mtcute/packages/client/src/methods/users/resolve-peer.ts

import Long from 'long'

import {
    getBasicPeerType,
    getMarkedPeerId,
    toggleChannelIdMark,
} from '@mtcute/core'
import { tl } from '@mtcute/tl'

import { TelegramClient } from '../../client'
import {
    InputPeerLike,
    MtNotFoundError,
    MtTypeAssertionError,
} from '../../types'
import { normalizeToInputPeer } from '../../utils/peer-utils'
import { assertTypeIs } from '../../utils/type-assertion'

/**
 * Get the `InputPeer` of a known peer id.
 * Useful when an `InputPeer` is needed.
 *
 * @param peerId  The peer identifier that you want to extract the `InputPeer` from.
 * @param force  Whether to force re-fetch the peer from the server
 * @internal
 */
export async function resolvePeer(
    this: TelegramClient,
    peerId: InputPeerLike,
    force = false,
): Promise<tl.TypeInputPeer> {
    // for convenience we also accept tl objects directly
    if (typeof peerId === 'object') {
        if (tl.isAnyPeer(peerId)) {
            peerId = getMarkedPeerId(peerId)
        } else {
            return normalizeToInputPeer(peerId)
        }
    }

    if (typeof peerId === 'number' && !force) {
        const fromStorage = await this.storage.getPeerById(peerId)
        if (fromStorage) return fromStorage
    }

    if (typeof peerId === 'string') {
        if (peerId === 'self' || peerId === 'me') return { _: 'inputPeerSelf' }

        peerId = peerId.replace(/[@+\s()]/g, '')

        if (peerId.match(/^\d+$/)) {
            // phone number
            const fromStorage = await this.storage.getPeerByPhone(peerId)
            if (fromStorage) return fromStorage

            const res = await this.call({
                _: 'contacts.getContacts',
                hash: Long.ZERO,
            })

            assertTypeIs('contacts.getContacts', res, 'contacts.contacts')

            const found = res.users.find(
                (it) => (it as tl.RawUser).phone === peerId,
            )

            if (found && found._ === 'user') {
                return {
                    _: 'inputPeerUser',
                    userId: found.id,
                    accessHash: found.accessHash!,
                }
            }

            throw new MtNotFoundError(
                `Could not find a peer by phone ${peerId}`,
            )
        } else {
            // username
            if (!force) {
                const fromStorage = await this.storage.getPeerByUsername(peerId)
                if (fromStorage) return fromStorage
            }

            const res = await this.call({
                _: 'contacts.resolveUsername',
                username: peerId,
            })

            if (res.peer._ === 'peerUser') {
                const id = res.peer.userId

                const found = res.users.find((it) => it.id === id)

                if (found && found._ === 'user') {
                    if (!found.accessHash) {
                        // no access hash, we can't use it
                        // this may happen when bot resolves a username
                        // of a user who hasn't started a conversation with it
                        throw new MtNotFoundError(
                            `Peer (user) with username ${peerId} was found, but it has no access hash`,
                        )
                    }

                    return {
                        _: 'inputPeerUser',
                        userId: found.id,
                        accessHash: found.accessHash,
                    }
                }
            } else if (res.peer._ === 'peerChannel') {
                const id = res.peer.channelId
                const found = res.chats.find((it) => it.id === id)

                if (found) {
                    if (
                        !(
                            found._ === 'channel' ||
                            found._ === 'channelForbidden'
                        )
                    ) {
                        // chats can't have usernames
                        // furthermore, our id is a channel id, so it must be a channel
                        // this should never happen, unless Telegram goes crazy
                        throw new MtTypeAssertionError(
                            'contacts.resolveUsername#chats',
                            'channel',
                            found._,
                        )
                    }

                    if (!found.accessHash) {
                        // shouldn't happen? but just in case
                        throw new MtNotFoundError(
                            `Peer (channel) with username ${peerId} was found, but it has no access hash`,
                        )
                    }

                    return {
                        _: 'inputPeerChannel',
                        channelId: found.id,
                        accessHash: found.accessHash,
                    }
                }
            } else {
                // chats can't have usernames
                throw new MtTypeAssertionError(
                    'contacts.resolveUsername',
                    'user or channel',
                    res.peer._,
                )
            }

            throw new MtNotFoundError(
                `Could not find a peer by username ${peerId}`,
            )
        }
    }

    const peerType = getBasicPeerType(peerId)

    // try fetching by id, with access_hash set to 0
    switch (peerType) {
        case 'user': {
            const res = await this.call({
                _: 'users.getUsers',
                id: [
                    {
                        _: 'inputUser',
                        userId: peerId,
                        accessHash: Long.ZERO,
                    },
                ],
            })

            const found = res.find((it) => it.id === peerId)

            if (found && found._ === 'user') {
                if (!found.accessHash) {
                    // shouldn't happen? but just in case
                    throw new MtNotFoundError(
                        `Peer (user) with username ${peerId} was found, but it has no access hash`,
                    )
                }

                return {
                    _: 'inputPeerUser',
                    userId: found.id,
                    accessHash: found.accessHash,
                }
            }

            break
        }
        case 'chat': {
            // do we really need to make a call?
            // const id = -peerId
            // const res = await this.call({
            //     _: 'messages.getChats',
            //     id: [id],
            // })
            //
            // const found = res.chats.find((it) => it.id === id)
            // if (found && (found._ === 'chat' || found._ === 'chatForbidden'))
            //     return {
            //         _: 'inputPeerChat',
            //         chatId: found.id
            //     }

            return {
                _: 'inputPeerChat',
                chatId: -peerId,
            }
            // break
        }
        case 'channel': {
            const id = toggleChannelIdMark(peerId)

            const res = await this.call({
                _: 'channels.getChannels',
                id: [
                    {
                        _: 'inputChannel',
                        channelId: id,
                        accessHash: Long.ZERO,
                    },
                ],
            })

            const found = res.chats.find((it) => it.id === id)

            if (
                found &&
                (found._ === 'channel' || found._ === 'channelForbidden')
            ) {
                if (!found.accessHash) {
                    // shouldn't happen? but just in case
                    throw new MtNotFoundError(
                        `Peer (channel) with username ${peerId} was found, but it has no access hash`,
                    )
                }

                return {
                    _: 'inputPeerChannel',
                    channelId: found.id,
                    accessHash: found.accessHash ?? Long.ZERO,
                }
            }

            break
        }
    }

    throw new MtNotFoundError(`Could not find a peer by ID ${peerId}`)
}