"""
App-wide settings: persists to ~/.dbclient/settings.json
"""
import json
import os
from pathlib import Path


APP_DIR = Path.home() / ".dbclient"
SETTINGS_FILE = APP_DIR / "settings.json"

DEFAULTS = {
    "theme": "dark",
    "font_family": "Consolas",
    "font_size": 13,
    "result_page_size": 1000,
    "query_timeout": 60,
    "auto_commit": True,
    "show_row_numbers": True,
    "word_wrap": False,
    "max_history": 500,
}


class Settings:
    """Thin wrapper around a JSON settings file."""

    def __init__(self):
        self._data: dict = {}
        self._load()

    def _load(self) -> None:
        APP_DIR.mkdir(parents=True, exist_ok=True)
        if SETTINGS_FILE.exists():
            try:
                with open(SETTINGS_FILE, "r", encoding="utf-8") as f:
                    self._data = json.load(f)
            except Exception:
                self._data = {}
        # Fill in missing defaults
        for k, v in DEFAULTS.items():
            self._data.setdefault(k, v)

    def save(self) -> None:
        APP_DIR.mkdir(parents=True, exist_ok=True)
        with open(SETTINGS_FILE, "w", encoding="utf-8") as f:
            json.dump(self._data, f, indent=2)

    def get(self, key: str, fallback=None):
        return self._data.get(key, DEFAULTS.get(key, fallback))

    def set(self, key: str, value) -> None:
        self._data[key] = value

    def __getitem__(self, key):
        return self.get(key)

    def __setitem__(self, key, value):
        self.set(key, value)


# Singleton
_settings: Settings | None = None


def get_settings() -> Settings:
    global _settings
    if _settings is None:
        _settings = Settings()
    return _settings