#!/usr/bin/python

"""
    Setup symlinks for pvl.verkko-rrd -> collectd based on define host/interface names
"""

__version__ = '0.1'

import os

import pvl.args
import pvl.rrd.hosts
from pvl.rrd.hosts import hostreverse

import optparse
import logging; log = logging.getLogger('main')

COLLECTD_RRD = '/var/lib/collectd/rrd'
COLLECTD_PLUGIN = 'interfaces'
COLLECTD_TYPE = 'if_octets'

def parse_argv (argv, doc = __doc__) :
    """
        Parse command-line argv, returning (options, args).
    """

    prog = argv.pop(0)
    args = argv

    # optparse
    parser = optparse.OptionParser(
        prog        = prog,
        usage       = '%prog: [options] [<input.txt> [...]]',
        version     = __version__,
        description = doc,
    )

    # common
    parser.add_option_group(pvl.args.parser(parser))

    # options
    parser.add_option('--collectd-rrd',     metavar='PATH',     default=COLLECTD_RRD,
            help="Path to collectd rrd: %default")
    parser.add_option('--collectd-plugin',  metavar='PLUGIN',   default=None,
            help="Collectd plugin to use: <input>-<plugin>.txt")
    parser.add_option('--collectd-type',    metavar='TYPE',     default=COLLECTD_TYPE,
            help="Collectd type to use: %default")
    
    # interface is by plugin, snmp is by type...
    parser.add_option('--collectd-instance-plugin',     action='store_const', dest='collectd_instance', const='plugin',
            help="Collectd by plugin instance")
    parser.add_option('--collectd-instance-type',       action='store_const', dest='collectd_instance', const='type',
            help="Collectd by type instance")
    
    # hostnames
    parser.add_option('--reverse-host',     action='store_true',
            help="Flip host.domain -> domain.host (default)")
    parser.add_option('--no-reverse-host',  action='store_false', dest='reverse_host',
            help="Keep host.domain as host.domain")
    parser.add_option('--domain',           metavar='DOMAIN',  
            help="Append domain to collectd hostnames: <input>.txt -> <input>")

    # output
    parser.add_option('--rrd',              metavar='PATH',
            help="Output directory for .rrd symlinks: <input>.txt -> <input>/")
    parser.add_option('--noop',             action='store_true',
            help="Scan symlinks, but do not update")

    parser.set_defaults(
            collectd_instance   = 'type',
            reverse_host        = True,
    )

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

    # apply
    pvl.args.apply(options)

    return options, args

def sync_links (options, links, rrddir) :
    """
        Sync given (collectd, name) symlinks in given dir.
    """

    log.info("%s", rrddir)

    for rrdpath, (domain, host, port) in links :
        linkpath = os.path.join(rrddir,
                hostreverse(domain) if options.reverse_host else domain,
                hostreverse(host) if options.reverse_host else host,
                port + '.rrd'
        )

        # sync
        if os.path.exists(linkpath) and os.readlink(linkpath) == rrdpath :
            continue
            
        log.info("%s: %s", linkpath, rrdpath)
        
        yield linkpath, rrdpath

def apply_links (options, links) :
    """
        Apply given symlinks
    """

    for link, path in links :
        linkdir = os.path.dirname(link)

        # do
        if not os.path.exists(linkdir) :
            log.warn("makedirs: %s", linkdir)
            os.makedirs(linkdir)

        os.symlink(path, link)

def main (argv) :
    options, args = parse_argv(argv)
    
    for path in args :
        # <path>/<domain>-<plugin>.txt -> <path>/<domain>-<plugin>
        if '.txt' in path:
            basepath, _ = os.path.splitext(path)
        else:
            basepath = path
        
        # <path>/<domain> -> <domain>
        _, basename = os.path.split(basepath)
        
        # <path>/<domain>-<plugin> -> <path>/<domain>, <plugin>
        if '-' in basename :
            basename, collectd_plugin = basename.rsplit('-', 1)
        else :
            collectd_plugin = None
        
        # domain?
        if options.domain is None :
            # reverse-order hostname
            domain = hostreverse(basename)
        else :
            # may be ''
            domain = options.domain
        
        # output dir?
        if not options.rrd:
            log.error("no --rrd output dir given")
            return 1

        rrddir = options.rrd

        # generate links from spec
        links = list(pvl.rrd.hosts.collectd_interfaces(options, open(path),
            collectd_domain     = domain,
            collectd_plugin     = options.collectd_plugin or collectd_plugin or COLLECTD_PLUGIN,
        ))

        if not os.path.exists(rrddir) :
            log.error("given --rrd must already exist: %s", rrddir)
            return 1

        # sync missing links
        links = list(sync_links(options, links,
            rrddir  = rrddir,
        ))
        
        # verbose
        if not options.quiet :
            for link, path in links :
                print link, '->', path
        
        # apply
        if not options.noop :
            apply_links(options, links)

    return 0
    
if __name__ == '__main__':
    import sys

    sys.exit(main(sys.argv))