## Generic Parts
# These functions are providing the functionality to load
# arbitrary configuration files.
#
# They can be imported by other code (see `ldap_config.py` for an example).

from os.path import abspath, isfile
from os import scandir
import importlib.util
import sys

def _filename(f):
  return f.name


def _import(module_name, path, loaded_configurations):
  spec = importlib.util.spec_from_file_location('', path)
  module = importlib.util.module_from_spec(spec)
  spec.loader.exec_module(module)
  sys.modules[module_name] = module

  loaded_configurations.insert(0, module)

  print(f"🧬 loaded config '{path}'")


def read_configurations(config_module, config_dir, main_config):
  loaded_configurations = []

  main_config_path = abspath(f'{config_dir}/{main_config}.py')
  if isfile(main_config_path):
    _import(f'{config_module}.{main_config}', main_config_path, loaded_configurations)
  else:
    print(f"⚠️ Main configuration '{main_config_path}' not found.")

  with scandir(config_dir) as it:
    for f in sorted(it, key=_filename):
      if not f.is_file():
        continue

      if f.name.startswith('__'):
        continue

      if not f.name.endswith('.py'):
        continue

      if f.name == f'{config_dir}.py':
        continue

      module_name = f"{config_module}.{f.name[:-len('.py')]}".replace(".", "_")
      _import(module_name, f.path, loaded_configurations)

  if len(loaded_configurations) == 0:
    print(f"‼️ No configuration files found in '{config_dir}'.")
    raise ImportError(f"No configuration files found in '{config_dir}'.")

  return loaded_configurations


## Specific Parts
# This section's code actually loads the various configuration files
# into the module with the given name.
# It contains the logic to resolve arbitrary configuration options by
# levaraging dynamic programming using `__getattr__`.


_loaded_configurations = read_configurations(
  config_dir = '/etc/netbox/config/',
  config_module = 'netbox.configuration',
  main_config = 'configuration')


def __getattr__(name):
  for config in _loaded_configurations:
    try:
      return getattr(config, name)
    except:
      pass
  raise AttributeError