export interface IUser {
  firstName?: string;
  lastName?: string;
  age?: number;
  weight?: number
}

const userDto: IUser = { // DTO (data transfer object)
  firstName: 'Cory',
  lastName: 'Rylan',
  age: 100,
  weight: 150
};
// mock API data instance for  User
export class User {
  private _firstName: string;
  private _lastName: string;
  private _age: number;

  get firstName() {
    return this._firstName;
  }

  get lastName() {
    return this._lastName;
  }

  get fullName() {
    return `${this.firstName} ${this.lastName}`;
  }

  get age() {
    return this._age;
  }

  constructor(firstName: string, lastName: string, age: number) {
    this.setName(firstName, lastName);
    this.setAge(age);
  }

  setName(firstName: string, lastName: string) {
    if (this.validName(firstName) && this.validName(lastName)) {
      this._firstName = firstName;
      this._lastName = lastName;
    }
  }

  setAge(age: number) {
    if (age >= 18) {
      this._age = age;
    } else {
      throw new Error('User age must be greater than 18');
    }
  }

  private validName(name: string) {
    if (name.length > 0 && /^[a-zA-Z]+$/.test(name)) {
      return true
    } else {
      throw new Error('Invalid name format');
    }
  }
}

const user = new User('John', 'Doe', 18);
user.setName('Jack', 'Doe');
console.log(user.fullName); // Jack Doe

const user2 = new User('John', 'Smith', 17);
// Error: User age must be greater than 18
-----------
export interface IUser {
  firstName?: string;
  lastName?: string;
  age?: number;
  weight?: number
}

export class User {
  private state: IUser = { };

  get firstName() {
    return this.state.firstName;
  }

  get lastName() {
    return this.state.lastName;
  }

  get fullName() {
    return `${this.firstName} ${this.lastName}`;
  }

  get age() {
    return this.state.age;
  }

  constructor(firstName: string, lastName: string, age: number) {
    this.setName(firstName, lastName);
    this.setAge(age);
  }

  setName(firstName: string, lastName: string) {
    if (this.validName(firstName) && this.validName(lastName)) {
      this.state.firstName = firstName;
      this.state.lastName = lastName;
    }
  }

  setAge(age: number) {
    if (age >= 18) {
      this.state.age = age;
    } else {
      throw new Error('User age must be greater than 18');
    }
  }

  private validName(name: string) {
    if (name.length > 0 && /^[a-zA-Z]+$/.test(name)) {
      return true
    } else {
      throw new Error('Invalid name format');
    }
  }
}


// We move the internal private properties to be on a single private internal state property. By moving the
// internal private properties onto a single object, we can use the state property to easily copy or hydrate the // class with the data from our API. Let’s look at the hydration logic that will copy our data over.

export interface Type<T> extends Function {
  new (...args: any[]): T;
}

export class DomainConverter {
  static fromDto<T>(domain: Type<T>, dto: any) {
    const instance = Object.create(domain.prototype);
    instance.state = dto;
    return instance as T;
  }

  static toDto<T>(domain: any) {
    return domain.state as T;
  }
}

const userDto: IUser = {
  firstName: 'Cory',
  lastName: 'Rylan',
  age: 27,
  weight: 150
};

const user: User = DomainConverter.fromDto<User>(User, userDto);

const userData: IUser = DomainConverter.toDto<User>(user);

console.log(userData);
// { firstName: "Cory", lastName: "Rylan", age: 27, weight: 150 }