Source code for duck.settings.settings

"""
Provides access to application settings.
"""
import os
import sys

from functools import lru_cache

from duck.exceptions.all import SettingsError
from duck.utils.importer import import_module_once


# Set default settings if not provided
os.environ.setdefault("DUCK_SETTINGS_MODULE", "web.settings")
SETTINGS_MODULE = os.environ.get("DUCK_SETTINGS_MODULE")




class Settings(dict):
    """
    A class for managing **Duck** settings.
    
    This class extends the built-in `dict` to store settings in a dictionary-like format.
    It also provides a custom representation of the settings for debugging and logging.  
    
    **Notes:**
    - These settings can be altered at runtime once imported but the `SETTINGS` should be imported and
      edited at top level before importing anything related to **Duck**.  
       
       **Example:**
       ```py
       from duck.settings import SETTINGS
       
       # Edit settings inplace .e.g.,
       SETTINGS['ENABLE_HTTPS'] = True
       
       from duck.app import App
       
       app = App()
       
       if __name__ == '__main__':
           app.run()
       ``` 
    """
    
    source = None
    """
    The source of settings e.g., `web.settings`.
    """
    


    def reload(self):
        """
        Re-execute the settings module and update this dict in-place.
        
        Notes:
            The settings module will be the latest one set in `DUCK_SETTINGS_MODULE`.
        """
        import importlib
        
        mod_str = os.environ.get("DUCK_SETTINGS_MODULE")
        mod = sys.modules.get(mod_str, None)
        mods = []
        
        if mod:
            importlib.reload_module(mod)
            mods.append(mod) 
        else:
            mod = import_module_once(mod_str)
            mods.append(import_module_once("duck.etc.settings"))
            mods.append(mod)
            
        # Apply settings inplace
        self.source = mod
        for mod in mods:
            for var in dir(mod):
                if var.isupper():
                    # is a valid setting variable
                    self[var] = getattr(mod, var)

                


    def __repr__(self):
        # Provide a more detailed and readable string representation of the Settings object
        return (
           "<" + f"{self.__class__.__name__} "
            f"source={repr(self.source)}".replace('<', "[").replace('>', "]") + ">"
        )






@lru_cache
def settings_to_dict(settings_module: str) -> Settings:
    """
    Converts a settings module to a dictionary.

    Args:
        settings_module (str): The path to the settings module.

    Returns:
        Settings: Settings object derived from a dictionary containing the settings.

    Raises:
        ImportError: If the settings module cannot be imported.
    """
    settings_mod = import_module_once(settings_module)
    settings = Settings({})
    settings.source = settings_mod
    
    for var in dir(settings_mod):
        if var.isupper():
            # is a valid setting variable
            settings[var] = getattr(settings_mod, var)
    return settings





def get_combined_settings() -> Settings:
    """
    Combines default and user settings into a single dictionary.

    Reads the default settings from `duck.etc.settings` and attempts to
    read user settings from a `settings` module in the current directory.

    Returns:
        Settings: Settings object derived from a dictionary containing the settings.

    Raises:
        SettingsError: If there's an error loading user settings.
    """
    default_settings = settings_to_dict("duck.etc.settings")
    
    try:
        user_settings = settings_to_dict(SETTINGS_MODULE)
    except Exception as e:
        raise SettingsError(
            f"Error loading Duck settings module, ensure environment variable DUCK_SETTINGS_MODULE is set correctly: {e}."
        ) from e
    
    # Update the default settings with custom ones.
    default_settings.update(user_settings)
    settings = Settings(default_settings)
    settings.source = user_settings.source
    return settings



# Set and load important settings, objects, etc.
SETTINGS: Settings = get_combined_settings()


# Set Django specific configurations
if not SETTINGS_MODULE.startswith("web") and SETTINGS['DJANGO_SETTINGS_MODULE'].startswith('web.backend.django.duckapp.duckapp.settings'):
    # Duck settings module is external yet the Django settings module is default.
    try:
        # Try to resolve the settings
        import_module_once(SETTINGS['DJANGO_SETTINGS_MODULE'])
    except ImportError:
        # We need to fix the Django settings module
        SETTINGS['DJANGO_SETTINGS_MODULE'] = SETTINGS_MODULE.rsplit('.', 1)[0] + ".backend.django.duckapp.duckapp.settings"
        

# Set django settings module
os.environ.setdefault('DJANGO_SETTINGS_MODULE', SETTINGS['DJANGO_SETTINGS_MODULE'])


if (os.getenv("DUCK_USE_DJANGO", None) == "true"
    or "-dj" in sys.argv or "--use-django" in sys.argv):
    SETTINGS["USE_DJANGO"] = True