List Slack channels, last message date, and whether it contains external members

import { WebClient as SlackWebClient } from "npm:@slack/web-api";

type Slack = {

  token: string

}

// Needed scopes are: users:read ; users:read.email ; channels:read ; channels:history

export async function main(slackResource: Slack, companyDomain: string) {

  // Initialize the Slack WebClient with the provided token

  const slackClient = new SlackWebClient(slackResource.token);

  try {

    // Call the conversations.list method to get all channels

    const listResult = await slackClient.conversations.list();

    // Check if the listResult was successful and channels are present

    if (listResult.ok && listResult.channels) {

      // Initialize an array to hold the channels with their last message date and external member status

      const channelsInfo = [];

      // Iterate over each channel to fetch the last message's date, check for external members

      for (const channel of listResult.channels) {

        // Initialize external as false

        let external = false;

        // Call the conversations.members method to get all members of the channel

        const membersResult = await slackClient.conversations.members({

          channel: channel.id,

        });

        // Check if the membersResult was successful and members are present

        if (membersResult.ok && membersResult.members) {

          // Iterate over each member to fetch their user info

          for (const memberId of membersResult.members) {

            const userInfo = await slackClient.users.info({ user: memberId });

            // Check if the userInfo was successful and user info is present

            if (userInfo.ok && userInfo.user) {

              if (userInfo.user.profile && userInfo.user.profile.email) {

                // Check if the email domain is not windmill.dev

                if (!userInfo.user.profile.email.endsWith(companyDomain)) {

                  external = true;

                }

              } else {

                // Assume external if the email is not available

                external = true;

              }

            }

          }

        }

        // Call the conversations.history method to get the last message of the channel

        const historyResult = await slackClient.conversations.history({

          channel: channel.id,

          limit: 1, // We only need the last message

        });

        // Initialize the lastMessageDate

        let lastMessageDate = "No messages found";

        // Check if the historyResult was successful and messages are present

        if (

          historyResult.ok && historyResult.messages &&

          historyResult.messages.length > 0

        ) {

          // Convert the timestamp to a Date object

          const date = new Date(

            parseFloat(historyResult.messages[0].ts) * 1000,

          );

          // Format the Date object to "YYYYMMDD"

          const year = date.getFullYear();

          const month = (date.getMonth() + 1).toString().padStart(2, "0"); // Pad with zero if needed

          const day = date.getDate().toString().padStart(2, "0"); // Pad with zero if needed

          lastMessageDate = `${year}${month}${day}`;

        }

        // Add the channel info to the array

        channelsInfo.push({

          id: channel.id,

          name: channel.name,

          lastMessageDate: lastMessageDate,

          external: external

        });

      }

      // Return the list of channels with the date of the last message, external member status

      return channelsInfo;

    } else {

      // Return an error message if the listResult was not successful or channels are not present

      return "Failed to retrieve channels or no channels found.";

    }

  } catch (error) {

    // Return the error if the API call fails

    return `Error retrieving channels: ${error}`;

  }

}