# Source code for mopidy.config.types

    import logging
    import re
    import socket

    from mopidy.config import validators
    from mopidy.internal import log, path

    def decode(value):
        if isinstance(value, bytes):
            value = value.decode(errors="surrogateescape")

        for char in ("\\", "\n", "\t"):
            value = value.replace(
                char.encode(encoding="unicode-escape").decode(), char
            )

        return value

    def encode(value):
        if isinstance(value, bytes):
            value = value.decode(errors="surrogateescape")

        for char in ("\\", "\n", "\t"):
            value = value.replace(
                char, char.encode(encoding="unicode-escape").decode()
            )

        return value

    class DeprecatedValue:
        pass

    class _TransformedValue(str):
        def __new__(cls, original, transformed):
            return super().__new__(cls, transformed)

        def __init__(self, original, transformed):
            self.original = original

    class ConfigValue:
        """Represents a config key's value and how to handle it.

        Normally you will only be interacting with sub-classes for config values
        that encode either deserialization behavior and/or validation.

        Each config value should be used for the following actions:

        1. Deserializing from a raw string and validating, raising ValueError on
           failure.
        2. Serializing a value back to a string that can be stored in a config.
        3. Formatting a value to a printable form (useful for masking secrets).

        :class:`None` values should not be deserialized, serialized or formatted,
        the code interacting with the config should simply skip None config values.
        """

        def deserialize(self, value):
            """Cast raw string to appropriate type."""
            return decode(value)

        def serialize(self, value, display=False):
            """Convert value back to string for saving."""
            if value is None:
                return ""
            return str(value)

    class Deprecated(ConfigValue):
        """Deprecated value.

        Used for ignoring old config values that are no longer in use, but should
        not cause the config parser to crash.
        """

        def deserialize(self, value):
            return DeprecatedValue()

        def serialize(self, value, display=False):
            return DeprecatedValue()

    class String(ConfigValue):
        """String value.

        Is decoded as utf-8 and \\n \\t escapes should work and be preserved.
        """

        def __init__(self, optional=False, choices=None, transformer=None):
            self._required = not optional
            self._choices = choices
            self._transformer = transformer

        def deserialize(self, value):
            value = decode(value).strip()
            validators.validate_required(value, self._required)
            if not value:
                return None

            # This is necessary for backwards-compatibility, in case subclasses
            # aren't calling their parent constructor.
            transformer = getattr(self, "_transformer", None)
            if transformer:
                transformed_value = transformer(value)
                value = _TransformedValue(value, transformed_value)

            validators.validate_choice(value, self._choices)
            return value

        def serialize(self, value, display=False):
            if value is None:
                return ""
            if isinstance(value, _TransformedValue):
                value = value.original
            return encode(value)

    class Secret(String):
        """Secret string value.

        Is decoded as utf-8 and \\n \\t escapes should work and be preserved.

        Should be used for passwords, auth tokens etc. Will mask value when being
        displayed.
        """

        def __init__(self, optional=False, choices=None, transformer=None):
            super().__init__(
                optional=optional,
                choices=None,  # Choices doesn't make sense for secrets
                transformer=transformer,
            )

        def serialize(self, value, display=False):
            if value is not None and display:
                return "********"
            return super().serialize(value, display)

    class Integer(ConfigValue):
        """Integer value."""

        def __init__(
            self, minimum=None, maximum=None, choices=None, optional=False
        ):
            self._required = not optional
            self._minimum = minimum
            self._maximum = maximum
            self._choices = choices

        def deserialize(self, value):
            value = decode(value)
            validators.validate_required(value, self._required)
            if not value:
                return None
            value = int(value)
            validators.validate_choice(value, self._choices)
            validators.validate_minimum(value, self._minimum)
            validators.validate_maximum(value, self._maximum)
            return value

    class Float(ConfigValue):
        """Float value."""

        def __init__(self, minimum=None, maximum=None, optional=False):
            self._required = not optional
            self._minimum = minimum
            self._maximum = maximum

        def deserialize(self, value):
            value = decode(value)
            validators.validate_required(value, self._required)
            if not value:
                return None
            value = float(value)
            validators.validate_minimum(value, self._minimum)
            validators.validate_maximum(value, self._maximum)
            return value

    class Boolean(ConfigValue):
        """Boolean value.

        Accepts ``1``, ``yes``, ``true``, and ``on`` with any casing as
        :class:`True`.

        Accepts ``0``, ``no``, ``false``, and ``off`` with any casing as
        :class:`False`.
        """

        true_values = ("1", "yes", "true", "on")
        false_values = ("0", "no", "false", "off")

        def __init__(self, optional=False):
            self._required = not optional

        def deserialize(self, value):
            value = decode(value)
            validators.validate_required(value, self._required)
            if not value:
                return None
            if value.lower() in self.true_values:
                return True
            elif value.lower() in self.false_values:
                return False
            raise ValueError(f"invalid value for boolean: {value!r}")

        def serialize(self, value, display=False):
            if value is True:
                return "true"
            elif value in (False, None):
                return "false"
            else:
                raise ValueError(f"{value!r} is not a boolean")

    class Pair(ConfigValue):
        """Pair value

        The value is expected to be a pair of elements, separated by a specified delimiter.
        Values can optionally not be a pair, in which case the whole input is provided for
        both sides of the value.
        """

        def __init__(
            self, optional=False, optional_pair=False, separator="|", subtypes=None
        ):
            self._required = not optional
            self._optional_pair = optional_pair
            self._separator = separator
            if subtypes:
                self._subtypes = subtypes
            else:
                self._subtypes = (String(), String())

        def deserialize(self, value):
            raw_value = decode(value).strip()
            validators.validate_required(raw_value, self._required)
            if not raw_value:
                return None

            if self._separator in raw_value:
                values = raw_value.split(self._separator, 1)
            elif self._optional_pair:
                values = (raw_value, raw_value)
            else:
                raise ValueError(
                    f"Config value must include {self._separator!r} separator: {raw_value}"
                )

            return (
                self._subtypes[0].deserialize(encode(values[0])),
                self._subtypes[1].deserialize(encode(values[1])),
            )

        def serialize(self, value, display=False):
            serialized_first_value = self._subtypes[0].serialize(
                value[0], display=display
            )
            serialized_second_value = self._subtypes[1].serialize(
                value[1], display=display
            )

            if (
                not display
                and self._optional_pair
                and serialized_first_value == serialized_second_value
            ):
                return serialized_first_value
            else:
                return "{0}{1}{2}".format(
                    serialized_first_value,
                    self._separator,
                    serialized_second_value,
                )

    class List(ConfigValue):
        """List value.

        Supports elements split by commas or newlines. Newlines take precedence and
        empty list items will be filtered out.

        Enforcing unique entries in the list will result in a set data structure
        being used. This does not preserve ordering, which could result in the
        serialized output being unstable.
        """

        def __init__(self, optional=False, unique=False, subtype=None):
            self._required = not optional
            self._unique = unique
            self._subtype = subtype if subtype else String()

        def deserialize(self, value):
            value = decode(value)
            if "\n" in value:
                values = re.split(r"\s*\n\s*", value)
            else:
                values = re.split(r"\s*,\s*", value)

            # This is necessary for backwards-compatibility, in case subclasses
            # aren't calling their parent constructor.
            subtype = getattr(self, "_subtype", String())

            values_iter = (
                subtype.deserialize(v.strip()) for v in values if v.strip()
            )
            if self._unique:
                values = frozenset(values_iter)
            else:
                values = tuple(values_iter)

            validators.validate_required(values, self._required)
            return values

        def serialize(self, value, display=False):
            if not value:
                return ""

            # This is necessary for backwards-compatibility, in case subclasses
            # aren't calling their parent constructor.
            subtype = getattr(self, "_subtype", String())

            serialized_values = []
            for item in value:
                serialized_value = subtype.serialize(item, display=display)
                if serialized_value:
                    serialized_values.append(serialized_value)

            return "\n  " + "\n  ".join(serialized_values)

    class LogColor(ConfigValue):

        def deserialize(self, value):
            value = decode(value)
            validators.validate_choice(value.lower(), log.COLORS)
            return value.lower()

        def serialize(self, value, display=False):
            if value.lower() in log.COLORS:
                return encode(value.lower())
            return ""

    class LogLevel(ConfigValue):
        """Log level value.

        Expects one of ``critical``, ``error``, ``warning``, ``info``, ``debug``,
        ``trace``, or ``all``, with any casing.
        """

        levels = {
            "critical": logging.CRITICAL,
            "error": logging.ERROR,
            "warning": logging.WARNING,
            "info": logging.INFO,
            "debug": logging.DEBUG,
            "trace": log.TRACE_LOG_LEVEL,
            "all": logging.NOTSET,
        }

        def deserialize(self, value):
            value = decode(value)
            validators.validate_choice(value.lower(), self.levels.keys())
            return self.levels.get(value.lower())

        def serialize(self, value, display=False):
            lookup = {v: k for k, v in self.levels.items()}
            if value in lookup:
                return encode(lookup[value])
            return ""

    class Hostname(ConfigValue):
        """Network hostname value."""

        def __init__(self, optional=False):
            self._required = not optional

        def deserialize(self, value, display=False):
            value = decode(value).strip()
            validators.validate_required(value, self._required)
            if not value:
                return None

            socket_path = path.get_unix_socket_path(value)
            if socket_path is not None:
                path_str = Path(not self._required).deserialize(socket_path)
                return f"unix:{path_str}"

            try:
                socket.getaddrinfo(value, None)
            except OSError:
                raise ValueError("must be a resolveable hostname or valid IP")

            return value

    class Port(Integer):
        """Network port value.

        Expects integer in the range 0-65535, zero tells the kernel to simply
        allocate a port for us.
        """

        def __init__(self, choices=None, optional=False):
            super().__init__(
                minimum=0, maximum=2**16 - 1, choices=choices, optional=optional
            )

    # Keep this for backwards compatibility
    class _ExpandedPath(_TransformedValue):
        pass

    class Path(ConfigValue):
        """File system path.

        The following expansions of the path will be done:

        - ``~`` to the current user's home directory
        - ``$XDG_CACHE_DIR`` according to the XDG spec
        - ``$XDG_CONFIG_DIR`` according to the XDG spec
        - ``$XDG_DATA_DIR`` according to the XDG spec
        - ``$XDG_MUSIC_DIR`` according to the XDG spec
        """

        def __init__(self, optional=False):
            self._required = not optional

        def deserialize(self, value):
            value = decode(value).strip()
            expanded = path.expand_path(value)
            validators.validate_required(value, self._required)
            validators.validate_required(expanded, self._required)
            if not value or expanded is None:
                return None
            return _ExpandedPath(value, expanded)

        def serialize(self, value, display=False):
            if value is None:
                return ""
            if isinstance(value, _ExpandedPath):
                value = value.original
            if isinstance(value, bytes):
                value = value.decode(errors="surrogateescape")
            return value