"""Configuration management module."""

import os
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional


@dataclass
class Config:
    """Application configuration."""
    default_format: str = "pdf"
    default_dpi: int = 150
    default_template: str = "default"
    page_size: str = "a4"

    @classmethod
    def from_env(cls) -> "Config":
        """Load configuration from environment variables."""
        return cls(
            default_format=os.getenv("MANCARD_DEFAULT_FORMAT", "pdf"),
            default_dpi=int(os.getenv("MANCARD_DEFAULT_DPI", "150")),
            default_template=os.getenv("MANCARD_DEFAULT_TEMPLATE", "default"),
            page_size=os.getenv("MANCARD_PAGE_SIZE", "a4")
        )

    @classmethod
    def from_dotenv(cls, path: Optional[str] = None) -> "Config":
        """Load configuration from .env file."""
        try:
            from dotenv import load_dotenv
            if path is None:
                path = Path(__file__).parent.parent / ".env"
            elif isinstance(path, str):
                path = Path(path)

            if path.exists():
                load_dotenv(path)
        except ImportError:
            pass

        return cls.from_env()

    def merge(self, **overrides) -> "Config":
        """Create a new config with overridden values."""
        data = {
            "default_format": self.default_format,
            "default_dpi": self.default_dpi,
            "default_template": self.default_template,
            "page_size": self.page_size
        }
        data.update({k: v for k, v in overrides.items() if v is not None})
        return cls(**data)