"""Module providing tools to handle preset dictionaries, which are stored in a JSON file."""
import json
import logging
import os
from dataclasses import dataclass
from .config import ENCODING, JSON_INDENT
logger = logging.getLogger(__name__)
[docs]@dataclass
class PresetManager:
"""Manager to handle preset dictionaries, which are stored in a JSON file.
Args:
file_path (str): Path to a JSON file containing preset dictionaries.
encoding (str): Encoding applied when writing to and reading from JSON files.
indent (int): Indent applied when writing to a JSON file.
"""
file_path: str
encoding: str = ENCODING
indent: int = JSON_INDENT
def __post_init__(self):
# Create dict with preset name (k) and preset key/value pairs (v)
data = self._load_data()
self._preset_dict = {dct.pop("name"): dct for dct in data}
def _load_data(self) -> list[dict[str, any]]:
"""Read preset dictionaries from the JSON file."""
if not os.path.isfile(self.file_path):
return []
with open(self.file_path, "r", encoding=self.encoding) as fobj:
json_str = fobj.read()
logger.debug(f"Loaded presets from: '{os.path.abspath(self.file_path)}'")
return json.loads(json_str)
def _write_data(self) -> None:
"""Write presets to the JSON file."""
# Get data
data = []
for k, v in self._preset_dict.items():
dct = {"name": k}
dct.update(v)
data.append(dct)
# Ensure parent directory exists
directory = os.path.dirname(self.file_path)
if not os.path.isdir(directory):
os.makedirs(directory, exist_ok=False)
logger.debug(f"Created preset directory: '{directory}'")
# Write data (it's printed to the file in order to maintain the indent)
json_str = json.dumps(data, indent=self.indent)
print(json_str, file=open(self.file_path, "wt", encoding=self.encoding))
logger.debug(f"Preset data written to: {self.file_path}")
@property
def has_preset(self) -> bool:
"""Check if registered presets are existing.
Returns:
bool: True if at least one preset is registered,
and False if no preset is registered.
"""
if len(self.get_names()) == 0:
return False
return True
[docs] def get_names(self) -> list[str]:
"""Retrieve a list with names of registered presets.
Returns:
list[str]: List containg the names of all registered presets.
"""
return list(self._preset_dict.keys())
[docs] def get_preset(self, name: str) -> dict[str, any]:
"""Retrieve a preset dictionary.
Args:
name (str): The name of the preset to be returned.
Returns:
dict[str, any]: Dictionary containg the preset key/value pairs.
"""
return self._preset_dict[name]
[docs] def add_preset(
self, name: str, preset_dct: dict[str, any], to_file: bool = True
) -> None:
"""Add a new preset (and write to JSON file).
Args:
name (str): The name of the preset to be added.
preset_dct (str): Dictionary containg the preset key/value pairs to be added.
to_file (bool): Flag to indicate to write the new presets to the JSON file.
Raises:
ValueError: If the preset name is already registered.
"""
if name in self.get_names():
raise ValueError(f"Preset with name {name!r} already existing.")
self._preset_dict[name] = preset_dct
logger.info(f"Added preset: {name!r}")
if to_file:
self._write_data()
[docs] def remove_preset(self, name: str, to_file: bool = True) -> None:
"""Remove a registered preset (and write to JSON file).
Args:
name (str): The name of the preset to be removed.
to_file (bool): Flag to indicate to write the new presets to the JSON file.
"""
if name not in self.get_names():
raise ValueError(f"Preset with name {name!r} not existing.")
self._preset_dict.pop(name)
logger.info(f"Removed preset: {name!r}")
if to_file:
if not self.has_preset:
os.remove(self.file_path)
logger.debug(f"Deleted empty preset file: {self.file_path!r}")
else:
self._write_data()