export const extractSchemaProps = <O extends object>(obj: O) =>
  Object.entries(obj).reduce((prev, [key, val]) => {
    const typeOf = <T>(arg: T) =>
      arg instanceof Array ? 'array' : arg === null ? 'undefined' : typeof arg

    const value = typeOf(val) === 'object' && '$type' in val && '$value' in val ? val?.$value : val
    const type = typeOf(value)

    let schema: any = {
      title: key,
      type,
      default: value
    }

    if (typeOf(value) === 'array') {
      const item = value[0] // TODO merge other item schema's into one
      if (typeOf(item) !== 'object') {
        schema.items = {
          type: 'object',
          properties: extractSchemaProps(item),
          default: item
        }
      }
      // TODO support primitive-value arrays
    }

    if (typeOf(value) === 'object') {
      schema.properties = extractSchemaProps(value)
    }
    return {
      ...prev,
      [key]: schema
    }
  }, {} as any)