/*
 eventBus.ts - ESP3D WebUI hooks file

 Copyright (c) 2024 Luc LEBOSSE. All rights reserved.


 This code is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.
 This code is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public
 License along with This code; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/*
 * Basic EventBus to share data between components without using context
 *
 */

interface Listener<T = any> {
    id: string | number
    callback: (data: T) => void
}

class EventBus {
    private listeners: Record<string, Listener[]>
    private listenerId: number

    //Constructor init listeners list
    constructor() {
        this.listeners = {}
        this.listenerId = 0
    }

    // Listener
    on<T = any>(event: string, callback: (data: T) => void, id: string | number | null = null): string | number {
        if (!this.listeners[event]) {
            this.listeners[event] = []
        }

        const listenerId = id !== null ? id : this.listenerId++

        // check if listener with this ID already exists
        const existingListenerIndex = this.listeners[event].findIndex(listener => listener.id === listenerId)
        if (existingListenerIndex !== -1) {
            //console.warn(`Listener with ID ${listenerId} for event ${event} already exists. Replacing.`);
            // Replace existing listener
            this.listeners[event][existingListenerIndex] = { id: listenerId, callback }
        } else {
            // Add new listener
            this.listeners[event].push({ id: listenerId, callback })
        }

        //console.log(`Listener ${existingListenerIndex !== -1 ? 'updated' : 'added'} for event: ${event}, ID: ${listenerId}, Total listeners: ${this.listeners[event].length}`);
        return listenerId
    }

    // Remove listener from memory
    off(event: string, id: string | number): void {
        if (!this.listeners[event]) return
        this.listeners[event] = this.listeners[event].filter(listener => listener.id !== id)
    }

    // Emitter
    emit<T = any>(event: string, data: T): void {
        //console.log(`Emitting event: ${event}`, data);
        ////console.log(`Current listeners for ${event}:`, this.listeners[event]);
        if (!this.listeners[event]) return
        this.listeners[event].forEach(listener => {
            ////console.log(`Calling listener with ID: ${listener.id}`);
            listener.callback(data)
        })
    }

    // List active listeners for debugging
    list(): void {
        //console.log("Active listeners:");
        for (const event in this.listeners) {
            this.listeners[event].forEach(_listener => {
                //console.log(`Event: ${event}, ID: ${listener.id}`);
            })
        }
    }
}

export const eventBus = new EventBus()