import argparse
import json


def shorten_names(regmap, iteration=0):
    word_to_remove = ''
    names = regmap.keys()
    longest = max(sorted(names), key=len)
    if len(longest) <= 40:
        return regmap
    ss = longest.split('_')  # ss: substrings
    # print(len(regmap), longest, len(longest))
    position = 0
    rebuilt_s = ''
    for s in ss:
        rebuilt_s += s + '_'
        if s.isdigit() or s in ['cavity', 'mode', 'shell']:
            continue

        def F(x):
            return x.replace(s + '_', '', 1) if x.startswith(rebuilt_s) else x
        rebuilt_set = set(map(F, names))
        if len(rebuilt_set) == len(names):
            word_to_remove = s
            break
        position += len(s) + 1
    if word_to_remove:
        # print(iteration, word_to_remove)
        S = {}
        for n in names:
            new = n.replace(word_to_remove + '_', '',
                            1) if n.startswith(rebuilt_s) else n
            S[new] = regmap[n]
        return shorten_names(S, iteration + 1)
    else:
        return regmap


def main():
    parser = argparse.ArgumentParser(
        description='Merge json files and complain on key collision')
    parser.add_argument(
        '-i',
        '--input_regmap_json',
        default='prc_regmap.json',
        help='A regmap json file whose keys are to be shortened')
    parser.add_argument(
        '-o',
        '--shortened_regmap_json',
        default='_output.json',
        type=str,
        help='Merged with json file')
    args = parser.parse_args()
    with open(args.input_regmap_json, 'r') as in_file:
        regmap = shorten_names(json.load(in_file))
        with open(args.shortened_regmap_json, 'w') as out_file:
            json.dump(
                regmap,
                out_file,
                sort_keys=True,
                indent=4,
                separators=(',', ': '))


if __name__ == "__main__":
    main()