"""
Persistence for the PT-E560BT label layout settings.

Stored as JSON next to the application so the operator's logo, static text and
QR template survive restarts. Kept deliberately tolerant: a missing or corrupt
file silently yields defaults rather than blocking printing.
"""

from __future__ import annotations

import json
import os

from ptouch_label import LabelConfig

CONFIG_FILENAME = "label_config.json"


def config_path(base_dir: str | None = None) -> str:
    """Absolute path to the settings file."""
    directory = base_dir or os.path.dirname(os.path.abspath(__file__))
    return os.path.join(directory, CONFIG_FILENAME)


def load_config(base_dir: str | None = None) -> LabelConfig:
    """Load settings, falling back to defaults when absent or unreadable."""
    path = config_path(base_dir)
    if not os.path.exists(path):
        return LabelConfig()
    try:
        with open(path, "r", encoding="utf-8") as handle:
            return LabelConfig.from_dict(json.load(handle))
    except (OSError, ValueError) as exc:
        print(f"Could not read {CONFIG_FILENAME} ({exc}); using defaults.")
        return LabelConfig()


def save_config(config: LabelConfig, base_dir: str | None = None) -> str:
    """Write settings to disk and return the path written."""
    path = config_path(base_dir)
    with open(path, "w", encoding="utf-8") as handle:
        json.dump(config.to_dict(), handle, indent=2, ensure_ascii=False)
    return path