import json
import os


FILENAME = 'extra-commands.json'


class ExtraCommands(dict):

    def __init__(self):
        self.last_mtime = 0

    def reload(self):
        with open(FILENAME) as f:
            commands = json.load(f)
        self.clear()
        self.update(commands)

    def reload_if_needed(self):
        mtime = os.stat(FILENAME).st_mtime
        if mtime > self.last_mtime:
            self.last_mtime = mtime
            self.reload()

    def save(self):
        with open(FILENAME, 'w') as f:
            json.dump(self, f, indent=4, sort_keys=True)