"""FastAPI dependencies: auth, tenant context, permissions."""
from fastapi import Depends, HTTPException, status, Request
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session
from app.database import get_db
from app.core.security import decode_access_token
from app.core.permissions import Role, has_role
from app.models.user import User
from typing import Set, Optional

security_scheme = HTTPBearer(auto_error=False)


async def get_current_user(
    request: Request,
    credentials: HTTPAuthorizationCredentials = Depends(security_scheme),
    db: Session = Depends(get_db),
) -> User:
    """Extract and validate the JWT token, return current user."""
    if not credentials:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Not authenticated",
            headers={"WWW-Authenticate": "Bearer"},
        )

    try:
        payload = decode_access_token(credentials.credentials)
        user_id = int(payload["sub"])
        tenant_id = payload["tid"]
        role = payload["role"]
    except Exception:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid or expired token",
            headers={"WWW-Authenticate": "Bearer"},
        )

    user = db.query(User).filter(User.id == user_id).first()
    if not user or not user.is_active:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User not found or inactive",
        )

    # Set tenant context on request state
    request.state.tenant_id = user.tenant_id
    request.state.user_id = user.id
    request.state.user_role = user.role

    return user


def require_roles(*roles: Role):
    """Dependency factory: require one of the specified roles."""
    role_set: Set[Role] = set(roles)

    async def _check(user: User = Depends(get_current_user)) -> User:
        if not has_role(user.role, role_set):
            raise HTTPException(
                status_code=status.HTTP_403_FORBIDDEN,
                detail=f"Requires role: {', '.join(r.value for r in role_set)}",
            )
        return user

    return _check


def get_tenant_id(user: User = Depends(get_current_user)) -> int:
    """Extract tenant_id from current user."""
    return user.tenant_id


# Common dependency aliases
CurrentUser = Depends(get_current_user)
TenantId = Depends(get_tenant_id)