"""JWT token authentication for wikijs-python-sdk.

This module implements JWT (JSON Web Token) authentication for Wiki.js instances.
JWT tokens are typically used for user-based authentication and have expiration times.
"""

import time
from datetime import timedelta
from typing import Dict, Optional

from .base import AuthHandler


class JWTAuth(AuthHandler):
    """JWT token authentication handler for Wiki.js.

    This handler manages JWT tokens with automatic refresh capabilities.
    JWT tokens typically expire and need to be refreshed periodically.

    Args:
        token: The JWT token string.
        base_url: The base URL of the Wiki.js instance (needed for token refresh).
        refresh_token: Optional refresh token for automatic renewal.
        expires_at: Optional expiration timestamp (Unix timestamp).

    Example:
        >>> auth = JWTAuth(
        ...     token="eyJ0eXAiOiJKV1QiLCJhbGc...",
        ...     base_url="https://wiki.example.com",
        ...     refresh_token="refresh_token_here"
        ... )
        >>> client = WikiJSClient("https://wiki.example.com", auth=auth)
    """

    def __init__(
        self,
        token: str,
        base_url: str,
        refresh_token: Optional[str] = None,
        expires_at: Optional[float] = None,
    ) -> None:
        """Initialize JWT authentication.

        Args:
            token: The JWT token string.
            base_url: The base URL of the Wiki.js instance.
            refresh_token: Optional refresh token for automatic renewal.
            expires_at: Optional expiration timestamp (Unix timestamp).

        Raises:
            ValueError: If token or base_url is empty or None.
        """
        if not token or not token.strip():
            raise ValueError("JWT token cannot be empty")

        if not base_url or not base_url.strip():
            raise ValueError("Base URL cannot be empty")

        self._token = token.strip()
        self._base_url = base_url.strip().rstrip("/")
        self._refresh_token = refresh_token.strip() if refresh_token else None
        self._expires_at = expires_at
        self._refresh_buffer = 300  # Refresh 5 minutes before expiration

    def get_headers(self) -> Dict[str, str]:
        """Get authentication headers with JWT token.

        Automatically attempts to refresh the token if it's expired.

        Returns:
            Dict[str, str]: Headers containing the Authorization header.

        Raises:
            AuthenticationError: If token is expired and cannot be refreshed.
        """
        # Try to refresh if token is near expiration
        if not self.is_valid():
            self.refresh()

        return {
            "Authorization": f"Bearer {self._token}",
            "Content-Type": "application/json",
        }

    def is_valid(self) -> bool:
        """Check if JWT token is valid and not expired.

        Returns:
            bool: True if token exists and is not expired, False otherwise.
        """
        if not self._token or not self._token.strip():
            return False

        # If no expiration time is set, assume token is valid
        if self._expires_at is None:
            return True

        # Check if token is expired (with buffer for refresh)
        current_time = time.time()
        return current_time < (self._expires_at - self._refresh_buffer)

    def refresh(self) -> None:
        """Refresh the JWT token using the refresh token.

        This method attempts to refresh the JWT token using the refresh token
        by making a request to the Wiki.js authentication endpoint.

        Raises:
            AuthenticationError: If refresh token is not available or refresh fails.
        """
        import requests
        from ..exceptions import AuthenticationError

        if not self._refresh_token:
            raise AuthenticationError(
                "JWT token expired and no refresh token available"
            )

        try:
            # Make request to Wiki.js token refresh endpoint
            refresh_url = f"{self._base_url}/api/auth/refresh"

            response = requests.post(
                refresh_url,
                json={"refreshToken": self._refresh_token},
                headers={
                    "Content-Type": "application/json",
                    "Accept": "application/json",
                },
                timeout=30,
            )

            # Check if request was successful
            if not response.ok:
                error_msg = "Token refresh failed"
                try:
                    error_data = response.json()
                    error_msg = error_data.get("message", error_msg)
                except Exception:
                    pass

                raise AuthenticationError(
                    f"Failed to refresh JWT token: {error_msg} (HTTP {response.status_code})"
                )

            # Parse response
            data = response.json()

            # Update token and expiration
            if "token" in data:
                self._token = data["token"]

            if "expiresAt" in data:
                self._expires_at = data["expiresAt"]
            elif "expires_at" in data:
                self._expires_at = data["expires_at"]

            # Optionally update refresh token if a new one is provided
            if "refreshToken" in data:
                self._refresh_token = data["refreshToken"]

        except requests.exceptions.RequestException as e:
            raise AuthenticationError(
                f"Failed to refresh JWT token: {str(e)}"
            ) from e
        except Exception as e:
            raise AuthenticationError(
                f"Unexpected error during token refresh: {str(e)}"
            ) from e

    def is_expired(self) -> bool:
        """Check if the JWT token is expired.

        Returns:
            bool: True if token is expired, False otherwise.
        """
        if self._expires_at is None:
            return False

        return time.time() >= self._expires_at

    def time_until_expiry(self) -> Optional[timedelta]:
        """Get time until token expires.

        Returns:
            Optional[timedelta]: Time until expiration, or None if no expiration set.
        """
        if self._expires_at is None:
            return None

        remaining_seconds = self._expires_at - time.time()
        return timedelta(seconds=max(0, remaining_seconds))

    @property
    def token_preview(self) -> str:
        """Get a preview of the JWT token for logging/debugging.

        Returns:
            str: Masked token showing only first and last few characters.
        """
        if not self._token:
            return "None"

        if len(self._token) <= 20:
            return "*" * len(self._token)

        return f"{self._token[:10]}...{self._token[-10:]}"

    def __repr__(self) -> str:
        """String representation of the auth handler.

        Returns:
            str: Safe representation with masked token.
        """
        return f"JWTAuth(token='{self.token_preview}', expires_at={self._expires_at})"