#!/usr/bin/python3

"""
This file parses the seed.yaml file for the chroot and appends it to the
given manifest file.
"""

import re
import sys
import yaml
import os.path

sys.stderr.write("Parsing seed.yaml\n")

CHROOT_ROOT = sys.argv[1] if len(sys.argv) > 1 and len(sys.argv[1]) > 0 \
                          else ''
'''The chroot rooth path should be passed in by the caller'''
sys.stderr.write("CHROOT_ROOT: {}\n".format(CHROOT_ROOT))

if len(CHROOT_ROOT) > 0 and CHROOT_ROOT[-1] == '/':
    CHROOT_ROOT = CHROOT_ROOT[:-1]
YAML_PATH = CHROOT_ROOT + '/var/lib/snapd/seed/seed.yaml'
'''This is where we expect to find the seed.yaml file'''
LINE_PREFIX = 'snap:'
'''Snaps are prepended with this string in the manifest'''

sys.stderr.write("yaml path: {}\n".format(YAML_PATH))
if not os.path.isfile(YAML_PATH):
    sys.stderr.write("yaml path not found.\n")
    exit(1)
else:
    sys.stderr.write("yaml path found.\n")

# Open the seed.yaml and ingest its contents
with open(YAML_PATH, 'r') as fh:
    yaml_lines = yaml.load(fh)['snaps']

to_write = ''
# Loop over dict items, generating one manifest line from each
# triplet
for item in yaml_lines:
    filestring = item['file']
    revision = filestring[filestring.rindex('_')+1:]
    revision = re.sub(r'[^0-9]', '', revision)
    to_write += "{}{}\t{}\t{}\n".format(LINE_PREFIX,
                                        item['name'],
                                        item['channel'],
                                        revision,
                                        )

# write accumulated text to stdout for redirection
print(to_write.strip('\n'))