"""
# Marshmallow to Flask-RestX model

This module makes possible converting a marshmallow schema to a restx model.

Usage:

```py

from flask import Flask, request
import flask_restx as restx
from flask_restx import Resource, Api
import marshmallow as ma
from licenseware.common import marshmallow_to_restx_model # import the converter function

app = Flask(__name__)
api = Api(app)


class SimpleNestedSchema(ma.Schema):
    simple_nested_field = ma.fields.String(required=False, metadata={'description': 'the description of simple_nested_field'})

class SimpleSchema(ma.Schema):
    simple_field1 = ma.fields.String(required=True, metadata={'description': 'the description of simple_field1'})
    simple_nest = ma.fields.Nested(SimpleNestedSchema)

# Give it as parameters the flask-restx `Api` or `Namespace` instance and the Marshmallow schema
simple_nest_from_schema = marshmallow_to_restx_model(api, SimpleSchema)


@api.route('/marshmallow-simple-nest')
class MaSimpleNest(Resource):
    # Place it where you need a restx model
    @api.expect(simple_nest_from_schema, validate=True)
    def post(self):
        return request.json


if __name__ == '__main__':
    app.run(debug=True)


```

No more duplicate schemas! :)

"""


import marshmallow as ma
import flask_restx as restx
from flask_restx import Api
from typing import Callable, Union


__all__ = [
    "restx_fields",
    "marshmallow_to_restx_model"
]


# Flask-RestX replacements for marshmallow fields
restx_fields_mapper = {
    "Str": "String",
    "Bool": "Boolean",
    "Int": "Integer",
    "Email": "String",
    "Mapping": "Raw",
    "Dict": "Raw",
    "Tuple": "List",
    "UUID": "String",
    "Number": "Integer",
    "Decimal": "Float",
    "NaiveDateTime": "DateTime",
    "AwareDateTime": "DateTime",
    "Time": "DateTime",
    "Date": "DateTime",
    "TimeDelta": "DateTime",
    "URL": "String",
    "Url": "String",
    "IP": "String",
    "IPv4": "String",
    "IPv6": "String",
    "IPInterface": "String",
    "IPv4Interface": "String",
    "IPv6Interface": "String",
    "Constant": "String"
}


def restx_fields(
        description: str = None,
        enum: str = None,
        discriminator: str = None,
        min_length: int = None,
        max_length: int = None,
        pattern: str = None,
        attribute: str = None,
        default: Union[int, float, str, bool, dict, list] = None,
        title: str = None,
        required: bool = True,
        readonly: bool = False,
        example: str = None,
        mask: dict = None
):
    """
    To be used in marshmallow field `metadata` if there are conflicting keys.
    Let's say you need `description` field from metadata in other place than for restx field.
    Ex:
    ```py
        class MaSchema(ma.Schema):
            name = ma.fields(
                required=True,
                metadata={
                    **restx_fields(description="The username"),
                    'description': 'needed for something else'
                }
            )
    ```

    If you don't use `metadata` parameter for other operations you can just specify the fields in the dict
    No need to use `restx_fields` function
    Ex:
    ```py
        class MaSchema(ma.Schema):
            name = ma.fields(required=True, metadata={'description': 'The username'})
    ```

    """
    return {'restx_params': {
        'description': description,
        'enum': enum,
        'discriminator': discriminator,
        'min_length': min_length,
        'max_length': max_length,
        'pattern': pattern,
        'attribute': attribute,
        'default': default,
        'title': title,
        'required': required,
        'readonly': readonly,
        'example': example,
        'mask': mask
    }}


def get_marshmallow_field_type(ma_field: Callable) -> Union[str, None]:
    """
    Get string name for field type
    :param ma_field: marshmallow field
    :return: string name of the field
    """
    attr_name = getattr(type(ma_field), "__name__")
    if attr_name in restx_fields_mapper:
        return restx_fields_mapper[attr_name]
    return attr_name


def get_restx_params(ma_params: dict):
    """
    On `metadata` field from marshmallow if `restx_params` key is present
    field will be used to add restx field kwargs
    if not all keys from `metadata` will be used as kwargs for flask restx fields
    :param ma_params: vars from marshmallow field
    :return: flask restx field kwargs
    """
    restx_params = ma_params['metadata'].get('restx_params') or ma_params['metadata']
    return {
        'required': ma_params['required'],
        **restx_params,
    }


def get_field_data(ma_field):
    """
    Get data required to create restx model
    :param ma_field: marshmallow field
    :return: dict with info needed to create restx model
    """
    return {
        "params": get_restx_params(vars(ma_field)),
        "type": get_marshmallow_field_type(ma_field),
        "nested": None,
        "raw": ma_field
    }


def get_marshmallow_metadata(schema: Callable):
    """
    Returns from marshmallow schema the following dict:
    ```json
        {
            "schema1": {
                "field_name1": {
                    "params": {},
                    "type": "String",
                    "nested": None,
                    'inner': field data
                    "raw": marshmallow_field,
                },
                "field_name2": {
                    "params": {},
                    "type": "String",
                    'inner': field data
                    "raw": marshmallow_field,
                    "nested": {
                        "schema2": {
                            "field_name1": {
                                "params": {},
                                "type": "String",
                                "nested": None,
                                'inner': field data
                                "raw": marshmallow_field
                            }
                        }
                    }
                }
            }
        }
    ```

    """

    marshmallow_metadata = {schema.__name__: {}}

    # Simple fields
    for field_name, ma_field in schema().declared_fields.items():
        marshmallow_metadata[schema.__name__][field_name] = get_field_data(ma_field)

    # Added recursion for nested fields
    for field_name, field_data in marshmallow_metadata[schema.__name__].items():

        if field_data['nested'] is None:

            if isinstance(field_data['raw'], ma.fields.Nested):
                marshmallow_metadata[schema.__name__][field_name]['nested'] = get_marshmallow_metadata(
                    field_data['raw'].nested)

            if isinstance(field_data['raw'], ma.fields.List):
                if hasattr(field_data['raw'].inner, 'nested'):
                    marshmallow_metadata[schema.__name__][field_name]['nested'] = get_marshmallow_metadata(
                        field_data['raw'].inner.nested)
                else:
                    # ex: ma.fields.List(ma.fields.String)
                    marshmallow_metadata[schema.__name__][field_name]['inner'] = get_field_data(field_data['raw'].inner)

    return marshmallow_metadata


def get_restx_field(api: Api, ma_field_meta: dict, *, nested: bool = False):
    if nested:
        return restx.fields.Nested(
            api.model,
            **ma_field_meta['params']
        )

    if ma_field_meta['type'] == "List" and "inner" in ma_field_meta:
        return restx.fields.List(
            getattr(restx.fields, ma_field_meta['inner']['type'])(**ma_field_meta['inner']['params']),
            **ma_field_meta['params']
        )

    restx_field = getattr(restx.fields, ma_field_meta['type'])
    restx_field_instance = restx_field(api.model, **ma_field_meta['params'])
    restx_field_instance.default = None
    return restx_field_instance


def ma_metadata_to_restx_model(api: Api, ma_metadata: dict):
    restx_model = {}

    for schema_name, mameta in ma_metadata.items():

        for field_name, ma_field_meta in mameta.items():

            if ma_field_meta['nested'] is None:
                restx_model[field_name] = get_restx_field(api, ma_field_meta)
            else:
                restx_model[field_name] = ma_metadata[schema_name][field_name]

    # Added recursion for nested fields
    for field_name, field_instance in restx_model.items():

        if isinstance(field_instance, dict):

            if 'inner' in field_instance:
                restx_model[field_name] = get_restx_field(api, ma_field_meta)

            if field_instance['type'] == 'Nested':
                restx_model[field_name] = get_restx_field(api, field_instance, nested=True)
                restx_model[field_name].model = ma_metadata_to_restx_model(api, field_instance['nested'])

            if field_instance['type'] == 'List' and field_instance['nested'] is not None:
                restx_model[field_name] = restx.fields.List(
                    restx.fields.Nested(ma_metadata_to_restx_model(api, field_instance['nested'])),
                    **ma_field_meta['params']
                )

    return api.model(schema_name, restx_model)


def marshmallow_to_restx_model(api: Union[restx.Api, restx.Namespace], schema: Callable):
    """
    Convert a marshmallow schema to a Flask-Restx model
    :param api: Restx Api instance or Namespace instance
    :param schema: Marshmallow schema
    :return: Restx model from marshmallow schema
    """
    ma_metadata = get_marshmallow_metadata(schema)
    restx_model = ma_metadata_to_restx_model(api, ma_metadata)
    return restx_model