"""OpenAPI core schemas models module"""
import attr
import functools
import logging
from collections import defaultdict
from datetime import date, datetime
import re
import warnings

from six import iteritems, integer_types, binary_type, text_type

from openapi_core.extensions.models.factories import ModelFactory
from openapi_core.schema.schemas.enums import SchemaFormat, SchemaType
from openapi_core.schema.schemas.exceptions import (
    InvalidSchemaValue, UndefinedSchemaProperty, MissingSchemaProperty,
    OpenAPISchemaError, NoOneOfSchema, MultipleOneOfSchema, NoValidSchema,
    UndefinedItemsSchema, InvalidCustomFormatSchemaValue, InvalidSchemaProperty,
)
from openapi_core.schema.schemas.util import (
    forcebool, format_date, format_datetime,
)
from openapi_core.schema.schemas.validators import (
    TypeValidator, AttributeValidator,
)

log = logging.getLogger(__name__)


@attr.s
class Format(object):
    unmarshal = attr.ib()
    validate = attr.ib()


class Schema(object):
    """Represents an OpenAPI Schema."""

    DEFAULT_CAST_CALLABLE_GETTER = {
        SchemaType.INTEGER: int,
        SchemaType.NUMBER: float,
        SchemaType.BOOLEAN: forcebool,
    }

    STRING_FORMAT_CALLABLE_GETTER = {
        SchemaFormat.NONE: Format(text_type, TypeValidator(text_type)),
        SchemaFormat.DATE: Format(format_date, TypeValidator(date, exclude=datetime)),
        SchemaFormat.DATETIME: Format(format_datetime, TypeValidator(datetime)),
        SchemaFormat.BINARY: Format(binary_type, TypeValidator(binary_type)),
    }

    TYPE_VALIDATOR_CALLABLE_GETTER = {
        SchemaType.ANY: lambda x: x,
        SchemaType.BOOLEAN: TypeValidator(bool),
        SchemaType.INTEGER: TypeValidator(integer_types, exclude=bool),
        SchemaType.NUMBER: TypeValidator(integer_types, float, exclude=bool),
        SchemaType.STRING: TypeValidator(
            text_type, date, datetime, binary_type),
        SchemaType.ARRAY: TypeValidator(list, tuple),
        SchemaType.OBJECT: AttributeValidator('__dict__'),
    }

    def __init__(
            self, schema_type=None, model=None, properties=None, items=None,
            schema_format=None, required=None, default=None, nullable=False,
            enum=None, deprecated=False, all_of=None, one_of=None,
            additional_properties=None, min_items=None, max_items=None,
            min_length=None, max_length=None, pattern=None, unique_items=False,
            minimum=None, maximum=None, multiple_of=None,
            exclusive_minimum=False, exclusive_maximum=False,
            min_properties=None, max_properties=None):
        self.type = SchemaType(schema_type)
        self.model = model
        self.properties = properties and dict(properties) or {}
        self.items = items
        self.format = schema_format
        self.required = required or []
        self.default = default
        self.nullable = nullable
        self.enum = enum
        self.deprecated = deprecated
        self.all_of = all_of and list(all_of) or []
        self.one_of = one_of and list(one_of) or []
        self.additional_properties = additional_properties
        self.min_items = int(min_items) if min_items is not None else None
        self.max_items = int(max_items) if max_items is not None else None
        self.min_length = int(min_length) if min_length is not None else None
        self.max_length = int(max_length) if max_length is not None else None
        self.pattern = pattern and re.compile(pattern) or None
        self.unique_items = unique_items
        self.minimum = int(minimum) if minimum is not None else None
        self.maximum = int(maximum) if maximum is not None else None
        self.multiple_of = int(multiple_of)\
            if multiple_of is not None else None
        self.exclusive_minimum = exclusive_minimum
        self.exclusive_maximum = exclusive_maximum
        self.min_properties = int(min_properties)\
            if min_properties is not None else None
        self.max_properties = int(max_properties)\
            if max_properties is not None else None

        self._all_required_properties_cache = None
        self._all_optional_properties_cache = None

    def __getitem__(self, name):
        return self.properties[name]

    def get_all_properties(self):
        properties = self.properties.copy()

        for subschema in self.all_of:
            subschema_props = subschema.get_all_properties()
            properties.update(subschema_props)

        return properties

    def get_all_properties_names(self):
        all_properties = self.get_all_properties()
        return set(all_properties.keys())

    def get_all_required_properties(self):
        if self._all_required_properties_cache is None:
            self._all_required_properties_cache =\
                self._get_all_required_properties()

        return self._all_required_properties_cache

    def _get_all_required_properties(self):
        all_properties = self.get_all_properties()
        required = self.get_all_required_properties_names()

        return dict(
            (prop_name, val)
            for prop_name, val in iteritems(all_properties)
            if prop_name in required
        )

    def get_all_required_properties_names(self):
        required = self.required[:]

        for subschema in self.all_of:
            subschema_req = subschema.get_all_required_properties()
            required += subschema_req

        return set(required)

    def get_cast_mapping(self, custom_formatters=None):
        pass_defaults = lambda f: functools.partial(
          f, custom_formatters=custom_formatters)
        mapping = self.DEFAULT_CAST_CALLABLE_GETTER.copy()
        mapping.update({
            SchemaType.STRING: pass_defaults(self._unmarshal_string),
            SchemaType.ANY: pass_defaults(self._unmarshal_any),
            SchemaType.ARRAY: pass_defaults(self._unmarshal_collection),
            SchemaType.OBJECT: pass_defaults(self._unmarshal_object),
        })

        return defaultdict(lambda: lambda x: x, mapping)

    def cast(self, value, custom_formatters=None):
        """Cast value to schema type"""
        if value is None:
            if not self.nullable:
                raise InvalidSchemaValue("Null value for non-nullable schema", value, self.type)
            return self.default

        cast_mapping = self.get_cast_mapping(custom_formatters=custom_formatters)

        if self.type is not SchemaType.STRING and value == '':
            return None

        cast_callable = cast_mapping[self.type]
        try:
            return cast_callable(value)
        except ValueError:
            raise InvalidSchemaValue(
                "Failed to cast value {value} to type {type}", value, self.type)

    def unmarshal(self, value, custom_formatters=None):
        """Unmarshal parameter from the value."""
        if self.deprecated:
            warnings.warn("The schema is deprecated", DeprecationWarning)

        casted = self.cast(value, custom_formatters=custom_formatters)

        if casted is None and not self.required:
            return None

        if self.enum and casted not in self.enum:
            raise InvalidSchemaValue(
                "Value {value} not in enum choices: {type}", value, self.enum)

        return casted

    def _unmarshal_string(self, value, custom_formatters=None):
        try:
            schema_format = SchemaFormat(self.format)
        except ValueError:
            msg = "Unsupported format {type} unmarshalling for value {value}"
            if custom_formatters is not None:
                formatstring = custom_formatters.get(self.format)
                if formatstring is None:
                    raise InvalidSchemaValue(msg, value, self.format)
            else:
                raise InvalidSchemaValue(msg, value, self.format)
        else:
            formatstring = self.STRING_FORMAT_CALLABLE_GETTER[schema_format]

        try:
            return formatstring.unmarshal(value)
        except ValueError as exc:
            raise InvalidCustomFormatSchemaValue(
                "Failed to format value {value} to format {type}: {exception}", value, self.format, exc)

    def _unmarshal_any(self, value, custom_formatters=None):
        types_resolve_order = [
            SchemaType.OBJECT, SchemaType.ARRAY, SchemaType.BOOLEAN,
            SchemaType.INTEGER, SchemaType.NUMBER, SchemaType.STRING,
        ]
        cast_mapping = self.get_cast_mapping()
        for schema_type in types_resolve_order:
            cast_callable = cast_mapping[schema_type]
            try:
                return cast_callable(value)
            # @todo: remove ValueError when validation separated
            except (OpenAPISchemaError, TypeError, ValueError):
                continue

        raise NoValidSchema(value)

    def _unmarshal_collection(self, value, custom_formatters=None):
        if self.items is None:
            raise UndefinedItemsSchema(self.type)

        f = functools.partial(self.items.unmarshal,
                              custom_formatters=custom_formatters)
        return list(map(f, value))

    def _unmarshal_object(self, value, model_factory=None,
                          custom_formatters=None):
        if not isinstance(value, (dict, )):
            raise InvalidSchemaValue("Value {value} is not of type {type}", value, self.type)

        model_factory = model_factory or ModelFactory()

        if self.one_of:
            properties = None
            for one_of_schema in self.one_of:
                try:
                    found_props = self._unmarshal_properties(
                        value, one_of_schema, custom_formatters=custom_formatters)
                except OpenAPISchemaError:
                    pass
                else:
                    if properties is not None:
                        raise MultipleOneOfSchema(self.type)
                    properties = found_props

            if properties is None:
                raise NoOneOfSchema(self.type)

        else:
            properties = self._unmarshal_properties(
              value, custom_formatters=custom_formatters)

        return model_factory.create(properties, name=self.model)

    def _unmarshal_properties(self, value, one_of_schema=None,
                              custom_formatters=None):
        all_props = self.get_all_properties()
        all_props_names = self.get_all_properties_names()
        all_req_props_names = self.get_all_required_properties_names()

        if one_of_schema is not None:
            all_props.update(one_of_schema.get_all_properties())
            all_props_names |= one_of_schema.\
                get_all_properties_names()
            all_req_props_names |= one_of_schema.\
                get_all_required_properties_names()

        value_props_names = value.keys()
        extra_props = set(value_props_names) - set(all_props_names)
        if extra_props and self.additional_properties is None:
            raise UndefinedSchemaProperty(extra_props)

        properties = {}
        for prop_name in extra_props:
            prop_value = value[prop_name]
            properties[prop_name] = self.additional_properties.unmarshal(
                prop_value, custom_formatters=custom_formatters)

        for prop_name, prop in iteritems(all_props):
            try:
                prop_value = value[prop_name]
            except KeyError:
                if prop_name in all_req_props_names:
                    raise MissingSchemaProperty(prop_name)
                if not prop.nullable and not prop.default:
                    continue
                prop_value = prop.default
            try:
                properties[prop_name] = prop.unmarshal(
                  prop_value, custom_formatters=custom_formatters)
            except OpenAPISchemaError as exc:
                raise InvalidSchemaProperty(prop_name, exc)

        self._validate_properties(properties, one_of_schema=one_of_schema,
                                  custom_formatters=custom_formatters)

        return properties

    def get_validator_mapping(self):
        mapping = {
            SchemaType.ARRAY: self._validate_collection,
            SchemaType.STRING: self._validate_string,
            SchemaType.OBJECT: self._validate_object,
            SchemaType.INTEGER: self._validate_number,
            SchemaType.NUMBER: self._validate_number,
        }

        def default(x, **kw):
            return x

        return defaultdict(lambda: default, mapping)

    def validate(self, value, custom_formatters=None):
        if value is None:
            if not self.nullable:
                raise InvalidSchemaValue("Null value for non-nullable schema of type {type}", value, self.type)
            return

        # type validation
        type_validator_callable = self.TYPE_VALIDATOR_CALLABLE_GETTER[
            self.type]
        if not type_validator_callable(value):
            raise InvalidSchemaValue(
                "Value {value} not valid type {type}", value, self.type.value)

        # structure validation
        validator_mapping = self.get_validator_mapping()
        validator_callable = validator_mapping[self.type]
        validator_callable(value, custom_formatters=custom_formatters)

        return value

    def _validate_collection(self, value, custom_formatters=None):
        if self.items is None:
            raise UndefinedItemsSchema(self.type)

        if self.min_items is not None:
            if self.min_items < 0:
                raise OpenAPISchemaError(
                    "Schema for collection invalid:"
                    " minItems must be non-negative"
                )
            if len(value) < self.min_items:
                raise InvalidSchemaValue(
                    "Value must contain at least {type} item(s),"
                    " {value} found", len(value), self.min_items)
        if self.max_items is not None:
            if self.max_items < 0:
                raise OpenAPISchemaError(
                    "Schema for collection invalid:"
                    " maxItems must be non-negative"
                )
            if len(value) > self.max_items:
                raise InvalidSchemaValue(
                    "Value must contain at most {value} item(s),"
                    " {type} found", len(value), self.max_items)
        if self.unique_items and len(set(value)) != len(value):
            raise OpenAPISchemaError("Value may not contain duplicate items")

        f = functools.partial(self.items.validate,
                              custom_formatters=custom_formatters)
        return list(map(f, value))

    def _validate_number(self, value, custom_formatters=None):
        if self.minimum is not None:
            if self.exclusive_minimum and value <= self.minimum:
                raise InvalidSchemaValue(
                    "Value {value} is not less than or equal to {type}", value, self.minimum)
            elif value < self.minimum:
                raise InvalidSchemaValue(
                    "Value {value} is not less than {type}", value, self.minimum)

        if self.maximum is not None:
            if self.exclusive_maximum and value >= self.maximum:
                raise InvalidSchemaValue(
                    "Value {value} is not greater than or equal to {type}", value, self.maximum)
            elif value > self.maximum:
                raise InvalidSchemaValue(
                    "Value {value} is not greater than {type}", value, self.maximum)

        if self.multiple_of is not None and value % self.multiple_of:
            raise InvalidSchemaValue(
                "Value {value} is not a multiple of {type}",
                    value, self.multiple_of)

    def _validate_string(self, value, custom_formatters=None):
        try:
            schema_format = SchemaFormat(self.format)
        except ValueError:
            msg = "Unsupported {0} format validation".format(self.format)
            if custom_formatters is not None:
                formatstring = custom_formatters.get(self.format)
                if formatstring is None:
                    raise OpenAPISchemaError(msg)
            else:
                raise OpenAPISchemaError(msg)
        else:
            formatstring =\
                self.STRING_FORMAT_CALLABLE_GETTER[schema_format]

        if not formatstring.validate(value):
            raise InvalidSchemaValue(
                "Value {value} not valid format {type}", value, self.format)

        if self.min_length is not None:
            if self.min_length < 0:
                raise OpenAPISchemaError(
                    "Schema for string invalid:"
                    " minLength must be non-negative"
                )
            if len(value) < self.min_length:
                raise InvalidSchemaValue(
                    "Value is shorter ({value}) than the minimum length of {type}",
                    len(value), self.min_length
                )
        if self.max_length is not None:
            if self.max_length < 0:
                raise OpenAPISchemaError(
                    "Schema for string invalid:"
                    " maxLength must be non-negative"
                )
            if len(value) > self.max_length:
                raise InvalidSchemaValue(
                    "Value is longer ({value}) than the maximum length of {type}",
                    len(value), self.max_length
                )
        if self.pattern is not None and not self.pattern.search(value):
            raise InvalidSchemaValue(
                "Value {value} does not match the pattern {type}",
                    value, self.pattern.pattern
            )

        return True

    def _validate_object(self, value, custom_formatters=None):
        properties = value.__dict__

        if self.one_of:
            valid_one_of_schema = None
            for one_of_schema in self.one_of:
                try:
                    self._validate_properties(
                      properties, one_of_schema,
                      custom_formatters=custom_formatters)
                except OpenAPISchemaError:
                    pass
                else:
                    if valid_one_of_schema is not None:
                        raise MultipleOneOfSchema(self.type)
                    valid_one_of_schema = True

            if valid_one_of_schema is None:
                raise NoOneOfSchema(self.type)

        else:
            self._validate_properties(properties,
                                      custom_formatters=custom_formatters)

        if self.min_properties is not None:
            if self.min_properties < 0:
                raise OpenAPISchemaError(
                    "Schema for object invalid:"
                    " minProperties must be non-negative"
                )

            if len(properties) < self.min_properties:
                raise InvalidSchemaValue(
                    "Value must contain at least {type} properties,"
                    " {value} found", len(properties), self.min_properties
                )

        if self.max_properties is not None:
            if self.max_properties < 0:
                raise OpenAPISchemaError(
                    "Schema for object invalid:"
                    " maxProperties must be non-negative"
                )
            if len(properties) > self.max_properties:
                raise InvalidSchemaValue(
                    "Value must contain at most {type} properties,"
                    " {value} found", len(properties), self.max_properties
                )

        return True

    def _validate_properties(self, value, one_of_schema=None,
                             custom_formatters=None):
        all_props = self.get_all_properties()
        all_props_names = self.get_all_properties_names()
        all_req_props_names = self.get_all_required_properties_names()

        if one_of_schema is not None:
            all_props.update(one_of_schema.get_all_properties())
            all_props_names |= one_of_schema.\
                get_all_properties_names()
            all_req_props_names |= one_of_schema.\
                get_all_required_properties_names()

        value_props_names = value.keys()
        extra_props = set(value_props_names) - set(all_props_names)
        if extra_props and self.additional_properties is None:
            raise UndefinedSchemaProperty(extra_props)

        for prop_name in extra_props:
            prop_value = value[prop_name]
            self.additional_properties.validate(
                prop_value, custom_formatters=custom_formatters)

        for prop_name, prop in iteritems(all_props):
            try:
                prop_value = value[prop_name]
            except KeyError:
                if prop_name in all_req_props_names:
                    raise MissingSchemaProperty(prop_name)
                if not prop.nullable and not prop.default:
                    continue
                prop_value = prop.default
            try:
                prop.validate(prop_value, custom_formatters=custom_formatters)
            except OpenAPISchemaError as exc:
                raise InvalidSchemaProperty(prop_name, original_exception=exc)

        return True