from marshmallow import post_dump, pre_load


class SanitizeEmptyStringsMixin:
    """Mixin to add sanitization functionality."""

    @pre_load
    def sanitize_empty_strings(self, data, **kwargs):
        return {key: (value if value != '' else None) for key, value in data.items()}


class SanitizeSpacesMixin:
    """Mixin to add spaces sanitization functionality."""

    @post_dump
    @pre_load
    def sanitise_spaces(self, data, **kwargs):
        for field, value in data.items():
            if isinstance(value, str):
                data[field] = value.strip()
            if isinstance(value, list):
                for item in value:
                    if 'value' in item and isinstance(item['value'], str):
                        item['value'] = item['value'].strip()
        return data