def prepare_input_measures(property_recommendations, goal):
    """
    Basic function to convert recommendations_to_upload to a format that is
    suitable for the optimiser - large
    :param property_recommendations:   object containing the recommendations, created in the plan trigger api
    :param goal:    goal to be optimised for, should be one of the keys in gain_map. E.g. if the gain is SAP points,
                    the goal should reflect that desired gain
    :return:    Nested list of input measures
    """

    goal_map = {
        "Increase EPC": "sap_points"
    }

    goal_key = goal_map[goal]
    if not goal_key:
        raise NotImplementedError("Not implemented this gain type - investigate me")

    ventilation_rec = [rec for rec in property_recommendations if rec[0]["type"] == "mechanical_ventilation"][0]

    input_measures = []
    for recs in property_recommendations:

        # We don't actually optimise ventilation
        if recs[0]["type"] == "mechanical_ventilation":
            continue

        if recs[0]["type"] in ["internal_wall_insulation", "external_wall_insulation", "cavity_wall_insulation"]:
            # Wall insulation and mechanical ventilation are paired. You can't have wall insulation without mechanical
            # ventilation
            
            ventilation_cost = ventilation_rec[0]["total"] if ventilation_rec else 0
            ventilation_gain = ventilation_rec[0][goal_key] if ventilation_rec else 0

            input_measures.append(
                [
                    {
                        "id": rec["recommendation_id"],
                        "cost": rec["total"] + ventilation_cost,
                        "gain": rec[goal_key] + ventilation_gain,
                        "type": rec["type"]
                    }
                    for rec in recs
                ]
            )
        else:
            input_measures.append(
                [
                    {
                        "id": rec["recommendation_id"],
                        "cost": rec["total"],
                        "gain": rec[goal_key],
                        "type": rec["type"]
                    }
                    for rec in recs
                ]
            )

    return input_measures