import { MethodNotAllowed } from '@feathersjs/errors/lib'
import { HookContext, NullableId, Params } from '@feathersjs/feathers'
import encodeUrl from 'encodeurl'

export const METHOD_HEADER = 'x-service-method'

export interface ServiceParams {
  id: NullableId
  data: any
  params: Params
}

export const statusCodes = {
  created: 201,
  noContent: 204,
  methodNotAllowed: 405,
  success: 200,
  seeOther: 303
}

export const knownMethods: { [key: string]: string } = {
  post: 'create',
  patch: 'patch',
  put: 'update',
  delete: 'remove'
}

export function getServiceMethod(_httpMethod: string, id: unknown, headerOverride?: string) {
  const httpMethod = _httpMethod.toLowerCase()

  if (httpMethod === 'post' && headerOverride) {
    return headerOverride
  }

  const mappedMethod = knownMethods[httpMethod]

  if (mappedMethod) {
    return mappedMethod
  }

  if (httpMethod === 'get') {
    return id === null ? 'find' : 'get'
  }

  throw new MethodNotAllowed(`Method ${_httpMethod} not allowed`)
}

export const argumentsFor = {
  get: ({ id, params }: ServiceParams) => [id, params],
  find: ({ params }: ServiceParams) => [params],
  create: ({ data, params }: ServiceParams) => [data, params],
  update: ({ id, data, params }: ServiceParams) => [id, data, params],
  patch: ({ id, data, params }: ServiceParams) => [id, data, params],
  remove: ({ id, params }: ServiceParams) => [id, params],
  default: ({ data, params }: ServiceParams) => [data, params]
}

export function getStatusCode(context: HookContext, body: any, location: string | string[]) {
  const { http = {} } = context

  if (http.status) {
    return http.status
  }

  if (context.method === 'create') {
    return statusCodes.created
  }

  if (location !== undefined) {
    return statusCodes.seeOther
  }

  if (!body) {
    return statusCodes.noContent
  }

  return statusCodes.success
}

export function getResponse(context: HookContext) {
  const { http = {} } = context
  const body = context.dispatch !== undefined ? context.dispatch : context.result

  let headers = http.headers || {}
  let location = headers.Location

  if (http.location !== undefined) {
    location = encodeUrl(http.location)
    headers = { ...headers, Location: location }
  }

  const status = getStatusCode(context, body, location)

  return { status, headers, body }
}