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-rw-r--r--src/state/messages/convo.ts900
1 files changed, 900 insertions, 0 deletions
diff --git a/src/state/messages/convo.ts b/src/state/messages/convo.ts
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index 000000000..81ab94f43
--- /dev/null
+++ b/src/state/messages/convo.ts
@@ -0,0 +1,900 @@
+import {AppBskyActorDefs} from '@atproto/api'
+import {
+  BskyAgent,
+  ChatBskyConvoDefs,
+  ChatBskyConvoSendMessage,
+} from '@atproto-labs/api'
+import {nanoid} from 'nanoid/non-secure'
+
+import {logger} from '#/logger'
+import {isNative} from '#/platform/detection'
+
+export type ConvoParams = {
+  convoId: string
+  agent: BskyAgent
+  __tempFromUserDid: string
+}
+
+export enum ConvoStatus {
+  Uninitialized = 'uninitialized',
+  Initializing = 'initializing',
+  Resuming = 'resuming',
+  Ready = 'ready',
+  Error = 'error',
+  Backgrounded = 'backgrounded',
+  Suspended = 'suspended',
+}
+
+export enum ConvoItemError {
+  HistoryFailed = 'historyFailed',
+  ResumeFailed = 'resumeFailed',
+  PollFailed = 'pollFailed',
+}
+
+export enum ConvoError {
+  InitFailed = 'initFailed',
+}
+
+export type ConvoItem =
+  | {
+      type: 'message' | 'pending-message'
+      key: string
+      message: ChatBskyConvoDefs.MessageView
+      nextMessage:
+        | ChatBskyConvoDefs.MessageView
+        | ChatBskyConvoDefs.DeletedMessageView
+        | null
+    }
+  | {
+      type: 'deleted-message'
+      key: string
+      message: ChatBskyConvoDefs.DeletedMessageView
+      nextMessage:
+        | ChatBskyConvoDefs.MessageView
+        | ChatBskyConvoDefs.DeletedMessageView
+        | null
+    }
+  | {
+      type: 'pending-retry'
+      key: string
+      retry: () => void
+    }
+  | {
+      type: 'error-recoverable'
+      key: string
+      code: ConvoItemError
+      retry: () => void
+    }
+
+export type ConvoState =
+  | {
+      status: ConvoStatus.Uninitialized
+      items: []
+      convo: undefined
+      error: undefined
+      sender: undefined
+      recipients: undefined
+      isFetchingHistory: false
+      deleteMessage: undefined
+      sendMessage: undefined
+      fetchMessageHistory: undefined
+    }
+  | {
+      status: ConvoStatus.Initializing
+      items: []
+      convo: undefined
+      error: undefined
+      sender: undefined
+      recipients: undefined
+      isFetchingHistory: boolean
+      deleteMessage: undefined
+      sendMessage: undefined
+      fetchMessageHistory: undefined
+    }
+  | {
+      status: ConvoStatus.Ready
+      items: ConvoItem[]
+      convo: ChatBskyConvoDefs.ConvoView
+      error: undefined
+      sender: AppBskyActorDefs.ProfileViewBasic
+      recipients: AppBskyActorDefs.ProfileViewBasic[]
+      isFetchingHistory: boolean
+      deleteMessage: (messageId: string) => Promise<void>
+      sendMessage: (
+        message: ChatBskyConvoSendMessage.InputSchema['message'],
+      ) => void
+      fetchMessageHistory: () => void
+    }
+  | {
+      status: ConvoStatus.Suspended
+      items: ConvoItem[]
+      convo: ChatBskyConvoDefs.ConvoView
+      error: undefined
+      sender: AppBskyActorDefs.ProfileViewBasic
+      recipients: AppBskyActorDefs.ProfileViewBasic[]
+      isFetchingHistory: boolean
+      deleteMessage: (messageId: string) => Promise<void>
+      sendMessage: (
+        message: ChatBskyConvoSendMessage.InputSchema['message'],
+      ) => Promise<void>
+      fetchMessageHistory: () => Promise<void>
+    }
+  | {
+      status: ConvoStatus.Backgrounded
+      items: ConvoItem[]
+      convo: ChatBskyConvoDefs.ConvoView
+      error: undefined
+      sender: AppBskyActorDefs.ProfileViewBasic
+      recipients: AppBskyActorDefs.ProfileViewBasic[]
+      isFetchingHistory: boolean
+      deleteMessage: (messageId: string) => Promise<void>
+      sendMessage: (
+        message: ChatBskyConvoSendMessage.InputSchema['message'],
+      ) => Promise<void>
+      fetchMessageHistory: () => Promise<void>
+    }
+  | {
+      status: ConvoStatus.Resuming
+      items: ConvoItem[]
+      convo: ChatBskyConvoDefs.ConvoView
+      error: undefined
+      sender: AppBskyActorDefs.ProfileViewBasic
+      recipients: AppBskyActorDefs.ProfileViewBasic[]
+      isFetchingHistory: boolean
+      deleteMessage: (messageId: string) => Promise<void>
+      sendMessage: (
+        message: ChatBskyConvoSendMessage.InputSchema['message'],
+      ) => Promise<void>
+      fetchMessageHistory: () => Promise<void>
+    }
+  | {
+      status: ConvoStatus.Error
+      items: []
+      convo: undefined
+      error: any
+      sender: undefined
+      recipients: undefined
+      isFetchingHistory: false
+      deleteMessage: undefined
+      sendMessage: undefined
+      fetchMessageHistory: undefined
+    }
+
+const ACTIVE_POLL_INTERVAL = 2e3
+const BACKGROUND_POLL_INTERVAL = 10e3
+
+export function isConvoItemMessage(
+  item: ConvoItem,
+): item is ConvoItem & {type: 'message'} {
+  if (!item) return false
+  return (
+    item.type === 'message' ||
+    item.type === 'deleted-message' ||
+    item.type === 'pending-message'
+  )
+}
+
+export class Convo {
+  private agent: BskyAgent
+  private __tempFromUserDid: string
+
+  private pollInterval = ACTIVE_POLL_INTERVAL
+  private status: ConvoStatus = ConvoStatus.Uninitialized
+  private error:
+    | {
+        code: ConvoError
+        exception?: Error
+        retry: () => void
+      }
+    | undefined
+  private historyCursor: string | undefined | null = undefined
+  private isFetchingHistory = false
+  private eventsCursor: string | undefined = undefined
+  private pollingFailure = false
+
+  private pastMessages: Map<
+    string,
+    ChatBskyConvoDefs.MessageView | ChatBskyConvoDefs.DeletedMessageView
+  > = new Map()
+  private newMessages: Map<
+    string,
+    ChatBskyConvoDefs.MessageView | ChatBskyConvoDefs.DeletedMessageView
+  > = new Map()
+  private pendingMessages: Map<
+    string,
+    {id: string; message: ChatBskyConvoSendMessage.InputSchema['message']}
+  > = new Map()
+  private deletedMessages: Set<string> = new Set()
+  private footerItems: Map<string, ConvoItem> = new Map()
+  private headerItems: Map<string, ConvoItem> = new Map()
+
+  private pendingEventIngestion: Promise<void> | undefined
+  private isProcessingPendingMessages = false
+
+  convoId: string
+  convo: ChatBskyConvoDefs.ConvoView | undefined
+  sender: AppBskyActorDefs.ProfileViewBasic | undefined
+  recipients: AppBskyActorDefs.ProfileViewBasic[] | undefined = undefined
+  snapshot: ConvoState | undefined
+
+  constructor(params: ConvoParams) {
+    this.convoId = params.convoId
+    this.agent = params.agent
+    this.__tempFromUserDid = params.__tempFromUserDid
+
+    this.subscribe = this.subscribe.bind(this)
+    this.getSnapshot = this.getSnapshot.bind(this)
+    this.sendMessage = this.sendMessage.bind(this)
+    this.deleteMessage = this.deleteMessage.bind(this)
+    this.fetchMessageHistory = this.fetchMessageHistory.bind(this)
+  }
+
+  private commit() {
+    this.snapshot = undefined
+    this.subscribers.forEach(subscriber => subscriber())
+  }
+
+  private subscribers: (() => void)[] = []
+
+  subscribe(subscriber: () => void) {
+    if (this.subscribers.length === 0) this.init()
+
+    this.subscribers.push(subscriber)
+
+    return () => {
+      this.subscribers = this.subscribers.filter(s => s !== subscriber)
+      if (this.subscribers.length === 0) this.suspend()
+    }
+  }
+
+  getSnapshot(): ConvoState {
+    if (!this.snapshot) this.snapshot = this.generateSnapshot()
+    // logger.debug('Convo: snapshotted', {}, logger.DebugContext.convo)
+    return this.snapshot
+  }
+
+  private generateSnapshot(): ConvoState {
+    switch (this.status) {
+      case ConvoStatus.Initializing: {
+        return {
+          status: ConvoStatus.Initializing,
+          items: [],
+          convo: undefined,
+          error: undefined,
+          sender: undefined,
+          recipients: undefined,
+          isFetchingHistory: this.isFetchingHistory,
+          deleteMessage: undefined,
+          sendMessage: undefined,
+          fetchMessageHistory: undefined,
+        }
+      }
+      case ConvoStatus.Suspended:
+      case ConvoStatus.Backgrounded:
+      case ConvoStatus.Resuming:
+      case ConvoStatus.Ready: {
+        return {
+          status: this.status,
+          items: this.getItems(),
+          convo: this.convo!,
+          error: undefined,
+          sender: this.sender!,
+          recipients: this.recipients!,
+          isFetchingHistory: this.isFetchingHistory,
+          deleteMessage: this.deleteMessage,
+          sendMessage: this.sendMessage,
+          fetchMessageHistory: this.fetchMessageHistory,
+        }
+      }
+      case ConvoStatus.Error: {
+        return {
+          status: ConvoStatus.Error,
+          items: [],
+          convo: undefined,
+          error: this.error,
+          sender: undefined,
+          recipients: undefined,
+          isFetchingHistory: false,
+          deleteMessage: undefined,
+          sendMessage: undefined,
+          fetchMessageHistory: undefined,
+        }
+      }
+      default: {
+        return {
+          status: ConvoStatus.Uninitialized,
+          items: [],
+          convo: undefined,
+          error: undefined,
+          sender: undefined,
+          recipients: undefined,
+          isFetchingHistory: false,
+          deleteMessage: undefined,
+          sendMessage: undefined,
+          fetchMessageHistory: undefined,
+        }
+      }
+    }
+  }
+
+  async init() {
+    logger.debug('Convo: init', {}, logger.DebugContext.convo)
+
+    if (
+      this.status === ConvoStatus.Uninitialized ||
+      this.status === ConvoStatus.Error
+    ) {
+      try {
+        this.status = ConvoStatus.Initializing
+        this.commit()
+
+        await this.refreshConvo()
+        this.status = ConvoStatus.Ready
+        this.commit()
+
+        await this.fetchMessageHistory()
+
+        this.pollEvents()
+      } catch (e: any) {
+        logger.error('Convo: failed to init')
+        this.error = {
+          exception: e,
+          code: ConvoError.InitFailed,
+          retry: () => {
+            this.error = undefined
+            this.init()
+          },
+        }
+        this.status = ConvoStatus.Error
+        this.commit()
+      }
+    } else {
+      logger.warn(`Convo: cannot init from ${this.status}`)
+    }
+  }
+
+  async resume() {
+    logger.debug('Convo: resume', {}, logger.DebugContext.convo)
+
+    if (
+      this.status === ConvoStatus.Suspended ||
+      this.status === ConvoStatus.Backgrounded
+    ) {
+      const fromStatus = this.status
+
+      try {
+        this.status = ConvoStatus.Resuming
+        this.commit()
+
+        await this.refreshConvo()
+        this.status = ConvoStatus.Ready
+        this.commit()
+
+        // throw new Error('UNCOMMENT TO TEST RESUME FAILURE')
+
+        this.pollInterval = ACTIVE_POLL_INTERVAL
+        this.pollEvents()
+      } catch (e) {
+        logger.error('Convo: failed to resume')
+
+        this.footerItems.set(ConvoItemError.ResumeFailed, {
+          type: 'error-recoverable',
+          key: ConvoItemError.ResumeFailed,
+          code: ConvoItemError.ResumeFailed,
+          retry: () => {
+            this.footerItems.delete(ConvoItemError.ResumeFailed)
+            this.resume()
+          },
+        })
+
+        this.status = fromStatus
+        this.commit()
+      }
+    } else {
+      logger.warn(`Convo: cannot resume from ${this.status}`)
+    }
+  }
+
+  async background() {
+    logger.debug('Convo: backgrounded', {}, logger.DebugContext.convo)
+    this.status = ConvoStatus.Backgrounded
+    this.pollInterval = BACKGROUND_POLL_INTERVAL
+    this.commit()
+  }
+
+  async suspend() {
+    logger.debug('Convo: suspended', {}, logger.DebugContext.convo)
+    this.status = ConvoStatus.Suspended
+    this.commit()
+  }
+
+  async refreshConvo() {
+    const response = await this.agent.api.chat.bsky.convo.getConvo(
+      {
+        convoId: this.convoId,
+      },
+      {
+        headers: {
+          Authorization: this.__tempFromUserDid,
+        },
+      },
+    )
+    this.convo = response.data.convo
+    this.sender = this.convo.members.find(m => m.did === this.__tempFromUserDid)
+    this.recipients = this.convo.members.filter(
+      m => m.did !== this.__tempFromUserDid,
+    )
+
+    /*
+     * Prevent invalid states
+     */
+    if (!this.sender) {
+      throw new Error('Convo: could not find sender in convo')
+    }
+    if (!this.recipients) {
+      throw new Error('Convo: could not find recipients in convo')
+    }
+  }
+
+  async fetchMessageHistory() {
+    logger.debug('Convo: fetch message history', {}, logger.DebugContext.convo)
+
+    /*
+     * If historyCursor is null, we've fetched all history.
+     */
+    if (this.historyCursor === null) return
+
+    /*
+     * Don't fetch again if a fetch is already in progress
+     */
+    if (this.isFetchingHistory) return
+
+    /*
+     * If we've rendered a retry state for history fetching, exit. Upon retry,
+     * this will be removed and we'll try again.
+     */
+    if (this.headerItems.has(ConvoItemError.HistoryFailed)) return
+
+    try {
+      this.isFetchingHistory = true
+      this.commit()
+
+      /*
+       * Delay if paginating while scrolled to prevent momentum scrolling from
+       * jerking the list around, plus makes it feel a little more human.
+       */
+      if (this.pastMessages.size > 0) {
+        await new Promise(y => setTimeout(y, 500))
+        // throw new Error('UNCOMMENT TO TEST RETRY')
+      }
+
+      const response = await this.agent.api.chat.bsky.convo.getMessages(
+        {
+          cursor: this.historyCursor,
+          convoId: this.convoId,
+          limit: isNative ? 25 : 50,
+        },
+        {
+          headers: {
+            Authorization: this.__tempFromUserDid,
+          },
+        },
+      )
+      const {cursor, messages} = response.data
+
+      this.historyCursor = cursor ?? null
+
+      for (const message of messages) {
+        if (
+          ChatBskyConvoDefs.isMessageView(message) ||
+          ChatBskyConvoDefs.isDeletedMessageView(message)
+        ) {
+          this.pastMessages.set(message.id, message)
+
+          // set to latest rev
+          if (
+            message.rev > (this.eventsCursor = this.eventsCursor || message.rev)
+          ) {
+            this.eventsCursor = message.rev
+          }
+        }
+      }
+    } catch (e: any) {
+      logger.error('Convo: failed to fetch message history')
+
+      this.headerItems.set(ConvoItemError.HistoryFailed, {
+        type: 'error-recoverable',
+        key: ConvoItemError.HistoryFailed,
+        code: ConvoItemError.HistoryFailed,
+        retry: () => {
+          this.headerItems.delete(ConvoItemError.HistoryFailed)
+          this.fetchMessageHistory()
+        },
+      })
+    } finally {
+      this.isFetchingHistory = false
+      this.commit()
+    }
+  }
+
+  private async pollEvents() {
+    if (
+      this.status === ConvoStatus.Ready ||
+      this.status === ConvoStatus.Backgrounded
+    ) {
+      if (this.pendingEventIngestion) return
+
+      /*
+       * Represents a failed state, which is retryable.
+       */
+      if (this.pollingFailure) return
+
+      setTimeout(async () => {
+        this.pendingEventIngestion = this.ingestLatestEvents()
+        await this.pendingEventIngestion
+        this.pendingEventIngestion = undefined
+        this.pollEvents()
+      }, this.pollInterval)
+    }
+  }
+
+  async ingestLatestEvents() {
+    try {
+      // throw new Error('UNCOMMENT TO TEST POLL FAILURE')
+      const response = await this.agent.api.chat.bsky.convo.getLog(
+        {
+          cursor: this.eventsCursor,
+        },
+        {
+          headers: {
+            Authorization: this.__tempFromUserDid,
+          },
+        },
+      )
+      const {logs} = response.data
+
+      let needsCommit = false
+
+      for (const log of logs) {
+        /*
+         * If there's a rev, we should handle it. If there's not a rev, we don't
+         * know what it is.
+         */
+        if (typeof log.rev === 'string') {
+          /*
+           * We only care about new events
+           */
+          if (log.rev > (this.eventsCursor = this.eventsCursor || log.rev)) {
+            /*
+             * Update rev regardless of if it's a log type we care about or not
+             */
+            this.eventsCursor = log.rev
+
+            /*
+             * This is VERY important. We don't want to insert any messages from
+             * your other chats.
+             */
+            if (log.convoId !== this.convoId) continue
+
+            if (
+              ChatBskyConvoDefs.isLogCreateMessage(log) &&
+              ChatBskyConvoDefs.isMessageView(log.message)
+            ) {
+              if (this.newMessages.has(log.message.id)) {
+                // Trust the log as the source of truth on ordering
+                this.newMessages.delete(log.message.id)
+              }
+              this.newMessages.set(log.message.id, log.message)
+              needsCommit = true
+            } else if (
+              ChatBskyConvoDefs.isLogDeleteMessage(log) &&
+              ChatBskyConvoDefs.isDeletedMessageView(log.message)
+            ) {
+              /*
+               * Update if we have this in state. If we don't, don't worry about it.
+               */
+              if (this.pastMessages.has(log.message.id)) {
+                /*
+                 * For now, we remove deleted messages from the thread, if we receive one.
+                 *
+                 * To support them, it'd look something like this:
+                 *   this.pastMessages.set(log.message.id, log.message)
+                 */
+                this.pastMessages.delete(log.message.id)
+                this.newMessages.delete(log.message.id)
+                this.deletedMessages.delete(log.message.id)
+                needsCommit = true
+              }
+            }
+          }
+        }
+      }
+
+      if (needsCommit) {
+        this.commit()
+      }
+    } catch (e: any) {
+      logger.error('Convo: failed to poll events')
+      this.pollingFailure = true
+      this.footerItems.set(ConvoItemError.PollFailed, {
+        type: 'error-recoverable',
+        key: ConvoItemError.PollFailed,
+        code: ConvoItemError.PollFailed,
+        retry: () => {
+          this.footerItems.delete(ConvoItemError.PollFailed)
+          this.pollingFailure = false
+          this.commit()
+          this.pollEvents()
+        },
+      })
+      this.commit()
+    }
+  }
+
+  async sendMessage(message: ChatBskyConvoSendMessage.InputSchema['message']) {
+    // Ignore empty messages for now since they have no other purpose atm
+    if (!message.text.trim()) return
+
+    logger.debug('Convo: send message', {}, logger.DebugContext.convo)
+
+    const tempId = nanoid()
+
+    this.pendingMessages.set(tempId, {
+      id: tempId,
+      message,
+    })
+    this.commit()
+
+    if (!this.isProcessingPendingMessages) {
+      this.processPendingMessages()
+    }
+  }
+
+  async processPendingMessages() {
+    logger.debug(
+      `Convo: processing messages (${this.pendingMessages.size} remaining)`,
+      {},
+      logger.DebugContext.convo,
+    )
+
+    const pendingMessage = Array.from(this.pendingMessages.values()).shift()
+
+    /*
+     * If there are no pending messages, we're done.
+     */
+    if (!pendingMessage) {
+      this.isProcessingPendingMessages = false
+      return
+    }
+
+    try {
+      this.isProcessingPendingMessages = true
+
+      // throw new Error('UNCOMMENT TO TEST RETRY')
+      const {id, message} = pendingMessage
+
+      const response = await this.agent.api.chat.bsky.convo.sendMessage(
+        {
+          convoId: this.convoId,
+          message,
+        },
+        {
+          encoding: 'application/json',
+          headers: {
+            Authorization: this.__tempFromUserDid,
+          },
+        },
+      )
+      const res = response.data
+
+      /*
+       * Insert into `newMessages` as soon as we have a real ID. That way, when
+       * we get an event log back, we can replace in situ.
+       */
+      this.newMessages.set(res.id, {
+        ...res,
+        $type: 'chat.bsky.convo.defs#messageView',
+        sender: this.sender,
+      })
+      this.pendingMessages.delete(id)
+
+      await this.processPendingMessages()
+
+      this.commit()
+    } catch (e) {
+      this.footerItems.set('pending-retry', {
+        type: 'pending-retry',
+        key: 'pending-retry',
+        retry: this.batchRetryPendingMessages.bind(this),
+      })
+      this.commit()
+    }
+  }
+
+  async batchRetryPendingMessages() {
+    logger.debug(
+      `Convo: retrying ${this.pendingMessages.size} pending messages`,
+      {},
+      logger.DebugContext.convo,
+    )
+
+    this.footerItems.delete('pending-retry')
+    this.commit()
+
+    try {
+      const messageArray = Array.from(this.pendingMessages.values())
+      const {data} = await this.agent.api.chat.bsky.convo.sendMessageBatch(
+        {
+          items: messageArray.map(({message}) => ({
+            convoId: this.convoId,
+            message,
+          })),
+        },
+        {
+          encoding: 'application/json',
+          headers: {
+            Authorization: this.__tempFromUserDid,
+          },
+        },
+      )
+      const {items} = data
+
+      /*
+       * Insert into `newMessages` as soon as we have a real ID. That way, when
+       * we get an event log back, we can replace in situ.
+       */
+      for (const item of items) {
+        this.newMessages.set(item.id, {
+          ...item,
+          $type: 'chat.bsky.convo.defs#messageView',
+          sender: this.convo?.members.find(
+            m => m.did === this.__tempFromUserDid,
+          ),
+        })
+      }
+
+      for (const pendingMessage of messageArray) {
+        this.pendingMessages.delete(pendingMessage.id)
+      }
+
+      this.commit()
+    } catch (e) {
+      this.footerItems.set('pending-retry', {
+        type: 'pending-retry',
+        key: 'pending-retry',
+        retry: this.batchRetryPendingMessages.bind(this),
+      })
+      this.commit()
+    }
+  }
+
+  async deleteMessage(messageId: string) {
+    logger.debug('Convo: delete message', {}, logger.DebugContext.convo)
+
+    this.deletedMessages.add(messageId)
+    this.commit()
+
+    try {
+      await this.agent.api.chat.bsky.convo.deleteMessageForSelf(
+        {
+          convoId: this.convoId,
+          messageId,
+        },
+        {
+          encoding: 'application/json',
+          headers: {
+            Authorization: this.__tempFromUserDid,
+          },
+        },
+      )
+    } catch (e) {
+      this.deletedMessages.delete(messageId)
+      this.commit()
+      throw e
+    }
+  }
+
+  /*
+   * Items in reverse order, since FlatList inverts
+   */
+  getItems(): ConvoItem[] {
+    const items: ConvoItem[] = []
+
+    this.headerItems.forEach(item => {
+      items.push(item)
+    })
+
+    this.pastMessages.forEach(m => {
+      if (ChatBskyConvoDefs.isMessageView(m)) {
+        items.unshift({
+          type: 'message',
+          key: m.id,
+          message: m,
+          nextMessage: null,
+        })
+      } else if (ChatBskyConvoDefs.isDeletedMessageView(m)) {
+        items.unshift({
+          type: 'deleted-message',
+          key: m.id,
+          message: m,
+          nextMessage: null,
+        })
+      }
+    })
+
+    this.newMessages.forEach(m => {
+      if (ChatBskyConvoDefs.isMessageView(m)) {
+        items.push({
+          type: 'message',
+          key: m.id,
+          message: m,
+          nextMessage: null,
+        })
+      } else if (ChatBskyConvoDefs.isDeletedMessageView(m)) {
+        items.push({
+          type: 'deleted-message',
+          key: m.id,
+          message: m,
+          nextMessage: null,
+        })
+      }
+    })
+
+    this.pendingMessages.forEach(m => {
+      items.push({
+        type: 'pending-message',
+        key: m.id,
+        message: {
+          ...m.message,
+          id: nanoid(),
+          rev: '__fake__',
+          sentAt: new Date().toISOString(),
+          sender: this.sender,
+        },
+        nextMessage: null,
+      })
+    })
+
+    this.footerItems.forEach(item => {
+      items.push(item)
+    })
+
+    return items
+      .filter(item => {
+        if (isConvoItemMessage(item)) {
+          return !this.deletedMessages.has(item.message.id)
+        }
+        return true
+      })
+      .map((item, i, arr) => {
+        let nextMessage = null
+        const isMessage = isConvoItemMessage(item)
+
+        if (isMessage) {
+          if (
+            isMessage &&
+            (ChatBskyConvoDefs.isMessageView(item.message) ||
+              ChatBskyConvoDefs.isDeletedMessageView(item.message))
+          ) {
+            const next = arr[i + 1]
+
+            if (
+              isConvoItemMessage(next) &&
+              next &&
+              (ChatBskyConvoDefs.isMessageView(next.message) ||
+                ChatBskyConvoDefs.isDeletedMessageView(next.message))
+            ) {
+              nextMessage = next.message
+            }
+          }
+
+          return {
+            ...item,
+            nextMessage,
+          }
+        }
+
+        return item
+      })
+  }
+}