from collections import OrderedDict
from os import path
import json
class Mapping():

    def __init__(self, configuration):
        self.init_mapping = configuration["mapping"]
        self.mapping = OrderedDict()
        tmp_mapping = dict(self.init_mapping)
        for key in tmp_mapping.keys() :
            json_file = self.init_mapping[key]
            if not path.exists(json_file):
                print("The file '%s' does not exists" % json_file)
                continue
            with open(json_file, "r") as file:
                json_data = file.read()
                j = json.loads(json_data)
                self.mapping[key] = j

    def reset(self):
        """ Remove all the keys added and not in the configuration file.
        """
        # Create a copy of the dictonnary before updating the keys
        tmp_mapping = dict(self.mapping)
        for key in tmp_mapping.keys() :
            if key not in self.init_mapping.keys():
                del self.mapping[key]

    def get(self, key, default):
        return self.mapping.get(key, default)

    def __getitem__(self, key):
        return self.mapping.get(key, None)

    def __setitem__(self, key, value):
        self.mapping[key] = value

    def items(self):
        """ Implement the keys items from the dictionnary
        """
        return self.mapping.items()

    def keys(self):
        """ Implement the keys method from the dictionnary
        """
        return self.mapping.keys()