"""schema is a library for validating Python data structures, such as those
obtained from config-files, forms, external services or command-line
parsing, converted from JSON/YAML (or something else) to Python data-types."""

import re

__version__ = "0.6.6"
__all__ = [
    "Schema",
    "And",
    "Or",
    "Regex",
    "Optional",
    "Use",
    "SchemaError",
    "SchemaWrongKeyError",
    "SchemaMissingKeyError",
    "SchemaUnexpectedTypeError",
]


class SchemaError(Exception):
    """Error during Schema validation."""

    def __init__(self, autos, errors=None):
        self.autos = autos if type(autos) is list else [autos]
        self.errors = errors if type(errors) is list else [errors]
        Exception.__init__(self, self.code)

    @property
    def code(self):
        """
        Removes duplicates values in auto and error list.
        parameters.
        """

        def uniq(seq):
            """
            Utility function that removes duplicate.
            """
            seen = set()
            seen_add = seen.add
            # This way removes duplicates while preserving the order.
            return [x for x in seq if x not in seen and not seen_add(x)]

        data_set = uniq(i for i in self.autos if i is not None)
        error_list = uniq(i for i in self.errors if i is not None)
        if error_list:
            return "\n".join(error_list)
        return "\n".join(data_set)


class SchemaWrongKeyError(SchemaError):
    """Error Should be raised when an unexpected key is detected within the
    data set being."""

    pass


class SchemaMissingKeyError(SchemaError):
    """Error should be raised when a mandatory key is not found within the
    data set being vaidated"""

    pass


class SchemaUnexpectedTypeError(SchemaError):
    """Error should be raised when a type mismatch is detected within the
    data set being validated."""

    pass


class And(object):
    """
    Utility function to combine validation directives in AND Boolean fashion.
    """

    def __init__(self, *args, **kw):
        self._args = args
        assert set(kw).issubset(["error", "schema", "ignore_extra_keys"])
        self._error = kw.get("error")
        self._ignore_extra_keys = kw.get("ignore_extra_keys", False)
        # You can pass your inherited Schema class.
        self._schema = kw.get("schema", Schema)

    def __repr__(self):
        return "%s(%s)" % (
            self.__class__.__name__,
            ", ".join(repr(a) for a in self._args),
        )

    def validate(self, data):
        """
        Validate data using defined sub schema/expressions ensuring all
        values are valid.
        :param data: to be validated with sub defined schemas.
        :return: returns validated data
        """
        for s in [
            self._schema(
                s, error=self._error, ignore_extra_keys=self._ignore_extra_keys
            )
            for s in self._args
        ]:
            data = s.validate(data)
        return data


class Or(And):
    """Utility function to combine validation directives in a OR Boolean
    fashion."""

    def validate(self, data):
        """
        Validate data using sub defined schema/expressions ensuring at least
        one value is valid.
        :param data: data to be validated by provided schema.
        :return: return validated data if not validation
        """
        x = SchemaError([], [])
        for s in [
            self._schema(
                s, error=self._error, ignore_extra_keys=self._ignore_extra_keys
            )
            for s in self._args
        ]:
            try:
                return s.validate(data)
            except SchemaError as _x:
                x = _x
        raise SchemaError(
            ["%r did not validate %r" % (self, data)] + x.autos,
            [self._error.format(data) if self._error else None] + x.errors,
        )


class Regex(object):
    """
    Enables schema.py to validate string using regular expressions.
    """

    # Map all flags bits to a more readable description
    NAMES = [
        "re.ASCII",
        "re.DEBUG",
        "re.VERBOSE",
        "re.UNICODE",
        "re.DOTALL",
        "re.MULTILINE",
        "re.LOCALE",
        "re.IGNORECASE",
        "re.TEMPLATE",
    ]

    def __init__(self, pattern_str, flags=0, error=None):
        self._pattern_str = pattern_str
        flags_list = [
            Regex.NAMES[i]
            for i, f in enumerate("{0:09b}".format(flags))  # Name for each bit
            if f != "0"
        ]

        if flags_list:
            self._flags_names = ", flags=" + "|".join(flags_list)
        else:
            self._flags_names = ""

        self._pattern = re.compile(pattern_str, flags=flags)
        self._error = error

    def __repr__(self):
        return "%s(%r%s)" % (
            self.__class__.__name__,
            self._pattern_str,
            self._flags_names,
        )

    def validate(self, data):
        """
        Validated data using defined regex.
        :param data: data to be validated
        :return: return validated data.
        """
        e = self._error

        try:
            if self._pattern.search(data):
                return data
            else:
                raise SchemaError("%r does not match %r" % (self, data), e)
        except TypeError:
            raise SchemaError("%r is not string nor buffer" % data, e)


class Use(object):
    """
    For more general use cases, you can use the Use class to transform
    the data while it is being validate.
    """

    def __init__(self, callable_, error=None):
        assert callable(callable_)
        self._callable = callable_
        self._error = error

    def __repr__(self):
        return "%s(%r)" % (self.__class__.__name__, self._callable)

    def validate(self, data):
        try:
            return self._callable(data)
        except SchemaError as x:
            raise SchemaError(
                [None] + x.autos,
                [self._error.format(data) if self._error else None] + x.errors,
            )
        except BaseException as x:
            f = _callable_str(self._callable)
            raise SchemaError(
                "%s(%r) raised %r" % (f, data, x),
                self._error.format(data) if self._error else None,
            )


COMPARABLE, CALLABLE, VALIDATOR, TYPE, DICT, ITERABLE = range(6)


def _priority(s):
    """Return priority for a given object."""
    if type(s) in (list, tuple, set, frozenset):
        return ITERABLE
    if type(s) is dict:
        return DICT
    if issubclass(type(s), type):
        return TYPE
    if hasattr(s, "validate"):
        return VALIDATOR
    if callable(s):
        return CALLABLE
    else:
        return COMPARABLE


class Schema(object):
    """
    Entry point of the library, use this class to instantiate validation
    schema for the data that will be validated.
    """

    def __init__(self, schema, error=None, ignore_extra_keys=False):
        self._schema = schema
        self._error = error
        self._ignore_extra_keys = ignore_extra_keys

    def __repr__(self):
        return "%s(%r)" % (self.__class__.__name__, self._schema)

    @staticmethod
    def _dict_key_priority(s):
        """Return priority for a given key object."""
        if isinstance(s, Optional):
            return _priority(s._schema) + 0.5
        return _priority(s)

    def validate(self, data):
        Schema = self.__class__
        s = self._schema
        e = self._error
        i = self._ignore_extra_keys
        flavor = _priority(s)
        if flavor == ITERABLE:
            data = Schema(type(s), error=e).validate(data)
            o = Or(*s, error=e, schema=Schema, ignore_extra_keys=i)
            return type(data)(o.validate(d) for d in data)
        if flavor == DICT:
            data = Schema(dict, error=e).validate(data)
            new = type(data)()  # new - is a dict of the validated values
            coverage = set()  # matched schema keys
            # for each key and value find a schema entry matching them, if any
            sorted_skeys = sorted(s, key=self._dict_key_priority)
            for key, value in data.items():
                for skey in sorted_skeys:
                    svalue = s[skey]
                    try:
                        nkey = Schema(skey, error=e).validate(key)
                    except SchemaError:
                        pass
                    else:
                        try:
                            nvalue = Schema(
                                svalue, error=e, ignore_extra_keys=i
                            ).validate(value)
                        except SchemaError as x:
                            k = "Key '%s' error:" % nkey
                            raise SchemaError([k] + x.autos, [e] + x.errors)
                        else:
                            new[nkey] = nvalue
                            coverage.add(skey)
                            break
            required = set(k for k in s if type(k) is not Optional)
            if not required.issubset(coverage):
                missing_keys = required - coverage
                s_missing_keys = ", ".join(
                    repr(k) for k in sorted(missing_keys, key=repr)
                )
                raise SchemaMissingKeyError(
                    "Missing keys: " + s_missing_keys, e
                )
            if not self._ignore_extra_keys and (len(new) != len(data)):
                wrong_keys = set(data.keys()) - set(new.keys())
                s_wrong_keys = ", ".join(
                    repr(k) for k in sorted(wrong_keys, key=repr)
                )
                raise SchemaWrongKeyError(
                    "Wrong keys %s in %r" % (s_wrong_keys, data),
                    e.format(data) if e else None,
                )

            # Apply default-having optionals that haven't been used:
            defaults = (
                set(
                    k
                    for k in s
                    if type(k) is Optional and hasattr(k, "default")
                )
                - coverage
            )
            for default in defaults:
                new[default.key] = default.default

            return new
        if flavor == TYPE:
            if isinstance(data, s):
                return data
            else:
                raise SchemaUnexpectedTypeError(
                    "%r should be instance of %r" % (data, s.__name__),
                    e.format(data) if e else None,
                )
        if flavor == VALIDATOR:
            try:
                return s.validate(data)
            except SchemaError as x:
                raise SchemaError([None] + x.autos, [e] + x.errors)
            except BaseException as x:
                raise SchemaError(
                    "%r.validate(%r) raised %r" % (s, data, x),
                    self._error.format(data) if self._error else None,
                )
        if flavor == CALLABLE:
            f = _callable_str(s)
            try:
                if s(data):
                    return data
            except SchemaError as x:
                raise SchemaError([None] + x.autos, [e] + x.errors)
            except BaseException as x:
                raise SchemaError(
                    "%s(%r) raised %r" % (f, data, x),
                    self._error.format(data) if self._error else None,
                )
            raise SchemaError("%s(%r) should evaluate to True" % (f, data), e)
        if s == data:
            return data
        else:
            raise SchemaError(
                "%r does not match %r" % (s, data),
                e.format(data) if e else None,
            )


class Optional(Schema):
    """Marker for an optional part of the validation Schema."""

    _MARKER = object()

    def __init__(self, *args, **kwargs):
        default = kwargs.pop("default", self._MARKER)
        super(Optional, self).__init__(*args, **kwargs)
        if default is not self._MARKER:
            # See if I can come up with a static key to use for myself:
            if _priority(self._schema) != COMPARABLE:
                raise TypeError(
                    "Optional keys with defaults must have simple, "
                    "predictable values, like literal strings or ints. "
                    '"%r" is too complex.' % (self._schema,)
                )
            self.default = default
            self.key = self._schema


def _callable_str(callable_):
    if hasattr(callable_, "__name__"):
        return callable_.__name__
    return str(callable_)
