from __future__ import print_function
from argparse import ArgumentParser
import json, sys, re
from common import *

"""
Extract and output selected fields of metadata
"""

def main (args):
    p = ArgumentParser("extract & display meta data from a specific .meta.json file, or for a given padid (nb: it still looks for a .meta.json file)")
    p.add_argument("--path", default=None, help="read from a meta.json file")
    p.add_argument("--padid", default=None, help="read meta for this padid")
    p.add_argument("--format", default="{padid}", help="format str, default: {padid}")
    args = p.parse_args(args)

    path = args.path
    if not path and args.padid:
        path = padpath(args.padid) + ".meta.json"

    if not path:
        print ("Must specify either --path or --padid")
        sys.exit(-1)

    with open(path) as f:
        meta = json.load(f)

    formatstr = args.format.decode("utf-8")
    formatstr = re.sub(r"{(\w+)}", r"{0[\1]}", formatstr)
    print (formatstr.format(meta).encode("utf-8"))