from .common import resolve_schema_instance


class SchemaResolver:
    """Resolve marshmallow Schemas in OpenAPI components and translate to OpenAPI
    `schema objects
    <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#schema-object>`_,
    `parameter objects
    <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#parameter-object>`_
    or `reference objects
    <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#reference-object>`_.
    """

    def __init__(self, openapi_version, converter):
        self.openapi_version = openapi_version
        self.converter = converter

    def resolve_parameters(self, parameters):
        """Resolve marshmallow Schemas in a list of OpenAPI `Parameter Objects
        <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#parameter-object>`_.
        Each parameter object that contains a Schema will be translated into
        one or more Parameter Objects.

        If the value of a `schema` key is marshmallow Schema class, instance or
        a string that resolves to a Schema Class each field in the Schema will
        be expanded as a separate Parameter Object.

        Example: ::

            #Input
            class UserSchema(Schema):
                name = fields.String()
                id = fields.Int()

            [
                {"in": "query", "schema": "UserSchema"}
            ]

            #Output
            [
                {"in": "query", "name": "id", "required": False, "schema": {"type": "integer", "format": "int32"}},
                {"in": "query", "name": "name", "required": False, "schema": {"type": "string"}}
            ]

        If the Parameter Object contains a `content` key a single Parameter
        Object is returned with the Schema translated into a Schema Object or
        Reference Object.

        Example: ::

            #Input
            [{"in": "query", "name": "pet", "content":{"application/json": {"schema": "PetSchema"}} }]

            #Output
            [
                {
                    "in": "query",
                    "name": "pet",
                    "content": {
                        "application/json": {
                            "schema": {"$ref": "#/components/schemas/Pet"}
                        }
                    }
                }
            ]


        :param list parameters: the list of OpenAPI parameter objects to resolve.
        """
        resolved = []
        for parameter in parameters:
            if (
                isinstance(parameter, dict)
                and not isinstance(parameter.get("schema", {}), dict)
                and "in" in parameter
            ):
                schema_instance = resolve_schema_instance(parameter.pop("schema"))
                resolved += self.converter.schema2parameters(
                    schema_instance, default_in=parameter.pop("in"), **parameter
                )
            else:
                self.resolve_schema(parameter)
                resolved.append(parameter)
        return resolved

    def resolve_response(self, response):
        """Resolve marshmallow Schemas in OpenAPI `Response Objects
        <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#responseObject>`_.
        Schemas may appear in either a Media Type Object or a Header Object.

        Example: ::

            #Input
            {
                "content": {"application/json": {"schema": "PetSchema"}},
                "description": "successful operation",
                "headers": {"PetHeader": {"schema": "PetHeaderSchema"}},
            }

            #Output
            {
                "content": {
                    "application/json":{"schema": {"$ref": "#/components/schemas/Pet"}}
                },
                "description": "successful operation",
                "headers": {
                    "PetHeader": {"schema": {"$ref": "#/components/schemas/PetHeader"}}
                },
            }

        :param dict response: the response object to resolve.
        """
        self.resolve_schema(response)
        if "headers" in response:
            for header in response["headers"].values():
                self.resolve_schema(header)

    def resolve_schema(self, data):
        """Resolve marshmallow Schemas in an OpenAPI component or header -
        modifies the input dictionary to translate marshmallow Schemas to OpenAPI
        Schema Objects or Reference Objects.

        OpenAPIv3 Components: ::

            #Input
            {
                "description": "user to add to the system",
                "content": {
                    "application/json": {
                        "schema": "UserSchema"
                    }
                }
            }

            #Output
            {
                "description": "user to add to the system",
                "content": {
                    "application/json": {
                        "schema": {
                            "$ref": "#/components/schemas/User"
                        }
                    }
                }
            }

        :param dict|str data: either a parameter or response dictionary that may
            contain a schema, or a reference provided as string
        """
        if not isinstance(data, dict):
            return

        # OAS 2 component or OAS 3 header
        if "schema" in data:
            data["schema"] = self.resolve_schema_dict(data["schema"])
        # OAS 3 component except header
        if self.openapi_version.major >= 3:
            if "content" in data:
                for content in data["content"].values():
                    if "schema" in content:
                        content["schema"] = self.resolve_schema_dict(content["schema"])

    def resolve_schema_dict(self, schema):
        """Resolve a marshmallow Schema class, object, or a string that resolves
        to a Schema class or an OpenAPI Schema Object containing one of the above
        to an OpenAPI Schema Object or Reference Object.

        If the input is a marshmallow Schema class, object or a string that resolves
        to a Schema class the Schema will be translated to an OpenAPI Schema Object
        or Reference Object.

        Example: ::

            #Input
            "PetSchema"

            #Output
            {"$ref": "#/components/schemas/Pet"}

        If the input is a dictionary representation of an OpenAPI Schema Object
        recursively search for a marshmallow Schemas to resolve. For `"type": "array"`,
        marshmallow Schemas may appear as the value of the `items` key. For
        `"type": "object"` Marshmalow Schemas may appear as values in the `properties`
        dictionary.

        Examples: ::

            #Input
            {"type": "array", "items": "PetSchema"}

            #Output
            {"type": "array", "items": {"$ref": "#/components/schemas/Pet"}}

            #Input
            {"type": "object", "properties": {"pet": "PetSchcema", "user": "UserSchema"}}

            #Output
            {
                "type": "object",
                "properties": {
                    "pet": {"$ref": "#/components/schemas/Pet"},
                    "user": {"$ref": "#/components/schemas/User"}
                }
            }

        :param string|Schema|dict schema: the schema to resolve.
        """
        if isinstance(schema, dict):
            if schema.get("type") == "array" and "items" in schema:
                schema["items"] = self.resolve_schema_dict(schema["items"])
            if schema.get("type") == "object" and "properties" in schema:
                schema["properties"] = {
                    k: self.resolve_schema_dict(v)
                    for k, v in schema["properties"].items()
                }
            return schema

        return self.converter.resolve_nested_schema(schema)
