oppia/oppia

// Copyright 2018 The Oppia Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/**
 * @fileoverview Model for creating and mutating instances of frontend
 * subtopic domain objects.
 */

import {ShortSkillSummary} from 'domain/skill/short-skill-summary.model';

import {AppConstants} from 'app.constants';

export interface SubtopicBackendDict {
  id: number;
  title: string;
  skill_ids: string[];
  thumbnail_filename: string | null;
  thumbnail_bg_color: string | null;
  url_fragment: string | null;
}

export interface SkillIdToDescriptionMap {
  [skillId: string]: string;
}

export class Subtopic {
  _id: number;
  _title: string;
  _skillSummaries: ShortSkillSummary[];
  _skillIds: string[];
  // The thumbnail and URL fragment might not be set,
  // then they will be 'null'.
  _thumbnailFilename: string | null;
  _thumbnailBgColor: string | null;
  _urlFragment: string | null;
  constructor(
    subtopicId: number,
    title: string,
    skillIds: string[],
    skillIdToDescriptionMap: SkillIdToDescriptionMap,
    thumbnailFilename: string | null,
    thumbnailBgColor: string | null,
    urlFragment: string | null
  ) {
    this._id = subtopicId;
    this._title = title;
    this._skillIds = skillIds;
    this._thumbnailFilename = thumbnailFilename;
    this._thumbnailBgColor = thumbnailBgColor;
    this._urlFragment = urlFragment;
    this._skillSummaries = skillIds.map(skillId => {
      return ShortSkillSummary.create(
        skillId,
        skillIdToDescriptionMap[skillId]
      );
    });
  }

  getId(): number {
    return this._id;
  }

  decrementId(): number {
    return --this._id;
  }

  incrementId(): number {
    return ++this._id;
  }

  // Returns the title of the subtopic.
  getTitle(): string {
    return this._title;
  }

  setTitle(title: string): void {
    this._title = title;
  }

  // Returns 'null' if there is no url fragment.
  getUrlFragment(): string | null {
    return this._urlFragment;
  }

  setUrlFragment(urlFragment: string): void {
    this._urlFragment = urlFragment;
  }

  validate(): string[] {
    let issues: string[] = [];
    const VALID_URL_FRAGMENT_REGEX = new RegExp(
      AppConstants.VALID_URL_FRAGMENT_REGEX
    );
    if (
      this._urlFragment &&
      !VALID_URL_FRAGMENT_REGEX.test(this._urlFragment)
    ) {
      issues.push('Subtopic url fragment is invalid.');
    }
    if (this._title === '') {
      issues.push('Subtopic title should not be empty');
    }
    let skillIds = this._skillSummaries.map(skillSummary => {
      return skillSummary.getId();
    });
    for (let i = 0; i < skillIds.length; i++) {
      let skillId = skillIds[i];
      if (skillIds.indexOf(skillId) < skillIds.lastIndexOf(skillId)) {
        issues.push(
          'The skill with id ' +
            skillId +
            ' is duplicated in' +
            ' subtopic with id ' +
            this._id
        );
      }
    }
    return issues;
  }

  prepublishValidate(): string[] {
    let issues: string[] = [];
    if (!this._thumbnailFilename) {
      issues.push('Subtopic ' + this._title + ' should have a thumbnail.');
    }
    return issues;
  }

  // Returns the summaries of the skills in the subtopic.
  getSkillSummaries(): ShortSkillSummary[] {
    return this._skillSummaries.slice();
  }

  getSkillIds(): string[] {
    return this._skillIds.slice();
  }

  hasSkill(skillId: string): boolean {
    return this._skillSummaries.some(function (skillSummary) {
      return skillSummary.getId() === skillId;
    });
  }

  addSkill(skillId: string, skillDescription: string): boolean {
    if (!this.hasSkill(skillId)) {
      this._skillSummaries.push(
        ShortSkillSummary.create(skillId, skillDescription)
      );
      return true;
    }
    return false;
  }

  removeSkill(skillId: string): void {
    let index = this._skillSummaries
      .map(skillSummary => {
        return skillSummary.getId();
      })
      .indexOf(skillId);
    if (index > -1) {
      this._skillSummaries.splice(index, 1);
    } else {
      throw new Error("The given skill doesn't exist in the subtopic");
    }
  }

  setThumbnailFilename(thumbnailFilename: string): void {
    this._thumbnailFilename = thumbnailFilename;
  }

  // Returns 'null' if there is no thumbnail file.
  getThumbnailFilename(): string | null {
    return this._thumbnailFilename;
  }

  setThumbnailBgColor(thumbnailBgColor: string): void {
    this._thumbnailBgColor = thumbnailBgColor;
  }

  // Returns 'null' if there is no thumbnail background color.
  getThumbnailBgColor(): string | null {
    return this._thumbnailBgColor;
  }

  static create(
    subtopicBackendDict: SubtopicBackendDict,
    skillIdToDescriptionMap: SkillIdToDescriptionMap
  ): Subtopic {
    return new Subtopic(
      subtopicBackendDict.id,
      subtopicBackendDict.title,
      subtopicBackendDict.skill_ids,
      skillIdToDescriptionMap,
      subtopicBackendDict.thumbnail_filename,
      subtopicBackendDict.thumbnail_bg_color,
      subtopicBackendDict.url_fragment
    );
  }

  static createFromTitle(subtopicId: number, title: string): Subtopic {
    return this.create(
      {
        id: subtopicId,
        title: title,
        skill_ids: [],
        thumbnail_filename: null,
        thumbnail_bg_color: null,
        url_fragment: null,
      },
      {}
    );
  }
}