import $ from 'jquery';
import _ from 'underscore';
import Api from 'ee/api';
import { __ } from '~/locale';
import Flash from '~/flash';
import axios from '~/lib/utils/axios_utils';

export default class ApproversSelect {
  constructor() {
    this.$approverSelect = $('.js-select-user-and-group');
    const name = this.$approverSelect.data('name');
    this.fieldNames = [`${name}[approver_ids]`, `${name}[approver_group_ids]`];
    this.$loadWrapper = $('.load-wrapper');

    this.bindEvents();
    this.addEvents();
    this.initSelect2();
  }

  bindEvents() {
    this.handleSelectChange = this.handleSelectChange.bind(this);
    this.fetchGroups = this.fetchGroups.bind(this);
    this.fetchUsers = this.fetchUsers.bind(this);
  }

  addEvents() {
    $(document).on('click', '.js-add-approvers', () => this.addApprover());
    $(document).on('click', '.js-approver-remove', e => ApproversSelect.removeApprover(e));
  }

  static getApprovers(fieldName, approverList) {
    const input = $(`[name="${fieldName}"]`);
    const existingApprovers = $(approverList).map((i, el) => parseInt($(el).data('id'), 10));
    const selectedApprovers = input
      .val()
      .split(',')
      .filter(val => val !== '');
    return [...existingApprovers, ...selectedApprovers];
  }

  fetchGroups(term) {
    const options = {
      skip_groups: ApproversSelect.getApprovers(this.fieldNames[1], '.js-approver-group'),
    };
    return Api.groups(term, options);
  }

  fetchUsers(term) {
    const options = {
      skip_users: ApproversSelect.getApprovers(this.fieldNames[0], '.js-approver'),
      project_id: $('#project_id').val(),
    };
    return Api.approverUsers(term, options);
  }

  handleSelectChange(e) {
    const { added, removed } = e;
    const userInput = $(`[name="${this.fieldNames[0]}"]`);
    const groupInput = $(`[name="${this.fieldNames[1]}"]`);

    if (added) {
      if (added.full_name) {
        groupInput.val(`${groupInput.val()},${added.id}`.replace(/^,/, ''));
      } else {
        userInput.val(`${userInput.val()},${added.id}`.replace(/^,/, ''));
      }
    }

    if (removed) {
      if (removed.full_name) {
        groupInput.val(groupInput.val().replace(new RegExp(`,?${removed.id}`), ''));
      } else {
        userInput.val(userInput.val().replace(new RegExp(`,?${removed.id}`), ''));
      }
    }
  }

  initSelect2() {
    import(/* webpackChunkName: 'select2' */ 'select2/select2')
      .then(() => {
        this.$approverSelect
          .select2({
            placeholder: 'Search for users or groups',
            multiple: true,
            minimumInputLength: 0,
            query: query => {
              const fetchGroups = this.fetchGroups(query.term);
              const fetchUsers = this.fetchUsers(query.term);
              return Promise.all([fetchGroups, fetchUsers]).then(([groups, users]) => {
                const data = {
                  results: groups.concat(users),
                };
                return query.callback(data);
              });
            },
            formatResult: ApproversSelect.formatResult,
            formatSelection: ApproversSelect.formatSelection,
            dropdownCss() {
              const $input = $('.js-select-user-and-group .select2-input');
              const offset = $input.offset();
              let { left } = offset;
              const inputRightPosition = left + $input.outerWidth();
              const $dropdown = $('.select2-drop-active');

              if ($dropdown.outerWidth() > $input.outerWidth()) {
                left = `${inputRightPosition - $dropdown.width()}px`;
              }
              return {
                left,
                right: 'auto',
                width: 'auto',
              };
            },
          })
          .on('change', this.handleSelectChange);
      })
      .catch(() => {});
  }

  static formatSelection(group) {
    return _.escape(group.full_name || group.name);
  }

  static formatResult({
    name,
    username,
    avatar_url: avatarUrl,
    full_name: fullName,
    full_path: fullPath,
  }) {
    if (username) {
      const avatar = avatarUrl || gon.default_avatar_url;
      return `
        <div class="user-result">
          <div class="user-image">
            <img class="avatar s40" src="${avatar}">
          </div>
          <div class="user-info">
            <div class="user-name">${_.escape(name)}</div>
            <div class="user-username">@${_.escape(username)}</div>
          </div>
        </div>
      `;
    }

    return `
      <div class="group-result">
        <div class="group-name">${_.escape(fullName)}</div>
        <div class="group-path">${_.escape(fullPath)}</div>
      </div>
    `;
  }

  addApprover() {
    this.fieldNames.forEach(ApproversSelect.saveApprovers);
  }

  static saveApprovers(fieldName) {
    const $input = $(`[name="${fieldName}"]`);
    const newValue = $input.val();
    const $loadWrapper = $('.load-wrapper');
    const $approverSelect = $('.js-select-user-and-group');

    if (!newValue) {
      return;
    }

    const $form = $('.js-add-approvers').closest('form');
    $loadWrapper.removeClass('hidden');

    axios
      .post($form.attr('action'), `_method=PATCH&${[encodeURIComponent(fieldName)]}=${newValue}`, {
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
        },
      })
      .then(({ data }) => {
        ApproversSelect.updateApproverList(data);
        ApproversSelect.saveApproversComplete($input, $approverSelect, $loadWrapper);
      })
      .catch(() => {
        Flash(__('An error occurred while adding approver'));
        ApproversSelect.saveApproversComplete($input, $approverSelect, $loadWrapper);
      });
  }

  static saveApproversComplete($input, $approverSelect, $loadWrapper) {
    $input.val('');
    $approverSelect.select2('val', '').trigger('change');
    $loadWrapper.addClass('hidden');
  }

  static removeApprover(e) {
    e.preventDefault();
    const target = e.currentTarget;
    const $loadWrapper = $('.load-wrapper');
    $loadWrapper.removeClass('hidden');

    axios
      .post(target.getAttribute('href'), '_method=DELETE', {
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
        },
      })
      .then(({ data }) => {
        ApproversSelect.updateApproverList(data);
        $loadWrapper.addClass('hidden');
      })
      .catch(() => {
        Flash(__('An error occurred while removing approver'));
        $loadWrapper.addClass('hidden');
      });
  }

  static updateApproverList(html) {
    $('.js-current-approvers').html(
      $(html)
        .find('.js-current-approvers')
        .html(),
    );
  }
}
