#!/usr/bin/python3
#
# Maximilian Wilhelm <max@rfc2324.org>
#  --  Tue 20 Jun 2017 06:40:18 PM CEST
#

import argparse
import json
import os
import sys
import time

parser = argparse.ArgumentParser (description = 'Merge nodes.json files')
parser.add_argument ('files', help = 'Path for nodes.json file(s)', nargs = '+')
parser.add_argument ('--pretty-print', help = 'Pretty-print JSON output', action = 'store_true')
args = parser.parse_args ()

all_nodes = {}
uberdict = {}

# Read all nodes lists into all_nodes dict, thereby dropping any duplicate nodes.
for file_path in args.files:
	try:
		with open (file_path, 'rb') as fh:
			nodes = json.load (fh)
	except IOError as e:
		print (f"Error while reading file '{file_path}': {str(e)}")
		sys.exit (1)

	for node in nodes['nodes']:
		node_id = node['nodeinfo']['node_id']

		# If node_id has already been seen make sure to use the newer entry
		if node_id in all_nodes:
			try:
				node_lastseen = time.strptime (node['lastseen'], "%Y-%m-%dT%H:%M:%S%z")
				existing_node_lastseen = time.strptime (existing_node_lastseen['lastseen'], "%Y-%m-%dT%H:%M:%S%z")

				# If the node information already stored in all_nodes is more
				# recent than the node we just found, don't overwrite it.
				if existing_node_lastseen > node_lastseen:
					continue
			except Exception:
				# If parsing a timestamp fails just carry on
				continue

		all_nodes[node['nodeinfo']['node_id']] = node

	for key in nodes.keys ():
		if key != 'nodes':
			uberdict[key] = nodes[key]

uberdict['nodes'] = list(all_nodes.values ())

# Print merged nodes.json's to stdout
if args.pretty_print:
	print (json.dumps (uberdict, sort_keys = True, indent = 4, separators = (',', ': ')))
else:
	print (json.dumps (uberdict))