# Copyright (c) 2026 Roman Shaban. All rights reserved.

# Licensed under the Apache License 2.0.

# Part of the CIOS / Onto-Protocol Ecosystem.

from onto_models import OntoTask

ALLOWED_TRANSITIONS = {

    "pending": ["running", "blocked", "failed"],

    "running": ["completed", "blocked", "failed"],

    "blocked": [],

    "failed": [],

    "completed": []

}

def transition_task(task: OntoTask, new_status: str, output: str | None = None):

    current_status = task.result.status

    if new_status not in ALLOWED_TRANSITIONS[current_status]:

        raise ValueError(

            f"Invalid state transition: {current_status} -> {new_status}"

        )

    task.result.status = new_status

    if output is not None:

        task.result.output = output

    return task