"""C2 task → Simulation output mapping.

apply_task_to_simulation() writes task output into the simulation's
execution_result field and marks the task as mapping_applied=True so that
the operation is idempotent (safe to call multiple times for the same task).

Caller is responsible for committing the session.
"""
from __future__ import annotations

from datetime import UTC, datetime

from backend.app.models.c2_task import C2Task
from backend.app.models.simulation import Simulation


def apply_task_to_simulation(task: C2Task, simulation: Simulation) -> None:
    """Write task output into simulation.execution_result (append, newline-separated).

    No-op if task.mapping_applied is already True or task.output is empty.
    Marks task.mapping_applied = True on completion.
    """
    if task.mapping_applied:
        return

    output = (task.output or "").strip()
    if not output:
        task.mapping_applied = True
        return

    existing = (simulation.execution_result or "").rstrip("\n")
    if existing:
        simulation.execution_result = existing + "\n" + output
    else:
        simulation.execution_result = output

    simulation.updated_at = datetime.now(UTC)
    task.mapping_applied = True