from dataclasses import field

import pydantic

import ludwig.schema.utils as schema_utils
from ludwig.api_annotations import DeveloperAPI
from ludwig.error import ConfigValidationError
from ludwig.schema.features.utils import ecd_defaults_config_registry
from ludwig.utils.registry import Registry


@DeveloperAPI
def DefaultsDataclassField(feature_type: str, defaults_registry: Registry = ecd_defaults_config_registry):
    """Custom dataclass field that when used inside a dataclass will allow the user to specify a nested default
    config for a specific feature type.

    Returns: Initialized dataclass field that converts an untyped dict with params to a defaults config.
    """

    class DefaultConfigField(schema_utils.SchemaField):
        """Custom field that deserializes a dict for a valid defaults config from the feature_registry and creates
        a corresponding JSON schema for external usage."""

        def _deserialize(self, value, attr, data, **kwargs):
            if value is None:
                return None
            if isinstance(value, dict):
                defaults_class = defaults_registry[feature_type]
                try:
                    return defaults_class.model_validate(value)
                except (TypeError, ConfigValidationError) as error:
                    raise ConfigValidationError(f"Invalid params: {value}, see `{attr}` definition. Error: {error}")
            raise ConfigValidationError(f"Invalid params: {value}")

        def _jsonschema_type_mapping(self):
            defaults_cls = defaults_registry[feature_type]
            props = schema_utils.unload_jsonschema_from_config_class(defaults_cls)["properties"]
            return {
                "type": "object",
                "properties": props,
                "additionalProperties": False,
                "title": "defaults_options",
            }

    try:
        defaults_cls = defaults_registry[feature_type]
        try:
            dump_default = defaults_cls.model_validate({}).to_dict()
        except pydantic.ValidationError:
            dump_default = {}
        load_default = lambda: defaults_cls.model_validate({})

        return field(
            metadata={
                "marshmallow_field": DefaultConfigField(
                    allow_none=False,
                    dump_default=dump_default,
                    load_default=load_default,
                )
            },
            default_factory=load_default,
        )
    except Exception as e:
        raise ConfigValidationError(
            f"Unsupported feature type: {feature_type}. Allowed: {defaults_registry.keys()}. Details: {e}"
        )