = {'config': os.path.expanduser('~/.config/skel/config.yml'),
            'output': 'skel.tar.gz'}
_commands = {}
commands = _commands.get

def command(func):
    globals()['_commands'][func.func_code.co_name] = func
    return func

def ext2taropt(filename):
    if filename.endswith('.bz2'):
        return 'j'
    elif filename.endswith('.gz'):
        return 'z'
    return ''

def parse_options():
    from optparse import OptionParser
    parser = OptionParser(usage='''usage: %%prog [OPTIONS] [FILE] COMMAND

where COMMAND is one of:
    %s''' % '\n    '.join(_commands.keys()))
    parser.add_option('-c', '--config', dest='config', default=None,
                      help='Specify an alternate configuration file \
(default: %r).' % DEFAULTS['config'])
    parser.add_option('-o', '--output', dest='output', default=None,
                      help='Specify an alternate output file (default: \
%r).' % DEFAULTS['output'])
    options, args = parser.parse_args()
    if options.config is None:
        options.config = DEFAULTS['config']
    return options, args

class UpdateSkelConfig(YamlConfig):
    def __init__(self, options, args):
        super(UpdateSkelConfig, self).__init__(options, args)
        if 'output' not in self:
            if options.output is None:
                self['output'] = DEFAULTS['output']
            else:
                self['output'] = options.output
        if len(args) != 1:
            raise ConfigurationError('command must be specified')
        self['command'] = args[0]

@command
def bundle(config):
    from subprocess import call

    compress = ext2taropt(config['output'])
    rv = call(['tar', 'cf%s' % compress, config['output']] +
              ['--no-recursion', '-C', os.path.expanduser('~')] +
               config['files'])
    if rv != 0:
        sys.stderr.write('tar exited with error code %d\n' % rv)

@command
def pull(config):
    from subprocess import Popen, PIPE
    from urllib2 import urlopen
    u = urlopen(config['pull from'])
    compress = ext2taropt(config['pull from'])
    tar = Popen(['tar', 'xf%s' % compress, '-', '-C',
                 os.path.expanduser('~')], stdin=PIPE)
    try:
        tar.stdin.write(u.read())
    finally:
        tar.stdin.close()
    rv = tar.wait()
    if rv != 0:
        sys.stderr.write('tar exited with error code %d\n' % rv)

def main():
    config = UpdateSkelConfig(*parse_options())
    globals()[config['command']](config)

if __name__ == '__main__':
    main()