02. Pet House JS Advanced Exam - 27 June 2020

function solveClasses() {
  class Pet {
    constructor(owner, name) {
      this.owner = owner;
      this.name = name;
      this.comments = [];
    }

    addComment(comment) {
      if (this.comments.includes(comment)) {
        throw new Error('This comment is already added!');
      }

      this, this.comments.push(comment);

      return 'Comment is added.';
    }

    feed() {
      return `${this.name} is fed`;
    }

    toString() {
      const result = [];

      result.push(`Here is ${this.owner}'s pet ${this.name}.`);

      if (this.comments.length > 0) {
        result.push(`Special requirements: ${this.comments.join(', ')}`);
      }

      return result.join('\n');
    }
  }

  class Cat extends Pet {
    constructor(owner, name, insideHabits, scratching) {
      super(owner, name);
      this.insideHabits = insideHabits;
      this.scratching = scratching;
    }

    feed() {
      return `${super.feed()}, happy and purring.`;
    }

    toString() {
      const result = [];

      result.push(super.toString());
      result.push('Main information:');

      let tempResult = `${this.name} is a cat with ${this.insideHabits}`;

      if (this.scratching) {
        tempResult += ', but beware of scratches.';
      }

      result.push(tempResult);

      return result.join('\n');
    }
  }

  class Dog extends Pet {
    constructor(owner, name, runningNeeds, trainability) {
      super(owner, name);
      this.runningNeeds = runningNeeds;
      this.trainability = trainability;
    }

    feed() {
      return `${super.feed()}, happy and wagging tail.`;
    }

    toString() {
      const result = [];

      result.push(super.toString());
      result.push('Main information:');
      result.push(`${this.name} is a dog with need of ${this.runningNeeds}km running every day and ${this.trainability} trainability.`);

      return result.join('\n');
    }
  }

  return {
    Pet,
    Cat,
    Dog,
  };
}