"""Thin binding to the Balsam-167 physical EEPROM reader in the shared C core.

No address conversion, endian/CRC codec or memory-size inference in this port.
The caller owns serial scheduling, timeouts, cancellation and dump file storage.
"""
import ctypes as ct
from .native import get_native_protocol, NativeProtocolUnavailable


class _State(ct.Structure):
    _fields_ = [(name, ct.c_uint32) for name in ("controller", "start", "length", "received")]


def _api(name, args, result):
    try:
        function = getattr(get_native_protocol().lib, "pcan_abi_periph28335_eeprom_" + name)
    except AttributeError as error:
        raise NativeProtocolUnavailable("Обновите templates/setprotocol.dll: нет API чтения EEPROM 167") from error
    function.argtypes, function.restype = args, result
    return function


def capacity(m95m02=False):
    return int(_api("capacity_profile", [ct.c_uint], ct.c_uint32)(int(m95m02)))


def write_request(controller, destination, source, length, *, m95m02=False):
    values = (controller, destination, source, length)
    if any(type(v) is not int or not 0 <= v <= 0xffffffff for v in values):
        raise ValueError("Адрес или длина вне диапазона uint32")
    output = ct.create_string_buffer(18)
    size = _api("write_profile", [ct.c_uint32]*4 + [ct.c_uint, ct.c_void_p, ct.c_size_t], ct.c_size_t)(
        *values, int(m95m02), output, len(output))
    if not size:
        raise ValueError("LengthLoad или адрес выходит за область прошивки выбранной EEPROM либо пересекает область параметров. "
                         "Предел от адреса 0: AT25256B — 32508 байт, M95M02 — 261884 байт.")
    return output.raw[:size]


class Reader:
    def __init__(self, controller, start, length, *, block=False, m95m02=False):
        self.m95m02 = bool(m95m02)
        if m95m02 and not block:
            raise ValueError("Для M95M02 необходимо блочное чтение")
        self.block = block
        for value in (controller, start, length):
            if type(value) is not int or not 0 <= value <= 0xffffffff:
                raise ValueError("Адрес и длина должны быть неотрицательными целыми числами")
        self._state = _State()
        result = _api("begin_profile", [ct.c_void_p, ct.c_uint32, ct.c_uint32, ct.c_uint32, ct.c_uint], ct.c_int)(
            ct.byref(self._state), controller, start, length, int(self.m95m02))
        if result:
            raise ValueError(f"Диапазон вне выбранной EEPROM: 0…0x{capacity(self.m95m02)-1:X}; длина должна быть больше нуля")
        if block:
            # Detect an old DLL before the GUI acquires ownership of the port.
            _api("block_request_profile", [ct.c_void_p, ct.c_void_p, ct.c_size_t, ct.c_uint], ct.c_size_t)
            _api("block_accept_profile", [ct.c_void_p, ct.c_void_p, ct.c_size_t, ct.c_void_p, ct.c_size_t, ct.c_uint], ct.c_int)
            self.expected

    @property
    def received(self): return int(self._state.received)
    @property
    def length(self): return int(self._state.length)
    @property
    def start(self): return int(self._state.start)

    @property
    def expected(self):
        if not self.block: return 8
        return int(_api("block_expected_profile", [ct.c_void_p, ct.c_uint], ct.c_size_t)(ct.byref(self._state), int(self.m95m02)))

    def request(self):
        output = ct.create_string_buffer(8)
        args = [ct.c_void_p, ct.c_void_p, ct.c_size_t] + ([ct.c_uint] if self.block else [])
        extra = [int(self.m95m02)] if self.block else []
        size = _api("block_request_profile" if self.block else "request", args, ct.c_size_t)(
            ct.byref(self._state), output, len(output), *extra)
        return output.raw[:size]

    def accept(self, reply):
        output = ct.create_string_buffer(240 if self.block else 2)
        reply = bytes(reply)
        args = [ct.c_void_p, ct.c_void_p, ct.c_size_t, ct.c_void_p, ct.c_size_t] + ([ct.c_uint] if self.block else [])
        extra = [int(self.m95m02)] if self.block else []
        size = _api("block_accept_profile" if self.block else "accept", args, ct.c_int)(
            ct.byref(self._state), reply, len(reply), output, len(output), *extra)
        if size < 0:
            errors = {-3: "Неверная длина ответа EEPROM", -4: "Ошибка CRC ответа EEPROM",
                      -5: "Неверный адрес контроллера или команда ответа EEPROM"}
            raise ValueError(errors.get(size, "Ответ EEPROM не соответствует активному чтению"))
        return output.raw[:size]