import type { HookContext, NextFunction } from '@feathersjs/feathers'
import type { MaybeArray } from '../../internal.utils.js'
import { toArray } from '../../internal.utils.js'
import { FROM_CLIENT_FOR_SERVER_DEFAULT_KEY } from '../params-for-server/params-for-from-shared.js'

export type paramsFromClientOptions = {
  /**
   * @default '_$client'
   */
  keyToHide?: string
}

/**
 * Server-side hook that extracts whitelisted properties from `query._$client` back
 * into `context.params`. This is the counterpart to `paramsForServer`, which encodes
 * params on the client side for transport.
 *
 * @example
 * ```ts
 * import { paramsFromClient } from 'feathers-utils/hooks'
 *
 * // Server-side
 * app.service('users').hooks({
 *   before: { all: [paramsFromClient('populateParams')] }
 * })
 * ```
 *
 * @see https://utils.feathersjs.com/hooks/params-from-client.html
 */
export const paramsFromClient = (
  whitelist: MaybeArray<string>,
  options?: paramsFromClientOptions,
) => {
  const whitelistArr = toArray(whitelist)
  const { keyToHide = FROM_CLIENT_FOR_SERVER_DEFAULT_KEY } = options || {}
  function hook(context: HookContext): void
  function hook(context: HookContext, next: NextFunction): Promise<void>
  function hook(
    context: HookContext,
    next?: NextFunction,
  ): void | Promise<void> {
    if (
      !context.params?.query?.[keyToHide] ||
      typeof context.params.query[keyToHide] !== 'object'
    ) {
      if (next) return next()
      return
    }

    const params = {
      ...context.params,
      query: {
        ...context.params.query,
        [keyToHide]: {
          ...context.params.query[keyToHide],
        },
      },
    }

    const client = params.query[keyToHide]

    whitelistArr.forEach((key) => {
      if (key in client) {
        params[key] = client[key]
        delete client[key]
      }
    })

    if (Object.keys(client).length === 0) {
      delete params.query[keyToHide]
    }

    context.params = params

    if (next) return next()

    return
  }
  return hook
}