#!/usr/bin/python
# mclu (mini cluster)
# Copyright (C) 2014 Red Hat Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

import sys
import os
import re
import libvirt

# Helper function to ping all the nodes.
def ping_nodes (nodes):
    for node in nodes.values():
        node.ping ()

# Helper function to get node objects from a list of node names.
def get_nodes_by_name (all_nodes, names, all):
    if not all:
        return map (lambda name : get_node_by_name (all_nodes, name), names)
    else:
        return all_nodes.values()

def get_node_by_name (nodes, name):
    if name in nodes:
        return nodes[name]
    else:
        sys.exit ("error: node does not exist: %s" % name)

# Get separate list of running and inactive guests.
def get_all_guests (c, nodes):
    running = {}
    inactive = {}

    # Find running guests.
    for node in nodes:
        # Get the flat list of guests from this node:
        doms = node.guests ()
        # Store which node the guest is running on, and turn list into a map.
        for dom in doms:
            name = dom.name()
            if name in running:
                sys.exit ("error: virtual machine %s is running on two nodes!" % name)
            running[name] = { 'dom' : dom, 'node' : node }

    # Find inactive guests (XML configuration files).
    for name in get_guest_configs (c, nodes):
        if name not in running:
            inactive[name] = name

    return running, inactive

# Get the names of guests from the XML configuration files in xmls_dir.
def get_guest_configs (c, nodes):
    names = []
    for filename in sorted (os.listdir (c['xmls_dir'])):
        m = re.search (r'^(.*)\.xml$', filename)
        if m:
            names.append (m.group (1))
    return names

# Convert virDomainState to string.
# Copied from virt-manager.
def pretty_run_status (status):
    if status == libvirt.VIR_DOMAIN_RUNNING:
        return "running"
    elif status == libvirt.VIR_DOMAIN_PAUSED:
        return "paused"
    elif status == libvirt.VIR_DOMAIN_SHUTDOWN:
        return "shutting down"
    elif status == libvirt.VIR_DOMAIN_SHUTOFF:
        return "shutoff"
    elif status == libvirt.VIR_DOMAIN_CRASHED:
        return "crashed"
    elif status == libvirt.VIR_DOMAIN_PMSUSPENDED:
        return "suspended"

# Start a guest running on a given node.  The node must not be
# running anywhere already.
def start_guest (c, node, guest_name):
    fp = open ("%s/%s.xml" % (c['xmls_dir'], guest_name), "r")
    xml = fp.read ()
    fp.close ()

    conn = node.get_connection()
    conn.createXML (xml)

def pick_any_node_which_is_up (nodes):
    node = None
    for n in nodes.values():
        if n.ping ():
            node = n
            break
    if not node:
        sys.exit ("error: no nodes are up, use mclu wake [node|--all]")
    return node