"""Tiny rover adapter stub for NovaPlan MVP.

Demonstrates how a rover planner could expose a LocalProblem and consume
shared signals via delta-sync, returning a PlanDelta for governance.
"""
from __future__ import annotations

from nova_plan.planner import LocalProblem, simple_admm_step, delta_sync
from nova_plan.contracts import PlanDelta


def make_local_problem() -> LocalProblem:
    def objective(local_vars, shared_vars):
        # Simple objective: prefer lower local values while considering shareds
        return sum(local_vars.values()) - 0.5 * sum(shared_vars.values())

    return LocalProblem(id="rover-1", objective=objective, variables={"x": 1.0, "y": 0.5})


class RoverAdapter:
    def __init__(self):
        self.local = make_local_problem()

    def step(self, shared_vars: dict[str, float]) -> PlanDelta:
        # Perform a tiny ADMM-like step and emit a delta reflecting local changes
        simple_admm_step(self.local, shared_vars, rho=1.0)
        return delta_sync(self.local, shared_vars, agent_id=self.local.id, rho=1.0)