from fastapi import HTTPException, Depends, status, Request
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
import httpx
import structlog
from typing import Dict, Any, Optional

from app.core.config import settings

logger = structlog.get_logger()
security = HTTPBearer(auto_error=False)  # ✅ Don't auto-error, we'll handle manually

class AuthInfo:
    """Authentication information"""
    def __init__(self, user_id: str, email: str, tenant_id: str, roles: list):
        self.user_id = user_id
        self.email = email  
        self.tenant_id = tenant_id
        self.roles = roles

async def get_current_user(
    request: Request,
    credentials: Optional[HTTPAuthorizationCredentials] = Depends(security)
) -> AuthInfo:
    """Get current user from gateway headers or token verification"""
    
    # ✅ OPTION 1: Check for gateway headers (preferred when using gateway)
    user_id = request.headers.get("X-User-ID")
    email = request.headers.get("X-User-Email")
    tenant_id = request.headers.get("X-Tenant-ID")
    roles_header = request.headers.get("X-User-Roles", "")
    
    if user_id and email and tenant_id:
        # Gateway already authenticated the user
        roles = roles_header.split(",") if roles_header else ["user"]
        logger.info("Authenticated via gateway headers", user_id=user_id, email=email)
        return AuthInfo(user_id, email, tenant_id, roles)
    
    # ✅ OPTION 2: Direct token verification (when not using gateway)
    if not credentials:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Authentication required (no token or gateway headers)"
        )
    
    try:
        async with httpx.AsyncClient(timeout=5.0) as client:
            response = await client.post(
                f"{settings.AUTH_SERVICE_URL}/api/v1/auth/verify",
                headers={"Authorization": f"Bearer {credentials.credentials}"}
            )
            
            if response.status_code == 200:
                user_data = response.json()
                logger.info("Authenticated via direct token", user_id=user_data.get("user_id"))
                return AuthInfo(
                    user_id=user_data["user_id"],
                    email=user_data["email"],
                    tenant_id=user_data["tenant_id"],
                    roles=user_data.get("roles", ["user"])
                )
            else:
                logger.warning("Token verification failed", status_code=response.status_code)
                raise HTTPException(
                    status_code=status.HTTP_401_UNAUTHORIZED,
                    detail="Invalid authentication credentials"
                )
    except httpx.RequestError as e:
        logger.error("Auth service unavailable", error=str(e))
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="Authentication service unavailable"
        )