"""Application configuration."""
from typing import List
from pydantic import model_validator
from pydantic_settings import BaseSettings, SettingsConfigDict

DEFAULT_SECRET_KEY = "your-secret-key-change-in-production"

# Known weak/placeholder secrets that must never reach production.
WEAK_SECRET_KEYS = {
    DEFAULT_SECRET_KEY,
    "change-me-in-production",  # docker-compose fallback
    "change-me",
    "secret",
    "changeme",
}


class Settings(BaseSettings):
    """Application settings."""

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=False
    )

    # App
    app_name: str = "Space Booking API"
    debug: bool = False

    # Database
    database_url: str = "sqlite:///./space_booking.db"

    # JWT
    secret_key: str = DEFAULT_SECRET_KEY
    algorithm: str = "HS256"
    access_token_expire_minutes: int = 1440  # 24 hours

    # SMTP
    smtp_host: str = "localhost"
    smtp_port: int = 1025  # MailHog default
    smtp_user: str = ""
    smtp_password: str = ""
    smtp_from_address: str = "noreply@space-booking.local"
    smtp_enabled: bool = False  # Disable by default for dev

    # Frontend
    frontend_url: str = "http://localhost:5173"

    # Google Calendar OAuth
    google_client_id: str = ""
    google_client_secret: str = ""
    google_redirect_uri: str = "http://localhost:8000/api/integrations/google/callback"
    google_scopes: List[str] = [
        "https://www.googleapis.com/auth/calendar",
        "https://www.googleapis.com/auth/calendar.events"
    ]

    @model_validator(mode="after")
    def _enforce_production_secrets(self) -> "Settings":
        """Refuse to boot in production with a weak SECRET_KEY."""
        if not self.debug:
            if self.secret_key in WEAK_SECRET_KEYS or len(self.secret_key) < 32:
                raise ValueError(
                    "SECRET_KEY is weak or a placeholder. Set a strong, random value "
                    "(>= 32 chars) before running in production (DEBUG=false). "
                    "Generate one with: python -c \"import secrets; print(secrets.token_hex(32))\""
                )
        return self


settings = Settings()