telegraf/src/filters.ts

/* eslint-disable @typescript-eslint/ban-types */
import type {
  CallbackQuery,
  CommonMessageBundle,
  Message,
  Update,
} from '@telegraf/types'
import type { Deunionize, UnionKeys } from './deunionize'

type DistinctKeys<T extends object> = Exclude<UnionKeys<T>, keyof T>

type Keyed<T extends object, K extends DistinctKeys<T>> = Record<K, {}> &
  Deunionize<Record<K, {}>, T>

export type Filter<U extends Update> = (update: Update) => update is U

export const message =
  <Ks extends DistinctKeys<Message>[]>(...keys: Ks) =>
  (
    update: Update
  ): update is Update.MessageUpdate<Keyed<Message, Ks[number]>> => {
    if (!('message' in update)) return false
    for (const key of keys) {
      if (!(key in update.message)) return false
    }
    return true
  }

export const editedMessage =
  <Ks extends DistinctKeys<CommonMessageBundle>[]>(...keys: Ks) =>
  (
    update: Update
  ): update is Update.EditedMessageUpdate<
    Keyed<CommonMessageBundle, Ks[number]>
  > => {
    if (!('edited_message' in update)) return false
    for (const key of keys) {
      if (!(key in update.edited_message)) return false
    }
    return true
  }

export const channelPost =
  <Ks extends DistinctKeys<Message>[]>(...keys: Ks) =>
  (
    update: Update
  ): update is Update.ChannelPostUpdate<Keyed<Message, Ks[number]>> => {
    if (!('channel_post' in update)) return false
    for (const key of keys) {
      if (!(key in update.channel_post)) return false
    }
    return true
  }

export const editedChannelPost =
  <Ks extends DistinctKeys<CommonMessageBundle>[]>(...keys: Ks) =>
  (
    update: Update
  ): update is Update.EditedChannelPostUpdate<
    Keyed<CommonMessageBundle, Ks[number]>
  > => {
    if (!('edited_channel_post' in update)) return false
    for (const key of keys) {
      if (!(key in update.edited_channel_post)) return false
    }
    return true
  }

export const callbackQuery =
  <Ks extends DistinctKeys<CallbackQuery>[]>(...keys: Ks) =>
  (
    update: Update
  ): update is Update.CallbackQueryUpdate<Keyed<CallbackQuery, Ks[number]>> => {
    if (!('callback_query' in update)) return false
    for (const key of keys) {
      if (!(key in update.callback_query)) return false
    }
    return true
  }

export const either =
  <Us extends Update[]>(
    ...filters: {
      [UIdx in keyof Us]: Filter<Us[UIdx]>
    }
  ) =>
  (update: Update): update is Us[number] => {
    for (const filter of filters) {
      if (filter(update)) return true
    }
    return false
  }