const Eventer = () => {
  let events = {}

  const listen = (eventName, callback) => {
    try {
      if (!events[eventName]) {
        events[eventName] = {
          callbacks: [{ callbackFunction: callback }]
        }
      } else {
        events[eventName] = {
          callbacks: [...events[eventName].callbacks, { callbackFunction: callback }]
        }
      }
    } catch (err) { }
  }

  const removeCallback = (eventName, callbackIndex) => {
    events[eventName].callbacks[callbackIndex] = events[eventName].callbacks.filter((cb, index) => index != callbackIndex)
  }

  const emit = (eventName, data = {}) => {
    try {
      const callbackList = events[eventName]?.callbacks
      if (callbackList) {
        callbackList.forEach(({ callbackFunction, type }, index) => {
          if (type?.name === 'listenOnce') {
            callbackFunction(data)
            removeCallback(eventName, index)
            return
          }
          callbackFunction(data)
        })
      }
    } catch (err) { }
  }

  const removeEvent = (eventNameToBeRemoved) => {
    const newEvents = Object.keys(events).reduce((updatedEvents, eventName) => {
      if (eventName !== eventNameToBeRemoved) {
        return { ...updatedEvents, [eventName]: events[eventName] }
      }
      return updatedEvents
    }, {})

    events = newEvents
  }

  const listenOnce = (eventName, callback) => {
    try {
      if (!events[eventName]) {
        events[eventName] = {
          callbacks: [{ callbackFunction: callback, type: { name: 'listenOnce' } }],
        }
      } else {
        events[eventName] = {
          callbacks: [...events[eventName]?.callbacks, { callbackFunction: callback, type: { name: 'listenOnce' } }]
        }
      }
    } catch (err) { }
  }

  const removeAllEvents = () => {
    events = {}
  }

  return {
    listen,
    emit,
    removeEvent,
    listenOnce,
    removeAllEvents
  }
}

export const EventEmitter = Eventer()