from enum import Enum
from typing import Mapping

from .definition import (
    GraphQLArgument,
    GraphQLEnumType,
    GraphQLEnumValue,
    GraphQLField,
    GraphQLList,
    GraphQLNamedType,
    GraphQLNonNull,
    GraphQLObjectType,
    is_abstract_type,
    is_enum_type,
    is_input_object_type,
    is_interface_type,
    is_list_type,
    is_non_null_type,
    is_object_type,
    is_scalar_type,
    is_union_type,
)
from ..language import DirectiveLocation, print_ast
from ..pyutils import inspect
from .scalars import GraphQLBoolean, GraphQLString

__all__ = [
    "SchemaMetaFieldDef",
    "TypeKind",
    "TypeMetaFieldDef",
    "TypeNameMetaFieldDef",
    "introspection_types",
    "is_introspection_type",
]


__Schema: GraphQLObjectType = GraphQLObjectType(
    name="__Schema",
    description="A GraphQL Schema defines the capabilities of a GraphQL"
    " server. It exposes all available types and directives"
    " on the server, as well as the entry points for query,"
    " mutation, and subscription operations.",
    fields=lambda: {
        "description": GraphQLField(
            GraphQLString, resolve=lambda schema, _info: schema.description
        ),
        "types": GraphQLField(
            GraphQLNonNull(GraphQLList(GraphQLNonNull(__Type))),
            resolve=lambda schema, _info: schema.type_map.values(),
            description="A list of all types supported by this server.",
        ),
        "queryType": GraphQLField(
            GraphQLNonNull(__Type),
            resolve=lambda schema, _info: schema.query_type,
            description="The type that query operations will be rooted at.",
        ),
        "mutationType": GraphQLField(
            __Type,
            resolve=lambda schema, _info: schema.mutation_type,
            description="If this server supports mutation, the type that"
            " mutation operations will be rooted at.",
        ),
        "subscriptionType": GraphQLField(
            __Type,
            resolve=lambda schema, _info: schema.subscription_type,
            description="If this server support subscription, the type that"
            " subscription operations will be rooted at.",
        ),
        "directives": GraphQLField(
            GraphQLNonNull(GraphQLList(GraphQLNonNull(__Directive))),
            resolve=lambda schema, _info: schema.directives,
            description="A list of all directives supported by this server.",
        ),
    },
)


__Directive: GraphQLObjectType = GraphQLObjectType(
    name="__Directive",
    description="A Directive provides a way to describe alternate runtime"
    " execution and type validation behavior in a GraphQL"
    " document.\n\nIn some cases, you need to provide options"
    " to alter GraphQL's execution behavior in ways field"
    " arguments will not suffice, such as conditionally including"
    " or skipping a field. Directives provide this by describing"
    " additional information to the executor.",
    fields=lambda: {
        # Note: The fields onOperation, onFragment and onField are deprecated
        "name": GraphQLField(
            GraphQLNonNull(GraphQLString),
            resolve=DirectiveResolvers.name,
        ),
        "description": GraphQLField(
            GraphQLString,
            resolve=DirectiveResolvers.description,
        ),
        "isRepeatable": GraphQLField(
            GraphQLNonNull(GraphQLBoolean),
            resolve=DirectiveResolvers.is_repeatable,
        ),
        "locations": GraphQLField(
            GraphQLNonNull(GraphQLList(GraphQLNonNull(__DirectiveLocation))),
            resolve=DirectiveResolvers.locations,
        ),
        "args": GraphQLField(
            GraphQLNonNull(GraphQLList(GraphQLNonNull(__InputValue))),
            args={
                "includeDeprecated": GraphQLArgument(
                    GraphQLBoolean, default_value=False
                )
            },
            resolve=DirectiveResolvers.args,
        ),
    },
)


class DirectiveResolvers:
    @staticmethod
    def name(directive, _info):
        return directive.name

    @staticmethod
    def description(directive, _info):
        return directive.description

    @staticmethod
    def is_repeatable(directive, _info):
        return directive.is_repeatable

    @staticmethod
    def locations(directive, _info):
        return directive.locations

    # noinspection PyPep8Naming
    @staticmethod
    def args(directive, _info, includeDeprecated=False):
        items = directive.args.items()
        return (
            list(items)
            if includeDeprecated
            else [item for item in items if item[1].deprecation_reason is None]
        )


__DirectiveLocation: GraphQLEnumType = GraphQLEnumType(
    name="__DirectiveLocation",
    description="A Directive can be adjacent to many parts of the GraphQL"
    " language, a __DirectiveLocation describes one such possible"
    " adjacencies.",
    values={
        "QUERY": GraphQLEnumValue(
            DirectiveLocation.QUERY,
            description="Location adjacent to a query operation.",
        ),
        "MUTATION": GraphQLEnumValue(
            DirectiveLocation.MUTATION,
            description="Location adjacent to a mutation operation.",
        ),
        "SUBSCRIPTION": GraphQLEnumValue(
            DirectiveLocation.SUBSCRIPTION,
            description="Location adjacent to a subscription operation.",
        ),
        "FIELD": GraphQLEnumValue(
            DirectiveLocation.FIELD, description="Location adjacent to a field."
        ),
        "FRAGMENT_DEFINITION": GraphQLEnumValue(
            DirectiveLocation.FRAGMENT_DEFINITION,
            description="Location adjacent to a fragment definition.",
        ),
        "FRAGMENT_SPREAD": GraphQLEnumValue(
            DirectiveLocation.FRAGMENT_SPREAD,
            description="Location adjacent to a fragment spread.",
        ),
        "INLINE_FRAGMENT": GraphQLEnumValue(
            DirectiveLocation.INLINE_FRAGMENT,
            description="Location adjacent to an inline fragment.",
        ),
        "VARIABLE_DEFINITION": GraphQLEnumValue(
            DirectiveLocation.VARIABLE_DEFINITION,
            description="Location adjacent to a variable definition.",
        ),
        "SCHEMA": GraphQLEnumValue(
            DirectiveLocation.SCHEMA,
            description="Location adjacent to a schema definition.",
        ),
        "SCALAR": GraphQLEnumValue(
            DirectiveLocation.SCALAR,
            description="Location adjacent to a scalar definition.",
        ),
        "OBJECT": GraphQLEnumValue(
            DirectiveLocation.OBJECT,
            description="Location adjacent to an object type definition.",
        ),
        "FIELD_DEFINITION": GraphQLEnumValue(
            DirectiveLocation.FIELD_DEFINITION,
            description="Location adjacent to a field definition.",
        ),
        "ARGUMENT_DEFINITION": GraphQLEnumValue(
            DirectiveLocation.ARGUMENT_DEFINITION,
            description="Location adjacent to an argument definition.",
        ),
        "INTERFACE": GraphQLEnumValue(
            DirectiveLocation.INTERFACE,
            description="Location adjacent to an interface definition.",
        ),
        "UNION": GraphQLEnumValue(
            DirectiveLocation.UNION,
            description="Location adjacent to a union definition.",
        ),
        "ENUM": GraphQLEnumValue(
            DirectiveLocation.ENUM,
            description="Location adjacent to an enum definition.",
        ),
        "ENUM_VALUE": GraphQLEnumValue(
            DirectiveLocation.ENUM_VALUE,
            description="Location adjacent to an enum value definition.",
        ),
        "INPUT_OBJECT": GraphQLEnumValue(
            DirectiveLocation.INPUT_OBJECT,
            description="Location adjacent to an input object type definition.",
        ),
        "INPUT_FIELD_DEFINITION": GraphQLEnumValue(
            DirectiveLocation.INPUT_FIELD_DEFINITION,
            description="Location adjacent to an input object field definition.",
        ),
    },
)


__Type: GraphQLObjectType = GraphQLObjectType(
    name="__Type",
    description="The fundamental unit of any GraphQL Schema is the type."
    " There are many kinds of types in GraphQL as represented"
    " by the `__TypeKind` enum.\n\nDepending on the kind of a"
    " type, certain fields describe information about that type."
    " Scalar types provide no information beyond a name, description"
    " and optional `specifiedByURL`, while Enum types provide their values."
    " Object and Interface types provide the fields they describe."
    " Abstract types, Union and Interface, provide the Object"
    " types possible at runtime. List and NonNull types compose"
    " other types.",
    fields=lambda: {
        "kind": GraphQLField(GraphQLNonNull(__TypeKind), resolve=TypeResolvers.kind),
        "name": GraphQLField(GraphQLString, resolve=TypeResolvers.name),
        "description": GraphQLField(GraphQLString, resolve=TypeResolvers.description),
        "specifiedByURL": GraphQLField(
            GraphQLString, resolve=TypeResolvers.specified_by_url
        ),
        "fields": GraphQLField(
            GraphQLList(GraphQLNonNull(__Field)),
            args={
                "includeDeprecated": GraphQLArgument(
                    GraphQLBoolean, default_value=False
                )
            },
            resolve=TypeResolvers.fields,
        ),
        "interfaces": GraphQLField(
            GraphQLList(GraphQLNonNull(__Type)), resolve=TypeResolvers.interfaces
        ),
        "possibleTypes": GraphQLField(
            GraphQLList(GraphQLNonNull(__Type)),
            resolve=TypeResolvers.possible_types,
        ),
        "enumValues": GraphQLField(
            GraphQLList(GraphQLNonNull(__EnumValue)),
            args={
                "includeDeprecated": GraphQLArgument(
                    GraphQLBoolean, default_value=False
                )
            },
            resolve=TypeResolvers.enum_values,
        ),
        "inputFields": GraphQLField(
            GraphQLList(GraphQLNonNull(__InputValue)),
            args={
                "includeDeprecated": GraphQLArgument(
                    GraphQLBoolean, default_value=False
                )
            },
            resolve=TypeResolvers.input_fields,
        ),
        "ofType": GraphQLField(__Type, resolve=TypeResolvers.of_type),
    },
)


class TypeResolvers:
    @staticmethod
    def kind(type_, _info):
        if is_scalar_type(type_):
            return TypeKind.SCALAR
        if is_object_type(type_):
            return TypeKind.OBJECT
        if is_interface_type(type_):
            return TypeKind.INTERFACE
        if is_union_type(type_):
            return TypeKind.UNION
        if is_enum_type(type_):
            return TypeKind.ENUM
        if is_input_object_type(type_):
            return TypeKind.INPUT_OBJECT
        if is_list_type(type_):
            return TypeKind.LIST
        if is_non_null_type(type_):
            return TypeKind.NON_NULL

        # Not reachable. All possible types have been considered.
        raise TypeError(f"Unexpected type: {inspect(type_)}.")  # pragma: no cover

    @staticmethod
    def name(type_, _info):
        return getattr(type_, "name", None)

    @staticmethod
    def description(type_, _info):
        return getattr(type_, "description", None)

    @staticmethod
    def specified_by_url(type_, _info):
        return getattr(type_, "specified_by_url", None)

    # noinspection PyPep8Naming
    @staticmethod
    def fields(type_, _info, includeDeprecated=False):
        if is_object_type(type_) or is_interface_type(type_):
            items = type_.fields.items()
            return (
                list(items)
                if includeDeprecated
                else [item for item in items if item[1].deprecation_reason is None]
            )

    @staticmethod
    def interfaces(type_, _info):
        if is_object_type(type_) or is_interface_type(type_):
            return type_.interfaces

    @staticmethod
    def possible_types(type_, info):
        if is_abstract_type(type_):
            return info.schema.get_possible_types(type_)

    # noinspection PyPep8Naming
    @staticmethod
    def enum_values(type_, _info, includeDeprecated=False):
        if is_enum_type(type_):
            items = type_.values.items()
            return (
                items
                if includeDeprecated
                else [item for item in items if item[1].deprecation_reason is None]
            )

    # noinspection PyPep8Naming
    @staticmethod
    def input_fields(type_, _info, includeDeprecated=False):
        if is_input_object_type(type_):
            items = type_.fields.items()
            return (
                items
                if includeDeprecated
                else [item for item in items if item[1].deprecation_reason is None]
            )

    @staticmethod
    def of_type(type_, _info):
        return getattr(type_, "of_type", None)


__Field: GraphQLObjectType = GraphQLObjectType(
    name="__Field",
    description="Object and Interface types are described by a list of Fields,"
    " each of which has a name, potentially a list of arguments,"
    " and a return type.",
    fields=lambda: {
        "name": GraphQLField(
            GraphQLNonNull(GraphQLString), resolve=FieldResolvers.name
        ),
        "description": GraphQLField(GraphQLString, resolve=FieldResolvers.description),
        "args": GraphQLField(
            GraphQLNonNull(GraphQLList(GraphQLNonNull(__InputValue))),
            args={
                "includeDeprecated": GraphQLArgument(
                    GraphQLBoolean, default_value=False
                )
            },
            resolve=FieldResolvers.args,
        ),
        "type": GraphQLField(GraphQLNonNull(__Type), resolve=FieldResolvers.type),
        "isDeprecated": GraphQLField(
            GraphQLNonNull(GraphQLBoolean),
            resolve=FieldResolvers.is_deprecated,
        ),
        "deprecationReason": GraphQLField(
            GraphQLString, resolve=FieldResolvers.deprecation_reason
        ),
    },
)


class FieldResolvers:
    @staticmethod
    def name(item, _info):
        return item[0]

    @staticmethod
    def description(item, _info):
        return item[1].description

    # noinspection PyPep8Naming
    @staticmethod
    def args(item, _info, includeDeprecated=False):
        items = item[1].args.items()
        return (
            items
            if includeDeprecated
            else [item for item in items if item[1].deprecation_reason is None]
        )

    @staticmethod
    def type(item, _info):
        return item[1].type

    @staticmethod
    def is_deprecated(item, _info):
        return item[1].deprecation_reason is not None

    @staticmethod
    def deprecation_reason(item, _info):
        return item[1].deprecation_reason


__InputValue: GraphQLObjectType = GraphQLObjectType(
    name="__InputValue",
    description="Arguments provided to Fields or Directives and the input"
    " fields of an InputObject are represented as Input Values"
    " which describe their type and optionally a default value.",
    fields=lambda: {
        "name": GraphQLField(
            GraphQLNonNull(GraphQLString), resolve=InputValueFieldResolvers.name
        ),
        "description": GraphQLField(
            GraphQLString, resolve=InputValueFieldResolvers.description
        ),
        "type": GraphQLField(
            GraphQLNonNull(__Type), resolve=InputValueFieldResolvers.type
        ),
        "defaultValue": GraphQLField(
            GraphQLString,
            description="A GraphQL-formatted string representing"
            " the default value for this input value.",
            resolve=InputValueFieldResolvers.default_value,
        ),
        "isDeprecated": GraphQLField(
            GraphQLNonNull(GraphQLBoolean),
            resolve=InputValueFieldResolvers.is_deprecated,
        ),
        "deprecationReason": GraphQLField(
            GraphQLString, resolve=InputValueFieldResolvers.deprecation_reason
        ),
    },
)


class InputValueFieldResolvers:
    @staticmethod
    def name(item, _info):
        return item[0]

    @staticmethod
    def description(item, _info):
        return item[1].description

    @staticmethod
    def type(item, _info):
        return item[1].type

    @staticmethod
    def default_value(item, _info):
        # Since ast_from_value needs graphql.type, it can only be imported later
        from ..utilities import ast_from_value

        value_ast = ast_from_value(item[1].default_value, item[1].type)
        return print_ast(value_ast) if value_ast else None

    @staticmethod
    def is_deprecated(item, _info):
        return item[1].deprecation_reason is not None

    @staticmethod
    def deprecation_reason(item, _info):
        return item[1].deprecation_reason


__EnumValue: GraphQLObjectType = GraphQLObjectType(
    name="__EnumValue",
    description="One possible value for a given Enum. Enum values are unique"
    " values, not a placeholder for a string or numeric value."
    " However an Enum value is returned in a JSON response as a"
    " string.",
    fields=lambda: {
        "name": GraphQLField(
            GraphQLNonNull(GraphQLString), resolve=lambda item, _info: item[0]
        ),
        "description": GraphQLField(
            GraphQLString, resolve=lambda item, _info: item[1].description
        ),
        "isDeprecated": GraphQLField(
            GraphQLNonNull(GraphQLBoolean),
            resolve=lambda item, _info: item[1].deprecation_reason is not None,
        ),
        "deprecationReason": GraphQLField(
            GraphQLString, resolve=lambda item, _info: item[1].deprecation_reason
        ),
    },
)


class TypeKind(Enum):
    SCALAR = "scalar"
    OBJECT = "object"
    INTERFACE = "interface"
    UNION = "union"
    ENUM = "enum"
    INPUT_OBJECT = "input object"
    LIST = "list"
    NON_NULL = "non-null"


__TypeKind: GraphQLEnumType = GraphQLEnumType(
    name="__TypeKind",
    description="An enum describing what kind of type a given `__Type` is.",
    values={
        "SCALAR": GraphQLEnumValue(
            TypeKind.SCALAR, description="Indicates this type is a scalar."
        ),
        "OBJECT": GraphQLEnumValue(
            TypeKind.OBJECT,
            description="Indicates this type is an object."
            " `fields` and `interfaces` are valid fields.",
        ),
        "INTERFACE": GraphQLEnumValue(
            TypeKind.INTERFACE,
            description="Indicates this type is an interface."
            " `fields`, `interfaces`, and `possibleTypes` are valid fields.",
        ),
        "UNION": GraphQLEnumValue(
            TypeKind.UNION,
            description="Indicates this type is a union."
            " `possibleTypes` is a valid field.",
        ),
        "ENUM": GraphQLEnumValue(
            TypeKind.ENUM,
            description="Indicates this type is an enum."
            " `enumValues` is a valid field.",
        ),
        "INPUT_OBJECT": GraphQLEnumValue(
            TypeKind.INPUT_OBJECT,
            description="Indicates this type is an input object."
            " `inputFields` is a valid field.",
        ),
        "LIST": GraphQLEnumValue(
            TypeKind.LIST,
            description="Indicates this type is a list. `ofType` is a valid field.",
        ),
        "NON_NULL": GraphQLEnumValue(
            TypeKind.NON_NULL,
            description="Indicates this type is a non-null."
            " `ofType` is a valid field.",
        ),
    },
)


SchemaMetaFieldDef = GraphQLField(
    GraphQLNonNull(__Schema),  # name = '__schema'
    description="Access the current type schema of this server.",
    args={},
    resolve=lambda _source, info: info.schema,
)


TypeMetaFieldDef = GraphQLField(
    __Type,  # name = '__type'
    description="Request the type information of a single type.",
    args={"name": GraphQLArgument(GraphQLNonNull(GraphQLString))},
    resolve=lambda _source, info, **args: info.schema.get_type(args["name"]),
)


TypeNameMetaFieldDef = GraphQLField(
    GraphQLNonNull(GraphQLString),  # name='__typename'
    description="The name of the current Object type at runtime.",
    args={},
    resolve=lambda _source, info, **_args: info.parent_type.name,
)


# Since double underscore names are subject to name mangling in Python,
# the introspection classes are best imported via this dictionary:
introspection_types: Mapping[str, GraphQLNamedType] = {  # treat as read-only
    "__Schema": __Schema,
    "__Directive": __Directive,
    "__DirectiveLocation": __DirectiveLocation,
    "__Type": __Type,
    "__Field": __Field,
    "__InputValue": __InputValue,
    "__EnumValue": __EnumValue,
    "__TypeKind": __TypeKind,
}
"""A mapping containing all introspection types with their names as keys"""


def is_introspection_type(type_: GraphQLNamedType) -> bool:
    """Check whether the given named GraphQL type is an introspection type."""
    return type_.name in introspection_types