import cron from "node-cron";
import {Class} from "../types/Class";
import {randomUUID} from "node:crypto";
import {Container} from "../Container/Container";
import {Logger} from "log4js";
import {BaseEvent, EventEntry, EventType, HandlerEvents, TimedEvent} from "./EventHandler.types";

export class EventHandler {
  private static DEFAULT_EVENT_ENTRY: Omit<EventEntry, "method"> = {
    persistent: false
  }
  
  private eventHandlers: Map<string, Map<string, EventEntry>> = new Map();
  
  public get EventHandlers() {
    return this.eventHandlers;
  }

  constructor() {
  }

  public addHandler<T extends Class>(eventName: string, entry: EventEntry<T>): string {
    if (!this.eventHandlers.has(eventName)) {
      this.eventHandlers.set(eventName, new Map());
    }

    const id = randomUUID();
    this.eventHandlers.get(eventName)?.set(id, {
      ...EventHandler.DEFAULT_EVENT_ENTRY,
      ...entry
    });
    return id;
  }
  
  public removeHandler(eventName: string, id: string) {
    if (!this.eventHandlers.has(eventName)) {
      return;
    }
    
    const localEventHandlers = this.eventHandlers.get(eventName);
    if (!localEventHandlers || !localEventHandlers.has(id)) {
      return;
    }
    
    localEventHandlers.delete(id);
  }

  public dispatch<T extends HandlerEvents>(event: T) {
    const eventName = event.constructor.name;
    if (!this.eventHandlers.has(eventName)) {
      return;
    }

    this.eventHandlers.get(eventName)?.forEach((handler) => {
      try {
        handler.method(event);
      } catch (e: any) {
        Container.get<Logger>("logger").error(e);
      }
    })

    if (event.type !== EventType.Acknowledge) {
      return;
    }
    
    if (event.isAcknowledged()) {
      return;
    }
    
    event.handleUnacknowledgement();
  }

  public addTimed(event: TimedEvent) {
    if (!cron.validate(event.cronExpression)) {
      throw new Error(`Can't create event with name '${event.configuration.name}': Invalid cron expression.`)
    }

    cron.schedule(event.cronExpression, event.execute.bind(event), event.configuration);
  }
}