import { Component } from '@angular/core';

@Component({
 selector: 'my-app',
 templateUrl: './app.component.html',
 styleUrls: [ './app.component.css' ]
})
export class AppComponent  {}

class Planet {
  constructor(public name: string) {}

  @logMethod
  greet(greeting: string, isLoud: boolean = false) {
    const phrase = `${greeting} ${this.name}!`;
    console.log(isLoud ? phrase.toUpperCase(): phrase);
  }
}

const mars = new Planet('Mars');

mars.greet('Welcome to', true);

function logMethod(
  target: Object, 
  key: string, 
  descriptor: PropertyDescriptor
) {
  const original = descriptor.value;

  descriptor.value = function() {
    const targetName = target.constructor.name;
    const args = JSON.stringify(arguments);
    console.log(`Calling ${targetName}.${key} with ${args}`);
    const result = original.apply(this, arguments);
    return result;
  }

  return descriptor;
}

let cub = {};

cub.name = 'Rupert';

// Defaults - created by assignment
{ 
    configurable: true, 
    enumerable: true, 
    writable: true,
    value: 'Rupert'
}

Object.defineProperty(cub, 'name', {value: 'Rupert'});

// Defaults - created with Object.defineProperty
{ 
    configurable: false, 
    enumerable: false, 
    writable: false,
    value: 'Rupert'
}

function readonly(
  target: Object, 
  key: string, 
  descriptor: PropertyDescriptor
) {
  descriptor.writable = false;
  return descriptor;
}

class Moon {
  constructor(public radius: number) {}

  @readonly
  circumference() {
    return 2 * Math.PI * this.radius;
  }
}

const moon = new Moon(60268);

moon.circumference = () => 100;

function enumerable(value: boolean) {
  return function(
    target: Object, 
    key: string, 
    descriptor: PropertyDescriptor
  ) {
    descriptor.enumerable = value;
    return descriptor;
  };
}

class Moon {
  constructor(public radius: number) {}

  @enumerable(true)
  circumference() {
    return 2 * Math.PI * this.radius;
  }
}

const moon = new Moon(60268);

for (const key in moon) {
  console.log(`${key}: ${moon[key]}`);
}