#!/usr/bin/env python3
"""
backend.py - ffmap-backend runner
https://github.com/ffnord/ffmap-backend
"""
import argparse
import json
import os
from datetime import datetime

import networkx as nx
from networkx.readwrite import json_graph

from lib import graph, nodes
from lib.alfred import Alfred
from lib.batman import Batman
from lib.rrddb import RRD


def main(params):
    nodes_fn = os.path.join(params['dest_dir'], 'nodes.json')
    graph_fn = os.path.join(params['dest_dir'], 'graph.json')

    now = datetime.utcnow().replace(microsecond=0)

    with open(nodes_fn, 'r') as nodedb_handle:
        nodedb = json.load(nodedb_handle)

    # flush nodedb if it uses the old format
    if 'links' in nodedb:
        nodedb = {'nodes': dict()}

    nodedb['timestamp'] = now.isoformat()

    for node_id, node in nodedb['nodes'].items():
        node['flags']['online'] = False

    alfred = Alfred(unix_sockpath=params['alfred_sock'])

    nodes.import_nodeinfo(nodedb['nodes'], alfred.nodeinfo(),
                          now, assume_online=True)

    for aliases in params['aliases']:
        with open(aliases, 'r') as f:
            nodes.import_nodeinfo(nodedb['nodes'], json.load(f),
                                  now, assume_online=False)

    nodes.reset_statistics(nodedb['nodes'])
    nodes.import_statistics(nodedb['nodes'], alfred.statistics())

    bm = list(map(lambda d:
                  (d.vis_data(True), d.gateway_list()),
                  map(Batman, params['mesh'])))
    for vis_data, gateway_list in bm:
        nodes.import_mesh_ifs_vis_data(nodedb['nodes'], vis_data)
        nodes.import_vis_clientcount(nodedb['nodes'], vis_data)
        nodes.mark_vis_data_online(nodedb['nodes'], vis_data, now)
        nodes.mark_gateways(nodedb['nodes'], gateway_list)

    if params['prune']:
        nodes.prune_nodes(nodedb['nodes'], now, int(params['prune']))

    batadv_graph = nx.DiGraph()
    for vis_data, gateway_list in bm:
        graph.import_vis_data(batadv_graph, nodedb['nodes'], vis_data)

    if params['vpn']:
        graph.mark_vpn(batadv_graph, frozenset(params['vpn']))

    batadv_graph = graph.merge_nodes(batadv_graph)
    batadv_graph = graph.to_undirected(batadv_graph)

    with open(nodes_fn, 'w') as f:
        json.dump(nodedb, f)

    with open(graph_fn, 'w') as f:
        json.dump({'batadv': json_graph.node_link_data(batadv_graph)}, f)

    if params['rrd']:
        script_directory = os.path.dirname(os.path.realpath(__file__))
        rrd = RRD(os.path.join(script_directory, 'nodedb'),
                  os.path.join(params['dest_dir'], 'nodes'))
        rrd.update_database(nodedb['nodes'])
        rrd.update_images()


if __name__ == '__main__':
    parser = argparse.ArgumentParser()

    parser.add_argument('-a', '--aliases',
                        help='read aliases from FILE',
                        default=[], action='append',
                        metavar='FILE')
    parser.add_argument('-m', '--mesh', action='append',
                        default=['bat0'],
                        help='batman mesh interface (defaults to bat0)')
    parser.add_argument('-s', '--alfred-sock',
                        default=None,
                        help='alfred unix socket path')
    parser.add_argument('-d', '--dest-dir', action='store',
                        help='destination directory for generated files',
                        required=True)
    parser.add_argument('--vpn', action='append', metavar='MAC',
                        help='assume MAC to be part of the VPN')
    parser.add_argument('--prune', metavar='DAYS',
                        help='forget nodes offline for at least DAYS')
    parser.add_argument('--rrd', dest='rrd', action='store_true',
                        default=False,
                        help='create RRD graphs')

    options = vars(parser.parse_args())

    main(options)