"""Configuration management for ShellGen."""

import os
from pathlib import Path
from typing import Any, Optional

import yaml


class Config:
    """Configuration manager that loads from YAML and environment variables."""

    def __init__(self, config_path: Optional[str] = None):
        self._config: dict = {}
        self._config_path = config_path or self._find_config_file()

        if self._config_path and Path(self._config_path).exists():
            self._load_config()

    def _find_config_file(self) -> Optional[str]:
        """Find config file in common locations."""
        candidates = [
            "config.yaml",
            os.path.expanduser("~/.shellgen/config.yaml"),
            "/etc/shellgen/config.yaml",
        ]

        for candidate in candidates:
            if Path(candidate).exists():
                return candidate

        return None

    def _load_config(self) -> None:
        """Load configuration from YAML file."""
        try:
            config_path = self._config_path or "config.yaml"
            with open(config_path, "r") as f:
                self._config = yaml.safe_load(f) or {}
        except Exception:
            self._config = {}

    def get(self, key: str, default: Any = None) -> Any:
        """Get configuration value from environment or config file."""
        env_key = key.upper().replace(".", "_")

        env_value = os.environ.get(env_key)
        if env_value is not None:
            return env_value

        keys = key.split(".")
        value = self._config

        for k in keys:
            if isinstance(value, dict):
                value = value.get(k)
            else:
                return default

            if value is None:
                return default

        return value

    def set(self, key: str, value: Any) -> None:
        """Set configuration value."""
        keys = key.split(".")
        config = self._config

        for k in keys[:-1]:
            if k not in config:
                config[k] = {}
            config = config[k]

        config[keys[-1]] = value

    def save(self, path: Optional[str] = None) -> None:
        """Save configuration to file."""
        save_path = path or self._config_path
        if not save_path:
            save_path = "config.yaml"

        with open(save_path, "w") as f:
            yaml.dump(self._config, f, default_flow_style=False)