payload/packages/next/src/utilities/initPage/handleAdminPage.ts

import type {
  Payload,
  SanitizedCollectionConfig,
  SanitizedConfig,
  SanitizedGlobalConfig,
} from 'payload'

import { fieldAffectsData } from 'payload/shared'

import { getRouteWithoutAdmin, isAdminRoute } from './shared.js'

type Args = {
  adminRoute: string
  config: SanitizedConfig
  defaultIDType: Payload['db']['defaultIDType']
  payload?: Payload
  route: string
}

type RouteInfo = {
  collectionConfig?: SanitizedCollectionConfig
  collectionSlug?: string
  docID?: number | string
  globalConfig?: SanitizedGlobalConfig
  globalSlug?: string
}

export function getRouteInfo({
  adminRoute,
  config,
  defaultIDType,
  payload,
  route,
}: Args): RouteInfo {
  if (isAdminRoute({ adminRoute, config, route })) {
    const routeWithoutAdmin = getRouteWithoutAdmin({ adminRoute, route })
    const routeSegments = routeWithoutAdmin.split('/').filter(Boolean)
    const [entityType, entitySlug, createOrID] = routeSegments
    const collectionSlug = entityType === 'collections' ? entitySlug : undefined
    const globalSlug = entityType === 'globals' ? entitySlug : undefined

    let collectionConfig: SanitizedCollectionConfig | undefined
    let globalConfig: SanitizedGlobalConfig | undefined
    let idType = defaultIDType

    if (collectionSlug) {
      collectionConfig = config.collections.find((collection) => collection.slug === collectionSlug)
    }

    if (globalSlug) {
      globalConfig = config.globals.find((global) => global.slug === globalSlug)
    }

    // If the collection is using a custom ID, we need to determine it's type
    if (collectionConfig && payload) {
      if (payload.collections?.[collectionSlug]?.customIDType) {
        idType = payload.collections?.[collectionSlug].customIDType
      }
    }

    const docID =
      collectionSlug && createOrID !== 'create'
        ? idType === 'number'
          ? Number(createOrID)
          : createOrID
        : undefined

    return {
      collectionConfig,
      collectionSlug,
      docID,
      globalConfig,
      globalSlug,
    }
  }

  return {}
}