index.js

const { App, ExpressReceiver, LogLevel } = require('@slack/bolt');
const config = require('config');
const path = require('path');
const express = require('express');

const { MongoClient } = require('mongodb');

const { Migrations } = require('./utils/migrations');

const { Mutex } = require('async-mutex');

const port = config.get('port');
const signing_secret = config.get('signing_secret');
const slackCommand = config.get('command');
const helpLink = config.get('help_link');
const supportUrl = config.get('support_url');

const client = new MongoClient(config.get('mongo_url'));
let orgCol = null;
let votesCol = null;
let closedCol = null;
let hiddenCol = null;

let migrations = null;

const mutexes = {};

try {
  console.log('Connecting to database server...');
  client.connect();
  console.log('Connected successfully to server')
  const db = client.db(config.get('mongo_db_name'));
  orgCol = db.collection('token');
  votesCol = db.collection('votes');
  closedCol = db.collection('closed');
  hiddenCol = db.collection('hidden');

  migrations = new Migrations(db);
} catch (e) {
  client.close();
  console.error(e)
  process.exit();
}

const receiver = new ExpressReceiver({
  signingSecret: signing_secret,
  clientId: config.get('client_id'),
  clientSecret: config.get('client_secret'),
  scopes: ['commands', 'chat:write.public', 'chat:write', 'groups:write'],
  stateSecret: config.get('state_secret'),
  endpoints: {
    events: '/slack/events',
    commands: '/slack/commands',
    actions: '/slack/actions',
  },
  installerOptions: {
    installPath: '/slack/install',
    redirectUriPath: '/slack/oauth_redirect',
    callbackOptions: {
      success: (installation, installOptions, req, res) => {
        console.log('OAuth success callback called');
        console.log('Installation received:', JSON.stringify(installation, null, 2));
        res.redirect(config.get('oauth_success'));
      },
      failure: (error, installOptions , req, res) => {
        console.log('OAuth failure callback called');
        console.log('OAuth error:', error);
        res.redirect(config.get('oauth_failure'));
      },
    },
  },
  installationStore: {
    storeInstallation: async (installation) => {
      try {
        console.log('storeInstallation called for team:', installation.team?.id);
        const team = await orgCol.findOne({ 'team.id': installation.team.id });
        if (team) {
          console.log('Updating existing installation for team:', installation.team.id);
          await orgCol.replaceOne({ 'team.id': installation.team.id }, installation);
        } else {
          console.log('Inserting new installation for team:', installation.team.id);
          await orgCol.insertOne(installation);
        }
        console.log('Installation stored successfully for team:', installation.team.id);
        return installation.team.id;
      } catch (e) {
        console.error('Error storing installation:', e);
        throw e;
      }
    },
    fetchInstallation: async (InstallQuery) => {
      try {
        console.log('fetchInstallation called for team:', InstallQuery.teamId);
        const result = await orgCol.findOne({ 'team.id': InstallQuery.teamId });
        console.log('fetchInstallation result:', result ? 'found' : 'not found');
        return result;
      } catch (e) {
        console.error('Error fetching installation:', e);
        throw new Error('No matching authorizations');
      }
    },
  },
  logLevel: LogLevel.DEBUG,
});

receiver.router.get('/ping', (req, res) => {
  res.status(200).send('pong');
});

// Serve static files
receiver.router.use('/assets', express.static(path.join(__dirname, 'assets')));
receiver.router.use('/privacy', express.static(path.join(__dirname, 'privacy')));
receiver.router.use('/tos', express.static(path.join(__dirname, 'tos')));

// Serve index.html for root path
receiver.router.get('/', (req, res) => {
  res.sendFile(path.join(__dirname, 'index.html'));
});

const app = new App({
  receiver: receiver,
});

app.event('app_home_opened', async ({ event, client, context }) => {
  try {
    const result = await client.views.publish({
      user_id: event.user,
      view: {
        type: "home",
        blocks: [
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "Hello, here is how to create a poll with DMUN-Poll.",
            },
          },
          {
            type: "divider",
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Create poll",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*From command*\nJust typing `/poll` where you type the message, following with options (see below) and your choices surrounding by quotes.\nBe careful, this way open the shortcuts. But you just need to ignore it and continue typing options and choices.",
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*From shortcuts*\nOpen shortcuts (lightning bolt below to message input, or just type `/` into message input) and type \"poll\"",
            },
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Delete poll",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "When you create a poll, a red button will appear at bottom of your poll.\nOnly the creator can delete a poll.",
            },
          },
          {
            type: "divider",
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Options",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "The options are optionals settings to apply to the poll.\nDon't surround options with quotes.",
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Anonymous*\n`anonymous` inside command.\nThis option allow you to hide voters.",
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Limited choices*\n`limit x` inside command. Replace \"x\" by desired number.\nThis option limit maximum choice for each users. If \"2\", each user can only select 2 choices.",
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Hidden*\n`hidden` inside command.\nThis option hide the number of votes for each choice. You can reveal votes with a button at bottom of poll. Only the creator can reveal votes.",
            },
          },
          {
            type: "divider",
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Examples",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Simple poll*\nThis example will create a basic poll.",
            },
          },
          {
            type: "input",
            element: {
              type: "plain_text_input",
              initial_value: "/poll \"What's you favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\""
            },
            label: {
              type: "plain_text",
              text: " ",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Anonymous poll*\nThis example will create anonymous poll.",
            },
          },
          {
            type: "input",
            element: {
              type: "plain_text_input",
              initial_value: "/poll anonymous \"What's you favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"",
            },
            label: {
              type: "plain_text",
              text: " ",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Limited poll*\nThis example will create anonymous poll.",
            },
          },
          {
            type: "input",
            element: {
              type: "plain_text_input",
              initial_value: "/poll limit 2 \"What's you favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"",
            },
            label: {
              type: "plain_text",
              text: " ",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Hidden poll*\nThis example will create hidden poll and allow you to reveal votes.",
            },
          },
          {
            type: "input",
            element: {
              type: "plain_text_input",
              initial_value: "/poll hidden \"What's you favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"",
            },
            label: {
              type: "plain_text",
              text: " ",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Mixed options poll*\nThis example will create anonymous and limited poll.",
            },
          },
          {
            type: "input",
            element: {
              type: "plain_text_input",
              initial_value: "/poll anonymous limit 2 \"What's you favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"",
            },
            label: {
              type: "plain_text",
              text: " ",
              emoji: true,
            },
          },
          {
            type: "divider",
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Tips",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Private channel*\nTo create poll in private channels, you need to invite the bot inside with `/invite` command.",
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "*Private messages*\nTo create poll in private messages, you need to invite the bot inside with `/invite` command.",
            },
          },
          {
            type: "divider",
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Recurring poll",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "Slack has a feature called \"Workflow\" that allow you to create recurring poll. Check at <https://slack.com/slack-tips/speed-up-poll-creation-with-simple-poll|this example> from slack. But it require a paid plan.",
            },
          },
          {
            type: "divider",
          },
          {
            type: "header",
            text: {
              type: "plain_text",
              text: "Limitations",
              emoji: true,
            },
          },
          {
            type: "section",
            text: {
              type: "mrkdwn",
              text: "Slack have limitations and that include \"message length\". So you can't have more than 15 options per poll. You can create multiple polls if you want more options",
            },
          },
        ],
      },
    });
  } catch (error) {
    console.error(error);
  }
});

app.command(`/${slackCommand}`, async ({ ack, body, client, command, context, say }) => {
  await ack();

  let cmdBody = (command && command.text) ? command.text.trim() : null;

  const isHelp = cmdBody ? 'help' === cmdBody : false;

  const channel = (command && command.channel_id) ? command.channel_id : null;

  const userId = (command && command.user_id) ? command.user_id : null;

  if (isHelp) {
    const blocks = [
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: '*DMUN-Poll for Slack*',
        },
      },
      {
        type: 'divider',
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: '*Simple poll*',
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: "```\n/"+slackCommand+" \"What's your favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"\n```",
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: '*Anonymous poll*',
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: "```\n/"+slackCommand+" anonymous \"What's your favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"\n```",
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: '*Hidden poll votes*',
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: "```\n/"+slackCommand+" hidden \"What's your favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"\n```",
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: '*Limited choice poll*',
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: "```\n/"+slackCommand+" limit 2 \"What's your favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"\n```",
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: '*Anonymous limited choice poll*',
        },
      },
      {
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: "```\n/"+slackCommand+" anonymous limit 2 \"What's your favourite color ?\" \"Red\" \"Green\" \"Blue\" \"Yellow\"\n```",
        },
      },
    ];

    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: channel,
      user: userId,
      blocks: blocks,
    });

    return;
  } else if (!cmdBody) {
    createModal(context, client, body.trigger_id);
  } else {
    const cmd = `/${slackCommand} ${cmdBody}`;
    let question = null;
    const options = [];

    let isAnonymous = false;
    let isLimited = false;
    let limit = null;
    let isHidden = false;
    let fetchArgs = true;

    while (fetchArgs) {
      fetchArgs = false;
      if (cmdBody.startsWith('anonymous')) {
        fetchArgs = true;
        isAnonymous = true;
        cmdBody = cmdBody.substring(9).trim();
      } else if (cmdBody.startsWith('limit')) {
        fetchArgs = true;
        cmdBody = cmdBody.substring(5).trim();
        isLimited = true;
        if (!isNaN(parseInt(cmdBody.charAt(0)))) {
          limit = parseInt(cmdBody.substring(0, cmdBody.indexOf(' ')));
          cmdBody = cmdBody.substring(cmdBody.indexOf(' ')).trim();
        }
      } else if (cmdBody.startsWith('hidden')) {
        fetchArgs = true;
        cmdBody = cmdBody.substring(6).trim();
        isHidden = true;
      }
    }

    const lastSep = cmdBody.split('').pop();
    const firstSep = cmdBody.charAt(0);

    if (isLimited && null === limit) {
      limit = 1;
    }

    const regexp = new RegExp(firstSep+'[^'+firstSep+'\\\\]*(?:\\\\[\S\s][^'+lastSep+'\\\\]*)*'+lastSep, 'g');
    for (let option of cmdBody.match(regexp)) {
      let opt = option.substring(1, option.length - 1);
      if (question === null) {
        question = opt;
      } else {
        options.push(opt);
      }
    }

    const blocks = createPollView(question, options, isAnonymous, isLimited, limit, isHidden, userId, cmd);

    if (null === blocks) {
      return;
    }

    try {
      await app.client.chat.postMessage({
        token: context.botToken,
        channel: channel,
        blocks: blocks,
        text: `Poll : ${question}`,
      });
    } catch (e) {
      if (
        e && e.data && e.data && e.data.error
        && 'channel_not_found' === e.data.error
      ) {
        console.error('Channel not found error : ignored')
      }
    }
  }
});

const modalBlockInput = {
  type: 'input',
  element: {
    type: 'plain_text_input',
    placeholder: {
      type: 'plain_text',
      text: 'Write your choice',
    },
  },
  label: {
    type: 'plain_text',
    text: ' ',
  },
};

(async () => {
  console.log('Start database migration.');
  await migrations.init();
  await migrations.migrate();
  console.log('End database migration.')

  await app.start(process.env.PORT || port);

  console.log('Bolt app is running!');
})();

app.action('btn_add_choice', async ({ action, ack, body, client, context }) => {
  await ack();

  if (
    !body
    || !body.view
    || !body.view.blocks
    || !body.view.hash
    || !body.view.type
    || !body.view.title
    || !body.view.submit
    || !body.view.close
    || !body.view.id
    || !body.view.private_metadata
  ) {
    console.log('error');
    return;
  }

  let blocks = body.view.blocks;
  const hash = body.view.hash;

  let beginBlocks = blocks.slice(0, blocks.length - 1);
  let endBlocks = blocks.slice(-1);

  let tempModalBlockInput = JSON.parse(JSON.stringify(modalBlockInput));
  tempModalBlockInput.block_id = 'choice_'+(blocks.length-8);

  beginBlocks.push(tempModalBlockInput);
  blocks = beginBlocks.concat(endBlocks);

  const view = {
    type: body.view.type,
    private_metadata: body.view.private_metadata,
    callback_id: 'modal_poll_submit',
    title: body.view.title,
    submit: body.view.submit,
    close: body.view.close,
    blocks: blocks,
    external_id: body.view.id,
  };

  const result = await client.views.update({
    token: context.botToken,
    hash: hash,
    view: view,
    view_id: body.view.id,
  });
});

app.action('btn_my_votes', async ({ ack, body, client, context }) => {
  await ack();

  if (
    !body.hasOwnProperty('user')
    || !body.user.hasOwnProperty('id')
  ) {
    return;
  }

  const blocks = body.message.blocks;
  let votes = [];
  const userId = body.user.id;

  for (const block of blocks) {
    if (
      'section' !== block.type
      || !block.hasOwnProperty('accessory')
      || !block.accessory.hasOwnProperty('action_id')
      || 'btn_vote' !== block.accessory.action_id
      || !block.accessory.hasOwnProperty('value')
      || !block.hasOwnProperty('text')
      || !block.text.hasOwnProperty('text')
    ) {
      continue;
    }
    const value = JSON.parse(block.accessory.value);

    if (value.voters.includes(userId)) {
      votes.push({
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: block.text.text,
        },
      });
      votes.push({
        type: 'divider',
      });
    }
  }

  if (0 === votes.length) {
    votes.push({
      type: 'section',
      text: {
        type: 'mrkdwn',
        text: 'You have not voted yet',
      },
    });
  } else {
    votes.pop();
  }

  try {
    await client.views.open({
      token: context.botToken,
      trigger_id: body.trigger_id,
      view: {
        type: 'modal',
        title: {
          type: 'plain_text',
          text: 'Your votes',
        },
        close: {
          type: 'plain_text',
          text: 'Close',
        },
        blocks: votes,
      }
    });
  } catch (e) {
    console.error(e);
  }
});

app.action('btn_delete', async ({ action, ack, body, context }) => {
  await ack();

  if (
    !body
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.ts
    || !body.channel
    || !body.channel.id
    || !action
    || !action.value
  ) {
    console.log('error');
    return;
  }

  if (body.user.id != action.value) {
    console.log('invalid user');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "You can't delete poll from another user.",
    });
    return;
  }

  await app.client.chat.delete({
    token: context.botToken,
    channel: body.channel.id,
    ts: body.message.ts,
  });
});

app.action('btn_reveal', async ({ action, ack, body, context }) => {
  await ack();

  if (
    !body
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.ts
    || !body.message.blocks
    || !body.channel
    || !body.channel.id
    || !action
    || !action.value
  ) {
    console.log('error');
    return;
  }

  let value = JSON.parse(action.value);

  if (body.user.id !== value.user) {
    console.log('invalid user');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "You can't reveal poll from another user.",
    });
    return;
  }

  await app.client.chat.postEphemeral({
    token: context.botToken,
    channel: body.channel.id,
    user: body.user.id,
    attachments: [],
    text: 'Your poll is too old. Please create new one.',
  });
});

app.action('btn_vote', async ({ action, ack, body, context }) => {
  await ack();

  if (
    !body
    || !action
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.blocks
    || !body.message.ts
    || !body.channel
    || !body.channel.id
  ) {
    console.log('error');
    return;
  }

  const user_id = body.user.id;
  const message = body.message;
  let blocks = message.blocks;

  const channel = body.channel.id;

  let value = JSON.parse(action.value);

  if (!mutexes.hasOwnProperty(`${message.team}/${channel}/${message.ts}`)) {
    mutexes[`${message.team}/${channel}/${message.ts}`] = new Mutex();
  }

  let release = null;
  let countTry = 0;
  do {
    ++countTry;

    try {
      release = await mutexes[`${message.team}/${channel}/${message.ts}`].acquire();
    } catch (e) {
      console.log(`[Try #${countTry}] Error while attempt to acquire mutex lock.`, e)
    }
  } while (!release && countTry < 3);

  if (release) {
    try {

      let isClosed = false
      try {
        const data = await closedCol.findOne({ channel, ts: message.ts });
        isClosed = data !== null && data.closed;
      } catch {}

      if (isClosed) {
        await app.client.chat.postEphemeral({
          token: context.botToken,
          channel: body.channel.id,
          user: body.user.id,
          attachments: [],
          text: "You can't change your votes on closed poll.",
        });
        return;
      }

      let poll = null;
      const data = await votesCol.findOne({ channel: channel, ts: message.ts });
      if (data === null) {
        await votesCol.insertOne({
          team: message.team,
          channel,
          ts: message.ts,
          votes: {},
        });
        poll = {};
        for (const b of blocks) {
          if (
            b.hasOwnProperty('accessory')
            && b.accessory.hasOwnProperty('value')
          ) {
            const val = JSON.parse(b.accessory.value);
            poll[val.id] = val.voters ? val.voters : [];
          }
        }
        await votesCol.updateOne({
          channel,
          ts: message.ts,
        }, {
          $set: {
            votes: poll,
          }
        });
      } else {
        poll = data.votes;
      }

      const isHidden = await getInfos(
        'hidden',
        blocks, 
        {
          team: message.team,
          channel,
          ts: message.ts,
        },
      )

      button_id = 3 + (value.id * 2);
      context_id = 3 + (value.id * 2) + 1;
      let blockBtn = blocks[button_id];
      let block = blocks[context_id];
      let voters = value.voters ? value.voters : [];

      let removeVote = false;
      if (poll[value.id].includes(user_id)) {
        removeVote = true;
      }

      if (value.limited && value.limit) {
        let voteCount = 0;
        if (0 !== Object.keys(poll).length) {
          for (const p in poll) {
            if (poll[p].includes(user_id)) {
              ++voteCount;
            }
          }
        }

        if (removeVote) {
          voteCount -= 1;
        }

        if (voteCount >= value.limit) {
          await app.client.chat.postEphemeral({
            token: context.botToken,
            channel: channel,
            user: body.user.id,
            attachments: [],
            text: "You can't vote anymore. Remove a vote to choose another option.",
          });
          return;
        }
      }

      if (removeVote) {
        poll[value.id] = poll[value.id].filter(voter_id => voter_id != user_id);
      } else {
        poll[value.id].push(user_id);
      }

      for (const i in blocks) {
        b = blocks[i];
        if (
          b.hasOwnProperty('accessory')
          && b.accessory.hasOwnProperty('value')
        ) {
          let val = JSON.parse(b.accessory.value);
          if (!val.hasOwnProperty('voters')) {
            val.voters = [];
          }

          val.voters = poll[val.id];
          let newVoters = '';

          if (isHidden) {
            newVoters = 'Wait for reveal';
          } else if (poll[val.id].length === 0) {
            newVoters = 'No votes';
          } else {
            newVoters = '';
            for (const voter of poll[val.id]) {
              if (!val.anonymous) {
                newVoters += `<@${voter}> `;
              }
            }

            newVoters += poll[val.id].length +' ';
            if (poll[val.id].length === 1) {
              newVoters += 'vote';
            } else {
              newVoters += 'votes';
            }
          }

          blocks[i].accessory.value = JSON.stringify(val);
          const nextI = ''+(parseInt(i)+1);
          if (blocks[nextI].hasOwnProperty('elements')) {
            blocks[nextI].elements[0].text = newVoters;
          }
        }
      }

      const infosIndex = blocks.findIndex(el => el.type === 'context' && el.elements)
      blocks[infosIndex].elements = await buildInfosBlocks(
        blocks,
        {
          team: message.team,
          channel,
          ts: message.ts,
        }
      );
      blocks[0].accessory.option_groups[0].options =
        await buildMenu(blocks, {
          team: message.team,
          channel,
          ts: message.ts,
        });

      await votesCol.updateOne({
        channel,
        ts: message.ts,
      }, {
        $set: {
          votes: poll,
        }
      });

      await app.client.chat.update({
        token: context.botToken,
        channel: channel,
        ts: message.ts,
        blocks: blocks,
        text: message.text,
      });
    } catch (e) {
      console.error(e);
      await app.client.chat.postEphemeral({
        token: context.botToken,
        channel: body.channel.id,
        user: body.user.id,
        attachments: [],
        text: 'An error occurred during vote processing. Please try again in few seconds.',
      });
    } finally {
      release();
    }
  } else {
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: 'An error occurred during vote processing. Please try again in few seconds.',
    });
  }
});

app.shortcut('open_modal_new', async ({ shortcut, ack, context, client }) => {
  await ack();
  createModal(context, client, shortcut.trigger_id);
});

async function createModal(context, client, trigger_id) {
  try {
    let tempModalBlockInput = JSON.parse(JSON.stringify(modalBlockInput));
    tempModalBlockInput.block_id = 'choice_0';

    const privateMetadata = {
      anonymous: false,
      limited: false,
      hidden: false,
      channel: null,
    };

    const result = await client.views.open({
      token: context.botToken,
      trigger_id: trigger_id,
      view: {
        type: 'modal',
        callback_id: 'modal_poll_submit',
        private_metadata: JSON.stringify(privateMetadata),
        title: {
          type: 'plain_text',
          text: 'Create a poll',
        },
        submit: {
          type: 'plain_text',
          text: 'Create',
        },
        close: {
          type: 'plain_text',
          text: 'Cancel',
        },
        blocks: [
          {
            type: 'section',
            text: {
              type: 'mrkdwn',
              text: 'Create a poll by filling the following form.',
            },
          },
          {
            type: 'divider',
          },
          {
            type: 'section',
            text: {
              type: 'mrkdwn',
              text: 'Select a channel to post poll',
            },
          },
          {
            type: 'actions',
            block_id: 'channel',
            elements: [
              {
                type: 'conversations_select',
                action_id: 'modal_poll_channel',
                placeholder: {
                  type: 'plain_text',
                  text: 'Select a channel',
                },
              },
            ],
          },
          {
            type: 'context',
            elements: [
              {
                type: 'mrkdwn',
                text: ':warning: Some of channels may not be visible to the bot. This may result by impossibility to create the poll.',
              },
            ],
          },
          {
            type: 'divider',
          },
          {
            type: 'section',
            block_id: 'options',
            text: {
              type: 'mrkdwn',
              text: "Choose your poll's options"
            },
            accessory: {
              type: 'checkboxes',
              action_id: 'modal_poll_options',
              options: [
                {
                  text: {
                    type: 'mrkdwn',
                    text: '*Anonymous*'
                  },
                  description: {
                    type: 'mrkdwn',
                    text: '*This option makes your poll anonymous*'
                  },
                  value: 'anonymous'
                },
                {
                  text: {
                    type: 'mrkdwn',
                    text: '*Limited*'
                  },
                  description: {
                    type: 'mrkdwn',
                    text: '*This option limit the number of choices by user*'
                  },
                  value: 'limit'
                },
                {
                  text: {
                    type: 'mrkdwn',
                    text: '*Hidden*'
                  },
                  description: {
                    type: 'mrkdwn',
                    text: '*This option hide the votes until reveal*'
                  },
                  value: 'hidden'
                }
              ]
            }
          },
          {
            type: 'divider',
          },
          {
            type: 'input',
            label: {
              type: 'plain_text',
              text: 'Choose your limit',
            },
            element: {
              type: 'plain_text_input',
              placeholder: {
                type: 'plain_text',
                text: 'Type a number',
              },
            },
            optional: true,
            block_id: 'limit',
          },
          {
            type: 'divider',
          },
          {
            type: 'input',
            label: {
              type: 'plain_text',
              text: 'Ask your question :',
            },
            element: {
              type: 'plain_text_input',
              placeholder: {
                type: 'plain_text',
                text: 'Write your question',
              },
            },
            block_id: 'question',
          },
          {
            type: 'divider',
          },
          {
            type: 'section',
            text: {
              type: 'mrkdwn',
              text: '*Create your choice :*',
            },
          },
          tempModalBlockInput,
          {
            type: 'actions',
            elements: [
              {
                type: 'button',
                action_id: 'btn_add_choice',
                text: {
                  type: 'plain_text',
                  text: '+ Add a choice',
                  emoji: true,
                },
              },
            ],
          },
        ],
      }
    });
  } catch (error) {
    console.error(error);
  }
}

app.action('modal_poll_channel', async ({ action, ack, body, client, context }) => {
  await ack();

  if (
    !action
    && !action.selected_channel
  ) {
    return;
  }

  const privateMetadata = JSON.parse(body.view.private_metadata);
  privateMetadata.channel = action.selected_channel || action.selected_conversation;

  const view = {
    type: body.view.type,
    private_metadata: JSON.stringify(privateMetadata),
    callback_id: 'modal_poll_submit',
    title: body.view.title,
    submit: body.view.submit,
    close: body.view.close,
    blocks: body.view.blocks,
    external_id: body.view.id,
  };

  const result = await client.views.update({
    token: context.botToken,
    hash: body.view.hash,
    view: view,
    view_id: body.view.id,
  });
});

app.action('modal_poll_options', async ({ action, ack, body, client, context }) => {
  await ack();

  if (
    !body
    || !body.view
    || !body.view.private_metadata
  ) {
    return;
  }

  const privateMetadata = JSON.parse(body.view.private_metadata);

  privateMetadata.anonymous = false;
  privateMetadata.limited = false;
  for (const option of action.selected_options) {
    if ('anonymous' === option.value) {
      privateMetadata.anonymous = true;
    } else if ('limit' === option.value) {
      privateMetadata.limited = true;
    } else if ('hidden' === option.value) {
      privateMetadata.hidden = true;
    }
  }

  const view = {
    type: body.view.type,
    private_metadata: JSON.stringify(privateMetadata),
    callback_id: 'modal_poll_submit',
    title: body.view.title,
    submit: body.view.submit,
    close: body.view.close,
    blocks: body.view.blocks,
    external_id: body.view.id,
  };

  const result = await client.views.update({
    token: context.botToken,
    hash: body.view.hash,
    view: view,
    view_id: body.view.id,
  });
});

app.view('modal_poll_submit', async ({ ack, body, view, context }) => {
  await ack();

  if (
    !view
    || !body
    || !view.blocks
    || !view.state
    || !view.private_metadata
    || !body.user
    || !body.user.id
  ) {
    return;
  }

  const privateMetadata = JSON.parse(view.private_metadata);
  const userId = body.user.id;

  const state = view.state;
  let question = null;
  const options = [];
  const isAnonymous = privateMetadata.anonymous;
  const isLimited = privateMetadata.limited;
  let limit = 1;
  const isHidden = privateMetadata.hidden;
  const channel = privateMetadata.channel;

  if (state.values) {
    for (const optionName in state.values) {
      const option = state.values[optionName][Object.keys(state.values[optionName])[0]];
      if ('question' === optionName) {
        question = option.value;
      } else if ('limit' === optionName) {
        limit = parseInt(option.value, 10);
      } else if (optionName.startsWith('choice_')) {
        options.push(option.value);
      }
    }
  }

  if (
    !question
    || 0 === options.length
  ) {
    return;
  }

  const cmd = createCmdFromInfos(question, options, isAnonymous, isLimited, limit, isHidden);

  const blocks = createPollView(question, options, isAnonymous, isLimited, limit, isHidden, userId, cmd);

  try {
    await app.client.chat.postMessage({
      token: context.botToken,
      channel: channel,
      blocks: blocks,
      text: `Poll : ${question}`,
    });
  } catch (e) {
    if (
      e && e.data && e.data && e.data.error
      && 'channel_not_found' === e.data.error
    ) {
      console.error('Channel not found error : ignored')
    }
  }
});

function createCmdFromInfos(question, options, isAnonymous, isLimited, limit, isHidden) {
  let cmd = `/${slackCommand}`;
  if (isAnonymous) {
    cmd += ` anonymous`
  }
  if (isLimited) {
    cmd += ` limit`
  }
  if (limit > 1) {
    cmd += ` ${limit}`
  }
  if (isHidden) {
    cmd += ` hidden`
  }

  question = question.replace(/"/g, "\\\"");
  cmd += ` "${question}"`

  for (let option of options) {
    option = option.replace(/"/g, "\\\"");
    cmd += ` "${option}"`
  }

  return cmd;
}

function createPollView(question, options, isAnonymous, isLimited, limit, isHidden, userId, cmd) {
  if (
    !question
    || !options
    || 0 === options.length
  ) {
    return null;
  }

  const blocks = [];

  const staticSelectElements = [{
    label: {
      type: 'plain_text',
      text: 'Poll actions',
    },
    options: [{
      text: {
        type: 'plain_text',
        text: isHidden ? 'Reveal votes' : 'Hide votes',
      },
      value:
        JSON.stringify({action: 'btn_reveal', revealed: !isHidden, user: userId}),
    }, {
      text: {
        type: 'plain_text',
        text: 'See users votes',
      },
      value: JSON.stringify({action: 'btn_users_votes', user: userId}),
    }, {
      text: {
        type: 'plain_text',
        text: 'Delete the poll',
      },
      value: JSON.stringify({action: 'btn_delete', user: userId}),
    }, {
      text: {
        type: 'plain_text',
        text: 'Close the poll',
      },
      value: JSON.stringify({action: 'btn_close', user: userId}),
    }],
  }, {
    label: {
      type: 'plain_text',
      text: 'User actions',
    },
    options: [{
      text: {
        type: 'plain_text',
        text: 'See your votes',
      },
      value: JSON.stringify({action: 'btn_my_votes', user: userId}),
    }],
  }];

  if (supportUrl) {
    staticSelectElements.push({
      label: {
        type: 'plain_text',
        text: 'Support',
      },
      options: [{
        text: {
          type: 'plain_text',
          text: 'Love DMUN-Poll ?',
        },
        value: JSON.stringify({action: 'btn_love_dmun_poll', user: userId}),
      }],
    });
  }

  blocks.push({
    type: 'section',
    text: {
      type: 'mrkdwn',
      text: question,
    },
    accessory: {
      type: 'static_select',
      placeholder: { type: 'plain_text', text: 'Menu' },
      action_id: 'static_select_menu',
      option_groups: staticSelectElements,
    },
  });

  let voteLimit = 0;

  let elements = [];
  if (isAnonymous || isLimited || isHidden) {
    if (isAnonymous) {
      elements.push({
        type: 'mrkdwn',
        text: ':shushing_face: Anonymous poll',
      });
    }
    if (isLimited) {
      elements.push({
        type: 'mrkdwn',
        text: ':warning: Limited to '+ limit + ' vote' +(limit > 1 ? 's': ''),
      });
    }
    if (isHidden) {
      elements.push({
        type: 'mrkdwn',
        text: ':ninja: Votes are hidden'
      });
    }
  }
  elements.push({
    type: 'mrkdwn',
    text: ':writing_hand: by <@'+userId+'>'
  });
  blocks.push({
    type: 'context',
    elements: elements,
  });
  blocks.push({
    type: 'divider',
  });

  let button_value = {
    anonymous: isAnonymous,
    limited: isLimited,
    limit: limit,
    hidden: isHidden,
    voters: [],
    id: null,
  };

  for (let i in options) {
    let option = options[i];
    btn_value = JSON.parse(JSON.stringify(button_value));
    btn_value.id = i;
    let block = {
      type: 'section',
      text: {
        type: 'mrkdwn',
        text: option,
      },
      accessory: {
        type: 'button',
        action_id: 'btn_vote',
        text: {
          type: 'plain_text',
          emoji: true,
          text: 'Vote',
        },
        value: JSON.stringify(btn_value),
      },
    };
    blocks.push(block);
    block = {
      type: 'context',
      elements: [
        {
          type: 'mrkdwn',
          text: isHidden ? 'Wait for reveal' : 'No votes',
        }
      ],
    };
    blocks.push(block);
    blocks.push({
      type: 'divider',
    });
  }

  blocks.push({
    type: 'context',
    elements: [
      {
        type: 'mrkdwn',
        text: `<${helpLink}|Need help ?>`,
      },
      {
        type: 'mrkdwn',
        text: ':information_source: '+cmd,
      }
    ],
  });

  return blocks;
}

// btn actions
app.action('overflow_menu', btnActions);
app.action('static_select_menu', btnActions);
app.action('ignore_me', async ({ ack }) => { await ack() });

async function btnActions(args) {
  const {ack, action, body, client, context} = args;
  await ack();

  if (
    !action
    || !action.selected_option
    || !action.selected_option.value
  ) {
    return;
  }

  const value = JSON.parse(action.selected_option.value);

  if (!value || !value.action || !value.user) {
    return;
  }

  if ('btn_love_dmun_poll' === value.action)
    supportAction(body, client, context)
  else if ('btn_my_votes' === value.action)
    myVotes(body, client, context);
  else if ('btn_users_votes' === value.action)
    usersVotes(body, client, context, value);
  else if ('btn_reveal' === value.action)
    revealOrHideVotes(body, context, value);
  else if ('btn_delete' === value.action)
    deletePoll(body, context, value);
  else if ('btn_close' === value.action)
    closePoll(body, client, context, value);
}

async function supportAction(body, client, context) {
  if (
    !body.user
    || !body.user.id
    || !body.channel
    || !body.channel.id
  ) {
    return;
  }

  const blocks = [{
    type: 'section',
    text: {
      type: 'mrkdwn',
      text: ':heart: You love the app ?',
    },
  },
  { type: 'divider' },
  {
    type: 'section',
    text: {
      type: 'mrkdwn',
      text: ':technologist: Contribute on it',
    },
    accessory: {
      type: 'button',
      text: {
        type: 'plain_text',
        text: 'Open GitHub',
      },
      style: 'primary',
      url: helpLink,
      action_id: 'ignore_me',
    }
  }];

  // Only show support/donate button if supportUrl is configured
  if (supportUrl) {
    blocks.push({
      type: 'section',
      text: {
        type: 'mrkdwn',
        text: ':coffee: Support the project',
      },
      accessory: {
        type: 'button',
        text: {
          type: 'plain_text',
          text: 'Support',
        },
        url: supportUrl,
        action_id: 'ignore_me',
      }
    });
  }

  await client.chat.postEphemeral({
    token: context.botToken,
    channel: body.channel.id,
    user: body.user.id,
    blocks,
    text: 'Support DMUN-Poll',
  });
}

async function myVotes(body, client, context) {
  if (
    !body.hasOwnProperty('user')
    || !body.user.hasOwnProperty('id')
  ) {
    return;
  }

  const blocks = body.message.blocks;
  let votes = [];
  const userId = body.user.id;

  for (const block of blocks) {
    if (
      'section' !== block.type
      || !block.hasOwnProperty('accessory')
      || !block.accessory.hasOwnProperty('action_id')
      || 'btn_vote' !== block.accessory.action_id
      || !block.accessory.hasOwnProperty('value')
      || !block.hasOwnProperty('text')
      || !block.text.hasOwnProperty('text')
    ) {
      continue;
    }
    const value = JSON.parse(block.accessory.value);

    if (value.voters.includes(userId)) {
      votes.push({
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: block.text.text,
        },
      });
      votes.push({
        type: 'divider',
      });
    }
  }

  if (0 === votes.length) {
    votes.push({
      type: 'section',
      text: {
        type: 'mrkdwn',
        text: 'You have not voted yet',
      },
    });
  } else {
    votes.pop();
  }

  try {
    await client.views.open({
      token: context.botToken,
      trigger_id: body.trigger_id,
      view: {
        type: 'modal',
        title: {
          type: 'plain_text',
          text: 'Your votes',
        },
        close: {
          type: 'plain_text',
          text: 'Close',
        },
        blocks: votes,
      }
    });
  } catch (e) {
    console.error(e);
  }
}

async function usersVotes(body, client, context, value) {
  if (
    !body
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.ts
    || !body.message.blocks
    || !body.channel
    || !body.channel.id
    || !value
  ) {
    console.log('error');
    return;
  }

  if (body.user.id !== value.user) {
    console.log('invalid user');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "You can't see all users votes.",
    });
    return;
  }

  const message = body.message;
  const channel = body.channel.id;
  const blocks = message.blocks;

  const { anonymous } = await getInfos(['anonymous'], blocks)

  if (anonymous) {
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "Sorry but you can't see anonymous votes",
    });
    return;
  }

  const votes = [];
  let poll = null;

  try {
    const data = await votesCol.findOne({ channel: channel, ts: message.ts });
    if (data === null) {
      await votesCol.insertOne({
        team: message.team,
        channel,
        ts: message.ts,
        votes: {},
      });
      poll = {};
      for (const b of blocks) {
        if (
          b.hasOwnProperty('accessory')
          && b.accessory.hasOwnProperty('value')
        ) {
          const val = JSON.parse(b.accessory.value);
          poll[val.id] = val.voters ? val.voters : [];
        }
      }
      await votesCol.updateOne({
        channel,
        ts: message.ts,
      }, {
        $set: {
          votes: poll,
        }
      });
    } else {
      poll = data.votes;
    }
  } catch(e) {
  }

  for (const block of blocks) {
    if (
      block.hasOwnProperty('accessory')
      && block.accessory.hasOwnProperty('value')
    ) {
      const value = JSON.parse(block.accessory.value);
      const voters = poll ? (poll[value.id] || []) : [];
      votes.push({
        type: 'divider',
      });
      votes.push({
        type: 'section',
        text: {
          type: 'mrkdwn',
          text: block.text.text,
        },
      });
      votes.push({
        type: 'context',
        elements: [{
          type: 'mrkdwn',
          text: !voters.length
            ? 'No voters'
            : voters.map(el => {
                return `<@${el}>`;
              }).join(', '),
        }],
      });
    }
  }

  try {
    await client.views.open({
      token: context.botToken,
      trigger_id: body.trigger_id,
      view: {
        type: 'modal',
        title: {
          type: 'plain_text',
          text: 'Users votes',
        },
        close: {
          type: 'plain_text',
          text: 'Close',
        },
        blocks: votes,
      },
    });
  } catch (e) {
    console.error(e);
  }
}

async function revealOrHideVotes(body, context, value) {
  if (
    !body
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.ts
    || !body.message.blocks
    || !body.channel
    || !body.channel.id
    || !value
    || !body.message.blocks[0]
    || !body.message.blocks[0].accessory
    || (
      !body.message.blocks[0].accessory.options
      && !body.message.blocks[0].accessory.option_groups
    )
  ) {
    console.log('error');
    return;
  }

  if (body.user.id !== value.user) {
    console.log('invalid user');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "You can't reveal poll from another user.",
    });
    return;
  }

  if (!value.hasOwnProperty('revealed')) {
    console.log('Missing `revealed` information on poll');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: 'Unconsistent poll data',
    });
    return;
  }

  let isHidden = !value.revealed;
  let message = body.message;
  let channel = body.channel.id;
  let blocks = message.blocks;

  if (!mutexes.hasOwnProperty(`${message.team}/${channel}/${message.ts}`)) {
    mutexes[`${message.team}/${channel}/${message.ts}`] = new Mutex();
  }

  let release = null;
  let countTry = 0;
  do {
    ++countTry;

    try {
      release = await mutexes[`${message.team}/${channel}/${message.ts}`].acquire();
    } catch (e) {
      console.log(`[Try #${countTry}] Error while attempt to acquire mutex lock.`, e)
    }
  } while (!release && countTry < 3);

  if (release) {
    try {
      let poll = null;
      const data = await votesCol.findOne({ channel: channel, ts: message.ts });

      if (data === null) {
        await votesCol.insertOne({
          team: message.team,
          channel,
          ts: message.ts,
          votes: {},
        });
        poll = {};
        for (const b of blocks) {
          if (
            b.hasOwnProperty('accessory')
            && b.accessory.hasOwnProperty('value')
          ) {
            const val = JSON.parse(b.accessory.value);
            poll[val.id] = val.voters ? val.voters : [];
          }
        }
        await votesCol.updateOne({
          channel,
          ts: message.ts,
        }, {
          $set: {
            votes: poll,
          }
        });
      } else {
        poll = data.votes;
      }

      const infos = await getInfos(
        ['anonymous', 'limited', 'limit', 'hidden'],
        blocks,
        {
          team: message.team,
          channel,
          ts: message.ts,
        }
      );
      isHidden = !infos.hidden;

      await hiddenCol.updateOne({
        channel,
        ts: message.ts,
      }, {
        $set: {
          hidden: isHidden,
        },
      });

      for (const i in blocks) {
        let b = blocks[i];
        if (
          b.hasOwnProperty('accessory')
          && b.accessory.hasOwnProperty('value')
        ) {
          let val = JSON.parse(b.accessory.value);
          val.hidden = isHidden;

          val.voters = poll[val.id];
          let newVoters = '';

          if (isHidden) {
            newVoters = 'Wait for reveal';
          } else {
            if (poll[val.id].length === 0) {
              newVoters = 'No votes';
            } else {
              newVoters = '';
              for (const voter of poll[val.id]) {
                if (!val.anonymous) {
                  newVoters += `<@${voter}> `;
                }
              }

              const vLength = poll[val.id].length;
              newVoters += `${poll[val.id].length} vote${vLength === 1 ? '' : 's'}`;
            }
          }

          blocks[i].accessory.value = JSON.stringify(val);
          const nextI = ''+(parseInt(i)+1);
          if (blocks[nextI].hasOwnProperty('elements')) {
            blocks[nextI].elements[0].text = newVoters;
          }
        }
      }

      if (blocks[0].accessory.options) {
        blocks[0].accessory.options = await buildMenu(blocks, {
          team: message.team,
          channel,
          ts: message.ts,
        });
      } else if (blocks[0].accessory.option_groups) {
        blocks[0].accessory.option_groups[0].options = await buildMenu(blocks, {
          team: message.team,
          channel,
          ts: message.ts,
        });
      }

      const infosIndex = blocks.findIndex(el => el.type === 'context' && el.elements)
      blocks[infosIndex].elements = await buildInfosBlocks(
        blocks,
        {
          team: message.team,
          channel,
          ts: message.ts,
        }
      );

      await app.client.chat.update({
        token: context.botToken,
        channel: channel,
        ts: message.ts,
        blocks: blocks,
        text: message.text,
      });
    } catch (e) {
      console.error(e);
      await app.client.chat.postEphemeral({
        token: context.botToken,
        channel: body.channel.id,
        user: body.user.id,
        attachments: [],
        text: `An error occurred during ${isHidden ? 'hide' : 'reveal'} process. Please try again in few seconds.`,
      });
    } finally {
      release();
    }
  } else {
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: 'An error occurred during vote processing. Please try again in few seconds.',
    });
  }
}

async function deletePoll(body, context, value) {
  if (
    !body
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.ts
    || !body.channel
    || !body.channel.id
    || !value
  ) {
    console.log('error');
    return;
  }

  if (body.user.id != value.user) {
    console.log('invalid user');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "You can't delete poll from another user.",
    });
    return;
  }

  await app.client.chat.delete({
    token: context.botToken,
    channel: body.channel.id,
    ts: body.message.ts,
  });
}

async function closePoll(body, client, context, value) {
  if (
    !body
    || !body.user
    || !body.user.id
    || !body.message
    || !body.message.ts
    || !body.message.blocks
    || !body.channel
    || !body.channel.id
    || !value
  ) {
    console.log('error');
    return;
  }

  if (body.user.id !== value.user) {
    console.log('invalid user');
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: "You can't close the poll.",
    });
    return;
  }

  const message = body.message;
  const channel = body.channel.id;
  const blocks = message.blocks;

  if (!mutexes.hasOwnProperty(`${message.team}/${channel}/${message.ts}`)) {
    mutexes[`${message.team}/${channel}/${message.ts}`] = new Mutex();
  }

  let release = null;
  let countTry = 0;
  do {
    ++countTry;

    try {
      release = await mutexes[`${message.team}/${channel}/${message.ts}`].acquire();
    } catch (e) {
      console.log(`[Try #${countTry}] Error while attempt to acquire mutex lock.`, e)
    }
  } while (!release && countTry < 3);

  if (release) {
    try {
      let isClosed = false
      try {
        const data = await closedCol.findOne({ channel, ts: message.ts });
        if (data === null) {
          await closedCol.insertOne({
            team: message.team,
            ts: message.ts,
            closed: false,
          });
        }
        isClosed = data !== null && data.closed;
      } catch {}

      await closedCol.updateOne({
        channel,
        ts: message.ts,
      }, {
        $set: { closed: !isClosed }
      });

      if (isClosed) {
        for (const i in blocks) {
          const block = blocks[i];

          if (
            block.hasOwnProperty('accessory')
            && block.accessory.hasOwnProperty('value')
          ) {
            const value = JSON.parse(block.accessory.value);

            value.closed = false;

            blocks[i].accessory.value = JSON.stringify(value);
          }
        }
      } else {
        for (const i in blocks) {
          const block = blocks[i];

          if (
            block.hasOwnProperty('accessory')
            && block.accessory.hasOwnProperty('value')
          ) {
            const value = JSON.parse(block.accessory.value);

            value.closed = true;

            blocks[i].accessory.value = JSON.stringify(value);
          }
        }
      }

      if (blocks[0].accessory.option_groups) {
        const staticSelectMenu = blocks[0].accessory.option_groups[0].options;
        blocks[0].accessory.option_groups[0].options =
          await buildMenu(blocks, {
            team: message.team,
            channel,
            ts: message.ts,
          });
      }

      const infosIndex =
        blocks.findIndex(el => el.type === 'context' && el.elements);
      blocks[infosIndex].elements = await buildInfosBlocks(
        blocks,
        {
          team: message.team,
          channel,
          ts: message.ts,
        }
      );

      await app.client.chat.update({
        token: context.botToken,
        channel,
        ts: message.ts,
        blocks: blocks,
        text: message.text,
      });
    } catch (e) {
      console.error(e);
      await app.client.chat.postEphemeral({
        token: context.botToken,
        channel: body.channel.id,
        user: body.user.id,
        attachments: [],
        text: 'An error occurred while attempt to close the poll. Please try again in few seconds.',
      });
    } finally {
      release();
    }
  } else {
    await app.client.chat.postEphemeral({
      token: context.botToken,
      channel: body.channel.id,
      user: body.user.id,
      attachments: [],
      text: 'An error occurred while attempt to close the poll. Please try again in few seconds.',
    });
  }
}


// global functions
async function getInfos(infos, blocks, pollInfos) {
  const multi = Array.isArray(infos);
  let result = multi ? {} : null;
  let toFix = [];

  if (pollInfos) {
    if (multi && infos.includes('closed')) {
      const data = await closedCol.findOne({
        channel: pollInfos.channel,
        ts: pollInfos.ts,
      });

      if (data !== null) {
        result['closed'] = data.closed;
        infos = infos.filter(i => i !== 'closed');
      } else {
        toFix.push('closed');
      }
    } else if (infos === 'closed') {
      const data = await closedCol.findOne({
        channel: pollInfos.channel,
        ts: pollInfos.ts,
      });

      if (data !== null) return data.closed;
      else toFix.push('closed');
    }

    if (multi && infos.includes('hidden')) {
      const data = await hiddenCol.findOne({
        channel: pollInfos.channel,
        ts: pollInfos.ts,
      });

      if (data !== null) {
        result['hidden'] = data.hidden;
        infos = infos.filter(i => i !== 'hidden');
      } else {
        toFix.push('hidden');
      }
    } else if (infos === 'hidden') {
      const data = await hiddenCol.findOne({
        channel: pollInfos.channel,
        ts: pollInfos.ts,
      });

      if (data !== null) return data.hidden;
      else toFix.push('hidden');
    }
  }

  if (multi) {
    for (const i of infos) {
      result[i] = null;
    }
  }

  for (const block of blocks) {
    if (
      block.hasOwnProperty('accessory')
      && block.accessory.hasOwnProperty('value')
    ) {
      const value = JSON.parse(block.accessory.value);

      if (multi) {
        for (const i of infos) {
          if (result[i] === null && value.hasOwnProperty(i)) {
            result[i] = value[i];
          }
        }

        if (!Object.keys(result).find(i => result[i] === null)) {
          break;
        }
      } else {
        if (value.hasOwnProperty(infos)) {
          result = value[infos];
          break;
        }
      }
    }
  }

  if (toFix.length > 0) {
    if (multi) {
      if (toFix.includes('closed') && result['closed'] !== null) {
        closedCol.insertOne({
          team: pollInfos.team,
          channel: pollInfos.channel,
          ts: pollInfos.ts,
          closed: result['closed'],
        });
      }
      if (toFix.includes('hidden') && result['hidden'] !== null) {
        hiddenCol.insertOne({
          team: pollInfos.team,
          channel: pollInfos.channel,
          ts: pollInfos.ts,
          hidden: result['hidden'],
        });
      }
    } else {
      if (toFix.includes('closed') && result !== null) {
        closedCol.insertOne({
          team: pollInfos.team,
          channel: pollInfos.channel,
          ts: pollInfos.ts,
          closed: result,
        });
      } else if (toFix.includes('hidden') && result !== null) {
        hiddenCol.insertOne({
          team: pollInfos.team,
          channel: pollInfos.channel,
          ts: pollInfos.ts,
          hidden: result,
        });
      }
    }
  }

  return result;
}

async function buildInfosBlocks(blocks, pollInfos) {
  const infosIndex =
    blocks.findIndex(el => el.type === 'context' && el.elements);
  const infosBlocks = [];
  const infos = await getInfos(['anonymous', 'limited', 'limit', 'hidden', 'closed'], blocks, pollInfos);

  if (infos.anonymous) {
    infosBlocks.push({
      type: 'mrkdwn',
      text: ':shushing_face: Anonymous poll',
    });
  }
  if (infos.limited) {
    infosBlocks.push({
      type: 'mrkdwn',
      text: `:warning: Limited to ${infos.limit} vote${infos.limit > 1 ? 's' : ''}`,
    });
  }
  if (infos.hidden) {
    infosBlocks.push({
      type: 'mrkdwn',
      text: ':ninja: Votes are hidden',
    });
  }
  if (infos.closed) {
    infosBlocks.push({
      type: 'mrkdwn',
      text: ':x: Closed',
    });
  }
  infosBlocks.push(blocks[infosIndex].elements.pop());
  return infosBlocks;
}

async function buildMenu(blocks, pollInfos) {
  const infos = await getInfos(['closed', 'hidden'], blocks, pollInfos);

  if (blocks[0].accessory.option_groups) {
    return blocks[0].accessory.option_groups[0].options.map(el => {
      const value = JSON.parse(el.value);
      if (value && 'btn_close' === value.action) {
        el.text.text = infos['closed'] ? 'Reopen the poll' : 'Close the poll';
        value.closed = !value.closed;
        el.value = JSON.stringify(value);
      } else if (value && 'btn_reveal' === value.action) {
        el.text.text = infos['hidden'] ? 'Reveal votes' : 'Hide votes';
        value.revealed = !value.closed;
        el.value = JSON.stringify(value);
      }

      return el;
    });
  } else if (blocks[0].accessory.options) {
    return blocks[0].accessory.options.map((el) => {
      const value = JSON.parse(el.value);
      if (value && 'btn_reveal' === value.action) {
        el.text.text = infos['hidden'] ? 'Reveal votes' : 'Hide votes';
        value.revealed = !value.closed;
        el.value = JSON.stringify(value);
      }

      return el;
    });
  }

  return null;
}