"""当前业务口径：安全监控判开停，重大设备只提供风量。"""

SOURCE_SYSTEM_BY_ROLE = {'fan_state': 'safety', 'flow': 'equipment'}


def source_policy():
    return {'version': 'main-fan-sources-2026-10-21',
            'fan_state': 'safety', 'flow': 'equipment',
            'equipment_state_used_for_switch': False}


def select_history_points(points):
    return [point for point in points if SOURCE_SYSTEM_BY_ROLE.get(point.role) == point.system]


def validate_history_sources(points):
    for point in points:
        if SOURCE_SYSTEM_BY_ROLE.get(point.role) != point.system:
            raise ValueError('开停以安全监控为准，重大设备只取风量；请调整测点计划：'
                             + point.node_id + ' (' + point.system + '/' + point.role + ')')