# Source code for gpiozero.pins.local

    # vim: set fileencoding=utf-8:
    #
    # GPIO Zero: a library for controlling the Raspberry Pi's GPIO pins
    #
    # Copyright (c) 2016-2021 Dave Jones <dave@waveform.org.uk>
    # Copyright (c) 2020 Ben Nuttall <ben@bennuttall.com>
    # Copyright (c) 2016 Andrew Scheller <github@loowis.durge.org>
    #
    # SPDX-License-Identifier: BSD-3-Clause

    from __future__ import (
        unicode_literals,
        absolute_import,
        print_function,
        division,
        )
    nstr = str
    str = type('')

    import io
    import errno
    import struct
    import warnings
    from collections import defaultdict
    from threading import Lock
    try:
        from time import monotonic
    except ImportError:
        from time import time as monotonic

    try:
        from spidev import SpiDev
    except ImportError:
        SpiDev = None

    from . import SPI
    from .pi import PiFactory, PiPin, SPI_HARDWARE_PINS, spi_port_device
    from .spi import SPISoftwareBus
    from ..devices import Device, SharedMixin
    from ..output_devices import OutputDevice
    from ..exc import DeviceClosed, PinUnknownPi, SPIInvalidClockMode

    def get_pi_revision():
        revision = None
        try:
            with io.open('/proc/device-tree/system/linux,revision', 'rb') as f:
                revision = hex(struct.unpack(nstr('>L'), f.read(4))[0])[2:]
        except IOError as e:
            if e.errno != errno.ENOENT:
                raise e
            with io.open('/proc/cpuinfo', 'r') as f:
                for line in f:
                    if line.startswith('Revision'):
                        revision = line.split(':')[1].strip().lower()
        if revision is not None:
            overvolted = revision.startswith('100')
            if overvolted:
                revision = revision[-4:]
            return int(revision, base=16)
        raise PinUnknownPi(
            'unable to locate Pi revision in /proc/device-tree or /proc/cpuinfo')

    class LocalPiFactory(PiFactory):
        """
        Extends :class:`~gpiozero.pins.pi.PiFactory`. Abstract base class
        representing pins attached locally to a Pi. This forms the base class for
        local-only pin interfaces (:class:`~gpiozero.pins.rpigpio.RPiGPIOPin`,
        :class:`~gpiozero.pins.rpio.RPIOPin`, and
        :class:`~gpiozero.pins.native.NativePin`).
        """
        pins = {}
        _reservations = defaultdict(list)
        _res_lock = Lock()

        def __init__(self):
            super(LocalPiFactory, self).__init__()
            # Override the reservations and pins dict to be this class' attributes.
            # This is a bit of a dirty hack, but ensures that anyone evil enough to
            # mix pin implementations doesn't try and control the same pin with
            # different backends
            self.pins = LocalPiFactory.pins
            self._reservations = LocalPiFactory._reservations
            self._res_lock = LocalPiFactory._res_lock

        def _get_revision(self):
            return get_pi_revision()

        def _get_spi_class(self, shared, hardware):
            return {
                (False, True):  LocalPiHardwareSPI,
                (True,  True):  LocalPiHardwareSPIShared,
                (False, False): LocalPiSoftwareSPI,
                (True,  False): LocalPiSoftwareSPIShared,
                }[shared, hardware]

        @staticmethod
        def ticks():
            return monotonic()

        @staticmethod
        def ticks_diff(later, earlier):
            # NOTE: technically the guarantee to always return a positive result
            # cannot be maintained in versions where monotonic() is not available
            # and we fall back to time(). However, in that situation we've no
            # access to a true monotonic source, and no idea how far the clock has
            # skipped back so this is the best we can do anyway.
            return max(0, later - earlier)

    class LocalPiPin(PiPin):
        """
        Extends :class:`~gpiozero.pins.pi.PiPin`. Abstract base class representing
        a multi-function GPIO pin attached to the local Raspberry Pi.
        """
        def _call_when_changed(self, ticks=None, state=None):
            """
            Overridden to provide default ticks from the local Pi factory.

            .. warning::

                The local pin factory uses a seconds-based monotonic value for
                its ticks but you *must not* rely upon this behaviour. Ticks are
                an opaque value that should only be compared with the associated
                :meth:`Factory.ticks_diff` method.
            """
            super(LocalPiPin, self)._call_when_changed(
                self._factory.ticks() if ticks is None else ticks,
                self.state if state is None else state)

    class LocalPiHardwareSPI(SPI):
        def __init__(self, clock_pin, mosi_pin, miso_pin, select_pin, pin_factory):
            self._port, self._device = spi_port_device(
                clock_pin, mosi_pin, miso_pin, select_pin)
            self._interface = None
            if SpiDev is None:
                raise ImportError('failed to import spidev')
            super(LocalPiHardwareSPI, self).__init__(pin_factory=pin_factory)
            to_reserve = {clock_pin, select_pin}
            if mosi_pin is not None:
                to_reserve.add(mosi_pin)
            if miso_pin is not None:
                to_reserve.add(miso_pin)
            self.pin_factory.reserve_pins(self, *to_reserve)
            self._interface = SpiDev()
            self._interface.open(self._port, self._device)
            self._interface.max_speed_hz = 500000

        def close(self):
            if self._interface is not None:
                self._interface.close()
            self._interface = None
            self.pin_factory.release_all(self)
            super(LocalPiHardwareSPI, self).close()

        @property
        def closed(self):
            return self._interface is None

        def __repr__(self):
            try:
                self._check_open()
                return 'SPI(port=%d, device=%d)' % (self._port, self._device)
            except DeviceClosed:
                return 'SPI(closed)'

        def transfer(self, data):
            """
            Writes data (a list of integer words where each word is assumed to have
            :attr:`bits_per_word` bits or less) to the SPI interface, and reads an
            equivalent number of words, returning them as a list of integers.
            """
            return self._interface.xfer2(data)

        def _get_clock_mode(self):
            return self._interface.mode

        def _set_clock_mode(self, value):
            self._interface.mode = value

        def _get_lsb_first(self):
            return self._interface.lsbfirst

        def _set_lsb_first(self, value):
            self._interface.lsbfirst = bool(value)

        def _get_select_high(self):
            return self._interface.cshigh

        def _set_select_high(self, value):
            self._interface.cshigh = bool(value)

        def _get_bits_per_word(self):
            return self._interface.bits_per_word

        def _set_bits_per_word(self, value):
            self._interface.bits_per_word = value

        def _get_rate(self):
            return self._interface.max_speed_hz

        def _set_rate(self, value):
            self._interface.max_speed_hz = int(value)

    class LocalPiSoftwareSPI(SPI):
        def __init__(self, clock_pin, mosi_pin, miso_pin, select_pin, pin_factory):
            self._bus = None
            self._select = None
            super(LocalPiSoftwareSPI, self).__init__(pin_factory=pin_factory)
            try:
                self._clock_phase = False
                self._lsb_first = False
                self._bits_per_word = 8
                self._bus = SPISoftwareBus(clock_pin, mosi_pin, miso_pin)
                self._select = OutputDevice(
                    select_pin, active_high=False, pin_factory=pin_factory)
            except:
                self.close()
                raise

        def _conflicts_with(self, other):
            return not (
                isinstance(other, LocalPiSoftwareSPI) and
                (self._select.pin.number != other._select.pin.number)
                )

        def close(self):
            if self._select:
                self._select.close()
            self._select = None
            if self._bus is not None:
                self._bus.close()
            self._bus = None
            super(LocalPiSoftwareSPI, self).close()

        @property
        def closed(self):
            return self._bus is None

        def __repr__(self):
            try:
                self._check_open()
                return 'SPI(clock_pin=%d, mosi_pin=%d, miso_pin=%d, select_pin=%d)' % (
                    self._bus.clock.pin.number,
                    self._bus.mosi.pin.number,
                    self._bus.miso.pin.number,
                    self._select.pin.number)
            except DeviceClosed:
                return 'SPI(closed)'

        def transfer(self, data):
            with self._bus.lock:
                self._select.on()
                try:
                    return self._bus.transfer(
                        data, self._clock_phase, self._lsb_first, self._bits_per_word)
                finally:
                    self._select.off()

        def _get_clock_mode(self):
            with self._bus.lock:
                return (not self._bus.clock.active_high) << 1 | self._clock_phase

        def _set_clock_mode(self, value):
            if not (0 <= value < 4):
                raise SPIInvalidClockMode("%d is not a valid clock mode" % value)
            with self._bus.lock:
                self._bus.clock.active_high = not (value & 2)
                self._clock_phase = bool(value & 1)

        def _get_lsb_first(self):
            return self._lsb_first

        def _set_lsb_first(self, value):
            self._lsb_first = bool(value)

        def _get_bits_per_word(self):
            return self._bits_per_word

        def _set_bits_per_word(self, value):
            if value < 1:
                raise ValueError('bits_per_word must be positive')
            self._bits_per_word = int(value)

        def _get_select_high(self):
            return self._select.active_high

        def _set_select_high(self, value):
            with self._bus.lock:
                self._select.active_high = value
                self._select.off()

    class LocalPiHardwareSPIShared(SharedMixin, LocalPiHardwareSPI):
        @classmethod
        def _shared_key(cls, clock_pin, mosi_pin, miso_pin, select_pin,
                        pin_factory):
            return (clock_pin, select_pin)

    class LocalPiSoftwareSPIShared(SharedMixin, LocalPiSoftwareSPI):
        @classmethod
        def _shared_key(cls, clock_pin, mosi_pin, miso_pin, select_pin,
                        pin_factory):
            return (clock_pin, select_pin)