import EventEmitter from 'events'
import { inspect } from 'util'
import { PHASE } from '../ignite.mjs'
import { mainLogger } from '../logger/init-logger.mjs'
import type { PkgIdentifier } from '../types.mjs'

const _event_ = `event`
export const mainEmitter = new EventEmitter()
mainEmitter.setMaxListeners(50)

mainEmitter.on(_event_, payload => {
  mainLogger.log('event', inspect(payload, true, 5, true), { pkgId: payload.pkgId })
})

//export type EventPayload<EventTypeMap, Name extends keyof EventTypeMap = keyof EventTypeMap> = {  pkgId: PkgIdentifier  event: Name  data: EventTypeMap[Name]  at: string}
export type EventPayload<
  EventTypeMap,
  Name extends keyof EventTypeMap = keyof EventTypeMap,
> = Name extends infer K
  ? K extends Name
    ? {
        pkgId: PkgIdentifier
        event: K
        data: EventTypeMap[K]
        at: string
      }
    : never
  : never

export function pkgEmitter<EventTypeMap>(pkgId: PkgIdentifier) {
  return {
    emit,
    on,
    any,
  }

  function emit<Type extends keyof EventTypeMap>(event: Type, data: EventTypeMap[Type]) {
    if (PHASE !== 'running') {
      return
    }
    const payload: EventPayload<EventTypeMap, any> = {
      pkgId,
      event,
      data,
      at: new Date(Date.now()).toISOString(),
    }
    mainEmitter.emit(_event_, payload)
  }
  function on<Name extends keyof EventTypeMap>(
    eventName: Name,
    listener: (payload: EventPayload<EventTypeMap, Name>) => void,
  ) {
    return any(payload => payload.event === eventName && listener(payload as any))
  }
  function any(
    _listener: (
      payload: keyof EventTypeMap extends infer K
        ? K extends keyof EventTypeMap
          ? EventPayload<EventTypeMap, K>
          : never
        : never,
    ) => void,
  ) {
    function listener(payload: EventPayload<any>) {
      if (!isPkgEvent(payload)) {
        return
      }
      return _listener(payload as any)
    }
    mainEmitter.on(_event_, listener)
    return () => mainEmitter.off(_event_, listener)
  }
  function isPkgEvent(payload: EventPayload<any>): payload is EventPayload<EventTypeMap> {
    return payload.pkgId.name === pkgId.name
  }
}