#!/usr/bin/env python
import argparse
import sys
import json

import pycriu

def inf(opts):
	if opts['in']:
		return open(opts['in'], 'r')
	else:
		return sys.stdin

def outf(opts):
	if opts['out']:
		return open(opts['out'], 'w+')
	else:
		return sys.stdout


def decode(opts):
	indent = None

	try:
		img = pycriu.images.load(inf(opts), opts['pretty'])
	except pycriu.images.MagicException as exc:
		print >>sys.stderr, "Unknown magic %#x.\n"\
				"Maybe you are feeding me an image with "\
				"raw data(i.e. pages.img)?" % exc.magic
		sys.exit(1)

	if opts['pretty']:
		indent = 4

	f = outf(opts)
	json.dump(img, f, indent=indent)
	if f == sys.stdout:
		f.write("\n")

def encode(opts):
	img = json.load(inf(opts))
	pycriu.images.dump(img, outf(opts))

def main():
	desc = 'CRiu Image Tool'
	parser = argparse.ArgumentParser(description=desc,
			formatter_class=argparse.RawTextHelpFormatter)

	subparsers = parser.add_subparsers(help='Use crit CMD --help for command-specific help')

	# Decode
	decode_parser = subparsers.add_parser('decode',
			help = 'convert criu image from binary type json')
	decode_parser.add_argument('--pretty',
			help = 'Multiline with indents and some numerical fields in field-specific format',
			action = 'store_true')
	decode_parser.add_argument('-i',
			    '--in',
			help = 'criu image in binary format to be decoded (stdin by default)')
	decode_parser.add_argument('-o',
			    '--out',
			help = 'where to put criu image in json format (stdout by default)')
	decode_parser.set_defaults(func=decode)

	# Encode
	encode_parser = subparsers.add_parser('encode',
			help = 'convert criu image from json type to binary')
	encode_parser.add_argument('-i',
			    '--in',
			help = 'criu image in json format to be encoded (stdin by default)')
	encode_parser.add_argument('-o',
			    '--out',
			help = 'where to put criu image in binary format (stdout by default)')
	encode_parser.set_defaults(func=encode)

	# Show
	show_parser = subparsers.add_parser('show',
			help = "convert criu image from binary to human-readable json")
	show_parser.add_argument("in")
	show_parser.set_defaults(func=decode, pretty=True, out=None)

	opts = vars(parser.parse_args())

	opts["func"](opts)

if __name__ == '__main__':
	main()