dyaskur / google-chat-poll

import BaseHandler from './BaseHandler';

import NewPollFormCard from '../cards/NewPollFormCard';

import {addOptionToState, getStateFromCard} from '../helpers/state';

import {callMessageApi} from '../helpers/api';

import {createDialogActionResponse, createStatusActionResponse} from '../helpers/response';

import PollCard from '../cards/PollCard';

import {PollState, Voter, Votes} from '../helpers/interfaces';

import AddOptionFormCard from '../cards/AddOptionFormCard';

import {saveVotes} from '../helpers/vote';

import {MAX_NUM_OF_OPTIONS} from '../config/default';

import ClosePollFormCard from '../cards/ClosePollFormCard';

/*

This list methods are used in the poll chat message

 */

interface PollAction {

  saveOption(): Promise<chatV1.Schema$Message>;

  getEventPollState(): PollState;

}

export default class ActionHandler extends BaseHandler implements PollAction {

  async process(): Promise<chatV1.Schema$Message> {

    const action = this.event.common?.invokedFunction;

    switch (action) {

      case 'start_poll':

        return await this.startPoll();

      case 'vote':

        return this.recordVote();

      case 'add_option_form':

        return this.addOptionForm();

      case 'add_option':

        return await this.saveOption();

      case 'show_form':

        return createDialogActionResponse(new NewPollFormCard({topic: '', choices: []}).create());

      case 'close_poll_form':

        return createDialogActionResponse(new ClosePollFormCard().create());

      case 'close_poll':

        return await this.closePoll();

      default:

        return createStatusActionResponse('Unknown action!', 'UNKNOWN');

    }

  }

  /**

   * Handle the custom start_poll action.

   *

   * @returns {object} Response to send back to Chat

   */

  async startPoll() {

    // Get the form values

    const formValues = this.event.common?.formInputs;

    const topic = formValues?.['topic']?.stringInputs?.value?.[0]?.trim() ?? '';

    const isAnonymous = formValues?.['is_anonymous']?.stringInputs?.value?.[0] === '1';

    const allowAddOption = formValues?.['allow_add_option']?.stringInputs?.value?.[0] === '1';

    const choices = [];

    const votes: Votes = {};

    for (let i = 0; i < MAX_NUM_OF_OPTIONS; ++i) {

      const choice = formValues?.[`option${i}`]?.stringInputs?.value?.[0]?.trim();

      if (choice) {

        choices.push(choice);

        votes[i] = [];

      }

    }

    if (!topic || choices.length === 0) {

      // Incomplete form submitted, rerender

      const dialog = new NewPollFormCard({

        topic,

        choices,

      }).create();

      return {

        actionResponse: {

          type: 'DIALOG',

          dialogAction: {

            dialog: {

              body: dialog,

            },

          },

        },

      };

    }

    const pollCard = new PollCard({

      topic: topic, choiceCreator: undefined,

      author: this.event.user,

      choices: choices,

      votes: votes,

      anon: isAnonymous,

      optionable: allowAddOption,

    }).createCardWithId();

    // Valid configuration, make the voting card to display in the space

    const message = {

      cardsV2: [pollCard],

    };

    const request = {

      parent: this.event.space?.name,

      requestBody: message,

    };

    const apiResponse = await callMessageApi('create', request);

    if (apiResponse) {

      return createStatusActionResponse('Poll started.', 'OK');

    } else {

      return createStatusActionResponse('Failed to start poll.', 'UNKNOWN');

    }

  }

  /**

   * Handle the custom vote action. Updates the state to record

   * the user's vote then rerenders the card.

   *

   * @returns {object} Response to send back to Chat

   */

  recordVote() {

    const parameters = this.event.common?.parameters;

    if (!(parameters?.['index'])) {

      throw new Error('Index Out of Bounds');

    }

    const choice = parseInt(parameters['index']);

    const userId = this.event.user?.name ?? '';

    const userName = this.event.user?.displayName ?? '';

    const voter: Voter = {uid: userId, name: userName};

    const state = this.getEventPollState();

    // Add or update the user's selected option

    state.votes = saveVotes(choice, voter, state.votes!, state.anon);

    const card = new PollCard(state);

    return {

      thread: this.event.message?.thread,

      actionResponse: {

        type: 'UPDATE_MESSAGE',

      },

      cardsV2: [card.createCardWithId()],

    };

  }

  /**

   * Opens and starts a dialog that allows users to add details about a contact.

   *

   * @returns {object} open a dialog.

   */

  addOptionForm() {

    const state = this.getEventPollState();

    const dialog = new AddOptionFormCard(state).create();

    return createDialogActionResponse(dialog);

  };

  /**

   * Handle add new option input to the poll state

   * the user's vote then rerenders the card.

   *

   * @returns {object} Response to send back to Chat

   */

  async saveOption(): Promise<chatV1.Schema$Message> {

    const userName = this.event.user?.displayName ?? '';

    const state = this.getEventPollState();

    const formValues = this.event.common?.formInputs;

    const optionValue = formValues?.['value']?.stringInputs?.value?.[0]?.trim() || '';

    addOptionToState(optionValue, state, userName);

    const cardMessage = new PollCard(state).createMessage();

    const request = {

      name: this.event.message!.name,

      requestBody: cardMessage,

      updateMask: 'cardsV2',

    };

    const apiResponse = await callMessageApi('update', request);

    if (apiResponse) {

      return createStatusActionResponse('Option is added', 'OK');

    } else {

      return createStatusActionResponse('Failed to add option.', 'UNKNOWN');

    }

  }

  getEventPollState(): PollState {

    const state = getStateFromCard(this.event);

    if (!state) {

      throw new ReferenceError('no valid state in the event');

    }

    return JSON.parse(state);

  }

  }

}