#!/usr/bin/env python3
import argparse
import json
import os
import sys
from datetime import datetime

parser = argparse.ArgumentParser()

parser.add_argument('-n', '--nodesjson', action='store', required=True,
                    help='old nodes.json file you want to read firstseen from')

parser.add_argument('-s', '--state', action='store', required=True,
                    help='state.json you want to store')

args = parser.parse_args()

with open(os.path.realpath(args.nodesjson), encoding='UTF-8') as handle:
    legacy_db = json.load(handle)

# w/o a version tag we cannot decide how to walk and interpret the nodes.json
assert ('version' in legacy_db)

yanic_db_path = os.path.realpath(args.state)
with open(yanic_db_path, encoding='UTF-8') as handle:
    yanic_db = json.load(handle)

total = 0
updated = 0
yanic_date_format = '%Y-%m-%dT%H:%M:%S%z'
v1_date_format = '%Y-%m-%dT%H:%M:%S.%f'  # 2017-05-31T18:30:19.759610
v2_date_format = '%Y-%m-%dT%H:%M:%S.%fZ'  # 2015-08-22T16:05:02.000Z
version = legacy_db['version']

print('nodes.json is in v{} format'.format(version))

fallback_date_format = None
if version == 1:
    legacy_date_format = v1_date_format    # ffmap-backend
elif version == 2:
    legacy_date_format = v2_date_format    # hopglass
    fallback_date_format = yanic_date_format  # other yanic
else:
    print('unhandled nodes.json version number!', file=sys.stderr)
    sys.exit(1)

for nodeid, node in yanic_db.get('nodes', {}).items():
    legacy_node = None

    if version == 1:
        # v1 nodes.json is a dict, so lookups are cheap
        legacy_node = legacy_db.get('nodes', {}).get(nodeid, None)
    elif version == 2:
        # v2 nodes.json however carries nodes as a list of dicts …
        legacy_node = next((
            candidate for candidate in legacy_db.get('nodes', [])
            if candidate['nodeinfo']['node_id'] == nodeid), None)

    if legacy_node is not None:
        try:
            dt = datetime.strptime(legacy_node['firstseen'], legacy_date_format)
        except ValueError as ex:
            # time format mismatch, try fallback format
            if fallback_date_format is not None:
                dt = datetime.strptime(legacy_node['firstseen'],
                                       fallback_date_format)
            else:
                # or if none is set, re-raise the original exception
                raise ex

        dts = dt.strftime(yanic_date_format)

        if node['firstseen'] != dts:
            node['firstseen'] = dts
            updated += 1

        total += 1

with open(yanic_db_path, 'w') as f:
    json.dump(yanic_db, f)

print('found {} nodes, {} changed.'.format(total, updated))