"""Explicit interpretation of ProtoCAN registers with the UMP 167/v1 map.

This is a manually selected dictionary, not detection of the legacy service
CAN packet format or a claim that a particular firmware implements ProtoCAN.
"""
from protocan import protocan as pc
from protocan.gas_167 import REGISTERS, describe_word


def decode_gas167(frame, node):
    result = pc.decode(frame.can_id, frame.data, ide=frame.ide, rtr=frame.rtr)
    result.device_label = "УМП %d (выбран вручную)" % node
    result.protocol = "УМП %d / ProtoCAN GAS 167/v1" % node
    if not frame.ide or frame.rtr or frame.is_error:
        return result
    if result.id.msg_type not in (pc.MsgType.GENERAL_ADDRESS_SPACE,
                                  pc.MsgType.MODBUS_HOLDING):
        return result
    if result.id.msg_type == pc.MsgType.GENERAL_ADDRESS_SPACE:
        start = result.id.body
    else:
        start, _count = pc.split_modbus(result.id.body)
    words = result.registers
    if words is None:
        return result
    labels = []
    for address, value in words or [(start, None)]:
        offset = address if 0 <= address < 128 else address - 0x5000
        label = "0x%04X" % address
        if 0 <= offset < len(REGISTERS):
            entry = REGISTERS[offset]
            label += " · " + entry['description']
            result.fields += [
                ("  УМП 167/v1 0x%04X" % address, entry['description']),
                ("  Назначенные ID УМП 1/2", "%d / %d" % (entry['ump1_id'], entry['ump2_id'])),
                ("  Доступ", entry['access']),
            ]
        else:
            label += " · вне карты 167/v1"
        if value is not None:
            label += " = %d [0x%04X]" % (value, value)
            description = describe_word(offset, value)
            if description:
                label += " — " + description
                result.fields.append(("  Биты 0x%04X" % address, description))
        labels.append(label)
    result.summary = "УМП %d · GAS 167/v1%s: %s" % (
        node, " запрос" if not words else "", "; ".join(labels))
    result.fields.append(("  Карта", "167/v1 выбрана вручную"))
    return result