import { assign, defineProperty, defineProperties, readonlyDescriptor } from './object'

export class BvEvent {
  constructor(type, eventInit = {}) {
    // Start by emulating native Event constructor
    if (!type) {
      /* istanbul ignore next */
      throw new TypeError(
        `Failed to construct '${this.constructor.name}'. 1 argument required, ${
          arguments.length
        } given.`
      )
    }

    // Merge defaults first, the eventInit, and the type last
    // so it can't be overwritten
    assign(this, BvEvent.Defaults, this.constructor.Defaults, eventInit, { type })

    // Freeze some props as readonly, but leave them enumerable
    defineProperties(this, {
      type: readonlyDescriptor(),
      cancelable: readonlyDescriptor(),
      nativeEvent: readonlyDescriptor(),
      target: readonlyDescriptor(),
      relatedTarget: readonlyDescriptor(),
      vueTarget: readonlyDescriptor(),
      componentId: readonlyDescriptor()
    })

    // Create a private variable using closure scoping
    let defaultPrevented = false
    // Recreate preventDefault method. One way setter
    this.preventDefault = function preventDefault() {
      if (this.cancelable) {
        defaultPrevented = true
      }
    }

    // Create `defaultPrevented` publicly accessible prop that
    // can only be altered by the preventDefault method
    defineProperty(this, 'defaultPrevented', {
      enumerable: true,
      get() {
        return defaultPrevented
      }
    })
  }

  static get Defaults() {
    return {
      type: '',
      cancelable: true,
      nativeEvent: null,
      target: null,
      relatedTarget: null,
      vueTarget: null,
      componentId: null
    }
  }
}