#!/usr/bin/env python3

"""Checks YAML files for correct formatting.
Usage: yamlfmt.py [--apply] file.yaml
"""

import io
from ruamel.yaml import YAML
import sys

args = sys.argv[:]
try:
    args.remove('--apply')
    want_apply = True
except ValueError:
    want_apply = False

path = args[1]

def dump(yaml, yml):
    buf = io.BytesIO()
    yaml.dump(yml, buf)
    return buf.getvalue().decode('utf-8')

with open(path) as f:
    contents = f.read()
    yaml = YAML()
    yml = yaml.load(contents)
    formatted = dump(yaml, yml)
    well_formatted = formatted == contents
        
if not well_formatted:
    print('The yaml file is not correctly formatted:', path)
    if want_apply:
        print('Correcting', path)
        with open(path, 'w') as f:
            f.write(formatted)
    else:
        print('Please use the following correction:')
        print('----------corrected', path)
        print(formatted)
        print('----------end corrected', path)
        sys.exit(1)