from typing import Optional, List
from fastapi.exceptions import RequestValidationError
from backend.models.permission.models import RoleDoc, UserRoleDoc, PermissionDoc
from bson import ObjectId


class UserRoleHandler:
    def __init__(self):
        pass

    async def assign_roles_to_user(self, user_id: str, role_ids: List[str]) -> Optional[UserRoleDoc]:
        """Assign roles to a user by updating or creating the UserRoleDoc"""
        if not user_id or not role_ids:
            raise RequestValidationError("user_id and role_ids are required.")

        # Validate that all role_ids exist in the role collection
        for role_id in role_ids:
            role_doc = await RoleDoc.get(role_id)
            if not role_doc:
                raise RequestValidationError(f"Role with id {role_id} not found.")

        # Remove duplicates from role_ids
        unique_role_ids = list(dict.fromkeys(role_ids))

        # Check if UserRoleDoc already exists for this user
        existing_user_role = await UserRoleDoc.find_one(UserRoleDoc.user_id == user_id)

        if existing_user_role:
            # Update existing UserRoleDoc
            existing_user_role.role_ids = unique_role_ids
            await existing_user_role.save()
            return existing_user_role
        else:
            # Create new UserRoleDoc
            user_role_doc = UserRoleDoc(
                user_id=user_id,
                role_ids=unique_role_ids
            )
            await user_role_doc.insert()
            return user_role_doc

    async def get_role_and_permission_by_user_id(self, user_id: str) -> tuple[list[str], list[str]]:
        """Get all role names and permission keys for a user by user_id"""
        # Query user roles
        user_role_doc = await UserRoleDoc.find_one(UserRoleDoc.user_id == user_id)
        if not user_role_doc or not user_role_doc.role_ids:
            # No roles assigned
            return [], []
        # Query all roles by role_ids
        roles = await RoleDoc.find({"_id": {"$in": user_role_doc.role_ids}}).to_list()
        role_names = [role.role_name for role in roles]
        # Collect all permission_ids from all roles
        all_permission_ids = []
        for role in roles:
            if role.permission_ids:
                all_permission_ids.extend(role.permission_ids)
        # Remove duplicates
        unique_permission_ids = list(dict.fromkeys(all_permission_ids))
        # Query all permissions by permission_ids
        if unique_permission_ids:
            permissions = await PermissionDoc.find({"_id": {"$in": unique_permission_ids}}).to_list()
            permission_keys = [perm.permission_key for perm in permissions]
        else:
            permission_keys = []
        return role_names, permission_keys