import { snakeCase } from "case-anything"

// https://stackoverflow.com/questions/60269936/typescript-convert-generic-object-from-snake-to-camel-case

// Typescript magic to convert any string from camelCase to snake_case at compile time
type SnakeCase<S> = S extends string
    ? S extends `${infer T}${infer U}`
        ? `${T extends Capitalize<T> ? "_" : ""}${Lowercase<T>}${SnakeCase<U>}`
        : S
    : S

type SnakeCased<Type> = {
    [Property in keyof Type as SnakeCase<Property>]: SnakeCased<Type[Property]>
}

export default function snakeCaseTree<T>(object: T): SnakeCased<T> {
    const snakeObject: any = {}
    for (const key in object) {
        snakeObject[snakeCase(key, { keepSpecialCharacters: true })] =
            snakeCaseValue(object[key])
    }
    return snakeObject
}

function snakeCaseValue(value: any): any {
    if (typeof value === "object") {
        if (Array.isArray(value)) {
            return value.map(snakeCaseValue)
        } else {
            return snakeCaseTree(value)
        }
    } else {
        return value
    }
}